The series adds support for the basic extended CAN controller (bxCAN)
found in many low- to middle-end STM32 SoCs.
The driver design (one core module and one driver module) was inspired
by other ST drivers (e. g. drivers/iio/adc/stm32-adc.c,
drivers/iio/adc/stm32-adc-core.c) where device instances share resources.
The shared resources functions are implemented in the core module, the
device driver in a separate module.
The driver has been tested on the stm32f469i-discovery board with a
kernel version 5.19.0-rc2 in loopback + silent mode:
ip link set can0 type can bitrate 125000 loopback on listen-only on
ip link set up can0
candump can0 -L &
cansend can0 300#AC.AB.AD.AE.75.49.AD.D1
For uboot and kernel compilation, as well as for rootfs creation I used
buildroot:
make stm32f469_disco_sd_defconfig
make
but I had to patch can-utils and busybox as can-utils and iproute are
not compiled for MMU-less microcotrollers. In the case of can-utils,
replacing the calls to fork() with vfork(), I was able to compile the
package with working candump and cansend applications, while in the
case of iproute, I ran into more than one problem and finally I decided
to extend busybox's ip link command for CAN-type devices. I'm still
wondering if it was really necessary, but this way I was able to test
the driver.
Changes in v3:
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Add description to the parent of the two child nodes.
- Move "patterProperties:" after "properties: in top level before "required".
- Add "clocks" to the "required:" list of the child nodes.
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Add "clocks" to can@0 node.
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Remove a blank line.
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Fix the documentation file path in the MAINTAINERS entry.
- Do not increment the "stats->rx_bytes" if the frame is remote.
- Remove pr_debug() call from bxcan_rmw().
Changes in v2:
- Change the file name into 'st,stm32-bxcan-core.yaml'.
- Rename compatibles:
- st,stm32-bxcan-core -> st,stm32f4-bxcan-core
- st,stm32-bxcan -> st,stm32f4-bxcan
- Rename master property to st,can-master.
- Remove the status property from the example.
- Put the node child properties as required.
- Remove a blank line.
- Fix sparse errors.
- Create a MAINTAINERS entry.
- Remove the print of the registers address.
- Remove the volatile keyword from bxcan_rmw().
- Use tx ring algorithm to manage tx mailboxes.
- Use can_{get|put}_echo_skb().
- Update DT properties.
Dario Binacchi (4):
dt-bindings: net: can: add STM32 bxcan DT bindings
ARM: dts: stm32: add CAN support on stm32f429
ARM: dts: stm32: add pin map for CAN controller on stm32f4
can: bxcan: add support for ST bxCAN controller
.../bindings/net/can/st,stm32-bxcan.yaml | 142 +++
MAINTAINERS | 7 +
arch/arm/boot/dts/stm32f4-pinctrl.dtsi | 30 +
arch/arm/boot/dts/stm32f429.dtsi | 31 +
drivers/net/can/Kconfig | 1 +
drivers/net/can/Makefile | 1 +
drivers/net/can/bxcan/Kconfig | 34 +
drivers/net/can/bxcan/Makefile | 4 +
drivers/net/can/bxcan/bxcan-core.c | 200 ++++
drivers/net/can/bxcan/bxcan-core.h | 31 +
drivers/net/can/bxcan/bxcan-drv.c | 1045 +++++++++++++++++
11 files changed, 1526 insertions(+)
create mode 100644 Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
create mode 100644 drivers/net/can/bxcan/Kconfig
create mode 100644 drivers/net/can/bxcan/Makefile
create mode 100644 drivers/net/can/bxcan/bxcan-core.c
create mode 100644 drivers/net/can/bxcan/bxcan-core.h
create mode 100644 drivers/net/can/bxcan/bxcan-drv.c
--
2.32.0
Add support for bxcan (Basic eXtended CAN controller) to STM32F429. The
chip contains two CAN peripherals, CAN1 the master and CAN2 the slave,
that share some of the required logic like clock and filters. This means
that the slave CAN can't be used without the master CAN.
Signed-off-by: Dario Binacchi <[email protected]>
---
Changes in v3:
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Add "clocks" to can@0 node.
arch/arm/boot/dts/stm32f429.dtsi | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
index c31ceb821231..e04cf73a8caa 100644
--- a/arch/arm/boot/dts/stm32f429.dtsi
+++ b/arch/arm/boot/dts/stm32f429.dtsi
@@ -362,6 +362,37 @@ i2c3: i2c@40005c00 {
status = "disabled";
};
+ can: can@40006400 {
+ compatible = "st,stm32f4-bxcan-core";
+ reg = <0x40006400 0x800>;
+ resets = <&rcc STM32F4_APB1_RESET(CAN1)>;
+ clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ status = "disabled";
+
+ can1: can@0 {
+ compatible = "st,stm32f4-bxcan";
+ reg = <0x0>;
+ interrupts = <19>, <20>, <21>, <22>;
+ interrupt-names = "tx", "rx0", "rx1", "sce";
+ resets = <&rcc STM32F4_APB1_RESET(CAN1)>;
+ clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN1)>;
+ st,can-master;
+ status = "disabled";
+ };
+
+ can2: can@400 {
+ compatible = "st,stm32f4-bxcan";
+ reg = <0x400>;
+ interrupts = <63>, <64>, <65>, <66>;
+ interrupt-names = "tx", "rx0", "rx1", "sce";
+ resets = <&rcc STM32F4_APB1_RESET(CAN2)>;
+ clocks = <&rcc 0 STM32F4_APB1_CLOCK(CAN2)>;
+ status = "disabled";
+ };
+ };
+
dac: dac@40007400 {
compatible = "st,stm32f4-dac-core";
reg = <0x40007400 0x400>;
--
2.32.0
Add support for the basic extended CAN controller (bxCAN) found in many
low- to middle-end STM32 SoCs. It supports the Basic Extended CAN
protocol versions 2.0A and B with a maximum bit rate of 1 Mbit/s.
The controller supports two channels (CAN1 as master and CAN2 as slave)
and the driver can enable either or both of the channels. They share
some of the required logic (e. g. clocks and filters), and that means
you cannot use the slave CAN without enabling some hardware resources
managed by the master CAN.
Each channel has 3 transmit mailboxes, 2 receive FIFOs with 3 stages and
28 scalable filter banks.
It also manages 4 dedicated interrupt vectors:
- transmit interrupt
- FIFO 0 receive interrupt
- FIFO 1 receive interrupt
- status change error interrupt
Driver uses all 3 available mailboxes for transmission and FIFO 0 for
reception. Rx filter rules are configured to the minimum. They accept
all messages and assign filter 0 to CAN1 and filter 14 to CAN2 in
identifier mask mode with 32 bits width. It enables and uses transmit,
receive buffers for FIFO 0 and error and status change interrupts.
Signed-off-by: Dario Binacchi <[email protected]>
---
Changes in v3:
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Fix the documentation file path in the MAINTAINERS entry.
- Do not increment the "stats->rx_bytes" if the frame is remote.
- Remove pr_debug() call from bxcan_rmw().
Changes in v2:
- Fix sparse errors.
- Create a MAINTAINERS entry.
- Remove the print of the registers address.
- Remove the volatile keyword from bxcan_rmw().
- Use tx ring algorithm to manage tx mailboxes.
- Use can_{get|put}_echo_skb().
- Update DT properties.
MAINTAINERS | 7 +
drivers/net/can/Kconfig | 1 +
drivers/net/can/Makefile | 1 +
drivers/net/can/bxcan/Kconfig | 34 +
drivers/net/can/bxcan/Makefile | 4 +
drivers/net/can/bxcan/bxcan-core.c | 200 ++++++
drivers/net/can/bxcan/bxcan-core.h | 31 +
drivers/net/can/bxcan/bxcan-drv.c | 1045 ++++++++++++++++++++++++++++
8 files changed, 1323 insertions(+)
create mode 100644 drivers/net/can/bxcan/Kconfig
create mode 100644 drivers/net/can/bxcan/Makefile
create mode 100644 drivers/net/can/bxcan/bxcan-core.c
create mode 100644 drivers/net/can/bxcan/bxcan-core.h
create mode 100644 drivers/net/can/bxcan/bxcan-drv.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 07403024f3f2..609327f5cb35 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4461,6 +4461,13 @@ S: Maintained
F: drivers/scsi/BusLogic.*
F: drivers/scsi/FlashPoint.*
+BXCAN CAN NETWORK DRIVER
+M: Dario Binacchi <[email protected]>
+L: [email protected]
+S: Maintained
+F: Documentation/devicetree/bindings/net/can/st,stm32-bxcan.yaml
+F: drivers/net/can/bxcan/
+
C-MEDIA CMI8788 DRIVER
M: Clemens Ladisch <[email protected]>
L: [email protected] (moderated for non-subscribers)
diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index 3048ad77edb3..d55355a0e583 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -206,6 +206,7 @@ config PCH_CAN
is an IOH for x86 embedded processor (Intel Atom E6xx series).
This driver can access CAN bus.
+source "drivers/net/can/bxcan/Kconfig"
source "drivers/net/can/c_can/Kconfig"
source "drivers/net/can/cc770/Kconfig"
source "drivers/net/can/ctucanfd/Kconfig"
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index 61c75ce9d500..373f2c99689a 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -14,6 +14,7 @@ obj-y += usb/
obj-y += softing/
obj-$(CONFIG_CAN_AT91) += at91_can.o
+obj-$(CONFIG_CAN_BXCAN) += bxcan/
obj-$(CONFIG_CAN_CAN327) += can327.o
obj-$(CONFIG_CAN_CC770) += cc770/
obj-$(CONFIG_CAN_C_CAN) += c_can/
diff --git a/drivers/net/can/bxcan/Kconfig b/drivers/net/can/bxcan/Kconfig
new file mode 100644
index 000000000000..df34c212bf51
--- /dev/null
+++ b/drivers/net/can/bxcan/Kconfig
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# bxCAN driver configuration
+#
+menuconfig CAN_BXCAN
+ tristate "STMicroelectronics STM32 Basic Extended CAN (bxCAN) devices"
+ depends on ARCH_STM32 || COMPILE_TEST
+ depends on OF
+ depends on HAS_IOMEM
+ help
+ Say Y here if you want support for ST bxCAN controller framework.
+ This is common support for devices that embed the ST bxCAN IP.
+
+if CAN_BXCAN
+
+config CAN_BXCAN_CORE
+ tristate "STMicroelectronics STM32 bxCAN core"
+ help
+ Select this option to enable the core driver for STMicroelectronics
+ STM32 basic extended CAN controller (bxCAN).
+
+ This driver can also be built as a module. If so, the module
+ will be called bxcan-core.
+
+config CAN_BXCAN_DRV
+ tristate "STMicroelectronics STM32 bxCAN driver"
+ depends on CAN_BXCAN_CORE
+ help
+ Say yes here to build support for the STMicroelectronics STM32 basic
+ extended CAN Controller (bxCAN).
+
+ This driver can also be built as a module. If so, the module
+ will be called bxcan-drv.
+endif
diff --git a/drivers/net/can/bxcan/Makefile b/drivers/net/can/bxcan/Makefile
new file mode 100644
index 000000000000..60350f055271
--- /dev/null
+++ b/drivers/net/can/bxcan/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_CAN_BXCAN_CORE) += bxcan-core.o
+obj-$(CONFIG_CAN_BXCAN_DRV) += bxcan-drv.o
diff --git a/drivers/net/can/bxcan/bxcan-core.c b/drivers/net/can/bxcan/bxcan-core.c
new file mode 100644
index 000000000000..3644449095e9
--- /dev/null
+++ b/drivers/net/can/bxcan/bxcan-core.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0
+/* bxcan-core.c - STM32 Basic Extended CAN core controller driver
+ *
+ * This file is part of STM32 bxcan driver
+ *
+ * Copyright (c) 2022 Dario Binacchi <[email protected]>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include "bxcan-core.h"
+
+#define BXCAN_FILTER_ID(master) (master ? 0 : 14)
+
+/* Filter master register (FMR) bits */
+#define BXCAN_FMR_CANSB_MASK GENMASK(13, 8)
+#define BXCAN_FMR_CANSB(x) (((x) & 0x3f) << 8)
+#define BXCAN_FMR_FINIT BIT(0)
+
+/* Structure of the filter bank */
+struct bxcan_fb {
+ u32 fr1; /* filter 1 */
+ u32 fr2; /* filter 2 */
+};
+
+/* Structure of the hardware filter registers */
+struct bxcan_fregs {
+ u32 fmr; /* 0x00 - filter master */
+ u32 fm1r; /* 0x04 - filter mode */
+ u32 reserved2; /* 0x08 */
+ u32 fs1r; /* 0x0c - filter scale */
+ u32 reserved3; /* 0x10 */
+ u32 ffa1r; /* 0x14 - filter FIFO assignment */
+ u32 reserved4; /* 0x18 */
+ u32 fa1r; /* 0x1c - filter activation */
+ u32 reserved5[8]; /* 0x20 */
+ struct bxcan_fb fb[28]; /* 0x40 - filter banks */
+};
+
+struct bxcan_core_priv {
+ void __iomem *base;
+ struct bxcan_fregs __iomem *fregs;
+ struct clk *clk_master;
+ unsigned int clk_master_ref;
+};
+
+void bxcan_disable_filters(struct device *dev, bool master)
+{
+ struct bxcan_core_priv *priv = dev_get_drvdata(dev);
+ unsigned int fid = BXCAN_FILTER_ID(master);
+ u32 fmask = BIT(fid);
+
+ bxcan_rmw(&priv->fregs->fa1r, fmask, 0);
+}
+
+void bxcan_enable_filters(struct device *dev, bool master)
+{
+ struct bxcan_core_priv *priv = dev_get_drvdata(dev);
+ unsigned int fid = BXCAN_FILTER_ID(master);
+ u32 fmask = BIT(fid);
+
+ /* Filter settings:
+ *
+ * Accept all messages.
+ * Assign filter 0 to CAN1 and filter 14 to CAN2 in identifier
+ * mask mode with 32 bits width.
+ */
+
+ /* Enter filter initialization mode and assing filters to CAN
+ * controllers.
