When a need raise up to use JTAG interface for system's devices
programming or CPU debugging, usually the user layer
application implements jtag protocol by bit-bang or using a
proprietary connection to vendor hardware.
This method can be slow and not generic.
We propose to implement general JTAG interface and infrastructure
to communicate with user layer application. In such way, we can
have the standard JTAG interface core part and separation from
specific HW implementation.
This allow new capability to debug the CPU or program system's
device via BMC without additional devices nor cost.
This patch purpose is to add JTAG master core infrastructure by
defining new JTAG class and provide generic JTAG interface
to allow hardware specific drivers to connect this interface.
This will enable all JTAG drivers to use the common interface
part and will have separate for hardware implementation.
The JTAG (Joint Test Action Group) core driver provides minimal generic
JTAG interface, which can be used by hardware specific JTAG master
controllers. By providing common interface for the JTAG controllers,
user space device programing is hardware independent.
Modern SoC which in use for embedded system' equipped with
internal JTAG master interface.
This interface is used for programming and debugging system's
hardware components, like CPLD, FPGA, CPU, voltage and
industrial controllers.
Firmware for such devices can be upgraded through JTAG interface during
Runtime. The JTAG standard support for multiple devices programming,
is in case their lines are daisy-chained together.
For example, systems which equipped with host CPU, BMC SoC or/and
number of programmable devices are capable to connect a pin and
select system components dynamically for programming and debugging,
This is using by the BMC which is equipped with internal SoC master
controller.
For example:
BMC JTAG master --> pin selected to CPLDs chain for programming (filed
upgrade, production)
BMC JTAG master --> pin selected to voltage monitors for programming
(field upgrade, production)
BMC JTAG master --> pin selected to host CPU (on-site debugging
and developers debugging)
For example, we can have application in user space which using calls
to JTAG driver executes CPLD programming directly from SVF file
The JTAG standard (IEEE 1149.1) defines the next connector pins:
- TDI (Test Data In);
- TDO (Test Data Out);
- TCK (Test Clock);
- TMS (Test Mode Select);
- TRST (Test Reset) (Optional);
The SoC equipped with JTAG master controller, performs
device programming on command or vector level. For example
a file in a standard SVF (Serial Vector Format) that contains
boundary scan vectors, can be used by sending each vector
to the JTAG interface and the JTAG controller will execute
the programming.
Initial version provides the system calls set for:
- SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
number of clocks.
SoC which are not equipped with JTAG master interface, can be built
on top of JTAG core driver infrastructure, by applying bit-banging of
TDI, TDO, TCK and TMS pins within the hardware specific driver.
Oleksandr Shamray (4):
drivers: jtag: Add JTAG core driver
drivers: jtag: Add Aspeed SoC 24xx and 25xx families JTAG master
driver
Documentation: jtag: Add bindings for Aspeed SoC 24xx and 25xx
families JTAG master driver
Documentation: jtag: Add ABI documentation
Documentation/ABI/testing/jtag-dev | 27 +
.../devicetree/bindings/jtag/aspeed-jtag.txt | 22 +
Documentation/ioctl/ioctl-number.txt | 2 +
Documentation/jtag/overview | 28 +
Documentation/jtag/transactions | 109 +++
MAINTAINERS | 10 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/jtag/Kconfig | 31 +
drivers/jtag/Makefile | 2 +
drivers/jtag/jtag-aspeed.c | 769 ++++++++++++++++++++
drivers/jtag/jtag.c | 322 ++++++++
include/linux/jtag.h | 42 ++
include/uapi/linux/jtag.h | 102 +++
14 files changed, 1469 insertions(+), 0 deletions(-)
create mode 100644 Documentation/ABI/testing/jtag-dev
create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
create mode 100644 Documentation/jtag/overview
create mode 100644 Documentation/jtag/transactions
create mode 100644 drivers/jtag/Kconfig
create mode 100644 drivers/jtag/Makefile
create mode 100644 drivers/jtag/jtag-aspeed.c
create mode 100644 drivers/jtag/jtag.c
create mode 100644 include/linux/jtag.h
create mode 100644 include/uapi/linux/jtag.h
It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.
Signed-off-by: Oleksandr Shamray <[email protected]>
Signed-off-by: Jiri Pirko <[email protected]>
Acked-by: Rob Herring <[email protected]>
---
v21->v22
v20->v21
v19->v20
v18->v19
v17->v18
v16->v17
v15->v16
Comments pointed by Joel Stanley <[email protected]>
- change clocks = <&clk_apb> to proper clocks = <&syscon ASPEED_CLK_APB>
- add reset descriptions in bndings file
v14->v15
v13->v14
v12->v13
v11->v12
v10->v11
v9->v10
v8->v9
v7->v8
Comments pointed by pointed by Joel Stanley <[email protected]>
- Change compatible string to ast2400 and ast2000
V6->v7
Comments pointed by Tobias Klauser <[email protected]>
- Fix spell "Doccumentation" -> "Documentation"
v5->v6
Comments pointed by Tobias Klauser <[email protected]>
- Small nit: s/documentation/Documentation/
v4->v5
V3->v4
Comments pointed by Rob Herring <[email protected]>
- delete unnecessary "status" and "reg-shift" descriptions in
bndings file
v2->v3
Comments pointed by Rob Herring <[email protected]>
- split Aspeed jtag driver and binding to sepatrate patches
- delete unnecessary "status" and "reg-shift" descriptions in
bndings file
---
.../devicetree/bindings/jtag/aspeed-jtag.txt | 22 ++++++++++++++++++++
MAINTAINERS | 1 +
2 files changed, 23 insertions(+), 0 deletions(-)
create mode 100644 Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
diff --git a/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
new file mode 100644
index 0000000..7c36eb6
--- /dev/null
+++ b/Documentation/devicetree/bindings/jtag/aspeed-jtag.txt
@@ -0,0 +1,22 @@
+Aspeed JTAG driver for ast2400 and ast2500 SoC
+
+Required properties:
+- compatible: Should be one of
+ - "aspeed,ast2400-jtag"
+ - "aspeed,ast2500-jtag"
+- reg contains the offset and length of the JTAG memory
+ region
+- clocks root clock of bus, should reference the APB
+ clock in the second cell
+- resets phandle to reset controller with the reset number in
+ the second cell
+- interrupts should contain JTAG controller interrupt
+
+Example:
+jtag: jtag@1e6e4000 {
+ compatible = "aspeed,ast2500-jtag";
+ reg = <0x1e6e4000 0x1c>;
+ clocks = <&syscon ASPEED_CLK_APB>;
+ resets = <&syscon ASPEED_RESET_JTAG_MASTER>;
+ interrupts = <43>;
+};
diff --git a/MAINTAINERS b/MAINTAINERS
index e7b8b2c..a5e5f75 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7617,6 +7617,7 @@ S: Maintained
F: include/linux/jtag.h
F: include/uapi/linux/jtag.h
F: drivers/jtag/
+F: Documentation/devicetree/bindings/jtag/
K10TEMP HARDWARE MONITORING DRIVER
M: Clemens Ladisch <[email protected]>
--
1.7.1
Initial patch for JTAG driver
JTAG class driver provide infrastructure to support hardware/software
JTAG platform drivers. It provide user layer API interface for flashing
and debugging external devices which equipped with JTAG interface
using standard transactions.
Driver exposes set of IOCTL to user space for:
- XFER:
- SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
- SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
number of clocks).
- SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
Driver core provides set of internal APIs for allocation and
registration:
- jtag_register;
- jtag_unregister;
- jtag_alloc;
- jtag_free;
Platform driver on registration with jtag-core creates the next
entry in dev folder:
/dev/jtagX
Signed-off-by: Oleksandr Shamray <[email protected]>
Signed-off-by: Jiri Pirko <[email protected]>
Acked-by: Philippe Ombredanne <[email protected]>
---
v21->v22
Comments pointed by Andy Shevchenko <[email protected]>
- Fix 0x0f -> 0x0F in ioctl-number.txt
- Add description to #define MAX_JTAG_NAME_LEN
- Remove unnecessary entry *dev from struct jtag
- Remove redundant parens
- Described mandatory callbacks and removed unnecessary
- Set JTAG_MAX_XFER_DATA_LEN to power of 2
- rework driver alloc/register to devm_ variant
- increasing line length up to 84 in order to improve readability.
Comments pointed by Randy Dunlap <[email protected]>
- fix spell in ABI doccumentation
v20->v21
Comments pointed by Randy Dunlap <[email protected]>
- Fix JTAG dirver help in Kconfig
v19->v20
Comments pointed by Randy Dunlap <[email protected]>
- Fix JTAG dirver help in Kconfig
Notifications from kbuild test robot <[email protected]>
- fix incompatible type casts
v18->v19
Comments pointed by Julia Cartwright <[email protected]>
- Fix memory leak on jtag_alloc exit
v17->v18
Comments pointed by Julia Cartwright <[email protected]>
- Change to return -EOPNOTSUPP in case of error in JTAG_GIOCFREQ
- Add ops callbacks check to jtag_alloc
- Add err check for copy_to_user
- Move the kfree() above the if (err) in JTAG_IOCXFER
- remove unnecessary check for error after put_user
- add padding to struct jtag_xfer
v16->v17
Comments pointed by Julia Cartwright <[email protected]>
- Fix memory allocation on jtag alloc
- Move out unnecessary form lock on jtag open
- Rework jtag register behavior
v15->v16
Comments pointed by Florian Fainelli <[email protected]>
- move check jtag->ops->* in ioctl before get_user()
- change error type -EINVAL --> -EBUSY on open already opened jtag
- remove unnecessary ARCH_DMA_MINALIGN flag from kzalloc
- remove define ARCH_DMA_MINALIGN
v14->v15
v13->v14
Comments pointed by Philippe Ombredanne <[email protected]>
- Change style of head block comment from /**/ to //
v12->v13
Comments pointed by Philippe Ombredanne <[email protected]>
- Change jtag.c licence type to
SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
and reorder line with license in description
v11->v12
Comments pointed by Greg KH <[email protected]>
- Change jtag.h licence type to
SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
and reorder line with license in description
Comments pointed by Chip Bilbrey <[email protected]>
- Remove Apeed reference from uapi jtag.h header
- Remove access mode from xfer and idle transactions
- Add new ioctl JTAG_SIOCMODE for set hw mode
- Add single open per device blocking
v10->v11
Notifications from kbuild test robot <[email protected]>
- Add include types.h header to jtag.h
- fix incompatible type of xfer callback
- remove rdundant class defination
- Fix return order in case of xfer error
V9->v10
Comments pointed by Greg KH <[email protected]>
- remove unnecessary alignment for pirv data
- move jtag_copy_to_user and jtag_copy_from_user code just to ioctl
- move int jtag_run_test_idle_op and jtag_xfer_op code
just to ioctl
- change return error codes to more applicable
- add missing error checks
- fix error check order in ioctl
- remove unnecessary blank lines
- add param validation to ioctl
- remove compat_ioctl
- remove only one open per JTAG port blocking.
User will care about this.
- Fix idr memory leak on jtag_exit
- change cdev device type to misc
V8->v9
Comments pointed by Arnd Bergmann <[email protected]>
- use get_user() instead of __get_user().
- change jtag->open type from int to atomic_t
- remove spinlock on jtg_open
- remove mutex on jtag_register
- add unregister_chrdev_region on jtag_init err
- add unregister_chrdev_region on jtag_exit
- remove unnecessary pointer casts
- add *data parameter to xfer function prototype
v7->v8
Comments pointed by Moritz Fischer <[email protected]>
- Fix misspelling s/friver/driver
v6->v7
Notifications from kbuild test robot <[email protected]>
- Remove include asm/types.h from jtag.h
- Add include <linux/types.h> to jtag.c
v5->v6
v4->v5
v3->v4
Comments pointed by Arnd Bergmann <[email protected]>
- change transaction pointer tdio type to __u64
- change internal status type from enum to __u32
- reorder jtag_xfer members to avoid the implied padding
- add __packed attribute to jtag_xfer and jtag_run_test_idle
v2->v3
Notifications from kbuild test robot <[email protected]>
- Change include path to <linux/types.h> in jtag.h
v1->v2
Comments pointed by Greg KH <[email protected]>
- Change license type from GPLv2/BSD to GPLv2
- Change type of variables which crossed user/kernel to __type
- Remove "default n" from Kconfig
Comments pointed by Andrew Lunn <[email protected]>
- Change list_add_tail in jtag_unregister to list_del
Comments pointed by Neil Armstrong <[email protected]>
- Add SPDX-License-Identifier instead of license text
Comments pointed by Arnd Bergmann <[email protected]>
- Change __copy_to_user to memdup_user
- Change __put_user to put_user
- Change type of variables to __type for compatible 32 and 64-bit systems
- Add check for maximum xfer data size
- Change lookup data mechanism to get jtag data from inode
- Add .compat_ioctl to file ops
- Add mem alignment for jtag priv data
Comments pointed by Tobias Klauser <[email protected]>
- Change function names to avoid match with variable types
- Fix description for jtag_ru_test_idle in uapi jtag.h
- Fix misprints IDEL/IDLE, trough/through
---
Documentation/ioctl/ioctl-number.txt | 2 +
MAINTAINERS | 8 +
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/jtag/Kconfig | 17 ++
drivers/jtag/Makefile | 1 +
drivers/jtag/jtag.c | 322 ++++++++++++++++++++++++++++++++++
include/linux/jtag.h | 42 +++++
include/uapi/linux/jtag.h | 102 +++++++++++
9 files changed, 497 insertions(+), 0 deletions(-)
create mode 100644 drivers/jtag/Kconfig
create mode 100644 drivers/jtag/Makefile
create mode 100644 drivers/jtag/jtag.c
create mode 100644 include/linux/jtag.h
create mode 100644 include/uapi/linux/jtag.h
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 7f7413e..886e676 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -318,6 +318,8 @@ Code Seq#(hex) Include File Comments
0xB0 all RATIO devices in development:
<mailto:[email protected]>
0xB1 00-1F PPPoX <mailto:[email protected]>
+0xB2 00-0F linux/jtag.h JTAG driver
+ <mailto:[email protected]>
0xB3 00 linux/mmc/ioctl.h
0xB4 00-0F linux/gpio.h <mailto:[email protected]>
0xB5 00-0F uapi/linux/rpmsg.h <mailto:[email protected]>
diff --git a/MAINTAINERS b/MAINTAINERS
index 79bb02f..e7b8b2c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7610,6 +7610,14 @@ L: [email protected]
S: Maintained
F: drivers/tty/serial/jsm/
+JTAG SUBSYSTEM
+M: Oleksandr Shamray <[email protected]>
+M: Vadim Pasternak <[email protected]>
+S: Maintained
+F: include/linux/jtag.h
+F: include/uapi/linux/jtag.h
+F: drivers/jtag/
+
K10TEMP HARDWARE MONITORING DRIVER
M: Clemens Ladisch <[email protected]>
L: [email protected]
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 95b9ccc..bb71e48 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -217,4 +217,6 @@ source "drivers/siox/Kconfig"
source "drivers/slimbus/Kconfig"
+source "drivers/jtag/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 24cd470..c92636b 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -185,3 +185,4 @@ obj-$(CONFIG_TEE) += tee/
obj-$(CONFIG_MULTIPLEXER) += mux/
obj-$(CONFIG_UNISYS_VISORBUS) += visorbus/
obj-$(CONFIG_SIOX) += siox/
+obj-$(CONFIG_JTAG) += jtag/
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
new file mode 100644
index 0000000..47771fc
--- /dev/null
+++ b/drivers/jtag/Kconfig
@@ -0,0 +1,17 @@
+menuconfig JTAG
+ tristate "JTAG support"
+ help
+ This provides basic core functionality support for JTAG class devices.