+ */
+ bxcan_rmw(&priv->fregs->fmr, BXCAN_FMR_CANSB_MASK,
+ BXCAN_FMR_CANSB(14) | BXCAN_FMR_FINIT);
+
+ /* Deactivate filter */
+ bxcan_rmw(&priv->fregs->fa1r, fmask, 0);
+
+ /* Two 32-bit registers in identifier mask mode */
+ bxcan_rmw(&priv->fregs->fm1r, fmask, 0);
+
+ /* Single 32-bit scale configuration */
+ bxcan_rmw(&priv->fregs->fs1r, 0, fmask);
+
+ /* Assign filter to FIFO 0 */
+ bxcan_rmw(&priv->fregs->ffa1r, fmask, 0);
+
+ /* Accept all messages */
+ writel(0, &priv->fregs->fb[fid].fr1);
+ writel(0, &priv->fregs->fb[fid].fr2);
+
+ /* Activate filter */
+ bxcan_rmw(&priv->fregs->fa1r, 0, fmask);
+
+ /* Exit filter initialization mode */
+ bxcan_rmw(&priv->fregs->fmr, BXCAN_FMR_FINIT, 0);
+}
+
+int bxcan_enable_master_clk(struct device *dev)
+{
+ struct bxcan_core_priv *priv = dev_get_drvdata(dev);
+ int err;
+
+ if (priv->clk_master_ref == 0) {
+ err = clk_prepare_enable(priv->clk_master);
+ if (err)
+ return err;
+ }
+
+ priv->clk_master_ref++;
+ return 0;
+}
+
+void bxcan_disable_master_clk(struct device *dev)
+{
+ struct bxcan_core_priv *priv = dev_get_drvdata(dev);
+
+ if (priv->clk_master_ref == 0)
+ return;
+
+ if (priv->clk_master_ref == 1)
+ clk_disable_unprepare(priv->clk_master);
+
+ priv->clk_master_ref--;
+}
+
+unsigned long bxcan_get_master_clk_rate(struct device *dev)
+{
+ struct bxcan_core_priv *priv = dev_get_drvdata(dev);
+
+ return clk_get_rate(priv->clk_master);
+}
+
+void __iomem *bxcan_get_base_addr(struct device *dev)
+{
+ struct bxcan_core_priv *priv = dev_get_drvdata(dev);
+
+ return priv->base;
+}
+
+static const struct of_device_id bxcan_core_of_match[] = {
+ {.compatible = "st,stm32f4-bxcan-core"},
+ { /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, bxcan_core_of_match);
+
+static int bxcan_core_probe(struct platform_device *pdev)
+{
+ struct bxcan_core_priv *priv;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = pdev->dev.of_node;
+ void __iomem *regs;
+ struct clk *clk;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, priv);
+ regs = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(regs))
+ return PTR_ERR(regs);
+
+ clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk)) {
+ dev_err(dev, "failed to get clock\n");
+ return PTR_ERR(clk);
+ }
+
+ priv->base = regs;
+ priv->fregs = regs + 0x200;
+ priv->clk_master = clk;
+
+ ret = of_platform_populate(np, NULL, NULL, dev);
+ if (ret < 0) {
+ dev_err(dev, "failed to populate DT children\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct platform_driver bxcan_core_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = bxcan_core_of_match,
+ },
+ .probe = bxcan_core_probe,
+};
+
+module_platform_driver(bxcan_core_driver);
+
+MODULE_AUTHOR("Dario Binacchi <[email protected]>");
+MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN core driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/net/can/bxcan/bxcan-core.h b/drivers/net/can/bxcan/bxcan-core.h
new file mode 100644
index 000000000000..925449cbc3bd
--- /dev/null
+++ b/drivers/net/can/bxcan/bxcan-core.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * bxcan-core - STM32 Basic Extended CAN core controller driver
+ *
+ * Copyright (c) 2022 Dario Binacchi <[email protected]>
+ */
+
+#ifndef __BXCAN_CORE_H
+#define __BXCAN_CORE_H
+
+#include <linux/clk.h>
+#include <linux/io.h>
+
+int bxcan_enable_master_clk(struct device *dev);
+void bxcan_disable_master_clk(struct device *dev);
+unsigned long bxcan_get_master_clk_rate(struct device *dev);
+void __iomem *bxcan_get_base_addr(struct device *dev);
+void bxcan_enable_filters(struct device *dev, bool master);
+void bxcan_disable_filters(struct device *dev, bool master);
+
+static inline void bxcan_rmw(void __iomem *addr, u32 clear, u32 set)
+{
+ u32 old, val;
+
+ old = readl(addr);
+ val = (old & ~clear) | set;
+ if (val != old)
+ writel(val, addr);
+}
+
+#endif
diff --git a/drivers/net/can/bxcan/bxcan-drv.c b/drivers/net/can/bxcan/bxcan-drv.c
new file mode 100644
index 000000000000..7ac1ee7a4269
--- /dev/null
+++ b/drivers/net/can/bxcan/bxcan-drv.c
@@ -0,0 +1,1045 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// bxcan-drv.c - STM32 Basic Extended CAN controller driver
+//
+// Copyright (c) 2022 Dario Binacchi <[email protected]>
+//
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitfield.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/error.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#include "bxcan-core.h"
+
+#define BXCAN_NAPI_WEIGHT 3
+#define BXCAN_TIMEOUT_US 10000
+
+#define BXCAN_TX_MB_NUM 3
+
+/* Master control register (MCR) bits */
+#define BXCAN_MCR_DBF BIT(16)
+#define BXCAN_MCR_RESET BIT(15)
+#define BXCAN_MCR_TTCM BIT(7)
+#define BXCAN_MCR_ABOM BIT(6)
+#define BXCAN_MCR_AWUM BIT(5)
+#define BXCAN_MCR_NART BIT(4)
+#define BXCAN_MCR_RFLM BIT(3)
+#define BXCAN_MCR_TXFP BIT(2)
+#define BXCAN_MCR_SLEEP BIT(1)
+#define BXCAN_MCR_INRQ BIT(0)
+
+/* Master status register (MSR) bits */
+#define BXCAN_MSR_RX BIT(11)
+#define BXCAN_MSR_SAMP BIT(10)
+#define BXCAN_MSR_RXM BIT(9)
+#define BXCAN_MSR_TXM BIT(8)
+#define BXCAN_MSR_SLAKI BIT(4)
+#define BXCAN_MSR_WKUI BIT(3)
+#define BXCAN_MSR_ERRI BIT(2)
+#define BXCAN_MSR_SLAK BIT(1)
+#define BXCAN_MSR_INAK BIT(0)
+
+/* Transmit status register (TSR) bits */
+#define BXCAN_TSR_LOW2 BIT(31)
+#define BXCAN_TSR_LOW1 BIT(30)
+#define BXCAN_TSR_LOW0 BIT(29)
+#define BXCAN_TSR_TME GENMASK(28, 26)
+#define BXCAN_TSR_TME_SHIFT (26)
+#define BXCAN_TSR_TME2 BIT(28)
+#define BXCAN_TSR_TME1 BIT(27)
+#define BXCAN_TSR_TME0 BIT(26)
+#define BXCAN_TSR_CODE GENMASK(25, 24)
+#define BXCAN_TSR_ABRQ2 BIT(23)
+#define BXCAN_TSR_TERR2 BIT(19)
+#define BXCAN_TSR_ALST2 BIT(18)
+#define BXCAN_TSR_TXOK2 BIT(17)
+#define BXCAN_TSR_RQCP2 BIT(16)
+#define BXCAN_TSR_ABRQ1 BIT(15)
+#define BXCAN_TSR_TERR1 BIT(11)
+#define BXCAN_TSR_ALST1 BIT(10)
+#define BXCAN_TSR_TXOK1 BIT(9)
+#define BXCAN_TSR_RQCP1 BIT(8)
+#define BXCAN_TSR_ABRQ0 BIT(7)
+#define BXCAN_TSR_TERR0 BIT(3)
+#define BXCAN_TSR_ALST0 BIT(2)
+#define BXCAN_TSR_TXOK0 BIT(1)
+#define BXCAN_TSR_RQCP0 BIT(0)
+
+/* Receive FIFO 0 register (RF0R) bits */
+#define BXCAN_RF0R_RFOM0 BIT(5)
+#define BXCAN_RF0R_FOVR0 BIT(4)
+#define BXCAN_RF0R_FULL0 BIT(3)
+#define BXCAN_RF0R_FMP0 GENMASK(1, 0)
+
+/* Interrupt enable register (IER) bits */
+#define BXCAN_IER_SLKIE BIT(17)
+#define BXCAN_IER_WKUIE BIT(16)
+#define BXCAN_IER_ERRIE BIT(15)
+#define BXCAN_IER_LECIE BIT(11)
+#define BXCAN_IER_BOFIE BIT(10)
+#define BXCAN_IER_EPVIE BIT(9)
+#define BXCAN_IER_EWGIE BIT(8)
+#define BXCAN_IER_FOVIE1 BIT(6)
+#define BXCAN_IER_FFIE1 BIT(5)
+#define BXCAN_IER_FMPIE1 BIT(4)
+#define BXCAN_IER_FOVIE0 BIT(3)
+#define BXCAN_IER_FFIE0 BIT(2)
+#define BXCAN_IER_FMPIE0 BIT(1)
+#define BXCAN_IER_TMEIE BIT(0)
+
+/* Error status register (ESR) bits */
+#define BXCAN_ESR_REC_SHIFT (24)
+#define BXCAN_ESR_REC GENMASK(31, 24)
+#define BXCAN_ESR_TEC_SHIFT (16)
+#define BXCAN_ESR_TEC GENMASK(23, 16)
+#define BXCAN_ESR_LEC_SHIFT (4)
+#define BXCAN_ESR_LEC GENMASK(6, 4)
+#define BXCAN_ESR_BOFF BIT(1)
+#define BXCAN_ESR_EPVF BIT(1)
+#define BXCAN_ESR_EWGF BIT(0)
+#define BXCAN_TEC(esr) (((esr) & BXCAN_ESR_TEC) >> \
+ BXCAN_ESR_TEC_SHIFT)
+#define BXCAN_REC(esr) (((esr) & BXCAN_ESR_REC) >> \
+ BXCAN_ESR_REC_SHIFT)
+
+/* Bit timing register (BTR) bits */
+#define BXCAN_BTR_SILM BIT(31)
+#define BXCAN_BTR_LBKM BIT(30)
+#define BXCAN_BTR_SJW_MASK GENMASK(25, 24)
+#define BXCAN_BTR_SJW(x) (((x) & 0x03) << 24)
+#define BXCAN_BTR_TS2_MASK GENMASK(22, 20)
+#define BXCAN_BTR_TS2(x) (((x) & 0x07) << 20)
+#define BXCAN_BTR_TS1_MASK GENMASK(19, 16)
+#define BXCAN_BTR_TS1(x) (((x) & 0x0f) << 16)
+#define BXCAN_BTR_BRP_MASK GENMASK(9, 0)
+#define BXCAN_BTR_BRP(x) ((x) & 0x3ff)
+
+/* TX mailbox identifier register (TIxR, x = 0..2) bits */
+#define BXCAN_TIxR_STID(x) (((x) & 0x7ff) << 21)
+#define BXCAN_TIxR_EXID(x) ((x) << 3)
+#define BXCAN_TIxR_IDE BIT(2)
+#define BXCAN_TIxR_RTR BIT(1)
+#define BXCAN_TIxR_TXRQ BIT(0)
+
+/* TX mailbox data length and time stamp register (TDTxR, x = 0..2 bits */
+#define BXCAN_TDTxR_TIME(x) (((x) & 0x0f) << 16)
+#define BXCAN_TDTxR_TGT BIT(8)
+#define BXCAN_TDTxR_DLC_MASK GENMASK(3, 0)
+#define BXCAN_TDTxR_DLC(x) ((x) & 0x0f)
+
+/* RX FIFO mailbox identifier register (RIxR, x = 0..1 */
+#define BXCAN_RIxR_STID_SHIFT (21)
+#define BXCAN_RIxR_EXID_SHIFT (3)
+#define BXCAN_RIxR_IDE BIT(2)
+#define BXCAN_RIxR_RTR BIT(1)
+
+/* RX FIFO mailbox data length and timestamp register (RDTxR, x = 0..1) bits */
+#define BXCAN_RDTxR_TIME GENMASK(31, 16)
+#define BXCAN_RDTxR_FMI GENMASK(15, 8)
+#define BXCAN_RDTxR_DLC GENMASK(3, 0)
+
+enum bxcan_lec_code {
+ LEC_NO_ERROR = 0,
+ LEC_STUFF_ERROR,
+ LEC_FORM_ERROR,
+ LEC_ACK_ERROR,
+ LEC_BIT1_ERROR,
+ LEC_BIT0_ERROR,
+ LEC_CRC_ERROR,
+ LEC_UNUSED
+};
+
+/* Structure of the message buffer */
+struct bxcan_mb {
+ u32 id; /* can identifier */
+ u32 dlc; /* data length control and timestamp */
+ u32 data[2]; /* data */
+};
+
+/* Structure of the hardware registers */
+struct bxcan_regs {
+ u32 mcr; /* 0x00 - master control */
+ u32 msr; /* 0x04 - master status */
+ u32 tsr; /* 0x08 - transmit status */
+ u32 rf0r; /* 0x0c - FIFO 0 */
+ u32 rf1r; /* 0x10 - FIFO 1 */
+ u32 ier; /* 0x14 - interrupt enable */
+ u32 esr; /* 0x18 - error status */
+ u32 btr; /* 0x1c - bit timing*/
+ u32 reserved0[88]; /* 0x20 */
+ struct bxcan_mb tx_mb[BXCAN_TX_MB_NUM]; /* 0x180 - tx mailbox */
+ struct bxcan_mb rx_mb[2]; /* 0x1b0 - rx mailbox */
+};
+
+struct bxcan_priv {
+ struct can_priv can;
+ struct device *dev;
+ struct net_device *ndev;
+ struct napi_struct napi;
+
+ struct bxcan_regs __iomem *regs;
+ int tx_irq;
+ int sce_irq;
+ u8 tx_dlc[BXCAN_TX_MB_NUM];
+ bool master;
+ struct clk *clk;
+ unsigned int tx_head;
+ unsigned int tx_tail;
+};
+
+static const struct can_bittiming_const bxcan_bittiming_const = {
+ .name = KBUILD_MODNAME,
+ .tseg1_min = 1,
+ .tseg1_max = 16,
+ .tseg2_min = 1,
+ .tseg2_max = 8,
+ .sjw_max = 4,
+ .brp_min = 1,
+ .brp_max = 1024,
+ .brp_inc = 1,
+};
+
+static inline u8 bxcan_get_tx_head(const struct bxcan_priv *priv)
+{
+ return priv->tx_head % BXCAN_TX_MB_NUM;
+}
+
+static inline u8 bxcan_get_tx_tail(const struct bxcan_priv *priv)
+{
+ return priv->tx_tail % BXCAN_TX_MB_NUM;
+}
+
+static inline u8 bxcan_get_tx_free(const struct bxcan_priv *priv)
+{
+ return BXCAN_TX_MB_NUM - (priv->tx_head - priv->tx_tail);
+}
+
+static bool bxcan_tx_busy(const struct bxcan_priv *priv)
+{
+ if (bxcan_get_tx_free(priv) > 0)
+ return false;
+
+ netif_stop_queue(priv->ndev);
+
+ /* Memory barrier before checking tx_free (head and tail) */
+ smp_mb();
+
+ if (bxcan_get_tx_free(priv) == 0) {
+ netdev_dbg(priv->ndev,
+ "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n",
+ priv->tx_head, priv->tx_tail,
+ priv->tx_head - priv->tx_tail);
+
+ return true;
+ }
+
+ netif_start_queue(priv->ndev);
+
+ return false;
+}
+
+static int bxcan_chip_softreset(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = BXCAN_TIMEOUT_US / 10;
+
+ bxcan_rmw(®s->mcr, 0, BXCAN_MCR_RESET);
+ while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_SLAK))
+ udelay(10);
+
+ if (!(readl(®s->msr) & BXCAN_MSR_SLAK))
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int bxcan_enter_init_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = BXCAN_TIMEOUT_US / 10;
+
+ bxcan_rmw(®s->mcr, 0, BXCAN_MCR_INRQ);
+ while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_INAK))
+ udelay(100);
+
+ if (!(readl(®s->msr) & BXCAN_MSR_INAK))
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int bxcan_leave_init_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = BXCAN_TIMEOUT_US / 10;
+
+ bxcan_rmw(®s->mcr, BXCAN_MCR_INRQ, 0);
+ while (timeout-- && (readl(®s->msr) & BXCAN_MSR_INAK))
+ udelay(100);
+
+ if (readl(®s->msr) & BXCAN_MSR_INAK)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int bxcan_leave_sleep_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = BXCAN_TIMEOUT_US / 10;
+
+ bxcan_rmw(®s->mcr, BXCAN_MCR_SLEEP, 0);
+ while (timeout-- && (readl(®s->msr) & BXCAN_MSR_SLAK))
+ udelay(100);
+
+ if (readl(®s->msr) & BXCAN_MSR_SLAK)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int bxcan_enter_sleep_mode(struct bxcan_priv *priv)
+{
+ struct bxcan_regs __iomem *regs = priv->regs;
+ unsigned int timeout = BXCAN_TIMEOUT_US / 10;
+
+ bxcan_rmw(®s->mcr, 0, BXCAN_MCR_SLEEP);
+ while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_SLAK))
+ udelay(100);
+
+ if (!(readl(®s->msr) & BXCAN_MSR_SLAK))
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static irqreturn_t bxcan_rx_isr(int irq, void *dev_id)
+{
+ struct net_device *ndev = dev_id;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+
+ if (napi_schedule_prep(&priv->napi)) {
+ /* Disable Rx FIFO message pending interrupt */
+ bxcan_rmw(®s->ier, BXCAN_IER_FMPIE0, 0);
+ __napi_schedule(&priv->napi);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t bxcan_tx_isr(int irq, void *dev_id)
+{
+ struct net_device *ndev = dev_id;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct net_device_stats *stats = &ndev->stats;
+ u32 tsr, rqcp_bit, bytes = 0, pkts = 0;
+ int n, idx;
+
+ tsr = readl(®s->tsr);
+ for (n = 0, idx = bxcan_get_tx_tail(priv); n < BXCAN_TX_MB_NUM; n++) {
+ rqcp_bit = BXCAN_TSR_RQCP0 << (idx << 3);
+ if (tsr & rqcp_bit) {
+ pkts++;
+ bytes += can_get_echo_skb(ndev, idx, NULL);
+ }
+
+ idx += 1;
+ if (idx == BXCAN_TX_MB_NUM)
+ idx = 0;
+ }
+
+ if (!pkts)
+ return IRQ_HANDLED;
+
+ writel(tsr, ®s->tsr);
+
+ priv->tx_tail += pkts;
+ if (bxcan_get_tx_free(priv)) {
+ /* Make sure that anybody stopping the queue after
+ * this sees the new tx_ring->tail.
+ */
+ smp_mb();
+ netif_wake_queue(ndev);
+ }
+
+ stats->tx_bytes += bytes;
+ stats->tx_packets += pkts;
+
+ return IRQ_HANDLED;
+}
+
+static void bxcan_handle_state_change(struct net_device *ndev, u32 esr)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct net_device_stats *stats = &ndev->stats;
+ enum can_state new_state = priv->can.state;
+ struct can_berr_counter bec;
+ enum can_state rx_state, tx_state;
+ struct sk_buff *skb;
+ struct can_frame *cf;
+
+ /* Early exit if no error flag is set */
+ if (!(esr & (BXCAN_ESR_EWGF | BXCAN_ESR_EPVF | BXCAN_ESR_BOFF)))
+ return;
+
+ bec.txerr = BXCAN_TEC(esr);
+ bec.rxerr = BXCAN_REC(esr);
+
+ if (esr & BXCAN_ESR_BOFF)
+ new_state = CAN_STATE_BUS_OFF;
+ else if (esr & BXCAN_ESR_EPVF)
+ new_state = CAN_STATE_ERROR_PASSIVE;
+ else if (esr & BXCAN_ESR_EWGF)
+ new_state = CAN_STATE_ERROR_WARNING;
+
+ /* state hasn't changed */
+ if (unlikely(new_state == priv->can.state))
+ return;
+
+ skb = alloc_can_err_skb(ndev, &cf);
+ if (unlikely(!skb))
+ return;
+
+ tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
+ rx_state = bec.txerr <= bec.rxerr ? new_state : 0;
+ can_change_state(ndev, cf, tx_state, rx_state);
+
+ if (new_state == CAN_STATE_BUS_OFF)
+ can_bus_off(ndev);
+
+ stats->rx_bytes += cf->len;
+ stats->rx_packets++;
+ netif_rx(skb);
+}
+
+static void bxcan_handle_bus_err(struct net_device *ndev, u32 esr)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ enum bxcan_lec_code lec_code;
+ struct can_frame *cf;
+ struct sk_buff *skb;
+
+ lec_code = (esr & BXCAN_ESR_LEC_SHIFT) >> BXCAN_ESR_LEC_SHIFT;
+
+ /* Early exit if no lec update or no error.
+ * No lec update means that no CAN bus event has been detected
+ * since CPU wrote LEC_UNUSED value to status reg.
+ */
+ if (lec_code == LEC_UNUSED || lec_code == LEC_NO_ERROR)
+ return;
+
+ if (!(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
+ return;
+
+ /* Common for all type of bus errors */
+ priv->can.can_stats.bus_error++;
+
+ /* Propagate the error condition to the CAN stack */
+ skb = alloc_can_err_skb(ndev, &cf);
+ if (unlikely(!skb))
+ return;
+
+ ndev->stats.rx_bytes += cf->len;
+
+ /* Check for 'last error code' which tells us the
+ * type of the last error to occur on the CAN bus
+ */
+ cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+ switch (lec_code) {
+ case LEC_STUFF_ERROR:
+ netdev_dbg(ndev, "Stuff error\n");
+ ndev->stats.rx_errors++;
+ cf->data[2] |= CAN_ERR_PROT_STUFF;
+ break;
+ case LEC_FORM_ERROR:
+ netdev_dbg(ndev, "Form error\n");
+ ndev->stats.rx_errors++;
+ cf->data[2] |= CAN_ERR_PROT_FORM;
+ break;
+ case LEC_ACK_ERROR:
+ netdev_dbg(ndev, "Ack error\n");
+ ndev->stats.tx_errors++;
+ cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+ break;
+ case LEC_BIT1_ERROR:
+ netdev_dbg(ndev, "Bit error (recessive)\n");
+ ndev->stats.tx_errors++;
+ cf->data[2] |= CAN_ERR_PROT_BIT1;
+ break;
+ case LEC_BIT0_ERROR:
+ netdev_dbg(ndev, "Bit error (dominant)\n");
+ ndev->stats.tx_errors++;
+ cf->data[2] |= CAN_ERR_PROT_BIT0;
+ break;
+ case LEC_CRC_ERROR:
+ netdev_dbg(ndev, "CRC error\n");
+ ndev->stats.rx_errors++;
+ cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+ break;
+ default:
+ break;
+ }
+
+ netif_rx(skb);
+}
+
+static irqreturn_t bxcan_state_change_isr(int irq, void *dev_id)
+{
+ struct net_device *ndev = dev_id;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 msr, esr;
+
+ msr = readl(®s->msr);
+ if (!(msr & BXCAN_MSR_ERRI))
+ return IRQ_NONE;
+
+ esr = readl(®s->esr);
+ bxcan_handle_state_change(ndev, esr);
+ bxcan_handle_bus_err(ndev, esr);
+
+ msr |= BXCAN_MSR_ERRI;
+ writel(msr, ®s->msr);
+ return IRQ_HANDLED;
+}
+
+static int bxcan_start(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct can_bittiming *bt = &priv->can.bittiming;
+ u32 set;
+ int err;
+
+ err = bxcan_chip_softreset(priv);
+ if (err) {
+ netdev_err(ndev, "failed to reset chip, error %d\n", err);
+ return err;
+ }
+
+ err = bxcan_leave_sleep_mode(priv);
+ if (err) {
+ netdev_err(ndev, "failed to leave sleep mode, error %d\n", err);
+ goto failed_leave_sleep;
+ }
+
+ err = bxcan_enter_init_mode(priv);
+ if (err) {
+ netdev_err(ndev, "failed to enter init mode, error %d\n", err);
+ goto failed_enter_init;
+ }
+
+ /* MCR
+ *
+ * select request order priority
+ * disable time triggered mode
+ * bus-off state left on sw request
+ * sleep mode left on sw request
+ * retransmit automatically on error
+ * do not lock RX FIFO on overrun
+ */
+ bxcan_rmw(®s->mcr, BXCAN_MCR_TTCM | BXCAN_MCR_ABOM | BXCAN_MCR_AWUM |
+ BXCAN_MCR_NART | BXCAN_MCR_RFLM, BXCAN_MCR_TXFP);
+
+ /* Bit timing register settings */
+ set = BXCAN_BTR_BRP(bt->brp - 1) |
+ BXCAN_BTR_TS1(bt->phase_seg1 + bt->prop_seg - 1) |
+ BXCAN_BTR_TS2(bt->phase_seg2 - 1) | BXCAN_BTR_SJW(bt->sjw - 1);
+
+ /* loopback + silent mode put the controller in test mode,
+ * useful for hot self-test
+ */
+ if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
+ set |= BXCAN_BTR_LBKM;
+
+ if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+ set |= BXCAN_BTR_SILM;
+
+ netdev_dbg(ndev,
+ "TQ[ns]: %d, PrS: %d, PhS1: %d, PhS2: %d, SJW: %d, BRP: %d, CAN_BTR: 0x%08x\n",
+ bt->tq, bt->prop_seg, bt->phase_seg1, bt->phase_seg2,
+ bt->sjw, bt->brp, set);
+ bxcan_rmw(®s->btr, BXCAN_BTR_SILM | BXCAN_BTR_LBKM |
+ BXCAN_BTR_BRP_MASK | BXCAN_BTR_TS1_MASK | BXCAN_BTR_TS2_MASK |
+ BXCAN_BTR_SJW_MASK, set);
+
+ bxcan_enable_filters(priv->dev->parent, priv->master);
+
+ /* Clear all internal status */
+ priv->tx_head = 0;
+ priv->tx_tail = 0;
+
+ err = bxcan_leave_init_mode(priv);
+ if (err) {
+ netdev_err(ndev, "failed to leave init mode, error %d\n", err);
+ goto failed_leave_init;
+ }
+
+ /* Set a `lec` value so that we can check for updates later */
+ bxcan_rmw(®s->esr, BXCAN_ESR_LEC, LEC_UNUSED << BXCAN_ESR_LEC_SHIFT);
+
+ /* IER
+ *
+ * Enable interrupt for:
+ * bus-off
+ * passive error
+ * warning error
+ * last error code
+ * RX FIFO pending message
+ * TX mailbox empty
+ */
+ bxcan_rmw(®s->ier, BXCAN_IER_WKUIE | BXCAN_IER_SLKIE |
+ BXCAN_IER_FOVIE1 | BXCAN_IER_FFIE1 | BXCAN_IER_FMPIE1 |
+ BXCAN_IER_FOVIE0 | BXCAN_IER_FFIE0,
+ BXCAN_IER_ERRIE | BXCAN_IER_LECIE | BXCAN_IER_BOFIE |
+ BXCAN_IER_EPVIE | BXCAN_IER_EWGIE | BXCAN_IER_FMPIE0 |
+ BXCAN_IER_TMEIE);
+
+ priv->can.state = CAN_STATE_ERROR_ACTIVE;
+ return 0;
+
+failed_leave_init:
+failed_enter_init:
+failed_leave_sleep:
+ bxcan_chip_softreset(priv);
+ return err;
+}
+
+static int bxcan_open(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ int err;
+
+ err = open_candev(ndev);
+ if (err) {
+ netdev_err(ndev, "open_candev() failed, error %d\n", err);
+ goto failed_open;
+ }
+
+ napi_enable(&priv->napi);
+ err = request_irq(ndev->irq, bxcan_rx_isr, IRQF_SHARED, ndev->name,
+ ndev);
+ if (err) {
+ netdev_err(ndev, "failed to register rx irq(%d), error %d\n",
+ ndev->irq, err);
+ goto failed_rx_irq_request;
+ }
+
+ err = request_irq(priv->tx_irq, bxcan_tx_isr, IRQF_SHARED, ndev->name,
+ ndev);
+ if (err) {
+ netdev_err(ndev, "failed to register tx irq(%d), error %d\n",
+ priv->tx_irq, err);
+ goto failed_tx_irq_request;
+ }
+
+ err = request_irq(priv->sce_irq, bxcan_state_change_isr, IRQF_SHARED,
+ ndev->name, ndev);
+ if (err) {
+ netdev_err(ndev, "failed to register sce irq(%d), error %d\n",
+ priv->sce_irq, err);
+ goto failed_sce_irq_request;
+ }
+
+ err = bxcan_start(ndev);
+ if (err)
+ goto failed_start;
+
+ netif_start_queue(ndev);
+ return 0;
+
+failed_start:
+failed_sce_irq_request:
+ free_irq(priv->tx_irq, ndev);
+failed_tx_irq_request:
+ free_irq(ndev->irq, ndev);
+failed_rx_irq_request:
+ napi_disable(&priv->napi);
+ close_candev(ndev);
+failed_open:
+ return err;
+}
+
+static void bxcan_stop(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ bxcan_disable_filters(priv->dev->parent, priv->master);
+ bxcan_enter_sleep_mode(priv);
+ priv->can.state = CAN_STATE_STOPPED;
+}
+
+static int bxcan_close(struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ netif_stop_queue(ndev);
+ bxcan_stop(ndev);
+ free_irq(ndev->irq, ndev);
+ free_irq(priv->tx_irq, ndev);
+ free_irq(priv->sce_irq, ndev);
+ napi_disable(&priv->napi);
+ close_candev(ndev);
+ return 0;
+}
+
+static netdev_tx_t bxcan_start_xmit(struct sk_buff *skb,
+ struct net_device *ndev)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct can_frame *cf = (struct can_frame *)skb->data;
+ struct bxcan_regs __iomem *regs = priv->regs;
+ struct bxcan_mb __iomem *mb_regs;
+ unsigned int idx;
+ u32 id;
+ int i, j;
+
+ if (can_dropped_invalid_skb(ndev, skb))
+ return NETDEV_TX_OK;
+
+ if (bxcan_tx_busy(priv))
+ return NETDEV_TX_BUSY;
+
+ idx = bxcan_get_tx_head(priv);
+ priv->tx_head++;
+ if (bxcan_get_tx_free(priv) == 0)
+ netif_stop_queue(ndev);
+
+ mb_regs = ®s->tx_mb[idx];
+ if (cf->can_id & CAN_EFF_FLAG)
+ id = BXCAN_TIxR_EXID(cf->can_id & CAN_EFF_MASK) |
+ BXCAN_TIxR_IDE;
+ else
+ id = BXCAN_TIxR_STID(cf->can_id & CAN_SFF_MASK);
+
+ if (cf->can_id & CAN_RTR_FLAG)
+ id |= BXCAN_TIxR_RTR;
+
+ bxcan_rmw(&mb_regs->dlc, BXCAN_TDTxR_DLC_MASK,
+ BXCAN_TDTxR_DLC(cf->len));
+ can_put_echo_skb(skb, ndev, idx, 0);
+
+ for (i = 0, j = 0; i < cf->len; i += 4, j++)
+ writel(*(u32 *)(cf->data + i), &mb_regs->data[j]);
+
+ /* Start transmission */
+ writel(id | BXCAN_TIxR_TXRQ, &mb_regs->id);
+
+ return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops bxcan_netdev_ops = {
+ .ndo_open = bxcan_open,
+ .ndo_stop = bxcan_close,
+ .ndo_start_xmit = bxcan_start_xmit,
+ .ndo_change_mtu = can_change_mtu,
+};
+
+static void bxcan_rx_pkt(struct net_device *ndev,
+ struct bxcan_mb __iomem *mb_regs)
+{
+ struct net_device_stats *stats = &ndev->stats;
+ struct can_frame *cf;
+ struct sk_buff *skb;
+ u32 id, dlc;
+
+ skb = alloc_can_skb(ndev, &cf);
+ if (!skb) {
+ stats->rx_dropped++;
+ return;
+ }
+
+ id = readl(&mb_regs->id);
+ if (id & BXCAN_RIxR_IDE)
+ cf->can_id = (id >> BXCAN_RIxR_EXID_SHIFT) | CAN_EFF_FLAG;
+ else
+ cf->can_id = (id >> BXCAN_RIxR_STID_SHIFT) & CAN_SFF_MASK;
+
+ dlc = readl(&mb_regs->dlc) & BXCAN_RDTxR_DLC;
+ cf->len = can_cc_dlc2len(dlc);
+
+ if (id & BXCAN_RIxR_RTR) {
+ cf->can_id |= CAN_RTR_FLAG;
+ } else {
+ int i, j;
+
+ for (i = 0, j = 0; i < cf->len; i += 4, j++)
+ *(u32 *)(cf->data + i) = readl(&mb_regs->data[j]);
+
+ stats->rx_bytes += cf->len;
+ }
+
+ stats->rx_packets++;
+ netif_receive_skb(skb);
+}
+
+static int bxcan_rx_poll(struct napi_struct *napi, int quota)
+{
+ struct net_device *ndev = napi->dev;
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ int num_pkts;
+ u32 rf0r;
+
+ for (num_pkts = 0; num_pkts < quota; num_pkts++) {
+ rf0r = readl(®s->rf0r);
+ if (!(rf0r & BXCAN_RF0R_FMP0))
+ break;
+
+ bxcan_rx_pkt(ndev, ®s->rx_mb[0]);
+
+ rf0r |= BXCAN_RF0R_RFOM0;
+ writel(rf0r, ®s->rf0r);
+ }
+
+ if (num_pkts < quota) {
+ napi_complete_done(napi, num_pkts);
+ bxcan_rmw(®s->ier, 0, BXCAN_IER_FMPIE0);
+ }
+
+ return num_pkts;
+}
+
+static int bxcan_do_set_mode(struct net_device *ndev, enum can_mode mode)
+{
+ int err;
+
+ switch (mode) {
+ case CAN_MODE_START:
+ err = bxcan_start(ndev);
+ if (err)
+ return err;
+
+ netif_wake_queue(ndev);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static int bxcan_disable_clks(struct bxcan_priv *priv)
+{
+ if (priv->clk)
+ clk_disable_unprepare(priv->clk);
+
+ bxcan_disable_master_clk(priv->dev->parent);
+ return 0;
+}
+
+static int bxcan_enable_clks(struct bxcan_priv *priv)
+{
+ int err;
+
+ err = bxcan_enable_master_clk(priv->dev->parent);
+ if (err)
+ return err;
+
+ if (priv->clk) {
+ err = clk_prepare_enable(priv->clk);
+ if (err)
+ bxcan_disable_master_clk(priv->dev->parent);
+ }
+
+ return err;
+}
+
+static int bxcan_get_berr_counter(const struct net_device *ndev,
+ struct can_berr_counter *bec)
+{
+ struct bxcan_priv *priv = netdev_priv(ndev);
+ struct bxcan_regs __iomem *regs = priv->regs;
+ u32 esr;
+ int err;
+
+ err = bxcan_enable_clks(priv);
+ if (err)
+ return err;
+
+ esr = readl(®s->esr);
+ bec->txerr = BXCAN_TEC(esr);
+ bec->rxerr = BXCAN_REC(esr);
+ err = bxcan_disable_clks(priv);
+ return 0;
+}
+
+static int bxcan_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct device *dev = &pdev->dev;
+ struct net_device *ndev;
+ struct bxcan_priv *priv;
+ struct clk *clk = NULL;
+ bool master;
+ u32 offset;
+ int err, rx_irq, tx_irq, sce_irq;
+
+ master = of_property_read_bool(np, "st,can-master");
+ if (!master) {
+ clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(clk)) {
+ dev_err(dev, "failed to get clock\n");
+ return PTR_ERR(clk);
+ }
+ }
+
+ rx_irq = platform_get_irq_byname(pdev, "rx0");
+ if (rx_irq < 0) {
+ dev_err(dev, "failed to get rx0 irq\n");
+ return rx_irq;
+ }
+
+ tx_irq = platform_get_irq_byname(pdev, "tx");
+ if (tx_irq < 0) {
+ dev_err(dev, "failed to get tx irq\n");
+ return tx_irq;
+ }
+
+ sce_irq = platform_get_irq_byname(pdev, "sce");
+ if (sce_irq < 0) {
+ dev_err(dev, "failed to get sce irq\n");
+ return sce_irq;
+ }
+
+ err = of_property_read_u32(np, "reg", &offset);
+ if (err) {
+ dev_err(dev, "failed to get reg property\n");
+ return err;
+ }
+
+ ndev = alloc_candev(sizeof(struct bxcan_priv), BXCAN_TX_MB_NUM);
+ if (!ndev) {
+ dev_err(dev, "alloc_candev() failed\n");
+ return -ENOMEM;
+ }
+
+ priv = netdev_priv(ndev);
+ platform_set_drvdata(pdev, ndev);
+ SET_NETDEV_DEV(ndev, dev);
+ ndev->netdev_ops = &bxcan_netdev_ops;
+ ndev->irq = rx_irq;
+ ndev->flags |= IFF_ECHO;
+
+ priv->dev = dev;
+ priv->ndev = ndev;
+ priv->regs = bxcan_get_base_addr(dev->parent) + offset;
+ priv->clk = clk;
+ priv->tx_irq = tx_irq;
+ priv->sce_irq = sce_irq;
+ priv->master = master;
+ priv->can.clock.freq =
+ master ? bxcan_get_master_clk_rate(dev->parent) :
+ clk_get_rate(clk);
+ priv->tx_head = 0;
+ priv->tx_tail = 0;
+ priv->can.bittiming_const = &bxcan_bittiming_const;
+ priv->can.do_set_mode = bxcan_do_set_mode;
+ priv->can.do_get_berr_counter = bxcan_get_berr_counter;
+ priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
+ CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING;
+ netif_napi_add(ndev, &priv->napi, bxcan_rx_poll, BXCAN_NAPI_WEIGHT);
+
+ err = bxcan_enable_clks(priv);
+ if (err) {
+ dev_err(dev, "failed to enable clocks\n");
+ return err;
+ }
+
+ err = register_candev(ndev);
+ if (err) {
+ dev_err(dev, "failed to register netdev\n");
+ goto failed_register;
+ }
+
+ dev_info(dev, "clk: %d Hz, IRQs: %d, %d, %d\n", priv->can.clock.freq,
+ tx_irq, rx_irq, sce_irq);
+ return 0;
+
+failed_register:
+ netif_napi_del(&priv->napi);
+ free_candev(ndev);
+ return err;
+}
+
+static int bxcan_remove(struct platform_device *pdev)
+{
+ struct net_device *ndev = platform_get_drvdata(pdev);
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ unregister_candev(ndev);
+ bxcan_disable_clks(priv);
+ netif_napi_del(&priv->napi);
+ free_candev(ndev);
+ return 0;
+}
+
+static int __maybe_unused bxcan_suspend(struct device *dev)
+{
+ struct net_device *ndev = dev_get_drvdata(dev);
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ if (!netif_running(ndev))
+ return 0;
+
+ netif_stop_queue(ndev);
+ netif_device_detach(ndev);
+
+ bxcan_enter_sleep_mode(priv);
+ priv->can.state = CAN_STATE_SLEEPING;
+ bxcan_disable_clks(priv);
+ return 0;
+}
+
+static int __maybe_unused bxcan_resume(struct device *dev)
+{
+ struct net_device *ndev = dev_get_drvdata(dev);
+ struct bxcan_priv *priv = netdev_priv(ndev);
+
+ if (!netif_running(ndev))
+ return 0;
+
+ bxcan_enable_clks(priv);
+ bxcan_leave_sleep_mode(priv);
+ priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+ netif_device_attach(ndev);
+ netif_start_queue(ndev);
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(bxcan_pm_ops, bxcan_suspend, bxcan_resume);
+
+static const struct of_device_id bxcan_of_match[] = {
+ {.compatible = "st,stm32f4-bxcan"},
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, bxcan_of_match);
+
+static struct platform_driver bxcan_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .pm = &bxcan_pm_ops,
+ .of_match_table = bxcan_of_match,
+ },
+ .probe = bxcan_probe,
+ .remove = bxcan_remove,
+};
+
+module_platform_driver(bxcan_driver);
+
+MODULE_AUTHOR("Dario Binacchi <[email protected]>");
+MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN controller driver");
+MODULE_LICENSE("GPL");
--
2.32.0
Add pin configurations for using CAN controller on stm32f469-disco
board. They are located on the Arduino compatible connector CN5 (CAN1)
and on the extension connector CN12 (CAN2).
Signed-off-by: Dario Binacchi <[email protected]>
---
Changes in v3:
- Remove 'Dario Binacchi <[email protected]>' SOB.
- Remove a blank line.
Changes in v2:
- Remove a blank line.
arch/arm/boot/dts/stm32f4-pinctrl.dtsi | 30 ++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/arch/arm/boot/dts/stm32f4-pinctrl.dtsi b/arch/arm/boot/dts/stm32f4-pinctrl.dtsi
index 500bcc302d42..8a4d51f97248 100644
--- a/arch/arm/boot/dts/stm32f4-pinctrl.dtsi
+++ b/arch/arm/boot/dts/stm32f4-pinctrl.dtsi
@@ -448,6 +448,36 @@ pins2 {
slew-rate = <2>;
};
};
+
+ can1_pins_a: can1-0 {
+ pins1 {
+ pinmux = <STM32_PINMUX('B', 9, AF9)>; /* CAN1_TX */
+ };
+ pins2 {
+ pinmux = <STM32_PINMUX('B', 8, AF9)>; /* CAN1_RX */
+ bias-pull-up;
+ };
+ };
+
+ can2_pins_a: can2-0 {
+ pins1 {
+ pinmux = <STM32_PINMUX('B', 13, AF9)>; /* CAN2_TX */
+ };
+ pins2 {
+ pinmux = <STM32_PINMUX('B', 5, AF9)>; /* CAN2_RX */
+ bias-pull-up;
+ };
+ };
+
+ can2_pins_b: can2-1 {
+ pins1 {
+ pinmux = <STM32_PINMUX('B', 13, AF9)>; /* CAN2_TX */
+ };
+ pins2 {
+ pinmux = <STM32_PINMUX('B', 12, AF9)>; /* CAN2_RX */
+ bias-pull-up;
+ };
+ };
};
};
};
--
2.32.0
On 28.08.2022 15:33:29, Dario Binacchi wrote:
> Add support for the basic extended CAN controller (bxCAN) found in many
> low- to middle-end STM32 SoCs. It supports the Basic Extended CAN
> protocol versions 2.0A and B with a maximum bit rate of 1 Mbit/s.
>
> The controller supports two channels (CAN1 as master and CAN2 as slave)
> and the driver can enable either or both of the channels. They share
> some of the required logic (e. g. clocks and filters), and that means
> you cannot use the slave CAN without enabling some hardware resources
> managed by the master CAN.
I don't like the concept of the core driver. E.g. the r-m-w of shared
registers bxcan_enable_filters() is racy by design.
How is the memory layout?
- 0x000 - 0x1ff: CAN1
- 0x200 - 0x3ff: shared mem
- 0x400 - 0x5ff: CAN2
Better model the shared mem as a "syscon" node:
| https://elixir.bootlin.com/linux/v6.0-rc4/source/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c#L1445
Then you can use regmap_*() functions to access the register space. The
regmap functions are always locked against each other.
[...]
> diff --git a/drivers/net/can/bxcan/bxcan-core.c b/drivers/net/can/bxcan/bxcan-core.c
> new file mode 100644
> index 000000000000..3644449095e9
> --- /dev/null
> +++ b/drivers/net/can/bxcan/bxcan-core.c
> @@ -0,0 +1,200 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* bxcan-core.c - STM32 Basic Extended CAN core controller driver
> + *
> + * This file is part of STM32 bxcan driver
> + *
> + * Copyright (c) 2022 Dario Binacchi <[email protected]>
> + */
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +
> +#include "bxcan-core.h"
> +
> +#define BXCAN_FILTER_ID(master) (master ? 0 : 14)
> +
> +/* Filter master register (FMR) bits */
> +#define BXCAN_FMR_CANSB_MASK GENMASK(13, 8)
> +#define BXCAN_FMR_CANSB(x) (((x) & 0x3f) << 8)
> +#define BXCAN_FMR_FINIT BIT(0)
nitpick:
please use 1 space instead of tabs
> +
> +/* Structure of the filter bank */
> +struct bxcan_fb {
> + u32 fr1; /* filter 1 */
> + u32 fr2; /* filter 2 */
> +};
> +
> +/* Structure of the hardware filter registers */
> +struct bxcan_fregs {
> + u32 fmr; /* 0x00 - filter master */
> + u32 fm1r; /* 0x04 - filter mode */
> + u32 reserved2; /* 0x08 */
> + u32 fs1r; /* 0x0c - filter scale */
> + u32 reserved3; /* 0x10 */
> + u32 ffa1r; /* 0x14 - filter FIFO assignment */
> + u32 reserved4; /* 0x18 */
> + u32 fa1r; /* 0x1c - filter activation */
> + u32 reserved5[8]; /* 0x20 */
> + struct bxcan_fb fb[28]; /* 0x40 - filter banks */
> +};
> +
> +struct bxcan_core_priv {
> + void __iomem *base;
> + struct bxcan_fregs __iomem *fregs;
> + struct clk *clk_master;
> + unsigned int clk_master_ref;
> +};
> +
> +void bxcan_disable_filters(struct device *dev, bool master)
> +{
> + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> + unsigned int fid = BXCAN_FILTER_ID(master);
> + u32 fmask = BIT(fid);
> +
> + bxcan_rmw(&priv->fregs->fa1r, fmask, 0);
This is racy, same for bxcan_rmw() on other shared registers.