+ Hardware that is equipped with a JTAG microcontroller can be
+ supported by using this driver's interfaces.
+ This driver exposes a set of IOCTLs to the user space for
+ the following commands:
+ SDR: Performs an IEEE 1149.1 Data Register scan
+ SIR: Performs an IEEE 1149.1 Instruction Register scan.
+ RUNTEST: Forces the IEEE 1149.1 bus to a run state for a specified
+ number of clocks or a specified time period.
+
+ If you want this support, you should say Y here.
+
+ To compile this driver as a module, choose M here: the module will
+ be called jtag.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
new file mode 100644
index 0000000..af37493
--- /dev/null
+++ b/drivers/jtag/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_JTAG) += jtag.o
diff --git a/drivers/jtag/jtag.c b/drivers/jtag/jtag.c
new file mode 100644
index 0000000..f1e666b
--- /dev/null
+++ b/drivers/jtag/jtag.c
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// drivers/jtag/jtag.c
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+/*
+ * JTAG core driver supports up to 256 devices
+ * JTAG device name will be in range jtag0-jtag255
+ * Set maximum len of jtag id to 3
+ */
+
+#define MAX_JTAG_DEVS 255
+#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 3)
+
+struct jtag {
+ struct miscdevice miscdev;
+ const struct jtag_ops *ops;
+ int id;
+ bool opened;
+ struct mutex open_lock;
+ unsigned long priv[0];
+};
+
+static DEFINE_IDA(jtag_ida);
+
+static atomic_t jtag_refcount = ATOMIC_INIT(0);
+
+void *jtag_priv(struct jtag *jtag)
+{
+ return jtag->priv;
+}
+EXPORT_SYMBOL_GPL(jtag_priv);
+
+static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ struct jtag *jtag = file->private_data;
+ struct jtag_run_test_idle idle;
+ struct jtag_xfer xfer;
+ u8 *xfer_data;
+ u32 data_size;
+ u32 value;
+ int err;
+
+ if (!arg)
+ return -EINVAL;
+
+ switch (cmd) {
+ case JTAG_GIOCFREQ:
+ if (!jtag->ops->freq_get)
+ return -EOPNOTSUPP;
+
+ err = jtag->ops->freq_get(jtag, &value);
+ if (err)
+ break;
+
+ if (put_user(value, (__u32 __user *)arg))
+ err = -EFAULT;
+ break;
+
+ case JTAG_SIOCFREQ:
+ if (!jtag->ops->freq_set)
+ return -EOPNOTSUPP;
+
+ if (get_user(value, (__u32 __user *)arg))
+ return -EFAULT;
+ if (value == 0)
+ return -EINVAL;
+
+ err = jtag->ops->freq_set(jtag, value);
+ break;
+
+ case JTAG_IOCRUNTEST:
+ if (copy_from_user(&idle, (const void __user *)arg,
+ sizeof(struct jtag_run_test_idle)))
+ return -EFAULT;
+
+ if (idle.endstate > JTAG_STATE_PAUSEDR)
+ return -EINVAL;
+
+ err = jtag->ops->idle(jtag, &idle);
+ break;
+
+ case JTAG_IOCXFER:
+ if (copy_from_user(&xfer, (const void __user *)arg,
+ sizeof(struct jtag_xfer)))
+ return -EFAULT;
+
+ if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
+ return -EINVAL;
+
+ if (xfer.type > JTAG_SDR_XFER)
+ return -EINVAL;
+
+ if (xfer.direction > JTAG_WRITE_XFER)
+ return -EINVAL;
+
+ if (xfer.endstate > JTAG_STATE_PAUSEDR)
+ return -EINVAL;
+
+ data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
+ xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
+
+ if (IS_ERR(xfer_data))
+ return -EFAULT;
+
+ err = jtag->ops->xfer(jtag, &xfer, xfer_data);
+ if (err) {
+ kfree(xfer_data);
+ return -EFAULT;
+ }
+
+ err = copy_to_user(u64_to_user_ptr(xfer.tdio),
+ (void *)xfer_data, data_size);
+ kfree(xfer_data);
+ if (err)
+ return -EFAULT;
+
+ if (copy_to_user((void __user *)arg, (void *)&xfer,
+ sizeof(struct jtag_xfer)))
+ return -EFAULT;
+ break;
+
+ case JTAG_GIOCSTATUS:
+ err = jtag->ops->status_get(jtag, &value);
+ if (err)
+ break;
+
+ err = put_user(value, (__u32 __user *)arg);
+ break;
+ case JTAG_SIOCMODE:
+ if (!jtag->ops->mode_set)
+ return -EOPNOTSUPP;
+
+ if (get_user(value, (__u32 __user *)arg))
+ return -EFAULT;
+ if (value == 0)
+ return -EINVAL;
+
+ err = jtag->ops->mode_set(jtag, value);
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ return err;
+}
+
+static int jtag_open(struct inode *inode, struct file *file)
+{
+ struct jtag *jtag = container_of(file->private_data, struct jtag, miscdev);
+
+ if (mutex_lock_interruptible(&jtag->open_lock))
+ return -ERESTARTSYS;
+
+ if (jtag->opened) {
+ mutex_unlock(&jtag->open_lock);
+ return -EBUSY;
+ }
+ jtag->opened = true;
+ mutex_unlock(&jtag->open_lock);
+
+ nonseekable_open(inode, file);
+ file->private_data = jtag;
+ return 0;
+}
+
+static int jtag_release(struct inode *inode, struct file *file)
+{
+ struct jtag *jtag = file->private_data;
+
+ mutex_lock(&jtag->open_lock);
+ jtag->opened = false;
+ mutex_unlock(&jtag->open_lock);
+ return 0;
+}
+
+static const struct file_operations jtag_fops = {
+ .owner = THIS_MODULE,
+ .open = jtag_open,
+ .release = jtag_release,
+ .llseek = noop_llseek,
+ .unlocked_ioctl = jtag_ioctl,
+};
+
+struct jtag *jtag_alloc(struct device *host, size_t priv_size,
+ const struct jtag_ops *ops)
+{
+ struct jtag *jtag;
+
+ if (!host)
+ return NULL;
+
+ if (!ops)
+ return NULL;
+
+ if (!ops->idle || !ops->status_get || !ops->xfer)
+ return NULL;
+
+ jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
+ if (!jtag)
+ return NULL;
+
+ jtag->ops = ops;
+ jtag->miscdev.parent = host;
+
+ return jtag;
+}
+EXPORT_SYMBOL_GPL(jtag_alloc);
+
+void jtag_free(struct jtag *jtag)
+{
+ kfree(jtag);
+}
+EXPORT_SYMBOL_GPL(jtag_free);
+
+static int jtag_register(struct jtag *jtag)
+{
+ struct device *dev = jtag->miscdev.parent;
+ char *name;
+ int err;
+ int id;
+
+ if (!dev)
+ return -ENODEV;
+
+ if (atomic_read(&jtag_refcount) >= MAX_JTAG_DEVS)
+ return -ENOSPC;
+
+ id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
+ if (id < 0)
+ return id;
+
+ jtag->id = id;
+ jtag->opened = false;
+
+ name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
+ if (!name) {
+ err = -ENOMEM;
+ goto err_jtag_alloc;
+ }
+
+ err = snprintf(name, MAX_JTAG_NAME_LEN, "jtag%d", id);
+ if (err < 0)
+ goto err_jtag_name;
+
+ mutex_init(&jtag->open_lock);
+ jtag->miscdev.fops = &jtag_fops;
+ jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
+ jtag->miscdev.name = name;
+
+ err = misc_register(&jtag->miscdev);
+ if (err) {
+ dev_err(jtag->miscdev.parent, "Unable to register device\n");
+ goto err_jtag_name;
+ }
+ pr_info("%s %d\n", __func__, __LINE__);
+ atomic_inc(&jtag_refcount);
+ return 0;
+
+err_jtag_name:
+ kfree(name);
+err_jtag_alloc:
+ ida_simple_remove(&jtag_ida, id);
+ return err;
+}
+
+static void jtag_unregister(struct jtag *jtag)
+{
+ misc_deregister(&jtag->miscdev);
+ kfree(jtag->miscdev.name);
+ ida_simple_remove(&jtag_ida, jtag->id);
+ atomic_dec(&jtag_refcount);
+}
+
+static void devm_jtag_unregister(struct device *dev, void *res)
+{
+ jtag_unregister(*(struct jtag **)res);
+}
+
+int devm_jtag_register(struct device *dev, struct jtag *jtag)
+{
+ struct jtag **ptr;
+ int ret;
+
+ ptr = devres_alloc(devm_jtag_unregister, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ ret = jtag_register(jtag);
+ if (!ret) {
+ *ptr = jtag;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(devm_jtag_register);
+
+static void __exit jtag_exit(void)
+{
+ ida_destroy(&jtag_ida);
+}
+
+module_exit(jtag_exit);
+
+MODULE_AUTHOR("Oleksandr Shamray <[email protected]>");
+MODULE_DESCRIPTION("Generic jtag support");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/jtag.h b/include/linux/jtag.h
new file mode 100644
index 0000000..555812e
--- /dev/null
+++ b/include/linux/jtag.h
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/linux/jtag.h - JTAG class driver
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
+
+#ifndef __JTAG_H
+#define __JTAG_H
+
+#include <uapi/linux/jtag.h>
+
+#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
+
+#define JTAG_MAX_XFER_DATA_LEN 65535
+
+struct jtag;
+/**
+ * struct jtag_ops - callbacks for JTAG control functions:
+ *
+ * @freq_get: get frequency function. Filled by dev driver
+ * @freq_set: set frequency function. Filled by dev driver
+ * @status_get: set status function. Mandatory func. Filled by dev driver
+ * @idle: set JTAG to idle state function. Mandatory func. Filled by dev driver
+ * @xfer: send JTAG xfer function. Mandatory func. Filled by dev driver
+ * @mode_set: set specific work mode for JTAG. Filled by dev driver
+ */
+struct jtag_ops {
+ int (*freq_get)(struct jtag *jtag, u32 *freq);
+ int (*freq_set)(struct jtag *jtag, u32 freq);
+ int (*status_get)(struct jtag *jtag, u32 *state);
+ int (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
+ int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
+ int (*mode_set)(struct jtag *jtag, u32 mode_mask);
+};
+
+void *jtag_priv(struct jtag *jtag);
+int devm_jtag_register(struct device *dev, struct jtag *jtag);
+struct jtag *jtag_alloc(struct device *host, size_t priv_size,
+ const struct jtag_ops *ops);
+void jtag_free(struct jtag *jtag);
+
+#endif /* __JTAG_H */
diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
new file mode 100644
index 0000000..8bbf1a7
--- /dev/null
+++ b/include/uapi/linux/jtag.h
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/uapi/linux/jtag.h - JTAG class driver uapi
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
+
+#ifndef __UAPI_LINUX_JTAG_H
+#define __UAPI_LINUX_JTAG_H
+
+/*
+ * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived or bitbang
+ * mode. This is bitmask param of ioctl JTAG_SIOCMODE command
+ */
+#define JTAG_XFER_HW_MODE 1
+
+/**
+ * enum jtag_endstate:
+ *
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ */
+enum jtag_endstate {
+ JTAG_STATE_IDLE,
+ JTAG_STATE_PAUSEIR,
+ JTAG_STATE_PAUSEDR,
+};
+
+/**
+ * enum jtag_xfer_type:
+ *
+ * @JTAG_SIR_XFER: SIR transfer
+ * @JTAG_SDR_XFER: SDR transfer
+ */
+enum jtag_xfer_type {
+ JTAG_SIR_XFER,
+ JTAG_SDR_XFER,
+};
+
+/**
+ * enum jtag_xfer_direction:
+ *
+ * @JTAG_READ_XFER: read transfer
+ * @JTAG_WRITE_XFER: write transfer
+ */
+enum jtag_xfer_direction {
+ JTAG_READ_XFER,
+ JTAG_WRITE_XFER,
+};
+
+/**
+ * struct jtag_run_test_idle - forces JTAG state machine to
+ * RUN_TEST/IDLE state
+ *
+ * @reset: 0 - run IDLE/PAUSE from current state
+ * 1 - go through TEST_LOGIC/RESET state before IDLE/PAUSE
+ * @end: completion flag
+ * @tck: clock counter
+ *
+ * Structure provide interface to JTAG device for JTAG IDLE execution.
+ */
+struct jtag_run_test_idle {
+ __u8 reset;
+ __u8 endstate;
+ __u8 tck;
+};
+
+/**
+ * struct jtag_xfer - jtag xfer:
+ *
+ * @type: transfer type
+ * @direction: xfer direction
+ * @length: xfer bits len
+ * @tdio : xfer data array
+ * @endir: xfer end state
+ *
+ * Structure provide interface to JTAG device for JTAG SDR/SIR xfer execution.