> +}
> +
> +void bxcan_enable_filters(struct device *dev, bool master)
> +{
> + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> + unsigned int fid = BXCAN_FILTER_ID(master);
> + u32 fmask = BIT(fid);
> +
> + /* Filter settings:
> + *
> + * Accept all messages.
> + * Assign filter 0 to CAN1 and filter 14 to CAN2 in identifier
> + * mask mode with 32 bits width.
> + */
> +
> + /* Enter filter initialization mode and assing filters to CAN
> + * controllers.
> + */
> + bxcan_rmw(&priv->fregs->fmr, BXCAN_FMR_CANSB_MASK,
> + BXCAN_FMR_CANSB(14) | BXCAN_FMR_FINIT);
> +
> + /* Deactivate filter */
> + bxcan_rmw(&priv->fregs->fa1r, fmask, 0);
> +
> + /* Two 32-bit registers in identifier mask mode */
> + bxcan_rmw(&priv->fregs->fm1r, fmask, 0);
> +
> + /* Single 32-bit scale configuration */
> + bxcan_rmw(&priv->fregs->fs1r, 0, fmask);
> +
> + /* Assign filter to FIFO 0 */
> + bxcan_rmw(&priv->fregs->ffa1r, fmask, 0);
> +
> + /* Accept all messages */
> + writel(0, &priv->fregs->fb[fid].fr1);
> + writel(0, &priv->fregs->fb[fid].fr2);
> +
> + /* Activate filter */
> + bxcan_rmw(&priv->fregs->fa1r, 0, fmask);
> +
> + /* Exit filter initialization mode */
> + bxcan_rmw(&priv->fregs->fmr, BXCAN_FMR_FINIT, 0);
> +}
> +
> +int bxcan_enable_master_clk(struct device *dev)
> +{
> + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> + int err;
> +
> + if (priv->clk_master_ref == 0) {
> + err = clk_prepare_enable(priv->clk_master);
> + if (err)
> + return err;
> + }
> +
> + priv->clk_master_ref++;
In general, don't do clock ref-counting. You can enable and disable the
same clock several times.
If you convert to syscon, you can add a clock node to the syscon node
and the syscon driver will take care of the clocks.
> + return 0;
> +}
> +
> +void bxcan_disable_master_clk(struct device *dev)
> +{
> + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> +
> + if (priv->clk_master_ref == 0)
> + return;
> +
> + if (priv->clk_master_ref == 1)
> + clk_disable_unprepare(priv->clk_master);
> +
> + priv->clk_master_ref--;
> +}
> +
> +unsigned long bxcan_get_master_clk_rate(struct device *dev)
> +{
> + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> +
> + return clk_get_rate(priv->clk_master);
> +}
> +
> +void __iomem *bxcan_get_base_addr(struct device *dev)
> +{
> + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> +
> + return priv->base;
> +}
> +
> +static const struct of_device_id bxcan_core_of_match[] = {
> + {.compatible = "st,stm32f4-bxcan-core"},
> + { /* sentinel */ },
> +};
> +
> +MODULE_DEVICE_TABLE(of, bxcan_core_of_match);
> +
> +static int bxcan_core_probe(struct platform_device *pdev)
> +{
> + struct bxcan_core_priv *priv;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = pdev->dev.of_node;
> + void __iomem *regs;
> + struct clk *clk;
> + int ret;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, priv);
> + regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(regs))
> + return PTR_ERR(regs);
> +
> + clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk)) {
> + dev_err(dev, "failed to get clock\n");
> + return PTR_ERR(clk);
> + }
> +
> + priv->base = regs;
> + priv->fregs = regs + 0x200;
> + priv->clk_master = clk;
> +
> + ret = of_platform_populate(np, NULL, NULL, dev);
> + if (ret < 0) {
> + dev_err(dev, "failed to populate DT children\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static struct platform_driver bxcan_core_driver = {
> + .driver = {
> + .name = KBUILD_MODNAME,
> + .of_match_table = bxcan_core_of_match,
> + },
> + .probe = bxcan_core_probe,
> +};
> +
> +module_platform_driver(bxcan_core_driver);
> +
> +MODULE_AUTHOR("Dario Binacchi <[email protected]>");
> +MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN core driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/net/can/bxcan/bxcan-core.h b/drivers/net/can/bxcan/bxcan-core.h
> new file mode 100644
> index 000000000000..925449cbc3bd
> --- /dev/null
> +++ b/drivers/net/can/bxcan/bxcan-core.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * bxcan-core - STM32 Basic Extended CAN core controller driver
> + *
> + * Copyright (c) 2022 Dario Binacchi <[email protected]>
> + */
> +
> +#ifndef __BXCAN_CORE_H
> +#define __BXCAN_CORE_H
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +
> +int bxcan_enable_master_clk(struct device *dev);
> +void bxcan_disable_master_clk(struct device *dev);
> +unsigned long bxcan_get_master_clk_rate(struct device *dev);
> +void __iomem *bxcan_get_base_addr(struct device *dev);
> +void bxcan_enable_filters(struct device *dev, bool master);
> +void bxcan_disable_filters(struct device *dev, bool master);
> +
> +static inline void bxcan_rmw(void __iomem *addr, u32 clear, u32 set)
> +{
> + u32 old, val;
> +
> + old = readl(addr);
> + val = (old & ~clear) | set;
> + if (val != old)
> + writel(val, addr);
> +}
> +
> +#endif
> diff --git a/drivers/net/can/bxcan/bxcan-drv.c b/drivers/net/can/bxcan/bxcan-drv.c
> new file mode 100644
> index 000000000000..7ac1ee7a4269
> --- /dev/null
> +++ b/drivers/net/can/bxcan/bxcan-drv.c
> @@ -0,0 +1,1045 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// bxcan-drv.c - STM32 Basic Extended CAN controller driver
> +//
> +// Copyright (c) 2022 Dario Binacchi <[email protected]>
> +//
> +
> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> +
> +#include <linux/bitfield.h>
> +#include <linux/can.h>
> +#include <linux/can/dev.h>
> +#include <linux/can/error.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +
> +#include "bxcan-core.h"
> +
> +#define BXCAN_NAPI_WEIGHT 3
> +#define BXCAN_TIMEOUT_US 10000
> +
> +#define BXCAN_TX_MB_NUM 3
> +
> +/* Master control register (MCR) bits */
> +#define BXCAN_MCR_DBF BIT(16)
> +#define BXCAN_MCR_RESET BIT(15)
> +#define BXCAN_MCR_TTCM BIT(7)
> +#define BXCAN_MCR_ABOM BIT(6)
> +#define BXCAN_MCR_AWUM BIT(5)
> +#define BXCAN_MCR_NART BIT(4)
> +#define BXCAN_MCR_RFLM BIT(3)
> +#define BXCAN_MCR_TXFP BIT(2)
> +#define BXCAN_MCR_SLEEP BIT(1)
> +#define BXCAN_MCR_INRQ BIT(0)
> +
> +/* Master status register (MSR) bits */
> +#define BXCAN_MSR_RX BIT(11)
> +#define BXCAN_MSR_SAMP BIT(10)
> +#define BXCAN_MSR_RXM BIT(9)
> +#define BXCAN_MSR_TXM BIT(8)
> +#define BXCAN_MSR_SLAKI BIT(4)
> +#define BXCAN_MSR_WKUI BIT(3)
> +#define BXCAN_MSR_ERRI BIT(2)
> +#define BXCAN_MSR_SLAK BIT(1)
> +#define BXCAN_MSR_INAK BIT(0)
> +
> +/* Transmit status register (TSR) bits */
> +#define BXCAN_TSR_LOW2 BIT(31)
> +#define BXCAN_TSR_LOW1 BIT(30)
> +#define BXCAN_TSR_LOW0 BIT(29)
> +#define BXCAN_TSR_TME GENMASK(28, 26)
> +#define BXCAN_TSR_TME_SHIFT (26)
unused
> +#define BXCAN_TSR_TME2 BIT(28)
> +#define BXCAN_TSR_TME1 BIT(27)
> +#define BXCAN_TSR_TME0 BIT(26)
> +#define BXCAN_TSR_CODE GENMASK(25, 24)
> +#define BXCAN_TSR_ABRQ2 BIT(23)
> +#define BXCAN_TSR_TERR2 BIT(19)
> +#define BXCAN_TSR_ALST2 BIT(18)
> +#define BXCAN_TSR_TXOK2 BIT(17)
> +#define BXCAN_TSR_RQCP2 BIT(16)
> +#define BXCAN_TSR_ABRQ1 BIT(15)
> +#define BXCAN_TSR_TERR1 BIT(11)
> +#define BXCAN_TSR_ALST1 BIT(10)
> +#define BXCAN_TSR_TXOK1 BIT(9)
> +#define BXCAN_TSR_RQCP1 BIT(8)
> +#define BXCAN_TSR_ABRQ0 BIT(7)
> +#define BXCAN_TSR_TERR0 BIT(3)
> +#define BXCAN_TSR_ALST0 BIT(2)
> +#define BXCAN_TSR_TXOK0 BIT(1)
> +#define BXCAN_TSR_RQCP0 BIT(0)
> +
> +/* Receive FIFO 0 register (RF0R) bits */
> +#define BXCAN_RF0R_RFOM0 BIT(5)
> +#define BXCAN_RF0R_FOVR0 BIT(4)
> +#define BXCAN_RF0R_FULL0 BIT(3)
> +#define BXCAN_RF0R_FMP0 GENMASK(1, 0)
> +
> +/* Interrupt enable register (IER) bits */
> +#define BXCAN_IER_SLKIE BIT(17)
> +#define BXCAN_IER_WKUIE BIT(16)
> +#define BXCAN_IER_ERRIE BIT(15)
> +#define BXCAN_IER_LECIE BIT(11)
> +#define BXCAN_IER_BOFIE BIT(10)
> +#define BXCAN_IER_EPVIE BIT(9)
> +#define BXCAN_IER_EWGIE BIT(8)
> +#define BXCAN_IER_FOVIE1 BIT(6)
> +#define BXCAN_IER_FFIE1 BIT(5)
> +#define BXCAN_IER_FMPIE1 BIT(4)
> +#define BXCAN_IER_FOVIE0 BIT(3)
> +#define BXCAN_IER_FFIE0 BIT(2)
> +#define BXCAN_IER_FMPIE0 BIT(1)
> +#define BXCAN_IER_TMEIE BIT(0)
> +
> +/* Error status register (ESR) bits */
> +#define BXCAN_ESR_REC_SHIFT (24)
> +#define BXCAN_ESR_REC GENMASK(31, 24)
> +#define BXCAN_ESR_TEC_SHIFT (16)
> +#define BXCAN_ESR_TEC GENMASK(23, 16)
> +#define BXCAN_ESR_LEC_SHIFT (4)
please remove the _SHIFT macros, no need for them...
> +#define BXCAN_ESR_LEC GENMASK(6, 4)
> +#define BXCAN_ESR_BOFF BIT(1)
> +#define BXCAN_ESR_EPVF BIT(1)
> +#define BXCAN_ESR_EWGF BIT(0)
> +#define BXCAN_TEC(esr) (((esr) & BXCAN_ESR_TEC) >> \
> + BXCAN_ESR_TEC_SHIFT)
> +#define BXCAN_REC(esr) (((esr) & BXCAN_ESR_REC) >> \
> + BXCAN_ESR_REC_SHIFT)
... remove these and use FIELD_GET() directly.
> +
> +/* Bit timing register (BTR) bits */
> +#define BXCAN_BTR_SILM BIT(31)
> +#define BXCAN_BTR_LBKM BIT(30)
> +#define BXCAN_BTR_SJW_MASK GENMASK(25, 24)
> +#define BXCAN_BTR_SJW(x) (((x) & 0x03) << 24)
> +#define BXCAN_BTR_TS2_MASK GENMASK(22, 20)
> +#define BXCAN_BTR_TS2(x) (((x) & 0x07) << 20)
> +#define BXCAN_BTR_TS1_MASK GENMASK(19, 16)
> +#define BXCAN_BTR_TS1(x) (((x) & 0x0f) << 16)
> +#define BXCAN_BTR_BRP_MASK GENMASK(9, 0)
> +#define BXCAN_BTR_BRP(x) ((x) & 0x3ff)
same for these
> +
> +/* TX mailbox identifier register (TIxR, x = 0..2) bits */
> +#define BXCAN_TIxR_STID(x) (((x) & 0x7ff) << 21)
> +#define BXCAN_TIxR_EXID(x) ((x) << 3)
same here
> +#define BXCAN_TIxR_IDE BIT(2)
> +#define BXCAN_TIxR_RTR BIT(1)
> +#define BXCAN_TIxR_TXRQ BIT(0)
> +
> +/* TX mailbox data length and time stamp register (TDTxR, x = 0..2 bits */
> +#define BXCAN_TDTxR_TIME(x) (((x) & 0x0f) << 16)
same
> +#define BXCAN_TDTxR_TGT BIT(8)
> +#define BXCAN_TDTxR_DLC_MASK GENMASK(3, 0)
> +#define BXCAN_TDTxR_DLC(x) ((x) & 0x0f)
same
> +
> +/* RX FIFO mailbox identifier register (RIxR, x = 0..1 */
> +#define BXCAN_RIxR_STID_SHIFT (21)
> +#define BXCAN_RIxR_EXID_SHIFT (3)
> +#define BXCAN_RIxR_IDE BIT(2)
> +#define BXCAN_RIxR_RTR BIT(1)
> +
> +/* RX FIFO mailbox data length and timestamp register (RDTxR, x = 0..1) bits */
> +#define BXCAN_RDTxR_TIME GENMASK(31, 16)
> +#define BXCAN_RDTxR_FMI GENMASK(15, 8)
> +#define BXCAN_RDTxR_DLC GENMASK(3, 0)
> +
> +enum bxcan_lec_code {
> + LEC_NO_ERROR = 0,
> + LEC_STUFF_ERROR,
> + LEC_FORM_ERROR,
> + LEC_ACK_ERROR,
> + LEC_BIT1_ERROR,
> + LEC_BIT0_ERROR,
> + LEC_CRC_ERROR,
> + LEC_UNUSED
Please add BXCAN_ as prefix
> +};
> +
> +/* Structure of the message buffer */
> +struct bxcan_mb {
> + u32 id; /* can identifier */
> + u32 dlc; /* data length control and timestamp */
> + u32 data[2]; /* data */
> +};
> +
> +/* Structure of the hardware registers */
> +struct bxcan_regs {
> + u32 mcr; /* 0x00 - master control */
> + u32 msr; /* 0x04 - master status */
> + u32 tsr; /* 0x08 - transmit status */
> + u32 rf0r; /* 0x0c - FIFO 0 */
> + u32 rf1r; /* 0x10 - FIFO 1 */
> + u32 ier; /* 0x14 - interrupt enable */
> + u32 esr; /* 0x18 - error status */
> + u32 btr; /* 0x1c - bit timing*/
> + u32 reserved0[88]; /* 0x20 */
> + struct bxcan_mb tx_mb[BXCAN_TX_MB_NUM]; /* 0x180 - tx mailbox */
> + struct bxcan_mb rx_mb[2]; /* 0x1b0 - rx mailbox */
Please add a define for the "2", as well.
> +};
> +
> +struct bxcan_priv {
> + struct can_priv can;
> + struct device *dev;
> + struct net_device *ndev;
> + struct napi_struct napi;
consider using can_rx_offload().
The idea is to read from the mailbox in the IRQ handler and push the
frame into the networking stack in the napi.
> +
> + struct bxcan_regs __iomem *regs;
> + int tx_irq;
> + int sce_irq;
> + u8 tx_dlc[BXCAN_TX_MB_NUM];
unused
> + bool master;
> + struct clk *clk;
> + unsigned int tx_head;
> + unsigned int tx_tail;
> +};
> +
> +static const struct can_bittiming_const bxcan_bittiming_const = {
> + .name = KBUILD_MODNAME,
> + .tseg1_min = 1,
> + .tseg1_max = 16,
> + .tseg2_min = 1,
> + .tseg2_max = 8,
> + .sjw_max = 4,
> + .brp_min = 1,
> + .brp_max = 1024,
> + .brp_inc = 1,
> +};
> +
> +static inline u8 bxcan_get_tx_head(const struct bxcan_priv *priv)
> +{
> + return priv->tx_head % BXCAN_TX_MB_NUM;
> +}
> +
> +static inline u8 bxcan_get_tx_tail(const struct bxcan_priv *priv)
> +{
> + return priv->tx_tail % BXCAN_TX_MB_NUM;
> +}
> +
> +static inline u8 bxcan_get_tx_free(const struct bxcan_priv *priv)
> +{
> + return BXCAN_TX_MB_NUM - (priv->tx_head - priv->tx_tail);
> +}
> +
> +static bool bxcan_tx_busy(const struct bxcan_priv *priv)
> +{
> + if (bxcan_get_tx_free(priv) > 0)
> + return false;
> +
> + netif_stop_queue(priv->ndev);
> +
> + /* Memory barrier before checking tx_free (head and tail) */
> + smp_mb();
> +
> + if (bxcan_get_tx_free(priv) == 0) {
> + netdev_dbg(priv->ndev,
> + "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n",
> + priv->tx_head, priv->tx_tail,
> + priv->tx_head - priv->tx_tail);
> +
> + return true;
> + }
> +
> + netif_start_queue(priv->ndev);
> +
> + return false;
> +}
> +
> +static int bxcan_chip_softreset(struct bxcan_priv *priv)
> +{
> + struct bxcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> +
> + bxcan_rmw(®s->mcr, 0, BXCAN_MCR_RESET);
> + while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_SLAK))
> + udelay(10);
make use of readx_poll_timeout(), see:
| https://elixir.bootlin.com/linux/v6.0-rc4/source/drivers/net/can/spi/mcp251x.c#L410
> +
> + if (!(readl(®s->msr) & BXCAN_MSR_SLAK))
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int bxcan_enter_init_mode(struct bxcan_priv *priv)
> +{
> + struct bxcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> +
> + bxcan_rmw(®s->mcr, 0, BXCAN_MCR_INRQ);
> + while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_INAK))
> + udelay(100);
same here
> +
> + if (!(readl(®s->msr) & BXCAN_MSR_INAK))
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int bxcan_leave_init_mode(struct bxcan_priv *priv)
> +{
> + struct bxcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> +
> + bxcan_rmw(®s->mcr, BXCAN_MCR_INRQ, 0);
> + while (timeout-- && (readl(®s->msr) & BXCAN_MSR_INAK))
> + udelay(100);
same
> +
> + if (readl(®s->msr) & BXCAN_MSR_INAK)
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int bxcan_leave_sleep_mode(struct bxcan_priv *priv)
> +{
> + struct bxcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> +
> + bxcan_rmw(®s->mcr, BXCAN_MCR_SLEEP, 0);
> + while (timeout-- && (readl(®s->msr) & BXCAN_MSR_SLAK))
> + udelay(100);
same
> +
> + if (readl(®s->msr) & BXCAN_MSR_SLAK)
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static int bxcan_enter_sleep_mode(struct bxcan_priv *priv)
> +{
> + struct bxcan_regs __iomem *regs = priv->regs;
> + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> +
> + bxcan_rmw(®s->mcr, 0, BXCAN_MCR_SLEEP);
> + while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_SLAK))
> + udelay(100);
same
> +
> + if (!(readl(®s->msr) & BXCAN_MSR_SLAK))
> + return -ETIMEDOUT;
> +
> + return 0;
> +}
> +
> +static irqreturn_t bxcan_rx_isr(int irq, void *dev_id)
> +{
> + struct net_device *ndev = dev_id;
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct bxcan_regs __iomem *regs = priv->regs;
> +
> + if (napi_schedule_prep(&priv->napi)) {
> + /* Disable Rx FIFO message pending interrupt */
> + bxcan_rmw(®s->ier, BXCAN_IER_FMPIE0, 0);
> + __napi_schedule(&priv->napi);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t bxcan_tx_isr(int irq, void *dev_id)
> +{
> + struct net_device *ndev = dev_id;
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct bxcan_regs __iomem *regs = priv->regs;
> + struct net_device_stats *stats = &ndev->stats;
> + u32 tsr, rqcp_bit, bytes = 0, pkts = 0;
> + int n, idx;
> +
> + tsr = readl(®s->tsr);
> + for (n = 0, idx = bxcan_get_tx_tail(priv); n < BXCAN_TX_MB_NUM; n++) {
loop from tail to head:
| while (priv->tx_head - priv->tx_tail > 0) {
| ...
| idx = bxcan_get_tx_tail()
| ...
> + rqcp_bit = BXCAN_TSR_RQCP0 << (idx << 3);
> + if (tsr & rqcp_bit) {
> + pkts++;
> + bytes += can_get_echo_skb(ndev, idx, NULL);
> + }
> +
> + idx += 1;
> + if (idx == BXCAN_TX_MB_NUM)
> + idx = 0;
> + }
> +
> + if (!pkts)
> + return IRQ_HANDLED;
This looks wrong. Better check if any relevant bits in tsr are set, if
not return IRQ_NONE.
> +
> + writel(tsr, ®s->tsr);
> +
> + priv->tx_tail += pkts;
> + if (bxcan_get_tx_free(priv)) {
> + /* Make sure that anybody stopping the queue after
> + * this sees the new tx_ring->tail.
> + */
> + smp_mb();
> + netif_wake_queue(ndev);
> + }
> +
> + stats->tx_bytes += bytes;
> + stats->tx_packets += pkts;
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void bxcan_handle_state_change(struct net_device *ndev, u32 esr)
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct net_device_stats *stats = &ndev->stats;
> + enum can_state new_state = priv->can.state;
> + struct can_berr_counter bec;
> + enum can_state rx_state, tx_state;
> + struct sk_buff *skb;
> + struct can_frame *cf;
> +
> + /* Early exit if no error flag is set */
> + if (!(esr & (BXCAN_ESR_EWGF | BXCAN_ESR_EPVF | BXCAN_ESR_BOFF)))
> + return;
> +
> + bec.txerr = BXCAN_TEC(esr);
> + bec.rxerr = BXCAN_REC(esr);
> +
> + if (esr & BXCAN_ESR_BOFF)
> + new_state = CAN_STATE_BUS_OFF;
> + else if (esr & BXCAN_ESR_EPVF)
> + new_state = CAN_STATE_ERROR_PASSIVE;
> + else if (esr & BXCAN_ESR_EWGF)
> + new_state = CAN_STATE_ERROR_WARNING;
> +
> + /* state hasn't changed */
> + if (unlikely(new_state == priv->can.state))
> + return;
> +
> + skb = alloc_can_err_skb(ndev, &cf);
> + if (unlikely(!skb))
> + return;
Continue, even if you got no skb.
> +
> + tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
> + rx_state = bec.txerr <= bec.rxerr ? new_state : 0;
> + can_change_state(ndev, cf, tx_state, rx_state);
can_change_state() handles cf == NULL....
> +
> + if (new_state == CAN_STATE_BUS_OFF)
> + can_bus_off(ndev);
> +
> + stats->rx_bytes += cf->len;
> + stats->rx_packets++;
no statistics for error frames.
> + netif_rx(skb);
> +}
> +
> +static void bxcan_handle_bus_err(struct net_device *ndev, u32 esr)
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + enum bxcan_lec_code lec_code;
> + struct can_frame *cf;
> + struct sk_buff *skb;
> +
> + lec_code = (esr & BXCAN_ESR_LEC_SHIFT) >> BXCAN_ESR_LEC_SHIFT;
Use FIELD_GET()
> +
> + /* Early exit if no lec update or no error.
> + * No lec update means that no CAN bus event has been detected
> + * since CPU wrote LEC_UNUSED value to status reg.
> + */
> + if (lec_code == LEC_UNUSED || lec_code == LEC_NO_ERROR)
> + return;
> +
> + if (!(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
> + return;
Can you disable the generation of the bus error interrupt?
> +
> + /* Common for all type of bus errors */
> + priv->can.can_stats.bus_error++;
> +
> + /* Propagate the error condition to the CAN stack */
> + skb = alloc_can_err_skb(ndev, &cf);
> + if (unlikely(!skb))
> + return;
continue, even without skb
> +
> + ndev->stats.rx_bytes += cf->len;
no stats
> +
> + /* Check for 'last error code' which tells us the
> + * type of the last error to occur on the CAN bus
> + */
> + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> +
> + switch (lec_code) {
> + case LEC_STUFF_ERROR:
> + netdev_dbg(ndev, "Stuff error\n");
> + ndev->stats.rx_errors++;
> + cf->data[2] |= CAN_ERR_PROT_STUFF;
> + break;
> + case LEC_FORM_ERROR:
> + netdev_dbg(ndev, "Form error\n");
> + ndev->stats.rx_errors++;
> + cf->data[2] |= CAN_ERR_PROT_FORM;
> + break;
> + case LEC_ACK_ERROR:
> + netdev_dbg(ndev, "Ack error\n");
> + ndev->stats.tx_errors++;
> + cf->data[3] = CAN_ERR_PROT_LOC_ACK;
> + break;
> + case LEC_BIT1_ERROR:
> + netdev_dbg(ndev, "Bit error (recessive)\n");
> + ndev->stats.tx_errors++;
> + cf->data[2] |= CAN_ERR_PROT_BIT1;
> + break;
> + case LEC_BIT0_ERROR:
> + netdev_dbg(ndev, "Bit error (dominant)\n");
> + ndev->stats.tx_errors++;
> + cf->data[2] |= CAN_ERR_PROT_BIT0;
> + break;
> + case LEC_CRC_ERROR:
> + netdev_dbg(ndev, "CRC error\n");
> + ndev->stats.rx_errors++;
> + cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
> + break;
> + default:
> + break;
> + }
> +
> + netif_rx(skb);
> +}
> +
> +static irqreturn_t bxcan_state_change_isr(int irq, void *dev_id)
> +{
> + struct net_device *ndev = dev_id;
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct bxcan_regs __iomem *regs = priv->regs;
> + u32 msr, esr;
> +
> + msr = readl(®s->msr);
> + if (!(msr & BXCAN_MSR_ERRI))
> + return IRQ_NONE;
> +
> + esr = readl(®s->esr);
> + bxcan_handle_state_change(ndev, esr);
> + bxcan_handle_bus_err(ndev, esr);
> +
> + msr |= BXCAN_MSR_ERRI;
> + writel(msr, ®s->msr);
nitpick: please add an empty line in front of return
> + return IRQ_HANDLED;
> +}
> +
> +static int bxcan_start(struct net_device *ndev)
please rename to bxcan_chip_start()
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct bxcan_regs __iomem *regs = priv->regs;
> + struct can_bittiming *bt = &priv->can.bittiming;
> + u32 set;
> + int err;
> +
> + err = bxcan_chip_softreset(priv);
> + if (err) {
> + netdev_err(ndev, "failed to reset chip, error %d\n", err);
> + return err;
> + }
> +
> + err = bxcan_leave_sleep_mode(priv);
> + if (err) {
> + netdev_err(ndev, "failed to leave sleep mode, error %d\n", err);
> + goto failed_leave_sleep;
> + }
> +
> + err = bxcan_enter_init_mode(priv);
> + if (err) {
> + netdev_err(ndev, "failed to enter init mode, error %d\n", err);
> + goto failed_enter_init;
> + }
> +
> + /* MCR
> + *
> + * select request order priority
> + * disable time triggered mode
> + * bus-off state left on sw request
> + * sleep mode left on sw request
> + * retransmit automatically on error
> + * do not lock RX FIFO on overrun
> + */
> + bxcan_rmw(®s->mcr, BXCAN_MCR_TTCM | BXCAN_MCR_ABOM | BXCAN_MCR_AWUM |
> + BXCAN_MCR_NART | BXCAN_MCR_RFLM, BXCAN_MCR_TXFP);
> +
> + /* Bit timing register settings */
> + set = BXCAN_BTR_BRP(bt->brp - 1) |
> + BXCAN_BTR_TS1(bt->phase_seg1 + bt->prop_seg - 1) |
> + BXCAN_BTR_TS2(bt->phase_seg2 - 1) | BXCAN_BTR_SJW(bt->sjw - 1);
> +
> + /* loopback + silent mode put the controller in test mode,
> + * useful for hot self-test
> + */
> + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
> + set |= BXCAN_BTR_LBKM;
> +
> + if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> + set |= BXCAN_BTR_SILM;
> +
> + netdev_dbg(ndev,
> + "TQ[ns]: %d, PrS: %d, PhS1: %d, PhS2: %d, SJW: %d, BRP: %d, CAN_BTR: 0x%08x\n",
> + bt->tq, bt->prop_seg, bt->phase_seg1, bt->phase_seg2,
> + bt->sjw, bt->brp, set);
> + bxcan_rmw(®s->btr, BXCAN_BTR_SILM | BXCAN_BTR_LBKM |
> + BXCAN_BTR_BRP_MASK | BXCAN_BTR_TS1_MASK | BXCAN_BTR_TS2_MASK |
> + BXCAN_BTR_SJW_MASK, set);
> +
> + bxcan_enable_filters(priv->dev->parent, priv->master);
> +
> + /* Clear all internal status */
> + priv->tx_head = 0;
> + priv->tx_tail = 0;
> +
> + err = bxcan_leave_init_mode(priv);
> + if (err) {
> + netdev_err(ndev, "failed to leave init mode, error %d\n", err);
> + goto failed_leave_init;
> + }
> +
> + /* Set a `lec` value so that we can check for updates later */
> + bxcan_rmw(®s->esr, BXCAN_ESR_LEC, LEC_UNUSED << BXCAN_ESR_LEC_SHIFT);
> +
> + /* IER
> + *
> + * Enable interrupt for:
> + * bus-off
> + * passive error
> + * warning error
> + * last error code
> + * RX FIFO pending message
> + * TX mailbox empty
> + */
> + bxcan_rmw(®s->ier, BXCAN_IER_WKUIE | BXCAN_IER_SLKIE |
> + BXCAN_IER_FOVIE1 | BXCAN_IER_FFIE1 | BXCAN_IER_FMPIE1 |
> + BXCAN_IER_FOVIE0 | BXCAN_IER_FFIE0,
> + BXCAN_IER_ERRIE | BXCAN_IER_LECIE | BXCAN_IER_BOFIE |
> + BXCAN_IER_EPVIE | BXCAN_IER_EWGIE | BXCAN_IER_FMPIE0 |
> + BXCAN_IER_TMEIE);
> +
> + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> + return 0;
> +
> +failed_leave_init:
> +failed_enter_init:
> +failed_leave_sleep:
> + bxcan_chip_softreset(priv);
> + return err;
> +}
> +
> +static int bxcan_open(struct net_device *ndev)
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + int err;
> +
> + err = open_candev(ndev);
> + if (err) {
> + netdev_err(ndev, "open_candev() failed, error %d\n", err);
> + goto failed_open;
> + }
> +
> + napi_enable(&priv->napi);
> + err = request_irq(ndev->irq, bxcan_rx_isr, IRQF_SHARED, ndev->name,
> + ndev);
> + if (err) {
> + netdev_err(ndev, "failed to register rx irq(%d), error %d\n",
> + ndev->irq, err);
> + goto failed_rx_irq_request;
> + }
> +
> + err = request_irq(priv->tx_irq, bxcan_tx_isr, IRQF_SHARED, ndev->name,
> + ndev);
> + if (err) {
> + netdev_err(ndev, "failed to register tx irq(%d), error %d\n",
> + priv->tx_irq, err);
> + goto failed_tx_irq_request;
> + }
> +
> + err = request_irq(priv->sce_irq, bxcan_state_change_isr, IRQF_SHARED,
> + ndev->name, ndev);
> + if (err) {
> + netdev_err(ndev, "failed to register sce irq(%d), error %d\n",
> + priv->sce_irq, err);
> + goto failed_sce_irq_request;
> + }
> +
> + err = bxcan_start(ndev);
> + if (err)
> + goto failed_start;
> +
> + netif_start_queue(ndev);
> + return 0;
> +
> +failed_start:
> +failed_sce_irq_request:
> + free_irq(priv->tx_irq, ndev);
> +failed_tx_irq_request:
> + free_irq(ndev->irq, ndev);
> +failed_rx_irq_request:
> + napi_disable(&priv->napi);
> + close_candev(ndev);
> +failed_open:
> + return err;
> +}
> +
> +static void bxcan_stop(struct net_device *ndev)
please rename to bxcan_chip_stop()
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> +
> + bxcan_disable_filters(priv->dev->parent, priv->master);
do you have to disable the IRQs?
> + bxcan_enter_sleep_mode(priv);
> + priv->can.state = CAN_STATE_STOPPED;
> +}
> +
> +static int bxcan_close(struct net_device *ndev)
and this bxcan_stop() to match the .ndo_stop.
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> +
> + netif_stop_queue(ndev);
> + bxcan_stop(ndev);
> + free_irq(ndev->irq, ndev);
> + free_irq(priv->tx_irq, ndev);
> + free_irq(priv->sce_irq, ndev);
> + napi_disable(&priv->napi);
> + close_candev(ndev);
> + return 0;
> +}
> +
> +static netdev_tx_t bxcan_start_xmit(struct sk_buff *skb,
> + struct net_device *ndev)
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct can_frame *cf = (struct can_frame *)skb->data;
> + struct bxcan_regs __iomem *regs = priv->regs;
> + struct bxcan_mb __iomem *mb_regs;
> + unsigned int idx;
> + u32 id;
> + int i, j;
> +
> + if (can_dropped_invalid_skb(ndev, skb))
> + return NETDEV_TX_OK;
> +
> + if (bxcan_tx_busy(priv))
> + return NETDEV_TX_BUSY;
> +
> + idx = bxcan_get_tx_head(priv);
> + priv->tx_head++;
> + if (bxcan_get_tx_free(priv) == 0)
> + netif_stop_queue(ndev);
> +
> + mb_regs = ®s->tx_mb[idx];
> + if (cf->can_id & CAN_EFF_FLAG)
> + id = BXCAN_TIxR_EXID(cf->can_id & CAN_EFF_MASK) |
> + BXCAN_TIxR_IDE;
> + else
> + id = BXCAN_TIxR_STID(cf->can_id & CAN_SFF_MASK);
> +
> + if (cf->can_id & CAN_RTR_FLAG)
> + id |= BXCAN_TIxR_RTR;
> +
> + bxcan_rmw(&mb_regs->dlc, BXCAN_TDTxR_DLC_MASK,
> + BXCAN_TDTxR_DLC(cf->len));
Is rmw needed here, or does a pure write work, too?
> + can_put_echo_skb(skb, ndev, idx, 0);
> +
> + for (i = 0, j = 0; i < cf->len; i += 4, j++)
> + writel(*(u32 *)(cf->data + i), &mb_regs->data[j]);
> +
> + /* Start transmission */
> + writel(id | BXCAN_TIxR_TXRQ, &mb_regs->id);
> +
> + return NETDEV_TX_OK;
> +}
> +
> +static const struct net_device_ops bxcan_netdev_ops = {
> + .ndo_open = bxcan_open,
> + .ndo_stop = bxcan_close,
> + .ndo_start_xmit = bxcan_start_xmit,
> + .ndo_change_mtu = can_change_mtu,
> +};
> +
> +static void bxcan_rx_pkt(struct net_device *ndev,
> + struct bxcan_mb __iomem *mb_regs)
> +{
> + struct net_device_stats *stats = &ndev->stats;
> + struct can_frame *cf;
> + struct sk_buff *skb;
> + u32 id, dlc;
> +
> + skb = alloc_can_skb(ndev, &cf);
> + if (!skb) {
> + stats->rx_dropped++;
> + return;
> + }
> +
> + id = readl(&mb_regs->id);
> + if (id & BXCAN_RIxR_IDE)
> + cf->can_id = (id >> BXCAN_RIxR_EXID_SHIFT) | CAN_EFF_FLAG;
> + else
> + cf->can_id = (id >> BXCAN_RIxR_STID_SHIFT) & CAN_SFF_MASK;
> +
> + dlc = readl(&mb_regs->dlc) & BXCAN_RDTxR_DLC;
> + cf->len = can_cc_dlc2len(dlc);
> +
> + if (id & BXCAN_RIxR_RTR) {
> + cf->can_id |= CAN_RTR_FLAG;
> + } else {
> + int i, j;
> +
> + for (i = 0, j = 0; i < cf->len; i += 4, j++)
> + *(u32 *)(cf->data + i) = readl(&mb_regs->data[j]);
> +
> + stats->rx_bytes += cf->len;
> + }
> +
> + stats->rx_packets++;
> + netif_receive_skb(skb);
> +}
> +
> +static int bxcan_rx_poll(struct napi_struct *napi, int quota)
> +{
> + struct net_device *ndev = napi->dev;
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct bxcan_regs __iomem *regs = priv->regs;
> + int num_pkts;
> + u32 rf0r;
> +
> + for (num_pkts = 0; num_pkts < quota; num_pkts++) {
> + rf0r = readl(®s->rf0r);
> + if (!(rf0r & BXCAN_RF0R_FMP0))
> + break;
> +
> + bxcan_rx_pkt(ndev, ®s->rx_mb[0]);
> +
> + rf0r |= BXCAN_RF0R_RFOM0;
> + writel(rf0r, ®s->rf0r);
> + }
> +
> + if (num_pkts < quota) {
> + napi_complete_done(napi, num_pkts);
> + bxcan_rmw(®s->ier, 0, BXCAN_IER_FMPIE0);
> + }
> +
> + return num_pkts;
> +}
> +
> +static int bxcan_do_set_mode(struct net_device *ndev, enum can_mode mode)
> +{
> + int err;
> +
> + switch (mode) {
> + case CAN_MODE_START:
> + err = bxcan_start(ndev);
> + if (err)
> + return err;
> +
> + netif_wake_queue(ndev);
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static int bxcan_disable_clks(struct bxcan_priv *priv)
> +{
> + if (priv->clk)
> + clk_disable_unprepare(priv->clk);
> +
> + bxcan_disable_master_clk(priv->dev->parent);
> + return 0;
> +}
> +
> +static int bxcan_enable_clks(struct bxcan_priv *priv)
> +{
> + int err;
> +
> + err = bxcan_enable_master_clk(priv->dev->parent);
> + if (err)
> + return err;
> +
> + if (priv->clk) {
> + err = clk_prepare_enable(priv->clk);
clk_prepare_enable() works on NULL pointer, too.