+ */
+struct jtag_xfer {
+ __u8 type;
+ __u8 direction;
+ __u8 endstate;
+ __u8 padding;
+ __u32 length;
+ __u64 tdio;
+};
+
+/* ioctl interface */
+#define __JTAG_IOCTL_MAGIC 0xb2
+
+#define JTAG_IOCRUNTEST _IOW(__JTAG_IOCTL_MAGIC, 0,\
+ struct jtag_run_test_idle)
+#define JTAG_SIOCFREQ _IOW(__JTAG_IOCTL_MAGIC, 1, unsigned int)
+#define JTAG_GIOCFREQ _IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
+#define JTAG_IOCXFER _IOWR(__JTAG_IOCTL_MAGIC, 3, struct jtag_xfer)
+#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum jtag_endstate)
+#define JTAG_SIOCMODE _IOW(__JTAG_IOCTL_MAGIC, 5, unsigned int)
+
+#define JTAG_FIRST_MINOR 0
+#define JTAG_MAX_DEVICES 32
+
+#endif /* __UAPI_LINUX_JTAG_H */
--
1.7.1
Added document that describe the ABI for JTAG class drivrer
Signed-off-by: Oleksandr Shamray <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
---
v21->v22
Comments pointed by Randy Dunlap <[email protected]>
- fix spell in ABI doccumentation
v20->v21
Comments pointed by Randy Dunlap <[email protected]>
- Fix JTAG dirver help in Kconfig
v19->v20
Comments pointed by Randy Dunlap <[email protected]>
- Fix JTAG doccumentation
v18->v19
Pavel Machek <[email protected]>
- Added JTAG doccumentation to Documentation/jtag
v17->v18
v16->v17
v15->v16
v14->v15
v13->v14
v12->v13
v11->v12 Tobias Klauser <[email protected]>
Comments pointed by
- rename /Documentation/ABI/testing/jatg-dev -> jtag-dev
- Typo: s/interfase/interface
v10->v11
v9->v10
Fixes added by Oleksandr:
- change jtag-cdev to jtag-dev in documentation
- update KernelVersion and Date in jtag-dev documentation;
v8->v9
v7->v8
v6->v7
Comments pointed by Pavel Machek <[email protected]>
- Added jtag-cdev documentation to Documentation/ABI/testing folder
---
Documentation/ABI/testing/jtag-dev | 27 +++++++++
Documentation/jtag/overview | 28 +++++++++
Documentation/jtag/transactions | 109 ++++++++++++++++++++++++++++++++++++
MAINTAINERS | 1 +
4 files changed, 165 insertions(+), 0 deletions(-)
create mode 100644 Documentation/ABI/testing/jtag-dev
create mode 100644 Documentation/jtag/overview
create mode 100644 Documentation/jtag/transactions
diff --git a/Documentation/ABI/testing/jtag-dev b/Documentation/ABI/testing/jtag-dev
new file mode 100644
index 0000000..4325316
--- /dev/null
+++ b/Documentation/ABI/testing/jtag-dev
@@ -0,0 +1,27 @@
+What: /dev/jtag[0-9]+
+Date: May 2018
+KernelVersion: 4.18
+Contact: [email protected]
+Description:
+ The misc device files /dev/jtag* are the interface
+ between JTAG master interface and userspace.
+
+ The ioctl(2)-based ABI is defined and documented in
+ [include/uapi]<linux/jtag.h>.
+
+ The following file operations are supported:
+
+ open(2)
+ The argument flag currently support only one access
+ mode O_RDWR.
+
+ ioctl(2)
+ Initiate various actions.
+ See the inline documentation in [include/uapi]<linux/jtag.h>
+ for descriptions of all ioctls.
+
+ close(2)
+ Stops and free up the I/O contexts that was associated
+ with the file descriptor.
+
+Users: TBD
diff --git a/Documentation/jtag/overview b/Documentation/jtag/overview
new file mode 100644
index 0000000..42b487a
--- /dev/null
+++ b/Documentation/jtag/overview
@@ -0,0 +1,28 @@
+Linux kernel JTAG support
+=========================
+
+The JTAG is an industry standard for verifying hardware.
+JTAG provides access to many logic signals of a complex integrated circuit,
+including the device pins.
+
+A JTAG interface is a special interface added to a chip.
+Depending on the version of JTAG, two, four, or five pins are added.
+
+The connector pins are:
+ TDI (Test Data In)
+ TDO (Test Data Out)
+ TCK (Test Clock)
+ TMS (Test Mode Select)
+ TRST (Test Reset) optional
+
+JTAG interface is designed to have two parts - basic core driver and
+hardware specific driver. The basic driver introduces a general interface
+which is not dependent of specific hardware. It provides communication
+between user space and hardware specific driver.
+Each JTAG device is represented as a char device from (jtag0, jtag1, ...).
+Access to a JTAG device is performed through IOCTL calls.
+
+Call flow example:
+User: open -> /dev/jatgX
+User: ioctl -> /dev/jtagX -> JTAG core driver -> JTAG hardware specific driver
+User: close -> /dev/jatgX
diff --git a/Documentation/jtag/transactions b/Documentation/jtag/transactions
new file mode 100644
index 0000000..2abf833
--- /dev/null
+++ b/Documentation/jtag/transactions
@@ -0,0 +1,109 @@
+The JTAG API
+=============
+
+JTAG master devices can be accessed through a character misc-device.
+Each JTAG master interface can be accessed by using /dev/jtagN.
+
+JTAG system calls set:
+- SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
+- SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
+- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
+number of clocks.
+
+open(), close()
+-------
+open() opens JTAG device. Only one open operation per JTAG device
+can be performed. Two or more open for one device will return error.
+
+Open/Close device:
+- jtag_fd = open("/dev/jtag0", O_RDWR);
+- close(jtag_fd);
+
+ioctl()
+-------
+All access operations to JTAG devices performed through ioctl interface.
+The IOCTL interface supports these requests:
+ JTAG_IOCRUNTEST - Force JTAG state machine to RUN_TEST/IDLE state
+ JTAG_SIOCFREQ - Set JTAG TCK frequency
+ JTAG_GIOCFREQ - Get JTAG TCK frequency
+ JTAG_IOCXFER - send JTAG data Xfer
+ JTAG_GIOCSTATUS - get current JTAG TAP status
+ JTAG_SIOCMODE - set JTAG mode flags.
+
+JTAG_SIOCFREQ, JTAG_GIOCFREQ
+------
+Set/Get JTAG clock speed:
+
+ unsigned int jtag_fd;
+ ioctl(jtag_fd, JTAG_SIOCFREQ, &frq);
+ ioctl(jtag_fd, JTAG_GIOCFREQ, &frq);
+
+JTAG_IOCRUNTEST
+------
+Force JTAG state machine to RUN_TEST/IDLE state
+
+struct jtag_run_test_idle {
+ __u8 reset;
+ __u8 endstate;
+ __u8 tck;
+};
+
+reset: 0 - run IDLE/PAUSE from current state
+ 1 - go through TEST_LOGIC/RESET state before IDLE/PAUSE
+endstate: completion flag
+tck: clock counter
+
+Example:
+ struct jtag_run_test_idle runtest;
+
+ runtest.endstate = JTAG_STATE_IDLE;
+ runtest.reset = 0;
+ runtest.tck = data_p->tck;
+ usleep(25 * 1000);
+ ioctl(jtag_fd, JTAG_IOCRUNTEST, &runtest);
+
+JTAG_IOCXFER
+------
+Send SDR/SIR transaction
+
+struct jtag_xfer {
+ __u8 type;
+ __u8 direction;
+ __u8 endstate;
+ __u8 padding;
+ __u32 length;
+ __u64 tdio;
+};
+
+type: transfer type - JTAG_SIR_XFER/JTAG_SDR_XFER
+direction: xfer direction - JTAG_SIR_XFER/JTAG_SDR_XFER,
+length: xfer data len in bits
+tdio : xfer data array
+endstate: xfer end state after transaction finish
+ can be: JTAG_STATE_IDLE/JTAG_STATE_PAUSEIR/JTAG_STATE_PAUSEDR
+
+Example:
+ struct jtag_xfer xfer;
+ static char buf[64];
+ static unsigned int buf_len = 0;
+ [...]
+ xfer.type = JTAG_SDR_XFER;
+ xfer.tdio = (__u64)buf;
+ xfer.length = buf_len;
+ xfer.endstate = JTAG_STATE_IDLE;
+
+ if (is_read)
+ xfer.direction = JTAG_READ_XFER;
+ else
+ xfer.direction = JTAG_WRITE_XFER;
+
+ ioctl(jtag_fd, JTAG_IOCXFER, &xfer);
+
+JTAG_SIOCMODE
+------
+If hardware driver can support different running modes you can change it.
+
+Example:
+ unsigned int mode;
+ mode = JTAG_XFER_HW_MODE;
+ ioctl(jtag_fd, JTAG_SIOCMODE, &mode);
diff --git a/MAINTAINERS b/MAINTAINERS
index a5e5f75..e067eda 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7618,6 +7618,7 @@ F: include/linux/jtag.h
F: include/uapi/linux/jtag.h
F: drivers/jtag/
F: Documentation/devicetree/bindings/jtag/
+F: Documentation/ABI/testing/jtag-dev
K10TEMP HARDWARE MONITORING DRIVER
M: Clemens Ladisch <[email protected]>
--
1.7.1
Driver adds support of Aspeed 2500/2400 series SOC JTAG master controller.
Driver implements the following jtag ops:
- freq_get;
- freq_set;
- status_get;
- idle;
- xfer;
It has been tested on Mellanox system with BMC equipped with
Aspeed 2520 SoC for programming CPLD devices.
Signed-off-by: Oleksandr Shamray <[email protected]>
Signed-off-by: Jiri Pirko <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Philippe Ombredanne <[email protected]>
Acked-by: Joel Stanley <[email protected]>
---
v21->v22
Comments pointed by Andy Shevchenko <[email protected]>
- rearrange ASPEED register defines
- simplified JTAG divider calculation formula
- change delay function in bit-bang operation
- add helper functions for TAP states switching
- remove unnecessary comments
- remove redundant debug messages
- make dines for repetative register bit sets
- fixed indentation
- change checks from negative to positive
- add error check for clk_prepare_enable
- rework driver alloc/register to devm_ variant
- Increasing line length up to 85 in order to improve readability
v20->v21
v19->v20
Notifications from kbuild test robot <[email protected]>
- add static declaration to 'aspeed_jtag_init' and
'aspeed_jtag_deinit' functions
v18->v19
v17->v18
v16->v17
v15->v16
Comments pointed by Joel Stanley <[email protected]>
- Add reset_control on Jtag init/deinit
v14->v15
Comments pointed by Joel Stanley <[email protected]>
- Add ARCH_ASPEED || COMPILE_TEST to Kconfig
- remove unused offset variable
- remove "aspeed_jtag" from dev_err and dev_dbg messages
- change clk_prepare_enable initialisation order
v13->v14
Comments pointed by Philippe Ombredanne <[email protected]>
- Change style of head block comment from /**/ to //
v12->v13
Comments pointed by Philippe Ombredanne <[email protected]>
- Change jtag-aspeed.c licence type to
SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
and reorder line with license- add reset descriptions in bndings file
in description
Comments pointed by Kun Yi <[email protected]>
- Changed capability check for aspeed,ast2400-jtag/ast200-jtag
v11->v12
Comments pointed by Chip Bilbrey <[email protected]>
- Remove access mode from xfer and idle transactions
- Add new ioctl JTAG_SIOCMODE for set hw mode
v10->v11
v9->v10
V8->v9
Comments pointed by Arnd Bergmann <[email protected]>
- add *data parameter to xfer function prototype
v7->v8
Comments pointed by Joel Stanley <[email protected]>
- aspeed_jtag_init replace goto to return;
- change input variables type from __u32 to u32
in functios freq_get, freq_set, status_get
- change sm_ variables type from char to u8
- in jatg_init add disable clocks on error case
- remove release_mem_region on error case
- remove devm_free_irq on jtag_deinit
- Fix misspelling Disabe/Disable
- Change compatible string to ast2400 and ast2000
v6->v7
Notifications from kbuild test robot <[email protected]>
- Add include <linux/types.h> to jtag-asapeed.c
v5->v6
v4->v5
Comments pointed by Arnd Bergmann <[email protected]>
- Added HAS_IOMEM dependence in Kconfig to avoid
"undefined reference to `devm_ioremap_resource'" error,
because in some arch this not supported
v3->v4
Comments pointed by Arnd Bergmann <[email protected]>
- change transaction pointer tdio type to __u64
- change internal status type from enum to __u32
v2->v3
v1->v2
Comments pointed by Greg KH <[email protected]>
- change license type from GPLv2/BSD to GPLv2
Comments pointed by Neil Armstrong <[email protected]>
- Add clk_prepare_enable/clk_disable_unprepare in clock init/deinit
- Change .compatible to soc-specific compatible names
aspeed,aspeed4000-jtag/aspeed5000-jtag
- Added dt-bindings
Comments pointed by Arnd Bergmann <[email protected]>
- Reorder functions and removed the forward declarations
- Add static const qualifier to state machine states transitions
- Change .compatible to soc-specific compatible names
aspeed,aspeed4000-jtag/aspeed5000-jtag
- Add dt-bindings
Comments pointed by Randy Dunlap <[email protected]>
- Change module name jtag-aspeed in description in Kconfig
Comments pointed by kbuild test robot <[email protected]>
- Remove invalid include <asm/mach-types.h>
- add resource_size instead of calculation
---
drivers/jtag/Kconfig | 14 +
drivers/jtag/Makefile | 1 +
drivers/jtag/jtag-aspeed.c | 769 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 784 insertions(+), 0 deletions(-)
create mode 100644 drivers/jtag/jtag-aspeed.c
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
index 47771fc..0cc163f 100644
--- a/drivers/jtag/Kconfig
+++ b/drivers/jtag/Kconfig
@@ -15,3 +15,17 @@ menuconfig JTAG
To compile this driver as a module, choose M here: the module will
be called jtag.
+
+menuconfig JTAG_ASPEED
+ tristate "Aspeed SoC JTAG controller support"
+ depends on JTAG && HAS_IOMEM
+ depends on ARCH_ASPEED || COMPILE_TEST
+ help
+ This provides a support for Aspeed JTAG device, equipped on
+ Aspeed SoC 24xx and 25xx families. Drivers allows programming
+ of hardware devices, connected to SoC through the JTAG interface.
+
+ If you want this support, you should say Y here.
+
+ To compile this driver as a module, choose M here: the module will
+ be called jtag-aspeed.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
index af37493..04a855e 100644
--- a/drivers/jtag/Makefile
+++ b/drivers/jtag/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_JTAG) += jtag.o
+obj-$(CONFIG_JTAG_ASPEED) += jtag-aspeed.o
diff --git a/drivers/jtag/jtag-aspeed.c b/drivers/jtag/jtag-aspeed.c
new file mode 100644
index 0000000..b3559f8
--- /dev/null
+++ b/drivers/jtag/jtag-aspeed.c
@@ -0,0 +1,769 @@
+// SPDX-License-Identifier: GPL-2.0
+// drivers/jtag/aspeed-jtag.c
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/delay.h>
+#include <uapi/linux/jtag.h>
+
+#define ASPEED_JTAG_DATA 0x00
+#define ASPEED_JTAG_INST 0x04
+#define ASPEED_JTAG_CTRL 0x08
+#define ASPEED_JTAG_ISR 0x0C
+#define ASPEED_JTAG_SW 0x10
+#define ASPEED_JTAG_TCK 0x14
+#define ASPEED_JTAG_EC 0x18
+
+#define ASPEED_JTAG_DATA_MSB 0x01
+#define ASPEED_JTAG_DATA_CHUNK_SIZE 0x20
+
+/* ASPEED_JTAG_CTRL: Engine Control */
+#define ASPEED_JTAG_CTL_ENG_EN BIT(31)
+#define ASPEED_JTAG_CTL_ENG_OUT_EN BIT(30)
+#define ASPEED_JTAG_CTL_FORCE_TMS BIT(29)
+#define ASPEED_JTAG_CTL_INST_LEN(x) ((x) << 20)
+#define ASPEED_JTAG_CTL_LASPEED_INST BIT(17)
+#define ASPEED_JTAG_CTL_INST_EN BIT(16)
+#define ASPEED_JTAG_CTL_DR_UPDATE BIT(10)
+#define ASPEED_JTAG_CTL_DATA_LEN(x) ((x) << 4)
+#define ASPEED_JTAG_CTL_LASPEED_DATA BIT(1)
+#define ASPEED_JTAG_CTL_DATA_EN BIT(0)
+
+/* ASPEED_JTAG_ISR : Interrupt status and enable */
+#define ASPEED_JTAG_ISR_INST_PAUSE BIT(19)
+#define ASPEED_JTAG_ISR_INST_COMPLETE BIT(18)
+#define ASPEED_JTAG_ISR_DATA_PAUSE BIT(17)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE BIT(16)
+#define ASPEED_JTAG_ISR_INST_PAUSE_EN BIT(3)
+#define ASPEED_JTAG_ISR_INST_COMPLETE_EN BIT(2)
+#define ASPEED_JTAG_ISR_DATA_PAUSE_EN BIT(1)
+#define ASPEED_JTAG_ISR_DATA_COMPLETE_EN BIT(0)
+#define ASPEED_JTAG_ISR_INT_EN_MASK GENMASK(3, 0)
+#define ASPEED_JTAG_ISR_INT_MASK GENMASK(19, 16)
+
+/* ASPEED_JTAG_SW : Software Mode and Status */
+#define ASPEED_JTAG_SW_MODE_EN BIT(19)
+#define ASPEED_JTAG_SW_MODE_TCK BIT(18)
+#define ASPEED_JTAG_SW_MODE_TMS BIT(17)
+#define ASPEED_JTAG_SW_MODE_TDIO BIT(16)
+
+/* ASPEED_JTAG_TCK : TCK Control */
+#define ASPEED_JTAG_TCK_DIVISOR_MASK GENMASK(10, 0)
+#define ASPEED_JTAG_TCK_GET_DIV(x) ((x) & ASPEED_JTAG_TCK_DIVISOR_MASK)
+
+/* ASPEED_JTAG_EC : Controller set for go to IDLE */
+#define ASPEED_JTAG_EC_GO_IDLE BIT(0)
+
+#define ASPEED_JTAG_IOUT_LEN(len) \
+ (ASPEED_JTAG_CTL_ENG_EN | \
+ ASPEED_JTAG_CTL_ENG_OUT_EN | \
+ ASPEED_JTAG_CTL_INST_LEN(len))
+
+#define ASPEED_JTAG_DOUT_LEN(len) \
+ (ASPEED_JTAG_CTL_ENG_EN | \
+ ASPEED_JTAG_CTL_ENG_OUT_EN | \
+ ASPEED_JTAG_CTL_DATA_LEN(len))
+
+#define ASPEED_JTAG_SW_TDIO (ASPEED_JTAG_SW_MODE_EN | ASPEED_JTAG_SW_MODE_TDIO)
+
+#define ASPEED_JTAG_GET_TDI(direction, byte) \
+ ((direction == JTAG_READ_XFER) ? UINT_MAX : byte)
+
+#define ASPEED_JTAG_TCK_WAIT 10
+#define ASPEED_JTAG_RESET_CNTR 10
+
+#define ASPEED_JTAG_NAME "jtag-aspeed"
+
+struct aspeed_jtag {
+ void __iomem *reg_base;
+ struct device *dev;
+ struct clk *pclk;
+ enum jtag_endstate status;
+ int irq;
+ struct reset_control *rst;
+ u32 flag;
+ wait_queue_head_t jtag_wq;
+ u32 mode;
+};
+
+static char *end_status_str[] = {"idle", "ir pause", "drpause"};
+
+static u32 aspeed_jtag_read(struct aspeed_jtag *aspeed_jtag, u32 reg)
+{
+ return readl(aspeed_jtag->reg_base + reg);
+}
+
+static void
+aspeed_jtag_write(struct aspeed_jtag *aspeed_jtag, u32 val, u32 reg)
+{
+ writel(val, aspeed_jtag->reg_base + reg);
+}
+
+static int aspeed_jtag_freq_set(struct jtag *jtag, u32 freq)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+ unsigned long apb_frq;
+ u32 tck_val;
+ u16 div;
+
+ apb_frq = clk_get_rate(aspeed_jtag->pclk);
+ if (!apb_frq)
+ return -ENOTSUPP;
+
+ div = (apb_frq - 1) / freq;
+ tck_val = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+ aspeed_jtag_write(aspeed_jtag,
+ (tck_val & ASPEED_JTAG_TCK_DIVISOR_MASK) | div,
+ ASPEED_JTAG_TCK);
+ return 0;
+}
+
+static int aspeed_jtag_freq_get(struct jtag *jtag, u32 *frq)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+ u32 pclk;
+ u32 tck;
+
+ pclk = clk_get_rate(aspeed_jtag->pclk);
+ tck = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_TCK);
+ *frq = pclk / (ASPEED_JTAG_TCK_GET_DIV(tck) + 1);
+
+ return 0;
+}
+
+static int aspeed_jtag_mode_set(struct jtag *jtag, u32 mode)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+ aspeed_jtag->mode = mode;
+ return 0;
+}
+
+static void aspeed_jtag_sw_delay(struct aspeed_jtag *aspeed_jtag, int cnt)
+{
+ int i;
+
+ for (i = 0; i < cnt; i++)
+ aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW);
+}
+
+static char aspeed_jtag_tck_cycle(struct aspeed_jtag *aspeed_jtag,
+ u8 tms, u8 tdi)
+{
+ char tdo = 0;
+
+ /* TCK = 0 */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ (tms * ASPEED_JTAG_SW_MODE_TMS) |
+ (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+ ndelay(ASPEED_JTAG_TCK_WAIT);
+ aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+ /* TCK = 1 */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ ASPEED_JTAG_SW_MODE_TCK |
+ (tms * ASPEED_JTAG_SW_MODE_TMS) |
+ (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+
+ if (aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_SW) &
+ ASPEED_JTAG_SW_MODE_TDIO)
+ tdo = 1;
+
+ aspeed_jtag_sw_delay(aspeed_jtag, ASPEED_JTAG_TCK_WAIT);
+
+ /* TCK = 0 */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_MODE_EN |
+ (tms * ASPEED_JTAG_SW_MODE_TMS) |
+ (tdi * ASPEED_JTAG_SW_MODE_TDIO), ASPEED_JTAG_SW);
+ return tdo;
+}
+
+static void aspeed_jtag_wait_instruction_pause(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq,
+ aspeed_jtag->flag & ASPEED_JTAG_ISR_INST_PAUSE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_PAUSE;
+}
+
+static void
+aspeed_jtag_wait_instruction_complete(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq,
+ aspeed_jtag->flag & ASPEED_JTAG_ISR_INST_COMPLETE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_INST_COMPLETE;
+}
+
+static void
+aspeed_jtag_wait_data_pause_complete(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq,
+ aspeed_jtag->flag & ASPEED_JTAG_ISR_DATA_PAUSE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_PAUSE;
+}
+
+static void aspeed_jtag_wait_data_complete(struct aspeed_jtag *aspeed_jtag)
+{
+ wait_event_interruptible(aspeed_jtag->jtag_wq,
+ aspeed_jtag->flag & ASPEED_JTAG_ISR_DATA_COMPLETE);
+ aspeed_jtag->flag &= ~ASPEED_JTAG_ISR_DATA_COMPLETE;
+}
+
+static void aspeed_jtag_sm_cycle(struct aspeed_jtag *aspeed_jtag,
+ const u8 *tms, int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ aspeed_jtag_tck_cycle(aspeed_jtag, tms[i], 0);
+}
+
+static void aspeed_jtag_run_idle(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_run_test_idle *runtest)
+{
+ static const u8 sm_idle_irpause[] = {1, 1, 0, 1, 0};
+ static const u8 sm_idle_drpause[] = {1, 0, 1, 0};
+
+ switch (runtest->endstate) {
+ case JTAG_STATE_PAUSEIR:
+ /* ->DRSCan->IRSCan->IRCap->IRExit1->PauseIR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_irpause,
+ sizeof(sm_idle_irpause));
+ aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+ break;
+ case JTAG_STATE_PAUSEDR:
+ /* ->DRSCan->DRCap->DRExit1->PauseDR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_idle_drpause,
+ sizeof(sm_idle_drpause));
+
+ aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+ break;
+ case JTAG_STATE_IDLE:
+ /* IDLE */
+ aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+ aspeed_jtag->status = JTAG_STATE_IDLE;
+ break;
+ default:
+ break;
+ }
+}
+
+static void aspeed_jtag_run_pause(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_run_test_idle *runtest)
+{
+ static const u8 sm_pause_irpause[] = {1, 1, 1, 1, 0, 1, 0};
+ static const u8 sm_pause_drpause[] = {1, 1, 1, 0, 1, 0};
+ static const u8 sm_pause_idle[] = {1, 1, 0};
+
+ /* From IR/DR Pa.use */
+ switch (runtest->endstate) {
+ case JTAG_STATE_PAUSEIR:
+ /*
+ * to Exit2 IR/DR->Updt IR/DR->DRSCan->IRSCan->IRCap->
+ * IRExit1->PauseIR
+ */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_irpause,
+ sizeof(sm_pause_irpause));
+
+ aspeed_jtag->status = JTAG_STATE_PAUSEIR;
+ break;
+ case JTAG_STATE_PAUSEDR:
+ /*
+ * to Exit2 IR/DR->Updt IR/DR->DRSCan->DRCap->
+ * DRExit1->PauseDR
+ */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_drpause,
+ sizeof(sm_pause_drpause));
+ aspeed_jtag->status = JTAG_STATE_PAUSEDR;
+ break;
+ case JTAG_STATE_IDLE:
+ /* to Exit2 IR/DR->Updt IR/DR->IDLE */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+ sizeof(sm_pause_idle));
+ aspeed_jtag->status = JTAG_STATE_IDLE;
+ break;
+ default:
+ break;
+ }
+}
+
+static void aspeed_jtag_run_test_idle_sw(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_run_test_idle *runtest)
+{
+ int i;
+
+ /* SW mode from idle/pause-> to pause/idle */
+ if (runtest->reset) {
+ for (i = 0; i < ASPEED_JTAG_RESET_CNTR; i++)
+ aspeed_jtag_tck_cycle(aspeed_jtag, 1, 0);
+ }
+
+ switch (aspeed_jtag->status) {
+ case JTAG_STATE_IDLE:
+ aspeed_jtag_run_idle(aspeed_jtag, runtest);
+ break;
+
+ case JTAG_STATE_PAUSEIR:
+ /* Fall-through */
+ case JTAG_STATE_PAUSEDR:
+ aspeed_jtag_run_pause(aspeed_jtag, runtest);
+ break;
+
+ default:
+ dev_err(aspeed_jtag->dev, "aspeed_jtag_run_test_idle error\n");
+ break;
+ }
+
+ /* Stay on IDLE for at least TCK cycle */
+ for (i = 0; i < runtest->tck; i++)
+ aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+}
+
+static int aspeed_jtag_idle(struct jtag *jtag,
+ struct jtag_run_test_idle *runtest)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+ dev_dbg(aspeed_jtag->dev, "runtest, status:%d, mode:%s, state:%s, reset:%d, tck:%d\n",
+ aspeed_jtag->status,
+ aspeed_jtag->mode & JTAG_XFER_HW_MODE ? "HW" : "SW",
+ end_status_str[runtest->endstate], runtest->reset,
+ runtest->tck);
+
+ if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
+ aspeed_jtag_run_test_idle_sw(aspeed_jtag, runtest);
+ return 0;
+ }
+
+ /* Disable sw mode */
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+ /* x TMS high + 1 TMS low */
+ if (runtest->reset)
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+ ASPEED_JTAG_CTL_ENG_OUT_EN |
+ ASPEED_JTAG_CTL_FORCE_TMS, ASPEED_JTAG_CTRL);
+ else
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_EC_GO_IDLE,
+ ASPEED_JTAG_EC);
+
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_TDIO, ASPEED_JTAG_SW);
+
+ aspeed_jtag->status = JTAG_STATE_IDLE;
+ return 0;
+}
+
+static void aspeed_jtag_xfer_sw(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_xfer *xfer, u32 *data)
+{
+ static const u8 sm_update_shiftir[] = { 1, 1, 0, 0 };
+ static const u8 sm_update_shiftdr[] = { 1, 0, 0 };
+ static const u8 sm_pause_idle[] = { 1, 1, 0 };
+ static const u8 sm_pause_update[] = { 1, 1 };
+ unsigned long remain_xfer = xfer->length;
+ unsigned long shift_bits = 0;
+ unsigned long index = 0;
+ unsigned long tdi;
+ char tdo;
+
+ if (aspeed_jtag->status != JTAG_STATE_IDLE) {
+ /*IR/DR Pause->Exit2 IR / DR->Update IR /DR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_update,
+ sizeof(sm_pause_update));
+ }
+
+ if (xfer->type == JTAG_SIR_XFER)
+ /* ->IRSCan->CapIR->ShiftIR */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftir,
+ sizeof(sm_update_shiftir));
+ else
+ /* ->DRScan->DRCap->DRShift */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_update_shiftdr,
+ sizeof(sm_update_shiftdr));
+
+ tdi = ASPEED_JTAG_GET_TDI(xfer->direction, data[index]);
+
+ while (remain_xfer > 1) {
+ tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 0,
+ tdi & ASPEED_JTAG_DATA_MSB);
+ data[index] |= tdo << (shift_bits %
+ ASPEED_JTAG_DATA_CHUNK_SIZE);
+
+ tdi >>= 1;
+ shift_bits++;
+ remain_xfer--;
+
+ if (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE == 0) {
+ tdo = 0;
+ index++;
+
+ tdi = ASPEED_JTAG_GET_TDI(xfer->direction, data[index]);
+ }
+ }
+
+ tdo = aspeed_jtag_tck_cycle(aspeed_jtag, 1, tdi & ASPEED_JTAG_DATA_MSB);
+ data[index] |= tdo << (shift_bits % ASPEED_JTAG_DATA_CHUNK_SIZE);
+
+ /* DIPause/DRPause */
+ aspeed_jtag_tck_cycle(aspeed_jtag, 0, 0);
+
+ if (xfer->endstate == JTAG_STATE_IDLE) {
+ /* ->DRExit2->DRUpdate->IDLE */
+ aspeed_jtag_sm_cycle(aspeed_jtag, sm_pause_idle,
+ sizeof(sm_pause_idle));
+ }
+}
+
+static void aspeed_jtag_xfer_push_data(struct aspeed_jtag *aspeed_jtag,
+ enum jtag_xfer_type type, u32 bits_len)
+{
+ if (type == JTAG_SIR_XFER) {
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_IOUT_LEN(bits_len),
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+ ASPEED_JTAG_CTL_INST_EN, ASPEED_JTAG_CTRL);
+ } else {
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len),
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_DOUT_LEN(bits_len) |
+ ASPEED_JTAG_CTL_DATA_EN, ASPEED_JTAG_CTRL);
+ }
+}
+
+static void aspeed_jtag_xfer_push_data_last(struct aspeed_jtag *aspeed_jtag,
+ enum jtag_xfer_type type,
+ u32 shift_bits,
+ enum jtag_endstate endstate)
+{
+ if (endstate == JTAG_STATE_IDLE) {
+ if (type == JTAG_SIR_XFER) {
+ dev_dbg(aspeed_jtag->dev, "IR Keep Pause\n");
+
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits),
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_INST_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_instruction_pause(aspeed_jtag);
+ } else {
+ dev_dbg(aspeed_jtag->dev, "DR Keep Pause\n");
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_DR_UPDATE,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_DR_UPDATE |
+ ASPEED_JTAG_CTL_DATA_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_data_pause_complete(aspeed_jtag);
+ }
+ } else {
+ if (type == JTAG_SIR_XFER) {
+ dev_dbg(aspeed_jtag->dev, "IR go IDLE\n");
+
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_INST,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_IOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_INST |
+ ASPEED_JTAG_CTL_INST_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_instruction_complete(aspeed_jtag);
+ } else {
+ dev_dbg(aspeed_jtag->dev, "DR go IDLE\n");
+
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_DATA,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag,
+ ASPEED_JTAG_DOUT_LEN(shift_bits) |
+ ASPEED_JTAG_CTL_LASPEED_DATA |
+ ASPEED_JTAG_CTL_DATA_EN,
+ ASPEED_JTAG_CTRL);
+ aspeed_jtag_wait_data_complete(aspeed_jtag);
+ }
+ }
+}
+
+static void aspeed_jtag_xfer_hw(struct aspeed_jtag *aspeed_jtag,
+ struct jtag_xfer *xfer, u32 *data)
+{
+ unsigned long remain_xfer = xfer->length;
+ unsigned long index = 0;
+ char shift_bits;
+ u32 data_reg;
+
+ data_reg = xfer->type == JTAG_SIR_XFER ?