> + if (err)
> + bxcan_disable_master_clk(priv->dev->parent);
> + }
> +
> + return err;
> +}
> +
> +static int bxcan_get_berr_counter(const struct net_device *ndev,
> + struct can_berr_counter *bec)
> +{
> + struct bxcan_priv *priv = netdev_priv(ndev);
> + struct bxcan_regs __iomem *regs = priv->regs;
> + u32 esr;
> + int err;
> +
> + err = bxcan_enable_clks(priv);
> + if (err)
> + return err;
> +
> + esr = readl(®s->esr);
> + bec->txerr = BXCAN_TEC(esr);
> + bec->rxerr = BXCAN_REC(esr);
> + err = bxcan_disable_clks(priv);
> + return 0;
> +}
> +
> +static int bxcan_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct device *dev = &pdev->dev;
> + struct net_device *ndev;
> + struct bxcan_priv *priv;
> + struct clk *clk = NULL;
> + bool master;
> + u32 offset;
> + int err, rx_irq, tx_irq, sce_irq;
> +
> + master = of_property_read_bool(np, "st,can-master");
> + if (!master) {
> + clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(clk)) {
> + dev_err(dev, "failed to get clock\n");
> + return PTR_ERR(clk);
> + }
> + }
> +
> + rx_irq = platform_get_irq_byname(pdev, "rx0");
> + if (rx_irq < 0) {
> + dev_err(dev, "failed to get rx0 irq\n");
> + return rx_irq;
> + }
> +
> + tx_irq = platform_get_irq_byname(pdev, "tx");
> + if (tx_irq < 0) {
> + dev_err(dev, "failed to get tx irq\n");
> + return tx_irq;
> + }
> +
> + sce_irq = platform_get_irq_byname(pdev, "sce");
> + if (sce_irq < 0) {
> + dev_err(dev, "failed to get sce irq\n");
> + return sce_irq;
> + }
> +
> + err = of_property_read_u32(np, "reg", &offset);
> + if (err) {
> + dev_err(dev, "failed to get reg property\n");
> + return err;
> + }
> +
> + ndev = alloc_candev(sizeof(struct bxcan_priv), BXCAN_TX_MB_NUM);
> + if (!ndev) {
> + dev_err(dev, "alloc_candev() failed\n");
> + return -ENOMEM;
> + }
> +
> + priv = netdev_priv(ndev);
> + platform_set_drvdata(pdev, ndev);
> + SET_NETDEV_DEV(ndev, dev);
> + ndev->netdev_ops = &bxcan_netdev_ops;
> + ndev->irq = rx_irq;
> + ndev->flags |= IFF_ECHO;
> +
> + priv->dev = dev;
> + priv->ndev = ndev;
> + priv->regs = bxcan_get_base_addr(dev->parent) + offset;
> + priv->clk = clk;
> + priv->tx_irq = tx_irq;
> + priv->sce_irq = sce_irq;
> + priv->master = master;
> + priv->can.clock.freq =
> + master ? bxcan_get_master_clk_rate(dev->parent) :
> + clk_get_rate(clk);
> + priv->tx_head = 0;
> + priv->tx_tail = 0;
> + priv->can.bittiming_const = &bxcan_bittiming_const;
> + priv->can.do_set_mode = bxcan_do_set_mode;
> + priv->can.do_get_berr_counter = bxcan_get_berr_counter;
> + priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
> + CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING;
> + netif_napi_add(ndev, &priv->napi, bxcan_rx_poll, BXCAN_NAPI_WEIGHT);
> +
> + err = bxcan_enable_clks(priv);
> + if (err) {
> + dev_err(dev, "failed to enable clocks\n");
> + return err;
> + }
> +
> + err = register_candev(ndev);
> + if (err) {
> + dev_err(dev, "failed to register netdev\n");
> + goto failed_register;
> + }
> +
> + dev_info(dev, "clk: %d Hz, IRQs: %d, %d, %d\n", priv->can.clock.freq,
> + tx_irq, rx_irq, sce_irq);
> + return 0;
> +
> +failed_register:
> + netif_napi_del(&priv->napi);
> + free_candev(ndev);
> + return err;
> +}
> +
> +static int bxcan_remove(struct platform_device *pdev)
> +{
> + struct net_device *ndev = platform_get_drvdata(pdev);
> + struct bxcan_priv *priv = netdev_priv(ndev);
> +
> + unregister_candev(ndev);
> + bxcan_disable_clks(priv);
> + netif_napi_del(&priv->napi);
> + free_candev(ndev);
> + return 0;
> +}
> +
> +static int __maybe_unused bxcan_suspend(struct device *dev)
> +{
> + struct net_device *ndev = dev_get_drvdata(dev);
> + struct bxcan_priv *priv = netdev_priv(ndev);
> +
> + if (!netif_running(ndev))
> + return 0;
> +
> + netif_stop_queue(ndev);
> + netif_device_detach(ndev);
> +
> + bxcan_enter_sleep_mode(priv);
> + priv->can.state = CAN_STATE_SLEEPING;
> + bxcan_disable_clks(priv);
> + return 0;
> +}
> +
> +static int __maybe_unused bxcan_resume(struct device *dev)
> +{
> + struct net_device *ndev = dev_get_drvdata(dev);
> + struct bxcan_priv *priv = netdev_priv(ndev);
> +
> + if (!netif_running(ndev))
> + return 0;
> +
> + bxcan_enable_clks(priv);
> + bxcan_leave_sleep_mode(priv);
> + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> +
> + netif_device_attach(ndev);
> + netif_start_queue(ndev);
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(bxcan_pm_ops, bxcan_suspend, bxcan_resume);
> +
> +static const struct of_device_id bxcan_of_match[] = {
> + {.compatible = "st,stm32f4-bxcan"},
> + { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, bxcan_of_match);
> +
> +static struct platform_driver bxcan_driver = {
> + .driver = {
> + .name = KBUILD_MODNAME,
> + .pm = &bxcan_pm_ops,
> + .of_match_table = bxcan_of_match,
> + },
> + .probe = bxcan_probe,
> + .remove = bxcan_remove,
> +};
> +
> +module_platform_driver(bxcan_driver);
> +
> +MODULE_AUTHOR("Dario Binacchi <[email protected]>");
> +MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN controller driver");
> +MODULE_LICENSE("GPL");
> --
> 2.32.0
>
>
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
On Tue, Sep 6, 2022 at 12:40 PM Marc Kleine-Budde <[email protected]> wrote:
>
> On 28.08.2022 15:33:29, Dario Binacchi wrote:
> > Add support for the basic extended CAN controller (bxCAN) found in many
> > low- to middle-end STM32 SoCs. It supports the Basic Extended CAN
> > protocol versions 2.0A and B with a maximum bit rate of 1 Mbit/s.
> >
> > The controller supports two channels (CAN1 as master and CAN2 as slave)
> > and the driver can enable either or both of the channels. They share
> > some of the required logic (e. g. clocks and filters), and that means
> > you cannot use the slave CAN without enabling some hardware resources
> > managed by the master CAN.
>
> I don't like the concept of the core driver. E.g. the r-m-w of shared
> registers bxcan_enable_filters() is racy by design.
>
> How is the memory layout?
> - 0x000 - 0x1ff: CAN1
> - 0x200 - 0x3ff: shared mem
> - 0x400 - 0x5ff: CAN2
>
Yes, but shared mem can be accessed by CAN2 only if CAN1 is enabled.
For example, if only CAN2 is used, the clock of CAN1 must still be enabled.
> Better model the shared mem as a "syscon" node:
>
> | https://elixir.bootlin.com/linux/v6.0-rc4/source/drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c#L1445
>
> Then you can use regmap_*() functions to access the register space. The
> regmap functions are always locked against each other.
Ok, I will use "syscon".
The device tree description also raised more than one question for the
shared memory description
by the reviewers.
Following your suggestions I think the device tree will also be improved.
>
> [...]
>
> > diff --git a/drivers/net/can/bxcan/bxcan-core.c b/drivers/net/can/bxcan/bxcan-core.c
> > new file mode 100644
> > index 000000000000..3644449095e9
> > --- /dev/null
> > +++ b/drivers/net/can/bxcan/bxcan-core.c
> > @@ -0,0 +1,200 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* bxcan-core.c - STM32 Basic Extended CAN core controller driver
> > + *
> > + * This file is part of STM32 bxcan driver
> > + *
> > + * Copyright (c) 2022 Dario Binacchi <[email protected]>
> > + */
> > +
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > +#include <linux/clk.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +
> > +#include "bxcan-core.h"
> > +
> > +#define BXCAN_FILTER_ID(master) (master ? 0 : 14)
> > +
> > +/* Filter master register (FMR) bits */
> > +#define BXCAN_FMR_CANSB_MASK GENMASK(13, 8)
> > +#define BXCAN_FMR_CANSB(x) (((x) & 0x3f) << 8)
> > +#define BXCAN_FMR_FINIT BIT(0)
>
> nitpick:
> please use 1 space instead of tabs
>
> > +
> > +/* Structure of the filter bank */
> > +struct bxcan_fb {
> > + u32 fr1; /* filter 1 */
> > + u32 fr2; /* filter 2 */
> > +};
> > +
> > +/* Structure of the hardware filter registers */
> > +struct bxcan_fregs {
> > + u32 fmr; /* 0x00 - filter master */
> > + u32 fm1r; /* 0x04 - filter mode */
> > + u32 reserved2; /* 0x08 */
> > + u32 fs1r; /* 0x0c - filter scale */
> > + u32 reserved3; /* 0x10 */
> > + u32 ffa1r; /* 0x14 - filter FIFO assignment */
> > + u32 reserved4; /* 0x18 */
> > + u32 fa1r; /* 0x1c - filter activation */
> > + u32 reserved5[8]; /* 0x20 */
> > + struct bxcan_fb fb[28]; /* 0x40 - filter banks */
> > +};
> > +
> > +struct bxcan_core_priv {
> > + void __iomem *base;
> > + struct bxcan_fregs __iomem *fregs;
> > + struct clk *clk_master;
> > + unsigned int clk_master_ref;
> > +};
> > +
> > +void bxcan_disable_filters(struct device *dev, bool master)
> > +{
> > + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> > + unsigned int fid = BXCAN_FILTER_ID(master);
> > + u32 fmask = BIT(fid);
> > +
> > + bxcan_rmw(&priv->fregs->fa1r, fmask, 0);
>
> This is racy, same for bxcan_rmw() on other shared registers.
>
> > +}
> > +
> > +void bxcan_enable_filters(struct device *dev, bool master)
> > +{
> > + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> > + unsigned int fid = BXCAN_FILTER_ID(master);
> > + u32 fmask = BIT(fid);
> > +
> > + /* Filter settings:
> > + *
> > + * Accept all messages.
> > + * Assign filter 0 to CAN1 and filter 14 to CAN2 in identifier
> > + * mask mode with 32 bits width.
> > + */
> > +
> > + /* Enter filter initialization mode and assing filters to CAN
> > + * controllers.
> > + */
> > + bxcan_rmw(&priv->fregs->fmr, BXCAN_FMR_CANSB_MASK,
> > + BXCAN_FMR_CANSB(14) | BXCAN_FMR_FINIT);
> > +
> > + /* Deactivate filter */
> > + bxcan_rmw(&priv->fregs->fa1r, fmask, 0);
> > +
> > + /* Two 32-bit registers in identifier mask mode */
> > + bxcan_rmw(&priv->fregs->fm1r, fmask, 0);
> > +
> > + /* Single 32-bit scale configuration */
> > + bxcan_rmw(&priv->fregs->fs1r, 0, fmask);
> > +
> > + /* Assign filter to FIFO 0 */
> > + bxcan_rmw(&priv->fregs->ffa1r, fmask, 0);
> > +
> > + /* Accept all messages */
> > + writel(0, &priv->fregs->fb[fid].fr1);
> > + writel(0, &priv->fregs->fb[fid].fr2);
> > +
> > + /* Activate filter */
> > + bxcan_rmw(&priv->fregs->fa1r, 0, fmask);
> > +
> > + /* Exit filter initialization mode */
> > + bxcan_rmw(&priv->fregs->fmr, BXCAN_FMR_FINIT, 0);
> > +}
> > +
> > +int bxcan_enable_master_clk(struct device *dev)
> > +{
> > + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> > + int err;
> > +
> > + if (priv->clk_master_ref == 0) {
> > + err = clk_prepare_enable(priv->clk_master);
> > + if (err)
> > + return err;
> > + }
> > +
> > + priv->clk_master_ref++;
>
> In general, don't do clock ref-counting. You can enable and disable the
> same clock several times.
I had used ref-counting to avoid disabling the clock of CAN1 with CAN2 enabled
and thus losing access to the shared memory.
>
> If you convert to syscon, you can add a clock node to the syscon node
> and the syscon driver will take care of the clocks.
I hope that syscon will allow me to guarantee the enabling of the CAN1
clock if CAN1 is disabled
and CAN2 enabled.
>
> > + return 0;
> > +}
> > +
> > +void bxcan_disable_master_clk(struct device *dev)
> > +{
> > + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> > +
> > + if (priv->clk_master_ref == 0)
> > + return;
> > +
> > + if (priv->clk_master_ref == 1)
> > + clk_disable_unprepare(priv->clk_master);
> > +
> > + priv->clk_master_ref--;
> > +}
> > +
> > +unsigned long bxcan_get_master_clk_rate(struct device *dev)
> > +{
> > + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> > +
> > + return clk_get_rate(priv->clk_master);
> > +}
> > +
> > +void __iomem *bxcan_get_base_addr(struct device *dev)
> > +{
> > + struct bxcan_core_priv *priv = dev_get_drvdata(dev);
> > +
> > + return priv->base;
> > +}
> > +
> > +static const struct of_device_id bxcan_core_of_match[] = {
> > + {.compatible = "st,stm32f4-bxcan-core"},
> > + { /* sentinel */ },
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, bxcan_core_of_match);
> > +
> > +static int bxcan_core_probe(struct platform_device *pdev)
> > +{
> > + struct bxcan_core_priv *priv;
> > + struct device *dev = &pdev->dev;
> > + struct device_node *np = pdev->dev.of_node;
> > + void __iomem *regs;
> > + struct clk *clk;
> > + int ret;
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + platform_set_drvdata(pdev, priv);
> > + regs = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(regs))
> > + return PTR_ERR(regs);
> > +
> > + clk = devm_clk_get(&pdev->dev, NULL);
> > + if (IS_ERR(clk)) {
> > + dev_err(dev, "failed to get clock\n");
> > + return PTR_ERR(clk);
> > + }
> > +
> > + priv->base = regs;
> > + priv->fregs = regs + 0x200;
> > + priv->clk_master = clk;
> > +
> > + ret = of_platform_populate(np, NULL, NULL, dev);
> > + if (ret < 0) {
> > + dev_err(dev, "failed to populate DT children\n");
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver bxcan_core_driver = {
> > + .driver = {
> > + .name = KBUILD_MODNAME,
> > + .of_match_table = bxcan_core_of_match,
> > + },
> > + .probe = bxcan_core_probe,
> > +};
> > +
> > +module_platform_driver(bxcan_core_driver);
> > +
> > +MODULE_AUTHOR("Dario Binacchi <[email protected]>");
> > +MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN core driver");
> > +MODULE_LICENSE("GPL");
> > diff --git a/drivers/net/can/bxcan/bxcan-core.h b/drivers/net/can/bxcan/bxcan-core.h
> > new file mode 100644
> > index 000000000000..925449cbc3bd
> > --- /dev/null
> > +++ b/drivers/net/can/bxcan/bxcan-core.h
> > @@ -0,0 +1,31 @@
> > +/* SPDX-License-Identifier: GPL-2.0
> > + *
> > + * bxcan-core - STM32 Basic Extended CAN core controller driver
> > + *
> > + * Copyright (c) 2022 Dario Binacchi <[email protected]>
> > + */
> > +
> > +#ifndef __BXCAN_CORE_H
> > +#define __BXCAN_CORE_H
> > +
> > +#include <linux/clk.h>
> > +#include <linux/io.h>
> > +
> > +int bxcan_enable_master_clk(struct device *dev);
> > +void bxcan_disable_master_clk(struct device *dev);
> > +unsigned long bxcan_get_master_clk_rate(struct device *dev);
> > +void __iomem *bxcan_get_base_addr(struct device *dev);
> > +void bxcan_enable_filters(struct device *dev, bool master);
> > +void bxcan_disable_filters(struct device *dev, bool master);
> > +
> > +static inline void bxcan_rmw(void __iomem *addr, u32 clear, u32 set)
> > +{
> > + u32 old, val;
> > +
> > + old = readl(addr);
> > + val = (old & ~clear) | set;
> > + if (val != old)
> > + writel(val, addr);
> > +}
> > +
> > +#endif
> > diff --git a/drivers/net/can/bxcan/bxcan-drv.c b/drivers/net/can/bxcan/bxcan-drv.c
> > new file mode 100644
> > index 000000000000..7ac1ee7a4269
> > --- /dev/null
> > +++ b/drivers/net/can/bxcan/bxcan-drv.c
> > @@ -0,0 +1,1045 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +//
> > +// bxcan-drv.c - STM32 Basic Extended CAN controller driver
> > +//
> > +// Copyright (c) 2022 Dario Binacchi <[email protected]>
> > +//
> > +
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/can.h>
> > +#include <linux/can/dev.h>
> > +#include <linux/can/error.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include "bxcan-core.h"
> > +
> > +#define BXCAN_NAPI_WEIGHT 3
> > +#define BXCAN_TIMEOUT_US 10000
> > +
> > +#define BXCAN_TX_MB_NUM 3
> > +
> > +/* Master control register (MCR) bits */
> > +#define BXCAN_MCR_DBF BIT(16)
> > +#define BXCAN_MCR_RESET BIT(15)
> > +#define BXCAN_MCR_TTCM BIT(7)
> > +#define BXCAN_MCR_ABOM BIT(6)
> > +#define BXCAN_MCR_AWUM BIT(5)
> > +#define BXCAN_MCR_NART BIT(4)
> > +#define BXCAN_MCR_RFLM BIT(3)
> > +#define BXCAN_MCR_TXFP BIT(2)
> > +#define BXCAN_MCR_SLEEP BIT(1)
> > +#define BXCAN_MCR_INRQ BIT(0)
> > +
> > +/* Master status register (MSR) bits */
> > +#define BXCAN_MSR_RX BIT(11)
> > +#define BXCAN_MSR_SAMP BIT(10)
> > +#define BXCAN_MSR_RXM BIT(9)
> > +#define BXCAN_MSR_TXM BIT(8)
> > +#define BXCAN_MSR_SLAKI BIT(4)
> > +#define BXCAN_MSR_WKUI BIT(3)
> > +#define BXCAN_MSR_ERRI BIT(2)
> > +#define BXCAN_MSR_SLAK BIT(1)
> > +#define BXCAN_MSR_INAK BIT(0)
> > +
> > +/* Transmit status register (TSR) bits */
> > +#define BXCAN_TSR_LOW2 BIT(31)
> > +#define BXCAN_TSR_LOW1 BIT(30)
> > +#define BXCAN_TSR_LOW0 BIT(29)
> > +#define BXCAN_TSR_TME GENMASK(28, 26)
> > +#define BXCAN_TSR_TME_SHIFT (26)
>
> unused
>
> > +#define BXCAN_TSR_TME2 BIT(28)
> > +#define BXCAN_TSR_TME1 BIT(27)
> > +#define BXCAN_TSR_TME0 BIT(26)
> > +#define BXCAN_TSR_CODE GENMASK(25, 24)
> > +#define BXCAN_TSR_ABRQ2 BIT(23)
> > +#define BXCAN_TSR_TERR2 BIT(19)
> > +#define BXCAN_TSR_ALST2 BIT(18)
> > +#define BXCAN_TSR_TXOK2 BIT(17)
> > +#define BXCAN_TSR_RQCP2 BIT(16)
> > +#define BXCAN_TSR_ABRQ1 BIT(15)
> > +#define BXCAN_TSR_TERR1 BIT(11)
> > +#define BXCAN_TSR_ALST1 BIT(10)
> > +#define BXCAN_TSR_TXOK1 BIT(9)
> > +#define BXCAN_TSR_RQCP1 BIT(8)
> > +#define BXCAN_TSR_ABRQ0 BIT(7)
> > +#define BXCAN_TSR_TERR0 BIT(3)
> > +#define BXCAN_TSR_ALST0 BIT(2)
> > +#define BXCAN_TSR_TXOK0 BIT(1)
> > +#define BXCAN_TSR_RQCP0 BIT(0)
> > +
> > +/* Receive FIFO 0 register (RF0R) bits */
> > +#define BXCAN_RF0R_RFOM0 BIT(5)
> > +#define BXCAN_RF0R_FOVR0 BIT(4)
> > +#define BXCAN_RF0R_FULL0 BIT(3)
> > +#define BXCAN_RF0R_FMP0 GENMASK(1, 0)
> > +
> > +/* Interrupt enable register (IER) bits */
> > +#define BXCAN_IER_SLKIE BIT(17)
> > +#define BXCAN_IER_WKUIE BIT(16)
> > +#define BXCAN_IER_ERRIE BIT(15)
> > +#define BXCAN_IER_LECIE BIT(11)
> > +#define BXCAN_IER_BOFIE BIT(10)
> > +#define BXCAN_IER_EPVIE BIT(9)
> > +#define BXCAN_IER_EWGIE BIT(8)
> > +#define BXCAN_IER_FOVIE1 BIT(6)
> > +#define BXCAN_IER_FFIE1 BIT(5)
> > +#define BXCAN_IER_FMPIE1 BIT(4)
> > +#define BXCAN_IER_FOVIE0 BIT(3)
> > +#define BXCAN_IER_FFIE0 BIT(2)
> > +#define BXCAN_IER_FMPIE0 BIT(1)
> > +#define BXCAN_IER_TMEIE BIT(0)
> > +
> > +/* Error status register (ESR) bits */
> > +#define BXCAN_ESR_REC_SHIFT (24)
> > +#define BXCAN_ESR_REC GENMASK(31, 24)
> > +#define BXCAN_ESR_TEC_SHIFT (16)
> > +#define BXCAN_ESR_TEC GENMASK(23, 16)
> > +#define BXCAN_ESR_LEC_SHIFT (4)
>
> please remove the _SHIFT macros, no need for them...