+ ASPEED_JTAG_INST : ASPEED_JTAG_DATA;
+ while (remain_xfer) {
+ if (xfer->direction == JTAG_WRITE_XFER)
+ aspeed_jtag_write(aspeed_jtag, data[index], data_reg);
+ else
+ aspeed_jtag_write(aspeed_jtag, 0, data_reg);
+
+ if (remain_xfer > ASPEED_JTAG_DATA_CHUNK_SIZE) {
+ shift_bits = ASPEED_JTAG_DATA_CHUNK_SIZE;
+
+ /*
+ * Read bytes were not equals to column length
+ * and go to Pause-DR
+ */
+ aspeed_jtag_xfer_push_data(aspeed_jtag, xfer->type,
+ shift_bits);
+ } else {
+ /*
+ * Read bytes equals to column length =>
+ * Update-DR
+ */
+ shift_bits = remain_xfer;
+ aspeed_jtag_xfer_push_data_last(aspeed_jtag, xfer->type,
+ shift_bits,
+ xfer->endstate);
+ }
+
+ if (xfer->direction == JTAG_READ_XFER) {
+ if (shift_bits < ASPEED_JTAG_DATA_CHUNK_SIZE) {
+ data[index] = aspeed_jtag_read(aspeed_jtag,
+ data_reg);
+
+ data[index] >>= ASPEED_JTAG_DATA_CHUNK_SIZE -
+ shift_bits;
+ } else {
+ data[index] = aspeed_jtag_read(aspeed_jtag,
+ data_reg);
+ }
+ }
+
+ remain_xfer = remain_xfer - shift_bits;
+ index++;
+ }
+}
+
+static int aspeed_jtag_xfer(struct jtag *jtag, struct jtag_xfer *xfer,
+ u8 *xfer_data)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+ dev_dbg(aspeed_jtag->dev, " %s %s xfer, mode:%s, END:%d, len:%d\n",
+ xfer->type == JTAG_SIR_XFER ? "SIR" : "SDR",
+ xfer->direction == JTAG_READ_XFER ? "READ" : "WRITE",
+ aspeed_jtag->mode & JTAG_XFER_HW_MODE ? "HW" : "SW",
+ xfer->endstate, xfer->length);
+
+ if (!(aspeed_jtag->mode & JTAG_XFER_HW_MODE)) {
+ /* SW mode */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_TDIO, ASPEED_JTAG_SW);
+
+ aspeed_jtag_xfer_sw(aspeed_jtag, xfer, (u32 *)xfer_data);
+ } else {
+ /* HW mode */
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_SW);
+ aspeed_jtag_xfer_hw(aspeed_jtag, xfer, (u32 *)xfer_data);
+ }
+
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_TDIO, ASPEED_JTAG_SW);
+ aspeed_jtag->status = xfer->endstate;
+ return 0;
+}
+
+static int aspeed_jtag_status_get(struct jtag *jtag, u32 *status)
+{
+ struct aspeed_jtag *aspeed_jtag = jtag_priv(jtag);
+
+ *status = aspeed_jtag->status;
+ return 0;
+}
+
+static irqreturn_t aspeed_jtag_interrupt(s32 this_irq, void *dev_id)
+{
+ struct aspeed_jtag *aspeed_jtag = dev_id;
+ irqreturn_t ret;
+ u32 status;
+
+ status = aspeed_jtag_read(aspeed_jtag, ASPEED_JTAG_ISR);
+
+ if (status & ASPEED_JTAG_ISR_INT_MASK) {
+ aspeed_jtag_write(aspeed_jtag,
+ (status & ASPEED_JTAG_ISR_INT_MASK)
+ | (status & ASPEED_JTAG_ISR_INT_EN_MASK),
+ ASPEED_JTAG_ISR);
+ aspeed_jtag->flag |= status & ASPEED_JTAG_ISR_INT_MASK;
+ }
+
+ if (aspeed_jtag->flag) {
+ wake_up_interruptible(&aspeed_jtag->jtag_wq);
+ ret = IRQ_HANDLED;
+ } else {
+ dev_err(aspeed_jtag->dev, "irq status:%x\n",
+ status);
+ ret = IRQ_NONE;
+ }
+ return ret;
+}
+
+static int aspeed_jtag_init(struct platform_device *pdev,
+ struct aspeed_jtag *aspeed_jtag)
+{
+ struct resource *res;
+ int err;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ aspeed_jtag->reg_base = devm_ioremap_resource(aspeed_jtag->dev, res);
+ if (IS_ERR(aspeed_jtag->reg_base))
+ return -ENOMEM;
+
+ aspeed_jtag->pclk = devm_clk_get(aspeed_jtag->dev, NULL);
+ if (IS_ERR(aspeed_jtag->pclk)) {
+ dev_err(aspeed_jtag->dev, "devm_clk_get failed\n");
+ return PTR_ERR(aspeed_jtag->pclk);
+ }
+
+ aspeed_jtag->irq = platform_get_irq(pdev, 0);
+ if (aspeed_jtag->irq < 0) {
+ dev_err(aspeed_jtag->dev, "no irq specified\n");
+ return -ENOENT;
+ }
+
+ if (clk_prepare_enable(aspeed_jtag->pclk)) {
+ dev_err(aspeed_jtag->dev, "no irq specified\n");
+ return -ENOENT;
+ }
+
+ aspeed_jtag->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
+ if (IS_ERR(aspeed_jtag->rst)) {
+ dev_err(aspeed_jtag->dev,
+ "missing or invalid reset controller device tree entry");
+ return PTR_ERR(aspeed_jtag->rst);
+ }
+ reset_control_deassert(aspeed_jtag->rst);
+
+ /* Enable clock */
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_CTL_ENG_EN |
+ ASPEED_JTAG_CTL_ENG_OUT_EN, ASPEED_JTAG_CTRL);
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_SW_TDIO, ASPEED_JTAG_SW);
+
+ err = devm_request_irq(aspeed_jtag->dev, aspeed_jtag->irq,
+ aspeed_jtag_interrupt, 0,
+ "aspeed-jtag", aspeed_jtag);
+ if (err) {
+ dev_err(aspeed_jtag->dev, "unable to get IRQ");
+ goto clk_unprep;
+ }
+
+ aspeed_jtag_write(aspeed_jtag, ASPEED_JTAG_ISR_INST_PAUSE |
+ ASPEED_JTAG_ISR_INST_COMPLETE |
+ ASPEED_JTAG_ISR_DATA_PAUSE |
+ ASPEED_JTAG_ISR_DATA_COMPLETE |
+ ASPEED_JTAG_ISR_INST_PAUSE_EN |
+ ASPEED_JTAG_ISR_INST_COMPLETE_EN |
+ ASPEED_JTAG_ISR_DATA_PAUSE_EN |
+ ASPEED_JTAG_ISR_DATA_COMPLETE_EN,
+ ASPEED_JTAG_ISR);
+
+ aspeed_jtag->flag = 0;
+ aspeed_jtag->mode = 0;
+ init_waitqueue_head(&aspeed_jtag->jtag_wq);
+ return 0;
+
+clk_unprep:
+ clk_disable_unprepare(aspeed_jtag->pclk);
+ return err;
+}
+
+static int aspeed_jtag_deinit(struct platform_device *pdev,
+ struct aspeed_jtag *aspeed_jtag)
+{
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_ISR);
+ /* Disable clock */
+ aspeed_jtag_write(aspeed_jtag, 0, ASPEED_JTAG_CTRL);
+ reset_control_assert(aspeed_jtag->rst);
+ clk_disable_unprepare(aspeed_jtag->pclk);
+ return 0;
+}
+
+static const struct jtag_ops aspeed_jtag_ops = {
+ .freq_get = aspeed_jtag_freq_get,
+ .freq_set = aspeed_jtag_freq_set,
+ .status_get = aspeed_jtag_status_get,
+ .idle = aspeed_jtag_idle,
+ .xfer = aspeed_jtag_xfer,
+ .mode_set = aspeed_jtag_mode_set
+};
+
+static int aspeed_jtag_probe(struct platform_device *pdev)
+{
+ struct aspeed_jtag *aspeed_jtag;
+ struct jtag *jtag;
+ int err;
+
+ jtag = jtag_alloc(&pdev->dev, sizeof(*aspeed_jtag), &aspeed_jtag_ops);
+ if (!jtag)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, jtag);
+ aspeed_jtag = jtag_priv(jtag);
+ aspeed_jtag->dev = &pdev->dev;
+
+ /* Initialize device*/
+ err = aspeed_jtag_init(pdev, aspeed_jtag);
+ if (err)
+ goto err_jtag_init;
+
+ /* Initialize JTAG core structure*/
+ err = devm_jtag_register(aspeed_jtag->dev, jtag);
+ if (err)
+ goto err_jtag_register;
+
+ return 0;
+
+err_jtag_register:
+ aspeed_jtag_deinit(pdev, aspeed_jtag);
+err_jtag_init:
+ jtag_free(jtag);
+ return err;
+}
+
+static int aspeed_jtag_remove(struct platform_device *pdev)
+{
+ struct jtag *jtag = platform_get_drvdata(pdev);
+
+ aspeed_jtag_deinit(pdev, jtag_priv(jtag));
+ return 0;
+}
+
+static const struct of_device_id aspeed_jtag_of_match[] = {
+ { .compatible = "aspeed,ast2400-jtag", },
+ { .compatible = "aspeed,ast2500-jtag", },
+ {}
+};
+
+static struct platform_driver aspeed_jtag_driver = {
+ .probe = aspeed_jtag_probe,
+ .remove = aspeed_jtag_remove,
+ .driver = {
+ .name = ASPEED_JTAG_NAME,
+ .of_match_table = aspeed_jtag_of_match,
+ },
+};
+module_platform_driver(aspeed_jtag_driver);
+
+MODULE_AUTHOR("Oleksandr Shamray <[email protected]>");
+MODULE_DESCRIPTION("ASPEED JTAG driver");
+MODULE_LICENSE("GPL v2");
--
1.7.1
On Mon, May 28, 2018 at 01:34:09PM +0300, Oleksandr Shamray wrote:
> Initial patch for JTAG driver
> JTAG class driver provide infrastructure to support hardware/software
> JTAG platform drivers. It provide user layer API interface for flashing
> and debugging external devices which equipped with JTAG interface
> using standard transactions.
>
> Driver exposes set of IOCTL to user space for:
> - XFER:
> - SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
> - SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
> - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
> number of clocks).
> - SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
>
> Driver core provides set of internal APIs for allocation and
> registration:
> - jtag_register;
> - jtag_unregister;
> - jtag_alloc;
> - jtag_free;
>
> Platform driver on registration with jtag-core creates the next
> entry in dev folder:
> /dev/jtagX
>
> Signed-off-by: Oleksandr Shamray <[email protected]>
> Signed-off-by: Jiri Pirko <[email protected]>
> Acked-by: Philippe Ombredanne <[email protected]>
> ---
> v21->v22
22 versions, way to stick with this...
Anyway, time to review it again. I feel it's really close, but I don't
want to apply it yet as the api feels odd in places. If others have
asked you to make these changes to look like this, I'm sorry, then
please push back on me:
> +/*
> + * JTAG core driver supports up to 256 devices
> + * JTAG device name will be in range jtag0-jtag255
> + * Set maximum len of jtag id to 3
> + */
> +
> +#define MAX_JTAG_DEVS 255
Why have a max at all? You should be able to just dynamically allocate
them. Anyway, if you do want a max, you need to be able to properly
keep the max number, and right now you have a race when registering (you
check the number, and then much later do you increment it, a pointless
use of an atomic value if I've ever seen one...)
> +#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 3)
> +
> +struct jtag {
> + struct miscdevice miscdev;
If you are a miscdev, why even have a max number? Just let the max
number of miscdev devices rule things.
> + const struct jtag_ops *ops;
> + int id;
> + bool opened;
You shouldn't care about this, but ok...
> + struct mutex open_lock;
> + unsigned long priv[0];
> +};
> +
> +static DEFINE_IDA(jtag_ida);
> +
> +static atomic_t jtag_refcount = ATOMIC_INIT(0);
Either use it as an atomic properly (test_and_set), or just leave it as
an int, or better yet, don't use it at all.
> +void *jtag_priv(struct jtag *jtag)
> +{
> + return jtag->priv;
> +}
> +EXPORT_SYMBOL_GPL(jtag_priv);
Api naming issue here. Traditionally this is a "get/set_drvdata" type
function, as in dev_get_drvdata(), or dev_set_drvdata. But, you are
right in that the network stack has a netdev_priv() call, where you
probably copied this idea from.
I don't know, I guess it's ok as-is, as it's the way networking does it,
it's your call though.
> +static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> + struct jtag *jtag = file->private_data;
> + struct jtag_run_test_idle idle;
> + struct jtag_xfer xfer;
> + u8 *xfer_data;
> + u32 data_size;
> + u32 value;
> + int err;
> +
> + if (!arg)
> + return -EINVAL;
> +
> + switch (cmd) {
> + case JTAG_GIOCFREQ:
> + if (!jtag->ops->freq_get)
> + return -EOPNOTSUPP;
> +
> + err = jtag->ops->freq_get(jtag, &value);
> + if (err)
> + break;
> +
> + if (put_user(value, (__u32 __user *)arg))
> + err = -EFAULT;
> + break;
> +
> + case JTAG_SIOCFREQ:
> + if (!jtag->ops->freq_set)
> + return -EOPNOTSUPP;
> +
> + if (get_user(value, (__u32 __user *)arg))
> + return -EFAULT;
> + if (value == 0)
> + return -EINVAL;
> +
> + err = jtag->ops->freq_set(jtag, value);
> + break;
> +
> + case JTAG_IOCRUNTEST:
> + if (copy_from_user(&idle, (const void __user *)arg,
> + sizeof(struct jtag_run_test_idle)))
> + return -EFAULT;
> +
> + if (idle.endstate > JTAG_STATE_PAUSEDR)
> + return -EINVAL;
No validation that idle contains sane values? Don't make every jtag
driver have to do this type of validation please.
> +
> + err = jtag->ops->idle(jtag, &idle);
> + break;
> +
> + case JTAG_IOCXFER:
> + if (copy_from_user(&xfer, (const void __user *)arg,
> + sizeof(struct jtag_xfer)))
> + return -EFAULT;
> +
> + if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
> + return -EINVAL;
> +
> + if (xfer.type > JTAG_SDR_XFER)
> + return -EINVAL;
> +
> + if (xfer.direction > JTAG_WRITE_XFER)
> + return -EINVAL;
> +
> + if (xfer.endstate > JTAG_STATE_PAUSEDR)
> + return -EINVAL;
> +
See, you do good error checking here, why not for the previous ioctl?
> + data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
> + xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
> +
No blank line.
> + if (IS_ERR(xfer_data))
> + return -EFAULT;
> +
> + err = jtag->ops->xfer(jtag, &xfer, xfer_data);
> + if (err) {
> + kfree(xfer_data);
> + return -EFAULT;
Why not return the error given to you? -EFAULT is only if there is a
memory error in a copy_to/from_user() call.
> + }
> +
> + err = copy_to_user(u64_to_user_ptr(xfer.tdio),
> + (void *)xfer_data, data_size);
> + kfree(xfer_data);
> + if (err)
> + return -EFAULT;
Like here, that's correct.
> +
> + if (copy_to_user((void __user *)arg, (void *)&xfer,
> + sizeof(struct jtag_xfer)))
> + return -EFAULT;
> + break;
> +
> + case JTAG_GIOCSTATUS:
> + err = jtag->ops->status_get(jtag, &value);
> + if (err)
> + break;
> +
> + err = put_user(value, (__u32 __user *)arg);
> + break;
> + case JTAG_SIOCMODE:
> + if (!jtag->ops->mode_set)
> + return -EOPNOTSUPP;
> +
> + if (get_user(value, (__u32 __user *)arg))
> + return -EFAULT;
> + if (value == 0)
> + return -EINVAL;
> +
> + err = jtag->ops->mode_set(jtag, value);
> + break;
> +
> + default:
> + return -EINVAL;
> + }
> + return err;
> +}
> +
> +static int jtag_open(struct inode *inode, struct file *file)
> +{
> + struct jtag *jtag = container_of(file->private_data, struct jtag, miscdev);
> +
> + if (mutex_lock_interruptible(&jtag->open_lock))
> + return -ERESTARTSYS;
Why restart? Just grab the lock, you don't want to have to do
restartable logic in userspace, right?
> +
> + if (jtag->opened) {
> + mutex_unlock(&jtag->open_lock);
> + return -EBUSY;
Why do you care about only 1 userspace open call? What does that buy
you? Userspace can always pass around that file descriptor and use it
in multiple places, so you are not really "protecting" yourself from
anything.
And better yet, if you get rid of this, your open/release functions get
very tiny and simple.
> + }
> + jtag->opened = true;
> + mutex_unlock(&jtag->open_lock);
> +
> + nonseekable_open(inode, file);
No error checking of the return value? Not good :(
> + file->private_data = jtag;
> + return 0;
> +}
> +
> +static int jtag_release(struct inode *inode, struct file *file)
> +{
> + struct jtag *jtag = file->private_data;
> +
> + mutex_lock(&jtag->open_lock);
> + jtag->opened = false;
> + mutex_unlock(&jtag->open_lock);
> + return 0;
> +}
> +
> +static const struct file_operations jtag_fops = {
> + .owner = THIS_MODULE,
> + .open = jtag_open,
> + .release = jtag_release,
> + .llseek = noop_llseek,
> + .unlocked_ioctl = jtag_ioctl,
> +};
> +
> +struct jtag *jtag_alloc(struct device *host, size_t priv_size,
> + const struct jtag_ops *ops)
> +{
> + struct jtag *jtag;
> +
> + if (!host)
> + return NULL;
> +
> + if (!ops)
> + return NULL;
> +
> + if (!ops->idle || !ops->status_get || !ops->xfer)
> + return NULL;
> +
> + jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
> + if (!jtag)
> + return NULL;
> +
> + jtag->ops = ops;
> + jtag->miscdev.parent = host;
> +
> + return jtag;
> +}
> +EXPORT_SYMBOL_GPL(jtag_alloc);
> +
> +void jtag_free(struct jtag *jtag)
> +{
> + kfree(jtag);
> +}
> +EXPORT_SYMBOL_GPL(jtag_free);
> +
> +static int jtag_register(struct jtag *jtag)
> +{
> + struct device *dev = jtag->miscdev.parent;
> + char *name;
> + int err;
> + int id;
> +
> + if (!dev)
> + return -ENODEV;
> +
> + if (atomic_read(&jtag_refcount) >= MAX_JTAG_DEVS)
> + return -ENOSPC;
Here, you are reading the value, and then setting it a long ways away.
What happens if two people call this at the same time. Not good.
Either do it correctly, or better yet, don't do it at all.
> +
> + id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
> + if (id < 0)
> + return id;
> +
> + jtag->id = id;
> + jtag->opened = false;
> +
> + name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
> + if (!name) {
> + err = -ENOMEM;
> + goto err_jtag_alloc;
> + }
> +
> + err = snprintf(name, MAX_JTAG_NAME_LEN, "jtag%d", id);
> + if (err < 0)
> + goto err_jtag_name;
> +
> + mutex_init(&jtag->open_lock);
> + jtag->miscdev.fops = &jtag_fops;
> + jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
> + jtag->miscdev.name = name;
> +
> + err = misc_register(&jtag->miscdev);
> + if (err) {
> + dev_err(jtag->miscdev.parent, "Unable to register device\n");
> + goto err_jtag_name;
> + }
> + pr_info("%s %d\n", __func__, __LINE__);
> + atomic_inc(&jtag_refcount);
> + return 0;
> +
> +err_jtag_name:
> + kfree(name);
> +err_jtag_alloc:
> + ida_simple_remove(&jtag_ida, id);
> + return err;
> +}
> +
> +static void jtag_unregister(struct jtag *jtag)
> +{
> + misc_deregister(&jtag->miscdev);
> + kfree(jtag->miscdev.name);
> + ida_simple_remove(&jtag_ida, jtag->id);
> + atomic_dec(&jtag_refcount);
> +}
> +
> +static void devm_jtag_unregister(struct device *dev, void *res)
> +{
> + jtag_unregister(*(struct jtag **)res);
> +}
> +
> +int devm_jtag_register(struct device *dev, struct jtag *jtag)
> +{
> + struct jtag **ptr;
> + int ret;
> +
> + ptr = devres_alloc(devm_jtag_unregister, sizeof(*ptr), GFP_KERNEL);
> + if (!ptr)
> + return -ENOMEM;
> +
> + ret = jtag_register(jtag);
> + if (!ret) {
> + *ptr = jtag;
> + devres_add(dev, ptr);
> + } else {
> + devres_free(ptr);
> + }
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(devm_jtag_register);
> +
> +static void __exit jtag_exit(void)
> +{
> + ida_destroy(&jtag_ida);
> +}
> +
> +module_exit(jtag_exit);
> +
> +MODULE_AUTHOR("Oleksandr Shamray <[email protected]>");
> +MODULE_DESCRIPTION("Generic jtag support");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/jtag.h b/include/linux/jtag.h
> new file mode 100644
> index 0000000..56d784d
> --- /dev/null
> +++ b/include/linux/jtag.h
> @@ -0,0 +1,43 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// include/linux/jtag.h - JTAG class driver
> +//
> +// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
> +// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
> +
> +#ifndef __JTAG_H
> +#define __JTAG_H
> +
> +#include <uapi/linux/jtag.h>
> +
> +#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
Why do you need such a horrid cast? What is this for? And why use
uintptr_t at all? It's not a "normal" kernel type.
> +
> +#define JTAG_MAX_XFER_DATA_LEN 65535
> +
> +struct jtag;
> +/**
> + * struct jtag_ops - callbacks for JTAG control functions:
> + *
> + * @freq_get: get frequency function. Filled by dev driver
> + * @freq_set: set frequency function. Filled by dev driver
> + * @status_get: set status function. Mandatory func. Filled by dev driver
> + * @idle: set JTAG to idle state function. Mandatory func. Filled by dev driver
> + * @xfer: send JTAG xfer function. Mandatory func. Filled by dev driver
> + * @mode_set: set specific work mode for JTAG. Filled by dev driver
> + */
> +struct jtag_ops {
> + int (*freq_get)(struct jtag *jtag, u32 *freq);
> + int (*freq_set)(struct jtag *jtag, u32 freq);
> + int (*status_get)(struct jtag *jtag, u32 *state);
> + int (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
> + int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
> + int (*mode_set)(struct jtag *jtag, u32 mode_mask);
> +};
> +
> +void *jtag_priv(struct jtag *jtag);
> +int devm_jtag_register(struct device *dev, struct jtag *jtag);
> +void devm_jtag_unregister(struct device *dev, void *res);
> +struct jtag *jtag_alloc(struct device *host, size_t priv_size,
> + const struct jtag_ops *ops);
> +void jtag_free(struct jtag *jtag);
> +
> +#endif /* __JTAG_H */
> diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
> new file mode 100644
> index 0000000..8bbf1a7
> --- /dev/null
> +++ b/include/uapi/linux/jtag.h
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// include/uapi/linux/jtag.h - JTAG class driver uapi
> +//
> +// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
> +// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
> +
> +#ifndef __UAPI_LINUX_JTAG_H
> +#define __UAPI_LINUX_JTAG_H
> +
> +/*
> + * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived or bitbang
> + * mode. This is bitmask param of ioctl JTAG_SIOCMODE command
> + */
> +#define JTAG_XFER_HW_MODE 1
> +
> +/**
> + * enum jtag_endstate:
> + *
> + * @JTAG_STATE_IDLE: JTAG state machine IDLE state
> + * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
> + * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
> + */
> +enum jtag_endstate {
> + JTAG_STATE_IDLE,
> + JTAG_STATE_PAUSEIR,
> + JTAG_STATE_PAUSEDR,
> +};
> +
> +/**
> + * enum jtag_xfer_type:
> + *
> + * @JTAG_SIR_XFER: SIR transfer
> + * @JTAG_SDR_XFER: SDR transfer
> + */
> +enum jtag_xfer_type {
> + JTAG_SIR_XFER,
> + JTAG_SDR_XFER,
> +};
> +
> +/**
> + * enum jtag_xfer_direction:
> + *
> + * @JTAG_READ_XFER: read transfer
> + * @JTAG_WRITE_XFER: write transfer
> + */
> +enum jtag_xfer_direction {
> + JTAG_READ_XFER,
> + JTAG_WRITE_XFER,
> +};
> +
> +/**
> + * struct jtag_run_test_idle - forces JTAG state machine to
> + * RUN_TEST/IDLE state
> + *
> + * @reset: 0 - run IDLE/PAUSE from current state
> + * 1 - go through TEST_LOGIC/RESET state before IDLE/PAUSE
> + * @end: completion flag
> + * @tck: clock counter
> + *
> + * Structure provide interface to JTAG device for JTAG IDLE execution.
> + */
> +struct jtag_run_test_idle {
> + __u8 reset;
> + __u8 endstate;
> + __u8 tck;
> +};
> +
> +/**
> + * struct jtag_xfer - jtag xfer:
> + *
> + * @type: transfer type
> + * @direction: xfer direction
> + * @length: xfer bits len
> + * @tdio : xfer data array
> + * @endir: xfer end state
> + *
> + * Structure provide interface to JTAG device for JTAG SDR/SIR xfer execution.
> + */
> +struct jtag_xfer {
> + __u8 type;
> + __u8 direction;
> + __u8 endstate;
> + __u8 padding;
> + __u32 length;
> + __u64 tdio;
> +};
> +
> +/* ioctl interface */
> +#define __JTAG_IOCTL_MAGIC 0xb2
> +
> +#define JTAG_IOCRUNTEST _IOW(__JTAG_IOCTL_MAGIC, 0,\
> + struct jtag_run_test_idle)
No need for 2 lines here, fits just fine on one.
> +#define JTAG_SIOCFREQ _IOW(__JTAG_IOCTL_MAGIC, 1, unsigned int)
> +#define JTAG_GIOCFREQ _IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
> +#define JTAG_IOCXFER _IOWR(__JTAG_IOCTL_MAGIC, 3, struct jtag_xfer)
> +#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum jtag_endstate)
> +#define JTAG_SIOCMODE _IOW(__JTAG_IOCTL_MAGIC, 5, unsigned int)
> +
> +#define JTAG_FIRST_MINOR 0
Why is this in a uapi file?
> +#define JTAG_MAX_DEVICES 32
This is never used, why is it in a uapi file?
So, almost there, with the above mentioned things, I think you can make
the code even simpler, which is always better, right?
thanks,
greg k-h
Hi Greg.
Thanks for your review.
Please see my comments inline.
Best Regards,
Oleksandr Shamray
> -----Original Message-----
> From: Greg KH [mailto:[email protected]]
> Sent: 28 ??? 2018 ?. 15:35
> To: Oleksandr Shamray <[email protected]>
> Cc: [email protected]; [email protected]; linux-arm-
> [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; Vadim Pasternak
> <[email protected]>; system-sw-low-level <system-sw-low-
> [email protected]>; [email protected]; openocd-devel-
> [email protected]; [email protected];
> [email protected]; [email protected]
> Subject: Re: [patch v22 1/4] drivers: jtag: Add JTAG core driver
>
> On Mon, May 28, 2018 at 01:34:09PM +0300, Oleksandr Shamray wrote:
> > Initial patch for JTAG driver
> > JTAG class driver provide infrastructure to support hardware/software
> > JTAG platform drivers. It provide user layer API interface for
> > flashing and debugging external devices which equipped with JTAG
> > interface using standard transactions.