>
> > +#define BXCAN_ESR_LEC GENMASK(6, 4)
> > +#define BXCAN_ESR_BOFF BIT(1)
> > +#define BXCAN_ESR_EPVF BIT(1)
> > +#define BXCAN_ESR_EWGF BIT(0)
> > +#define BXCAN_TEC(esr) (((esr) & BXCAN_ESR_TEC) >> \
> > + BXCAN_ESR_TEC_SHIFT)
> > +#define BXCAN_REC(esr) (((esr) & BXCAN_ESR_REC) >> \
> > + BXCAN_ESR_REC_SHIFT)
>
> ... remove these and use FIELD_GET() directly.
ok, definitely better
>
> > +
> > +/* Bit timing register (BTR) bits */
> > +#define BXCAN_BTR_SILM BIT(31)
> > +#define BXCAN_BTR_LBKM BIT(30)
> > +#define BXCAN_BTR_SJW_MASK GENMASK(25, 24)
> > +#define BXCAN_BTR_SJW(x) (((x) & 0x03) << 24)
> > +#define BXCAN_BTR_TS2_MASK GENMASK(22, 20)
> > +#define BXCAN_BTR_TS2(x) (((x) & 0x07) << 20)
> > +#define BXCAN_BTR_TS1_MASK GENMASK(19, 16)
> > +#define BXCAN_BTR_TS1(x) (((x) & 0x0f) << 16)
> > +#define BXCAN_BTR_BRP_MASK GENMASK(9, 0)
> > +#define BXCAN_BTR_BRP(x) ((x) & 0x3ff)
>
> same for these
>
> > +
> > +/* TX mailbox identifier register (TIxR, x = 0..2) bits */
> > +#define BXCAN_TIxR_STID(x) (((x) & 0x7ff) << 21)
> > +#define BXCAN_TIxR_EXID(x) ((x) << 3)
>
> same here
>
> > +#define BXCAN_TIxR_IDE BIT(2)
> > +#define BXCAN_TIxR_RTR BIT(1)
> > +#define BXCAN_TIxR_TXRQ BIT(0)
> > +
> > +/* TX mailbox data length and time stamp register (TDTxR, x = 0..2 bits */
> > +#define BXCAN_TDTxR_TIME(x) (((x) & 0x0f) << 16)
>
> same
>
> > +#define BXCAN_TDTxR_TGT BIT(8)
> > +#define BXCAN_TDTxR_DLC_MASK GENMASK(3, 0)
> > +#define BXCAN_TDTxR_DLC(x) ((x) & 0x0f)
>
> same
>
> > +
> > +/* RX FIFO mailbox identifier register (RIxR, x = 0..1 */
> > +#define BXCAN_RIxR_STID_SHIFT (21)
> > +#define BXCAN_RIxR_EXID_SHIFT (3)
> > +#define BXCAN_RIxR_IDE BIT(2)
> > +#define BXCAN_RIxR_RTR BIT(1)
> > +
> > +/* RX FIFO mailbox data length and timestamp register (RDTxR, x = 0..1) bits */
> > +#define BXCAN_RDTxR_TIME GENMASK(31, 16)
> > +#define BXCAN_RDTxR_FMI GENMASK(15, 8)
> > +#define BXCAN_RDTxR_DLC GENMASK(3, 0)
> > +
> > +enum bxcan_lec_code {
> > + LEC_NO_ERROR = 0,
> > + LEC_STUFF_ERROR,
> > + LEC_FORM_ERROR,
> > + LEC_ACK_ERROR,
> > + LEC_BIT1_ERROR,
> > + LEC_BIT0_ERROR,
> > + LEC_CRC_ERROR,
> > + LEC_UNUSED
>
> Please add BXCAN_ as prefix
>
> > +};
> > +
> > +/* Structure of the message buffer */
> > +struct bxcan_mb {
> > + u32 id; /* can identifier */
> > + u32 dlc; /* data length control and timestamp */
> > + u32 data[2]; /* data */
> > +};
> > +
> > +/* Structure of the hardware registers */
> > +struct bxcan_regs {
> > + u32 mcr; /* 0x00 - master control */
> > + u32 msr; /* 0x04 - master status */
> > + u32 tsr; /* 0x08 - transmit status */
> > + u32 rf0r; /* 0x0c - FIFO 0 */
> > + u32 rf1r; /* 0x10 - FIFO 1 */
> > + u32 ier; /* 0x14 - interrupt enable */
> > + u32 esr; /* 0x18 - error status */
> > + u32 btr; /* 0x1c - bit timing*/
> > + u32 reserved0[88]; /* 0x20 */
> > + struct bxcan_mb tx_mb[BXCAN_TX_MB_NUM]; /* 0x180 - tx mailbox */
> > + struct bxcan_mb rx_mb[2]; /* 0x1b0 - rx mailbox */
>
> Please add a define for the "2", as well.
>
> > +};
> > +
> > +struct bxcan_priv {
> > + struct can_priv can;
> > + struct device *dev;
> > + struct net_device *ndev;
> > + struct napi_struct napi;
>
> consider using can_rx_offload().
>
> The idea is to read from the mailbox in the IRQ handler and push the
> frame into the networking stack in the napi.
Ok, thanks for the suggestion and the explanation. I will use it.
>
> > +
> > + struct bxcan_regs __iomem *regs;
> > + int tx_irq;
> > + int sce_irq;
> > + u8 tx_dlc[BXCAN_TX_MB_NUM];
>
> unused
>
> > + bool master;
> > + struct clk *clk;
> > + unsigned int tx_head;
> > + unsigned int tx_tail;
> > +};
> > +
> > +static const struct can_bittiming_const bxcan_bittiming_const = {
> > + .name = KBUILD_MODNAME,
> > + .tseg1_min = 1,
> > + .tseg1_max = 16,
> > + .tseg2_min = 1,
> > + .tseg2_max = 8,
> > + .sjw_max = 4,
> > + .brp_min = 1,
> > + .brp_max = 1024,
> > + .brp_inc = 1,
> > +};
> > +
> > +static inline u8 bxcan_get_tx_head(const struct bxcan_priv *priv)
> > +{
> > + return priv->tx_head % BXCAN_TX_MB_NUM;
> > +}
> > +
> > +static inline u8 bxcan_get_tx_tail(const struct bxcan_priv *priv)
> > +{
> > + return priv->tx_tail % BXCAN_TX_MB_NUM;
> > +}
> > +
> > +static inline u8 bxcan_get_tx_free(const struct bxcan_priv *priv)
> > +{
> > + return BXCAN_TX_MB_NUM - (priv->tx_head - priv->tx_tail);
> > +}
> > +
> > +static bool bxcan_tx_busy(const struct bxcan_priv *priv)
> > +{
> > + if (bxcan_get_tx_free(priv) > 0)
> > + return false;
> > +
> > + netif_stop_queue(priv->ndev);
> > +
> > + /* Memory barrier before checking tx_free (head and tail) */
> > + smp_mb();
> > +
> > + if (bxcan_get_tx_free(priv) == 0) {
> > + netdev_dbg(priv->ndev,
> > + "Stopping tx-queue (tx_head=0x%08x, tx_tail=0x%08x, len=%d).\n",
> > + priv->tx_head, priv->tx_tail,
> > + priv->tx_head - priv->tx_tail);
> > +
> > + return true;
> > + }
> > +
> > + netif_start_queue(priv->ndev);
> > +
> > + return false;
> > +}
> > +
> > +static int bxcan_chip_softreset(struct bxcan_priv *priv)
> > +{
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> > +
> > + bxcan_rmw(®s->mcr, 0, BXCAN_MCR_RESET);
> > + while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_SLAK))
> > + udelay(10);
>
> make use of readx_poll_timeout(), see:
>
> | https://elixir.bootlin.com/linux/v6.0-rc4/source/drivers/net/can/spi/mcp251x.c#L410
definitely better
> > +
> > + if (!(readl(®s->msr) & BXCAN_MSR_SLAK))
> > + return -ETIMEDOUT;
> > +
> > + return 0;
> > +}
> > +
> > +static int bxcan_enter_init_mode(struct bxcan_priv *priv)
> > +{
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> > +
> > + bxcan_rmw(®s->mcr, 0, BXCAN_MCR_INRQ);
> > + while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_INAK))
> > + udelay(100);
>
> same here
>
> > +
> > + if (!(readl(®s->msr) & BXCAN_MSR_INAK))
> > + return -ETIMEDOUT;
> > +
> > + return 0;
> > +}
> > +
> > +static int bxcan_leave_init_mode(struct bxcan_priv *priv)
> > +{
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> > +
> > + bxcan_rmw(®s->mcr, BXCAN_MCR_INRQ, 0);
> > + while (timeout-- && (readl(®s->msr) & BXCAN_MSR_INAK))
> > + udelay(100);
>
> same
>
> > +
> > + if (readl(®s->msr) & BXCAN_MSR_INAK)
> > + return -ETIMEDOUT;
> > +
> > + return 0;
> > +}
> > +
> > +static int bxcan_leave_sleep_mode(struct bxcan_priv *priv)
> > +{
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> > +
> > + bxcan_rmw(®s->mcr, BXCAN_MCR_SLEEP, 0);
> > + while (timeout-- && (readl(®s->msr) & BXCAN_MSR_SLAK))
> > + udelay(100);
>
> same
>
> > +
> > + if (readl(®s->msr) & BXCAN_MSR_SLAK)
> > + return -ETIMEDOUT;
> > +
> > + return 0;
> > +}
> > +
> > +static int bxcan_enter_sleep_mode(struct bxcan_priv *priv)
> > +{
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + unsigned int timeout = BXCAN_TIMEOUT_US / 10;
> > +
> > + bxcan_rmw(®s->mcr, 0, BXCAN_MCR_SLEEP);
> > + while (timeout-- && !(readl(®s->msr) & BXCAN_MSR_SLAK))
> > + udelay(100);
>
> same
>
> > +
> > + if (!(readl(®s->msr) & BXCAN_MSR_SLAK))
> > + return -ETIMEDOUT;
> > +
> > + return 0;
> > +}
> > +
> > +static irqreturn_t bxcan_rx_isr(int irq, void *dev_id)
> > +{
> > + struct net_device *ndev = dev_id;
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > +
> > + if (napi_schedule_prep(&priv->napi)) {
> > + /* Disable Rx FIFO message pending interrupt */
> > + bxcan_rmw(®s->ier, BXCAN_IER_FMPIE0, 0);
> > + __napi_schedule(&priv->napi);
> > + }
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static irqreturn_t bxcan_tx_isr(int irq, void *dev_id)
> > +{
> > + struct net_device *ndev = dev_id;
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + struct net_device_stats *stats = &ndev->stats;
> > + u32 tsr, rqcp_bit, bytes = 0, pkts = 0;
> > + int n, idx;
> > +
> > + tsr = readl(®s->tsr);
> > + for (n = 0, idx = bxcan_get_tx_tail(priv); n < BXCAN_TX_MB_NUM; n++) {
>
> loop from tail to head:
>
> | while (priv->tx_head - priv->tx_tail > 0) {
> | ...
> | idx = bxcan_get_tx_tail()
> | ...
>
Ok, thanks
>
> > + rqcp_bit = BXCAN_TSR_RQCP0 << (idx << 3);
> > + if (tsr & rqcp_bit) {
> > + pkts++;
> > + bytes += can_get_echo_skb(ndev, idx, NULL);
> > + }
> > +
> > + idx += 1;
> > + if (idx == BXCAN_TX_MB_NUM)
> > + idx = 0;
> > + }
> > +
> > + if (!pkts)
> > + return IRQ_HANDLED;
>
> This looks wrong. Better check if any relevant bits in tsr are set, if
> not return IRQ_NONE.
Ok
>
> > +
> > + writel(tsr, ®s->tsr);
> > +
> > + priv->tx_tail += pkts;
> > + if (bxcan_get_tx_free(priv)) {
> > + /* Make sure that anybody stopping the queue after
> > + * this sees the new tx_ring->tail.
> > + */
> > + smp_mb();
> > + netif_wake_queue(ndev);
> > + }
> > +
> > + stats->tx_bytes += bytes;
> > + stats->tx_packets += pkts;
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static void bxcan_handle_state_change(struct net_device *ndev, u32 esr)
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct net_device_stats *stats = &ndev->stats;
> > + enum can_state new_state = priv->can.state;
> > + struct can_berr_counter bec;
> > + enum can_state rx_state, tx_state;
> > + struct sk_buff *skb;
> > + struct can_frame *cf;
> > +
> > + /* Early exit if no error flag is set */
> > + if (!(esr & (BXCAN_ESR_EWGF | BXCAN_ESR_EPVF | BXCAN_ESR_BOFF)))
> > + return;
> > +
> > + bec.txerr = BXCAN_TEC(esr);
> > + bec.rxerr = BXCAN_REC(esr);
> > +
> > + if (esr & BXCAN_ESR_BOFF)
> > + new_state = CAN_STATE_BUS_OFF;
> > + else if (esr & BXCAN_ESR_EPVF)
> > + new_state = CAN_STATE_ERROR_PASSIVE;
> > + else if (esr & BXCAN_ESR_EWGF)
> > + new_state = CAN_STATE_ERROR_WARNING;
> > +
> > + /* state hasn't changed */
> > + if (unlikely(new_state == priv->can.state))
> > + return;
> > +
> > + skb = alloc_can_err_skb(ndev, &cf);
> > + if (unlikely(!skb))
> > + return;
>
> Continue, even if you got no skb.
>
> > +
> > + tx_state = bec.txerr >= bec.rxerr ? new_state : 0;
> > + rx_state = bec.txerr <= bec.rxerr ? new_state : 0;
> > + can_change_state(ndev, cf, tx_state, rx_state);
>
> can_change_state() handles cf == NULL....
>
> > +
> > + if (new_state == CAN_STATE_BUS_OFF)
> > + can_bus_off(ndev);
> > +
> > + stats->rx_bytes += cf->len;
> > + stats->rx_packets++;
>
> no statistics for error frames.
>
> > + netif_rx(skb);
> > +}
> > +
> > +static void bxcan_handle_bus_err(struct net_device *ndev, u32 esr)
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + enum bxcan_lec_code lec_code;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > +
> > + lec_code = (esr & BXCAN_ESR_LEC_SHIFT) >> BXCAN_ESR_LEC_SHIFT;
>
> Use FIELD_GET()
>
> > +
> > + /* Early exit if no lec update or no error.
> > + * No lec update means that no CAN bus event has been detected
> > + * since CPU wrote LEC_UNUSED value to status reg.
> > + */
> > + if (lec_code == LEC_UNUSED || lec_code == LEC_NO_ERROR)
> > + return;
> > +
> > + if (!(priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
> > + return;
>
> Can you disable the generation of the bus error interrupt?
I thought to make the setting of the BXCAN_IER_LECIE bit in the ier register
depend on CAN_CTRLMODE_BERR_REPORTING.
What do you think?