> >
> > Driver exposes set of IOCTL to user space for:
> > - XFER:
> > - SIR (Scan Instruction Register, IEEE 1149.1 Data Register scan);
> > - SDR (Scan Data Register, IEEE 1149.1 Instruction Register scan);
> > - RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
> > number of clocks).
> > - SIOCFREQ/GIOCFREQ for setting and reading JTAG frequency.
> >
> > Driver core provides set of internal APIs for allocation and
> > registration:
> > - jtag_register;
> > - jtag_unregister;
> > - jtag_alloc;
> > - jtag_free;
> >
> > Platform driver on registration with jtag-core creates the next entry
> > in dev folder:
> > /dev/jtagX
> >
> > Signed-off-by: Oleksandr Shamray <[email protected]>
> > Signed-off-by: Jiri Pirko <[email protected]>
> > Acked-by: Philippe Ombredanne <[email protected]>
> > ---
> > v21->v22
>
> 22 versions, way to stick with this...
>
> Anyway, time to review it again. I feel it's really close, but I don't want to
> apply it yet as the api feels odd in places. If others have asked you to make
> these changes to look like this, I'm sorry, then please push back on me:
>
> > +/*
> > + * JTAG core driver supports up to 256 devices
> > + * JTAG device name will be in range jtag0-jtag255
> > + * Set maximum len of jtag id to 3
> > + */
> > +
> > +#define MAX_JTAG_DEVS 255
>
> Why have a max at all? You should be able to just dynamically allocate them.
> Anyway, if you do want a max, you need to be able to properly keep the max
> number, and right now you have a race when registering (you check the
> number, and then much later do you increment it, a pointless use of an
> atomic value if I've ever seen one...)
>
You are right. It's not good idea to have restriction of max dev number.
I will remove all regarding It.
> > +#define MAX_JTAG_NAME_LEN (sizeof("jtag") + 3)
> > +
> > +struct jtag {
> > + struct miscdevice miscdev;
>
> If you are a miscdev, why even have a max number? Just let the max
> number of miscdev devices rule things.
>
> > + const struct jtag_ops *ops;
> > + int id;
> > + bool opened;
>
> You shouldn't care about this, but ok...
Jtag HW not support to using with multiple requests from different users. So we prohibit this.
>
> > + struct mutex open_lock;
> > + unsigned long priv[0];
> > +};
> > +
> > +static DEFINE_IDA(jtag_ida);
> > +
> > +static atomic_t jtag_refcount = ATOMIC_INIT(0);
>
> Either use it as an atomic properly (test_and_set), or just leave it as an int, or
> better yet, don't use it at all.
It will be removed.
>
> > +void *jtag_priv(struct jtag *jtag)
> > +{
> > + return jtag->priv;
> > +}
> > +EXPORT_SYMBOL_GPL(jtag_priv);
>
> Api naming issue here. Traditionally this is a "get/set_drvdata" type function,
> as in dev_get_drvdata(), or dev_set_drvdata. But, you are right in that the
> network stack has a netdev_priv() call, where you probably copied this idea
> from.
>
> I don't know, I guess it's ok as-is, as it's the way networking does it, it's your
> call though.
>
Yes, I did as in networking.
> > +static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned
> > +long arg) {
> > + struct jtag *jtag = file->private_data;
> > + struct jtag_run_test_idle idle;
> > + struct jtag_xfer xfer;
> > + u8 *xfer_data;
> > + u32 data_size;
> > + u32 value;
> > + int err;
> > +
> > + if (!arg)
> > + return -EINVAL;
> > +
> > + switch (cmd) {
> > + case JTAG_GIOCFREQ:
> > + if (!jtag->ops->freq_get)
> > + return -EOPNOTSUPP;
> > +
> > + err = jtag->ops->freq_get(jtag, &value);
> > + if (err)
> > + break;
> > +
> > + if (put_user(value, (__u32 __user *)arg))
> > + err = -EFAULT;
> > + break;
> > +
> > + case JTAG_SIOCFREQ:
> > + if (!jtag->ops->freq_set)
> > + return -EOPNOTSUPP;
> > +
> > + if (get_user(value, (__u32 __user *)arg))
> > + return -EFAULT;
> > + if (value == 0)
> > + return -EINVAL;
> > +
> > + err = jtag->ops->freq_set(jtag, value);
> > + break;
> > +
> > + case JTAG_IOCRUNTEST:
> > + if (copy_from_user(&idle, (const void __user *)arg,
> > + sizeof(struct jtag_run_test_idle)))
> > + return -EFAULT;
> > +
> > + if (idle.endstate > JTAG_STATE_PAUSEDR)
> > + return -EINVAL;
>
> No validation that idle contains sane values? Don't make every jtag driver
> have to do this type of validation please.
>
I have partially validation of idle structure (if (idle.endstate > JTAG_STATE_PAUSEDR)).
But I will add more validation.
>
> > +
> > + err = jtag->ops->idle(jtag, &idle);
> > + break;
> > +
> > + case JTAG_IOCXFER:
> > + if (copy_from_user(&xfer, (const void __user *)arg,
> > + sizeof(struct jtag_xfer)))
> > + return -EFAULT;
> > +
> > + if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
> > + return -EINVAL;
> > +
> > + if (xfer.type > JTAG_SDR_XFER)
> > + return -EINVAL;
> > +
> > + if (xfer.direction > JTAG_WRITE_XFER)
> > + return -EINVAL;
> > +
> > + if (xfer.endstate > JTAG_STATE_PAUSEDR)
> > + return -EINVAL;
> > +
>
> See, you do good error checking here, why not for the previous ioctl?
>
>
> > + data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
> > + xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio),
> data_size);
> > +
>
> No blank line.
>
Will remove
> > + if (IS_ERR(xfer_data))
> > + return -EFAULT;
> > +
> > + err = jtag->ops->xfer(jtag, &xfer, xfer_data);
> > + if (err) {
> > + kfree(xfer_data);
> > + return -EFAULT;
>
> Why not return the error given to you? -EFAULT is only if there is a memory
> error in a copy_to/from_user() call.
>
Will change return code to err
> > + }
> > +
> > + err = copy_to_user(u64_to_user_ptr(xfer.tdio),
> > + (void *)xfer_data, data_size);
> > + kfree(xfer_data);
> > + if (err)
> > + return -EFAULT;
>
> Like here, that's correct.
>
> > +
> > + if (copy_to_user((void __user *)arg, (void *)&xfer,
> > + sizeof(struct jtag_xfer)))
> > + return -EFAULT;
> > + break;
> > +
> > + case JTAG_GIOCSTATUS:
> > + err = jtag->ops->status_get(jtag, &value);
> > + if (err)
> > + break;
> > +
> > + err = put_user(value, (__u32 __user *)arg);
> > + break;
> > + case JTAG_SIOCMODE:
> > + if (!jtag->ops->mode_set)
> > + return -EOPNOTSUPP;
> > +
> > + if (get_user(value, (__u32 __user *)arg))
> > + return -EFAULT;
> > + if (value == 0)
> > + return -EINVAL;
> > +
> > + err = jtag->ops->mode_set(jtag, value);
> > + break;
> > +
> > + default:
> > + return -EINVAL;
> > + }
> > + return err;
> > +}
> > +
> > +static int jtag_open(struct inode *inode, struct file *file) {
> > + struct jtag *jtag = container_of(file->private_data, struct jtag,
> > +miscdev);
> > +
> > + if (mutex_lock_interruptible(&jtag->open_lock))
> > + return -ERESTARTSYS;
>
> Why restart? Just grab the lock, you don't want to have to do restartable
> logic in userspace, right?
Will change like:
ret = mutex_lock_interruptible(&jtag->open_lock);
if (ret)
return ret;
>
> > +
> > + if (jtag->opened) {
> > + mutex_unlock(&jtag->open_lock);
> > + return -EBUSY;
>
> Why do you care about only 1 userspace open call? What does that buy you?
> Userspace can always pass around that file descriptor and use it in multiple
> places, so you are not really "protecting" yourself from anything.
>
Accessing to JTAG HW from multiple processes will make confusion in the work of the JTAG protocol.
And I want to prohibit this.
> And better yet, if you get rid of this, your open/release functions get very
> tiny and simple.
>
> > + }
> > + jtag->opened = true;
> > + mutex_unlock(&jtag->open_lock);
> > +
> > + nonseekable_open(inode, file);
>
> No error checking of the return value? Not good :(
Will add error handling
>
> > + file->private_data = jtag;
> > + return 0;
> > +}
> > +
> > +static int jtag_release(struct inode *inode, struct file *file) {
> > + struct jtag *jtag = file->private_data;
> > +
> > + mutex_lock(&jtag->open_lock);
> > + jtag->opened = false;
> > + mutex_unlock(&jtag->open_lock);
> > + return 0;
> > +}
> > +
> > +static const struct file_operations jtag_fops = {
> > + .owner = THIS_MODULE,
> > + .open = jtag_open,
> > + .release = jtag_release,
> > + .llseek = noop_llseek,
> > + .unlocked_ioctl = jtag_ioctl,
> > +};
> > +
> > +struct jtag *jtag_alloc(struct device *host, size_t priv_size,
> > + const struct jtag_ops *ops)
> > +{
> > + struct jtag *jtag;
> > +
> > + if (!host)
> > + return NULL;
> > +
> > + if (!ops)
> > + return NULL;
> > +
> > + if (!ops->idle || !ops->status_get || !ops->xfer)
> > + return NULL;
> > +
> > + jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
> > + if (!jtag)
> > + return NULL;
> > +
> > + jtag->ops = ops;
> > + jtag->miscdev.parent = host;
> > +
> > + return jtag;
> > +}
> > +EXPORT_SYMBOL_GPL(jtag_alloc);
> > +
> > +void jtag_free(struct jtag *jtag)
> > +{
> > + kfree(jtag);
> > +}
> > +EXPORT_SYMBOL_GPL(jtag_free);
> > +
> > +static int jtag_register(struct jtag *jtag) {
> > + struct device *dev = jtag->miscdev.parent;
> > + char *name;
> > + int err;
> > + int id;
> > +
> > + if (!dev)
> > + return -ENODEV;
> > +
> > + if (atomic_read(&jtag_refcount) >= MAX_JTAG_DEVS)
> > + return -ENOSPC;
>
> Here, you are reading the value, and then setting it a long ways away.
> What happens if two people call this at the same time. Not good.
> Either do it correctly, or better yet, don't do it at all.
>
Removed.
> > +
> > + id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
> > + if (id < 0)
> > + return id;
> > +
> > + jtag->id = id;
> > + jtag->opened = false;
> > +
> > + name = kzalloc(MAX_JTAG_NAME_LEN, GFP_KERNEL);
> > + if (!name) {
> > + err = -ENOMEM;
> > + goto err_jtag_alloc;
> > + }
> > +
> > + err = snprintf(name, MAX_JTAG_NAME_LEN, "jtag%d", id);
> > + if (err < 0)
> > + goto err_jtag_name;
> > +
> > + mutex_init(&jtag->open_lock);
> > + jtag->miscdev.fops = &jtag_fops;
> > + jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
> > + jtag->miscdev.name = name;
> > +
> > + err = misc_register(&jtag->miscdev);
> > + if (err) {
> > + dev_err(jtag->miscdev.parent, "Unable to register
> device\n");
> > + goto err_jtag_name;
> > + }
> > + pr_info("%s %d\n", __func__, __LINE__);
> > + atomic_inc(&jtag_refcount);
> > + return 0;
> > +
> > +err_jtag_name:
> > + kfree(name);
> > +err_jtag_alloc:
> > + ida_simple_remove(&jtag_ida, id);
> > + return err;
> > +}
> > +
> > +static void jtag_unregister(struct jtag *jtag) {
> > + misc_deregister(&jtag->miscdev);
> > + kfree(jtag->miscdev.name);
> > + ida_simple_remove(&jtag_ida, jtag->id);
> > + atomic_dec(&jtag_refcount);
> > +}
> > +
> > +static void devm_jtag_unregister(struct device *dev, void *res) {
> > + jtag_unregister(*(struct jtag **)res); }
> > +
> > +int devm_jtag_register(struct device *dev, struct jtag *jtag) {
> > + struct jtag **ptr;
> > + int ret;
> > +
> > + ptr = devres_alloc(devm_jtag_unregister, sizeof(*ptr),
> GFP_KERNEL);
> > + if (!ptr)
> > + return -ENOMEM;
> > +
> > + ret = jtag_register(jtag);
> > + if (!ret) {
> > + *ptr = jtag;
> > + devres_add(dev, ptr);
> > + } else {
> > + devres_free(ptr);
> > + }
> > + return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(devm_jtag_register);
> > +
> > +static void __exit jtag_exit(void)
> > +{
> > + ida_destroy(&jtag_ida);
> > +}
> > +
> > +module_exit(jtag_exit);
> > +
> > +MODULE_AUTHOR("Oleksandr Shamray <[email protected]>");
> > +MODULE_DESCRIPTION("Generic jtag support"); MODULE_LICENSE("GPL
> v2");
> > diff --git a/include/linux/jtag.h b/include/linux/jtag.h new file mode
> > 100644 index 0000000..56d784d
> > --- /dev/null
> > +++ b/include/linux/jtag.h
> > @@ -0,0 +1,43 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// include/linux/jtag.h - JTAG class driver // // Copyright (c) 2018
> > +Mellanox Technologies. All rights reserved.
> > +// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
> > +
> > +#ifndef __JTAG_H
> > +#define __JTAG_H
> > +
> > +#include <uapi/linux/jtag.h>
> > +
> > +#define jtag_u64_to_ptr(arg) ((void *)(uintptr_t)arg)
>
> Why do you need such a horrid cast? What is this for? And why use uintptr_t
> at all? It's not a "normal" kernel type.
>
Not needed - will be removed.