>
> > +
> > + /* Common for all type of bus errors */
> > + priv->can.can_stats.bus_error++;
> > +
> > + /* Propagate the error condition to the CAN stack */
> > + skb = alloc_can_err_skb(ndev, &cf);
> > + if (unlikely(!skb))
> > + return;
>
> continue, even without skb
>
> > +
> > + ndev->stats.rx_bytes += cf->len;
>
> no stats
>
> > +
> > + /* Check for 'last error code' which tells us the
> > + * type of the last error to occur on the CAN bus
> > + */
> > + cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> > +
> > + switch (lec_code) {
> > + case LEC_STUFF_ERROR:
> > + netdev_dbg(ndev, "Stuff error\n");
> > + ndev->stats.rx_errors++;
> > + cf->data[2] |= CAN_ERR_PROT_STUFF;
> > + break;
> > + case LEC_FORM_ERROR:
> > + netdev_dbg(ndev, "Form error\n");
> > + ndev->stats.rx_errors++;
> > + cf->data[2] |= CAN_ERR_PROT_FORM;
> > + break;
> > + case LEC_ACK_ERROR:
> > + netdev_dbg(ndev, "Ack error\n");
> > + ndev->stats.tx_errors++;
> > + cf->data[3] = CAN_ERR_PROT_LOC_ACK;
> > + break;
> > + case LEC_BIT1_ERROR:
> > + netdev_dbg(ndev, "Bit error (recessive)\n");
> > + ndev->stats.tx_errors++;
> > + cf->data[2] |= CAN_ERR_PROT_BIT1;
> > + break;
> > + case LEC_BIT0_ERROR:
> > + netdev_dbg(ndev, "Bit error (dominant)\n");
> > + ndev->stats.tx_errors++;
> > + cf->data[2] |= CAN_ERR_PROT_BIT0;
> > + break;
> > + case LEC_CRC_ERROR:
> > + netdev_dbg(ndev, "CRC error\n");
> > + ndev->stats.rx_errors++;
> > + cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
> > + break;
> > + default:
> > + break;
> > + }
> > +
> > + netif_rx(skb);
> > +}
> > +
> > +static irqreturn_t bxcan_state_change_isr(int irq, void *dev_id)
> > +{
> > + struct net_device *ndev = dev_id;
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + u32 msr, esr;
> > +
> > + msr = readl(®s->msr);
> > + if (!(msr & BXCAN_MSR_ERRI))
> > + return IRQ_NONE;
> > +
> > + esr = readl(®s->esr);
> > + bxcan_handle_state_change(ndev, esr);
> > + bxcan_handle_bus_err(ndev, esr);
> > +
> > + msr |= BXCAN_MSR_ERRI;
> > + writel(msr, ®s->msr);
>
> nitpick: please add an empty line in front of return
>
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int bxcan_start(struct net_device *ndev)
>
> please rename to bxcan_chip_start()
>
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + struct can_bittiming *bt = &priv->can.bittiming;
> > + u32 set;
> > + int err;
> > +
> > + err = bxcan_chip_softreset(priv);
> > + if (err) {
> > + netdev_err(ndev, "failed to reset chip, error %d\n", err);
> > + return err;
> > + }
> > +
> > + err = bxcan_leave_sleep_mode(priv);
> > + if (err) {
> > + netdev_err(ndev, "failed to leave sleep mode, error %d\n", err);
> > + goto failed_leave_sleep;
> > + }
> > +
> > + err = bxcan_enter_init_mode(priv);
> > + if (err) {
> > + netdev_err(ndev, "failed to enter init mode, error %d\n", err);
> > + goto failed_enter_init;
> > + }
> > +
> > + /* MCR
> > + *
> > + * select request order priority
> > + * disable time triggered mode
> > + * bus-off state left on sw request
> > + * sleep mode left on sw request
> > + * retransmit automatically on error
> > + * do not lock RX FIFO on overrun
> > + */
> > + bxcan_rmw(®s->mcr, BXCAN_MCR_TTCM | BXCAN_MCR_ABOM | BXCAN_MCR_AWUM |
> > + BXCAN_MCR_NART | BXCAN_MCR_RFLM, BXCAN_MCR_TXFP);
> > +
> > + /* Bit timing register settings */
> > + set = BXCAN_BTR_BRP(bt->brp - 1) |
> > + BXCAN_BTR_TS1(bt->phase_seg1 + bt->prop_seg - 1) |
> > + BXCAN_BTR_TS2(bt->phase_seg2 - 1) | BXCAN_BTR_SJW(bt->sjw - 1);
> > +
> > + /* loopback + silent mode put the controller in test mode,
> > + * useful for hot self-test
> > + */
> > + if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
> > + set |= BXCAN_BTR_LBKM;
> > +
> > + if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
> > + set |= BXCAN_BTR_SILM;
> > +
> > + netdev_dbg(ndev,
> > + "TQ[ns]: %d, PrS: %d, PhS1: %d, PhS2: %d, SJW: %d, BRP: %d, CAN_BTR: 0x%08x\n",
> > + bt->tq, bt->prop_seg, bt->phase_seg1, bt->phase_seg2,
> > + bt->sjw, bt->brp, set);
> > + bxcan_rmw(®s->btr, BXCAN_BTR_SILM | BXCAN_BTR_LBKM |
> > + BXCAN_BTR_BRP_MASK | BXCAN_BTR_TS1_MASK | BXCAN_BTR_TS2_MASK |
> > + BXCAN_BTR_SJW_MASK, set);
> > +
> > + bxcan_enable_filters(priv->dev->parent, priv->master);
> > +
> > + /* Clear all internal status */
> > + priv->tx_head = 0;
> > + priv->tx_tail = 0;
> > +
> > + err = bxcan_leave_init_mode(priv);
> > + if (err) {
> > + netdev_err(ndev, "failed to leave init mode, error %d\n", err);
> > + goto failed_leave_init;
> > + }
> > +
> > + /* Set a `lec` value so that we can check for updates later */
> > + bxcan_rmw(®s->esr, BXCAN_ESR_LEC, LEC_UNUSED << BXCAN_ESR_LEC_SHIFT);
> > +
> > + /* IER
> > + *
> > + * Enable interrupt for:
> > + * bus-off
> > + * passive error
> > + * warning error
> > + * last error code
> > + * RX FIFO pending message
> > + * TX mailbox empty
> > + */
> > + bxcan_rmw(®s->ier, BXCAN_IER_WKUIE | BXCAN_IER_SLKIE |
> > + BXCAN_IER_FOVIE1 | BXCAN_IER_FFIE1 | BXCAN_IER_FMPIE1 |
> > + BXCAN_IER_FOVIE0 | BXCAN_IER_FFIE0,
> > + BXCAN_IER_ERRIE | BXCAN_IER_LECIE | BXCAN_IER_BOFIE |
> > + BXCAN_IER_EPVIE | BXCAN_IER_EWGIE | BXCAN_IER_FMPIE0 |
> > + BXCAN_IER_TMEIE);
> > +
> > + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > + return 0;
> > +
> > +failed_leave_init:
> > +failed_enter_init:
> > +failed_leave_sleep:
> > + bxcan_chip_softreset(priv);
> > + return err;
> > +}
> > +
> > +static int bxcan_open(struct net_device *ndev)
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + int err;
> > +
> > + err = open_candev(ndev);
> > + if (err) {
> > + netdev_err(ndev, "open_candev() failed, error %d\n", err);
> > + goto failed_open;
> > + }
> > +
> > + napi_enable(&priv->napi);
> > + err = request_irq(ndev->irq, bxcan_rx_isr, IRQF_SHARED, ndev->name,
> > + ndev);
> > + if (err) {
> > + netdev_err(ndev, "failed to register rx irq(%d), error %d\n",
> > + ndev->irq, err);
> > + goto failed_rx_irq_request;
> > + }
> > +
> > + err = request_irq(priv->tx_irq, bxcan_tx_isr, IRQF_SHARED, ndev->name,
> > + ndev);
> > + if (err) {
> > + netdev_err(ndev, "failed to register tx irq(%d), error %d\n",
> > + priv->tx_irq, err);
> > + goto failed_tx_irq_request;
> > + }
> > +
> > + err = request_irq(priv->sce_irq, bxcan_state_change_isr, IRQF_SHARED,
> > + ndev->name, ndev);
> > + if (err) {
> > + netdev_err(ndev, "failed to register sce irq(%d), error %d\n",
> > + priv->sce_irq, err);
> > + goto failed_sce_irq_request;
> > + }
> > +
> > + err = bxcan_start(ndev);
> > + if (err)
> > + goto failed_start;
> > +
> > + netif_start_queue(ndev);
> > + return 0;
> > +
> > +failed_start:
> > +failed_sce_irq_request:
> > + free_irq(priv->tx_irq, ndev);
> > +failed_tx_irq_request:
> > + free_irq(ndev->irq, ndev);
> > +failed_rx_irq_request:
> > + napi_disable(&priv->napi);
> > + close_candev(ndev);
> > +failed_open:
> > + return err;
> > +}
> > +
> > +static void bxcan_stop(struct net_device *ndev)
>
> please rename to bxcan_chip_stop()
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > +
> > + bxcan_disable_filters(priv->dev->parent, priv->master);
>
> do you have to disable the IRQs?
I do not think so. But I will re-read the reference manual carefully.
>
> > + bxcan_enter_sleep_mode(priv);
> > + priv->can.state = CAN_STATE_STOPPED;
> > +}
> > +
> > +static int bxcan_close(struct net_device *ndev)
>
> and this bxcan_stop() to match the .ndo_stop.
>
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > +
> > + netif_stop_queue(ndev);
> > + bxcan_stop(ndev);
> > + free_irq(ndev->irq, ndev);
> > + free_irq(priv->tx_irq, ndev);
> > + free_irq(priv->sce_irq, ndev);
> > + napi_disable(&priv->napi);
> > + close_candev(ndev);
> > + return 0;
> > +}
> > +
> > +static netdev_tx_t bxcan_start_xmit(struct sk_buff *skb,
> > + struct net_device *ndev)
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct can_frame *cf = (struct can_frame *)skb->data;
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + struct bxcan_mb __iomem *mb_regs;
> > + unsigned int idx;
> > + u32 id;
> > + int i, j;
> > +
> > + if (can_dropped_invalid_skb(ndev, skb))
> > + return NETDEV_TX_OK;
> > +
> > + if (bxcan_tx_busy(priv))
> > + return NETDEV_TX_BUSY;
> > +
> > + idx = bxcan_get_tx_head(priv);
> > + priv->tx_head++;
> > + if (bxcan_get_tx_free(priv) == 0)
> > + netif_stop_queue(ndev);
> > +
> > + mb_regs = ®s->tx_mb[idx];
> > + if (cf->can_id & CAN_EFF_FLAG)
> > + id = BXCAN_TIxR_EXID(cf->can_id & CAN_EFF_MASK) |
> > + BXCAN_TIxR_IDE;
> > + else
> > + id = BXCAN_TIxR_STID(cf->can_id & CAN_SFF_MASK);
> > +
> > + if (cf->can_id & CAN_RTR_FLAG)
> > + id |= BXCAN_TIxR_RTR;
> > +
> > + bxcan_rmw(&mb_regs->dlc, BXCAN_TDTxR_DLC_MASK,
> > + BXCAN_TDTxR_DLC(cf->len));
>
> Is rmw needed here, or does a pure write work, too?
I'll use a pure write.
>
> > + can_put_echo_skb(skb, ndev, idx, 0);
> > +
> > + for (i = 0, j = 0; i < cf->len; i += 4, j++)
> > + writel(*(u32 *)(cf->data + i), &mb_regs->data[j]);
> > +
> > + /* Start transmission */
> > + writel(id | BXCAN_TIxR_TXRQ, &mb_regs->id);
> > +
> > + return NETDEV_TX_OK;
> > +}
> > +
> > +static const struct net_device_ops bxcan_netdev_ops = {
> > + .ndo_open = bxcan_open,
> > + .ndo_stop = bxcan_close,
> > + .ndo_start_xmit = bxcan_start_xmit,
> > + .ndo_change_mtu = can_change_mtu,
> > +};
> > +
> > +static void bxcan_rx_pkt(struct net_device *ndev,
> > + struct bxcan_mb __iomem *mb_regs)
> > +{
> > + struct net_device_stats *stats = &ndev->stats;
> > + struct can_frame *cf;
> > + struct sk_buff *skb;
> > + u32 id, dlc;
> > +
> > + skb = alloc_can_skb(ndev, &cf);
> > + if (!skb) {
> > + stats->rx_dropped++;
> > + return;
> > + }
> > +
> > + id = readl(&mb_regs->id);
> > + if (id & BXCAN_RIxR_IDE)
> > + cf->can_id = (id >> BXCAN_RIxR_EXID_SHIFT) | CAN_EFF_FLAG;
> > + else
> > + cf->can_id = (id >> BXCAN_RIxR_STID_SHIFT) & CAN_SFF_MASK;
> > +
> > + dlc = readl(&mb_regs->dlc) & BXCAN_RDTxR_DLC;
> > + cf->len = can_cc_dlc2len(dlc);
> > +
> > + if (id & BXCAN_RIxR_RTR) {
> > + cf->can_id |= CAN_RTR_FLAG;
> > + } else {
> > + int i, j;
> > +
> > + for (i = 0, j = 0; i < cf->len; i += 4, j++)
> > + *(u32 *)(cf->data + i) = readl(&mb_regs->data[j]);
> > +
> > + stats->rx_bytes += cf->len;
> > + }
> > +
> > + stats->rx_packets++;
> > + netif_receive_skb(skb);
> > +}
> > +
> > +static int bxcan_rx_poll(struct napi_struct *napi, int quota)
> > +{
> > + struct net_device *ndev = napi->dev;
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + int num_pkts;
> > + u32 rf0r;
> > +
> > + for (num_pkts = 0; num_pkts < quota; num_pkts++) {
> > + rf0r = readl(®s->rf0r);
> > + if (!(rf0r & BXCAN_RF0R_FMP0))
> > + break;
> > +
> > + bxcan_rx_pkt(ndev, ®s->rx_mb[0]);
> > +
> > + rf0r |= BXCAN_RF0R_RFOM0;
> > + writel(rf0r, ®s->rf0r);
> > + }
> > +
> > + if (num_pkts < quota) {
> > + napi_complete_done(napi, num_pkts);
> > + bxcan_rmw(®s->ier, 0, BXCAN_IER_FMPIE0);
> > + }
> > +
> > + return num_pkts;
> > +}
> > +
> > +static int bxcan_do_set_mode(struct net_device *ndev, enum can_mode mode)
> > +{
> > + int err;
> > +
> > + switch (mode) {
> > + case CAN_MODE_START:
> > + err = bxcan_start(ndev);
> > + if (err)
> > + return err;
> > +
> > + netif_wake_queue(ndev);
> > + break;
> > + default:
> > + return -EOPNOTSUPP;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int bxcan_disable_clks(struct bxcan_priv *priv)
> > +{
> > + if (priv->clk)
> > + clk_disable_unprepare(priv->clk);
> > +
> > + bxcan_disable_master_clk(priv->dev->parent);
> > + return 0;
> > +}
> > +
> > +static int bxcan_enable_clks(struct bxcan_priv *priv)
> > +{
> > + int err;
> > +
> > + err = bxcan_enable_master_clk(priv->dev->parent);
> > + if (err)
> > + return err;
> > +
> > + if (priv->clk) {
> > + err = clk_prepare_enable(priv->clk);
>
> clk_prepare_enable() works on NULL pointer, too.
The slave has its own clock, the master uses the one owned by the core driver.
In this way I wanted to avoid having to enable the master clock twice
(and therefore
improperly increase the ref-counting).
Thanks for all your suggestions and explanations.
I'll develop them asap.
Thanks and regards,
Dario
>
> > + if (err)
> > + bxcan_disable_master_clk(priv->dev->parent);
> > + }
> > +
> > + return err;
> > +}
> > +
> > +static int bxcan_get_berr_counter(const struct net_device *ndev,
> > + struct can_berr_counter *bec)
> > +{
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > + struct bxcan_regs __iomem *regs = priv->regs;
> > + u32 esr;
> > + int err;
> > +
> > + err = bxcan_enable_clks(priv);
> > + if (err)
> > + return err;
> > +
> > + esr = readl(®s->esr);
> > + bec->txerr = BXCAN_TEC(esr);
> > + bec->rxerr = BXCAN_REC(esr);
> > + err = bxcan_disable_clks(priv);
> > + return 0;
> > +}
> > +
> > +static int bxcan_probe(struct platform_device *pdev)
> > +{
> > + struct device_node *np = pdev->dev.of_node;
> > + struct device *dev = &pdev->dev;
> > + struct net_device *ndev;
> > + struct bxcan_priv *priv;
> > + struct clk *clk = NULL;
> > + bool master;
> > + u32 offset;
> > + int err, rx_irq, tx_irq, sce_irq;
> > +
> > + master = of_property_read_bool(np, "st,can-master");
> > + if (!master) {
> > + clk = devm_clk_get(dev, NULL);
> > + if (IS_ERR(clk)) {
> > + dev_err(dev, "failed to get clock\n");
> > + return PTR_ERR(clk);
> > + }
> > + }
> > +
> > + rx_irq = platform_get_irq_byname(pdev, "rx0");
> > + if (rx_irq < 0) {
> > + dev_err(dev, "failed to get rx0 irq\n");
> > + return rx_irq;
> > + }
> > +
> > + tx_irq = platform_get_irq_byname(pdev, "tx");
> > + if (tx_irq < 0) {
> > + dev_err(dev, "failed to get tx irq\n");
> > + return tx_irq;
> > + }
> > +
> > + sce_irq = platform_get_irq_byname(pdev, "sce");
> > + if (sce_irq < 0) {
> > + dev_err(dev, "failed to get sce irq\n");
> > + return sce_irq;
> > + }
> > +
> > + err = of_property_read_u32(np, "reg", &offset);
> > + if (err) {
> > + dev_err(dev, "failed to get reg property\n");
> > + return err;
> > + }
> > +
> > + ndev = alloc_candev(sizeof(struct bxcan_priv), BXCAN_TX_MB_NUM);
> > + if (!ndev) {
> > + dev_err(dev, "alloc_candev() failed\n");
> > + return -ENOMEM;
> > + }
> > +
> > + priv = netdev_priv(ndev);
> > + platform_set_drvdata(pdev, ndev);
> > + SET_NETDEV_DEV(ndev, dev);
> > + ndev->netdev_ops = &bxcan_netdev_ops;
> > + ndev->irq = rx_irq;
> > + ndev->flags |= IFF_ECHO;
> > +
> > + priv->dev = dev;
> > + priv->ndev = ndev;
> > + priv->regs = bxcan_get_base_addr(dev->parent) + offset;
> > + priv->clk = clk;
> > + priv->tx_irq = tx_irq;
> > + priv->sce_irq = sce_irq;
> > + priv->master = master;
> > + priv->can.clock.freq =
> > + master ? bxcan_get_master_clk_rate(dev->parent) :
> > + clk_get_rate(clk);
> > + priv->tx_head = 0;
> > + priv->tx_tail = 0;
> > + priv->can.bittiming_const = &bxcan_bittiming_const;
> > + priv->can.do_set_mode = bxcan_do_set_mode;
> > + priv->can.do_get_berr_counter = bxcan_get_berr_counter;
> > + priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
> > + CAN_CTRLMODE_LISTENONLY | CAN_CTRLMODE_BERR_REPORTING;
> > + netif_napi_add(ndev, &priv->napi, bxcan_rx_poll, BXCAN_NAPI_WEIGHT);
> > +
> > + err = bxcan_enable_clks(priv);
> > + if (err) {
> > + dev_err(dev, "failed to enable clocks\n");
> > + return err;
> > + }
> > +
> > + err = register_candev(ndev);
> > + if (err) {
> > + dev_err(dev, "failed to register netdev\n");
> > + goto failed_register;
> > + }
> > +
> > + dev_info(dev, "clk: %d Hz, IRQs: %d, %d, %d\n", priv->can.clock.freq,
> > + tx_irq, rx_irq, sce_irq);
> > + return 0;
> > +
> > +failed_register:
> > + netif_napi_del(&priv->napi);
> > + free_candev(ndev);
> > + return err;
> > +}
> > +
> > +static int bxcan_remove(struct platform_device *pdev)
> > +{
> > + struct net_device *ndev = platform_get_drvdata(pdev);
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > +
> > + unregister_candev(ndev);
> > + bxcan_disable_clks(priv);
> > + netif_napi_del(&priv->napi);
> > + free_candev(ndev);
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused bxcan_suspend(struct device *dev)
> > +{
> > + struct net_device *ndev = dev_get_drvdata(dev);
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > +
> > + if (!netif_running(ndev))
> > + return 0;
> > +
> > + netif_stop_queue(ndev);
> > + netif_device_detach(ndev);
> > +
> > + bxcan_enter_sleep_mode(priv);
> > + priv->can.state = CAN_STATE_SLEEPING;
> > + bxcan_disable_clks(priv);
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused bxcan_resume(struct device *dev)
> > +{
> > + struct net_device *ndev = dev_get_drvdata(dev);
> > + struct bxcan_priv *priv = netdev_priv(ndev);
> > +
> > + if (!netif_running(ndev))
> > + return 0;
> > +
> > + bxcan_enable_clks(priv);
> > + bxcan_leave_sleep_mode(priv);
> > + priv->can.state = CAN_STATE_ERROR_ACTIVE;
> > +
> > + netif_device_attach(ndev);
> > + netif_start_queue(ndev);
> > + return 0;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(bxcan_pm_ops, bxcan_suspend, bxcan_resume);
> > +
> > +static const struct of_device_id bxcan_of_match[] = {
> > + {.compatible = "st,stm32f4-bxcan"},
> > + { /* sentinel */ },
> > +};
> > +MODULE_DEVICE_TABLE(of, bxcan_of_match);
> > +
> > +static struct platform_driver bxcan_driver = {
> > + .driver = {
> > + .name = KBUILD_MODNAME,
> > + .pm = &bxcan_pm_ops,
> > + .of_match_table = bxcan_of_match,
> > + },
> > + .probe = bxcan_probe,
> > + .remove = bxcan_remove,
> > +};
> > +
> > +module_platform_driver(bxcan_driver);
> > +
> > +MODULE_AUTHOR("Dario Binacchi <[email protected]>");
> > +MODULE_DESCRIPTION("STMicroelectronics Basic Extended CAN controller driver");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.32.0
> >
> >
>
> Marc
>
> --
> Pengutronix e.K. | Marc Kleine-Budde |
> Embedded Linux | https://www.pengutronix.de |
> Vertretung West/Dortmund | Phone: +49-231-2826-924 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
--
Dario Binacchi
Embedded Linux Developer
[email protected]
__________________________________
Amarula Solutions SRL
Via Le Canevare 30, 31100 Treviso, Veneto, IT
T. +39 042 243 5310
[email protected]
http://www.amarulasolutions.com