> > +
> > +#define JTAG_MAX_XFER_DATA_LEN 65535
> > +
> > +struct jtag;
> > +/**
> > + * struct jtag_ops - callbacks for JTAG control functions:
> > + *
> > + * @freq_get: get frequency function. Filled by dev driver
> > + * @freq_set: set frequency function. Filled by dev driver
> > + * @status_get: set status function. Mandatory func. Filled by dev
> > +driver
> > + * @idle: set JTAG to idle state function. Mandatory func. Filled by
> > +dev driver
> > + * @xfer: send JTAG xfer function. Mandatory func. Filled by dev
> > +driver
> > + * @mode_set: set specific work mode for JTAG. Filled by dev driver
> > +*/ struct jtag_ops {
> > + int (*freq_get)(struct jtag *jtag, u32 *freq);
> > + int (*freq_set)(struct jtag *jtag, u32 freq);
> > + int (*status_get)(struct jtag *jtag, u32 *state);
> > + int (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
> > + int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
> > + int (*mode_set)(struct jtag *jtag, u32 mode_mask); };
> > +
> > +void *jtag_priv(struct jtag *jtag);
> > +int devm_jtag_register(struct device *dev, struct jtag *jtag); void
> > +devm_jtag_unregister(struct device *dev, void *res); struct jtag
> > +*jtag_alloc(struct device *host, size_t priv_size,
> > + const struct jtag_ops *ops);
> > +void jtag_free(struct jtag *jtag);
> > +
> > +#endif /* __JTAG_H */
> > diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h new
> > file mode 100644 index 0000000..8bbf1a7
> > --- /dev/null
> > +++ b/include/uapi/linux/jtag.h
> > @@ -0,0 +1,102 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// include/uapi/linux/jtag.h - JTAG class driver uapi // // Copyright
> > +(c) 2018 Mellanox Technologies. All rights reserved.
> > +// Copyright (c) 2018 Oleksandr Shamray <[email protected]>
> > +
> > +#ifndef __UAPI_LINUX_JTAG_H
> > +#define __UAPI_LINUX_JTAG_H
> > +
> > +/*
> > + * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived
> or
> > +bitbang
> > + * mode. This is bitmask param of ioctl JTAG_SIOCMODE command */
> > +#define JTAG_XFER_HW_MODE 1
> > +
> > +/**
> > + * enum jtag_endstate:
> > + *
> > + * @JTAG_STATE_IDLE: JTAG state machine IDLE state
> > + * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
> > + * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state */
> enum
> > +jtag_endstate {
> > + JTAG_STATE_IDLE,
> > + JTAG_STATE_PAUSEIR,
> > + JTAG_STATE_PAUSEDR,
> > +};
> > +
> > +/**
> > + * enum jtag_xfer_type:
> > + *
> > + * @JTAG_SIR_XFER: SIR transfer
> > + * @JTAG_SDR_XFER: SDR transfer
> > + */
> > +enum jtag_xfer_type {
> > + JTAG_SIR_XFER,
> > + JTAG_SDR_XFER,
> > +};
> > +
> > +/**
> > + * enum jtag_xfer_direction:
> > + *
> > + * @JTAG_READ_XFER: read transfer
> > + * @JTAG_WRITE_XFER: write transfer
> > + */
> > +enum jtag_xfer_direction {
> > + JTAG_READ_XFER,
> > + JTAG_WRITE_XFER,
> > +};
> > +
> > +/**
> > + * struct jtag_run_test_idle - forces JTAG state machine to
> > + * RUN_TEST/IDLE state
> > + *
> > + * @reset: 0 - run IDLE/PAUSE from current state
> > + * 1 - go through TEST_LOGIC/RESET state before IDLE/PAUSE
> > + * @end: completion flag
> > + * @tck: clock counter
> > + *
> > + * Structure provide interface to JTAG device for JTAG IDLE execution.
> > + */
> > +struct jtag_run_test_idle {
> > + __u8 reset;
> > + __u8 endstate;
> > + __u8 tck;
> > +};
> > +
> > +/**
> > + * struct jtag_xfer - jtag xfer:
> > + *
> > + * @type: transfer type
> > + * @direction: xfer direction
> > + * @length: xfer bits len
> > + * @tdio : xfer data array
> > + * @endir: xfer end state
> > + *
> > + * Structure provide interface to JTAG device for JTAG SDR/SIR xfer
> execution.
> > + */
> > +struct jtag_xfer {
> > + __u8 type;
> > + __u8 direction;
> > + __u8 endstate;
> > + __u8 padding;
> > + __u32 length;
> > + __u64 tdio;
> > +};
> > +
> > +/* ioctl interface */
> > +#define __JTAG_IOCTL_MAGIC 0xb2
> > +
> > +#define JTAG_IOCRUNTEST _IOW(__JTAG_IOCTL_MAGIC, 0,\
> > + struct jtag_run_test_idle)
>
> No need for 2 lines here, fits just fine on one.
Ok
>
> > +#define JTAG_SIOCFREQ _IOW(__JTAG_IOCTL_MAGIC, 1, unsigned
> int)
> > +#define JTAG_GIOCFREQ _IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
> > +#define JTAG_IOCXFER _IOWR(__JTAG_IOCTL_MAGIC, 3, struct
> jtag_xfer)
> > +#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum
> jtag_endstate)
> > +#define JTAG_SIOCMODE _IOW(__JTAG_IOCTL_MAGIC, 5, unsigned
> int)
> > +
> > +#define JTAG_FIRST_MINOR 0
>
> Why is this in a uapi file?
Not needed - will be removed.
>
> > +#define JTAG_MAX_DEVICES 32
>
> This is never used, why is it in a uapi file?
>
Not needed - will be removed.
> So, almost there, with the above mentioned things, I think you can make the
> code even simpler, which is always better, right?
>
> thanks,
>
> greg k-h
Thanks.
BR,
Oleksandr Shamray
On 05/28/2018 05:00 AM, Oleksandr Shamray wrote:
> Added document that describe the ABI for JTAG class drivrer
>
> Signed-off-by: Oleksandr Shamray <[email protected]>
> Acked-by: Arnd Bergmann <[email protected]>
> ---
> ---
> Documentation/ABI/testing/jtag-dev | 27 +++++++++
> Documentation/jtag/overview | 28 +++++++++
> Documentation/jtag/transactions | 109 ++++++++++++++++++++++++++++++++++++
> MAINTAINERS | 1 +
> 4 files changed, 165 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/ABI/testing/jtag-dev
> create mode 100644 Documentation/jtag/overview
> create mode 100644 Documentation/jtag/transactions
>
> diff --git a/Documentation/jtag/overview b/Documentation/jtag/overview
> new file mode 100644
> index 0000000..42b487a
> --- /dev/null
> +++ b/Documentation/jtag/overview
> @@ -0,0 +1,28 @@
> +Linux kernel JTAG support
> +=========================
> +
> +The JTAG is an industry standard for verifying hardware.
JTAG is an
> +JTAG provides access to many logic signals of a complex integrated circuit,
> +including the device pins.
> +
> +A JTAG interface is a special interface added to a chip.
> +Depending on the version of JTAG, two, four, or five pins are added.
> +
> +The connector pins are:
> + TDI (Test Data In)
> + TDO (Test Data Out)
> + TCK (Test Clock)
> + TMS (Test Mode Select)
> + TRST (Test Reset) optional
> +
> +JTAG interface is designed to have two parts - basic core driver and
> +hardware specific driver. The basic driver introduces a general interface
> +which is not dependent of specific hardware. It provides communication
> +between user space and hardware specific driver.
> +Each JTAG device is represented as a char device from (jtag0, jtag1, ...).
> +Access to a JTAG device is performed through IOCTL calls.
> +
> +Call flow example:
> +User: open -> /dev/jatgX
> +User: ioctl -> /dev/jtagX -> JTAG core driver -> JTAG hardware specific driver
> +User: close -> /dev/jatgX
> diff --git a/Documentation/jtag/transactions b/Documentation/jtag/transactions
> new file mode 100644
> index 0000000..2abf833
> --- /dev/null
> +++ b/Documentation/jtag/transactions
> @@ -0,0 +1,109 @@
> +The JTAG API
> +=============
> +
> +JTAG master devices can be accessed through a character misc-device.
> +Each JTAG master interface can be accessed by using /dev/jtagN.
> +
> +JTAG system calls set:
> +- SIR (Scan Instruction Register, IEEE 1149.1 Instruction Register scan);
> +- SDR (Scan Data Register, IEEE 1149.1 Data Register scan);
> +- RUNTEST (Forces the IEEE 1149.1 bus to a run state for a specified
> +number of clocks.
> +
> +open(), close()
> +-------
> +open() opens JTAG device. Only one open operation per JTAG device
> +can be performed. Two or more open for one device will return error.
> +
> +Open/Close device:
> +- jtag_fd = open("/dev/jtag0", O_RDWR);
> +- close(jtag_fd);
> +
> +ioctl()
> +-------
> +All access operations to JTAG devices performed through ioctl interface.
to JTAG devices are performed through
> +The IOCTL interface supports these requests:
> + JTAG_IOCRUNTEST - Force JTAG state machine to RUN_TEST/IDLE state
> + JTAG_SIOCFREQ - Set JTAG TCK frequency
> + JTAG_GIOCFREQ - Get JTAG TCK frequency
> + JTAG_IOCXFER - send JTAG data Xfer
> + JTAG_GIOCSTATUS - get current JTAG TAP status
> + JTAG_SIOCMODE - set JTAG mode flags.
> +
> +JTAG_SIOCFREQ, JTAG_GIOCFREQ
> +------
> +Set/Get JTAG clock speed:
> +
> + unsigned int jtag_fd;
> + ioctl(jtag_fd, JTAG_SIOCFREQ, &frq);
> + ioctl(jtag_fd, JTAG_GIOCFREQ, &frq);
> +
> +JTAG_IOCRUNTEST
> +------
> +Force JTAG state machine to RUN_TEST/IDLE state
> +
> +struct jtag_run_test_idle {
> + __u8 reset;
> + __u8 endstate;
> + __u8 tck;
> +};
> +
> +reset: 0 - run IDLE/PAUSE from current state
> + 1 - go through TEST_LOGIC/RESET state before IDLE/PAUSE
before IDLE/PAUSE
> +endstate: completion flag
> +tck: clock counter
> +
> +Example:
> + struct jtag_run_test_idle runtest;
> +
> + runtest.endstate = JTAG_STATE_IDLE;
> + runtest.reset = 0;
> + runtest.tck = data_p->tck;
> + usleep(25 * 1000);
> + ioctl(jtag_fd, JTAG_IOCRUNTEST, &runtest);
> +
> +JTAG_IOCXFER
> +------
> +Send SDR/SIR transaction
> +
> +struct jtag_xfer {
> + __u8 type;
> + __u8 direction;
> + __u8 endstate;
> + __u8 padding;
> + __u32 length;
> + __u64 tdio;
> +};
> +
> +type: transfer type - JTAG_SIR_XFER/JTAG_SDR_XFER
> +direction: xfer direction - JTAG_SIR_XFER/JTAG_SDR_XFER,
drop ending comma ^
> +length: xfer data len in bits
s/len/length/
> +tdio : xfer data array
> +endstate: xfer end state after transaction finish
> + can be: JTAG_STATE_IDLE/JTAG_STATE_PAUSEIR/JTAG_STATE_PAUSEDR
> +
> +Example:
> + struct jtag_xfer xfer;
> + static char buf[64];
> + static unsigned int buf_len = 0;
> + [...]
> + xfer.type = JTAG_SDR_XFER;
> + xfer.tdio = (__u64)buf;
> + xfer.length = buf_len;
> + xfer.endstate = JTAG_STATE_IDLE;
> +
> + if (is_read)
> + xfer.direction = JTAG_READ_XFER;
> + else
> + xfer.direction = JTAG_WRITE_XFER;
> +
> + ioctl(jtag_fd, JTAG_IOCXFER, &xfer);
> +
> +JTAG_SIOCMODE
> +------
> +If hardware driver can support different running modes you can change it.
> +
> +Example:
> + unsigned int mode;
> + mode = JTAG_XFER_HW_MODE;
> + ioctl(jtag_fd, JTAG_SIOCMODE, &mode);
--
~Randy
On Mon, May 28, 2018 at 03:59:46PM +0000, Oleksandr Shamray wrote:
> > > + const struct jtag_ops *ops;
> > > + int id;
> > > + bool opened;
> >
> > You shouldn't care about this, but ok...
>
> Jtag HW not support to using with multiple requests from different users. So we prohibit this.
Ok, but then that's a userspace problem, not your driver's problem.
Serial ports can't handle multiple requests in a sane way either, and so
it's a userspace bug if they do that. It's not up to the kernel to try
to prevent it, and really, you are not preventing this from happening at
all, you are only keeping more than one open() call from happening. You
aren't serializing the device access at all.
So you are giving yourself a false sense of "We are protecting the
device" here. Just drop the whole "only one open() call" logic
entirely. It will make your kernel code simpler and you aren't giving
yourself false-hope that you really prevented userspace from doing
something stupid :)
> > > + case JTAG_IOCRUNTEST:
> > > + if (copy_from_user(&idle, (const void __user *)arg,
> > > + sizeof(struct jtag_run_test_idle)))
> > > + return -EFAULT;
> > > +
> > > + if (idle.endstate > JTAG_STATE_PAUSEDR)
> > > + return -EINVAL;
> >
> > No validation that idle contains sane values? Don't make every jtag driver
> > have to do this type of validation please.
> >
>
> I have partially validation of idle structure (if (idle.endstate > JTAG_STATE_PAUSEDR)).
> But I will add more validation.
Go to the nearest whiteboard and write this at the top:
ALL INPUT IS EVIL
Don't erase it. You have to validate all the things, otherwise
something bad will happen, I guarantee it. Wait until the syzbot gets
ahold of this layer if you don't believe me :)
> > > +static int jtag_open(struct inode *inode, struct file *file) {
> > > + struct jtag *jtag = container_of(file->private_data, struct jtag,
> > > +miscdev);
> > > +
> > > + if (mutex_lock_interruptible(&jtag->open_lock))
> > > + return -ERESTARTSYS;
> >
> > Why restart? Just grab the lock, you don't want to have to do restartable
> > logic in userspace, right?
>
> Will change like:
>
> ret = mutex_lock_interruptible(&jtag->open_lock);
> if (ret)
> return ret;
No, what's wrong with a simple:
mutex_lock();
?
You are only holding it for a very short time, people can wait, there is
no rush here or "fast path" happening.
Anyway, this whole lock should just go away entirely, due to the lack of
needing to track open() calls. But in the future, keep locks simple, no
need to add complexity when it is not warranted.
> > > + if (jtag->opened) {
> > > + mutex_unlock(&jtag->open_lock);
> > > + return -EBUSY;
> >
> > Why do you care about only 1 userspace open call? What does that buy you?
> > Userspace can always pass around that file descriptor and use it in multiple
> > places, so you are not really "protecting" yourself from anything.
> >
>
> Accessing to JTAG HW from multiple processes will make confusion in the work of the JTAG protocol.
> And I want to prohibit this.
See my previous comments for why your attempt at protecting open() does
not prevent this from happening. Hint, you forgot about dup(3) :(
thanks,
greg k-h
Hi Oleksandr,
I love your patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v4.17-rc7]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Oleksandr-Shamray/JTAG-driver-introduction/20180529-185749
config: i386-tinyconfig (attached as .config)
compiler: gcc-8 (Debian 8.1.0-3) 8.1.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All warnings (new ones prefixed by >>):
>> ./usr/include/linux/jtag.h:63: found __[us]{8,16,32,64} type without #include <linux/types.h>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation