From: Suneel Garapati <[email protected]>
Enable use of spi controller on Marvell OcteonTX2 SoC's. This supports
for 1KB data buffer and 4-bit bus width.
Also, support for using fixed time base (TBI Clk) or system
clock (SCLK) as reference clock for SPI bus is provided using
module param tbi_clk_en with default value to 1 (TBI clk).
Signed-off-by: Suneel Garapati <[email protected]>
Signed-off-by: Piyush Malgujar <[email protected]>
---
drivers/spi/Kconfig | 8 +
drivers/spi/Makefile | 1 +
drivers/spi/spi-octeontx2.c | 378 ++++++++++++++++++++++++++++++++++++
drivers/spi/spi-octeontx2.h | 152 +++++++++++++++
4 files changed, 539 insertions(+)
create mode 100644 drivers/spi/spi-octeontx2.c
create mode 100644 drivers/spi/spi-octeontx2.h
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 47bbba04fe3aedc667f54ce3ea930ff0361f6eeb..a81ec7e3532a923902f82d93c5a0c3f57b9bb277 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -694,6 +694,14 @@ config SPI_OCTEON
SPI host driver for the hardware found on some Cavium OCTEON
SOCs.
+config SPI_OCTEONTX2
+ tristate "Marvell OcteonTX2 SPI controller"
+ depends on PCI && 64BIT && (ARM64 || COMPILE_TEST)
+ help
+ This driver supports the OcteonTX2 SPI controller in master
+ mode. It supports single, dual and quad mode transfers.
+ This controller hardware is found on Marvell OcteonTX2 SoCs.
+
config SPI_OMAP_UWIRE
tristate "OMAP1 MicroWire"
depends on ARCH_OMAP1 || (ARM && COMPILE_TEST)
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index d87cf75bee6a45c4244a78f89c5c871bd0257555..64d4311e4cc529df401bd151b5f2e568c768ee24 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -91,6 +91,7 @@ obj-$(CONFIG_SPI_NXP_FLEXSPI) += spi-nxp-fspi.o
obj-$(CONFIG_SPI_OC_TINY) += spi-oc-tiny.o
spi-octeon-objs := spi-cavium.o spi-cavium-octeon.o
obj-$(CONFIG_SPI_OCTEON) += spi-octeon.o
+obj-$(CONFIG_SPI_OCTEONTX2) += spi-octeontx2.o
obj-$(CONFIG_SPI_OMAP_UWIRE) += spi-omap-uwire.o
obj-$(CONFIG_SPI_OMAP24XX) += spi-omap2-mcspi.o
obj-$(CONFIG_SPI_TI_QSPI) += spi-ti-qspi.o
diff --git a/drivers/spi/spi-octeontx2.c b/drivers/spi/spi-octeontx2.c
new file mode 100644
index 0000000000000000000000000000000000000000..80d9355d119de5486a1a3803f798dd0673b0adf1
--- /dev/null
+++ b/drivers/spi/spi-octeontx2.c
@@ -0,0 +1,378 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Marvell OcteonTX2 SPI driver.
+ *
+ * Copyright (C) 2018 Marvell International Ltd.
+ */
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pci.h>
+#include <linux/spi/spi.h>
+
+#include "spi-octeontx2.h"
+
+#define DRV_NAME "spi-octeontx2"
+
+#define TBI_FREQ 100000000 /* 100 Mhz */
+#define SYS_FREQ_DEFAULT 700000000 /* 700 Mhz */
+
+static int tbi_clk_en = 1;
+module_param(tbi_clk_en, uint, 0644);
+MODULE_PARM_DESC(tbi_clk_en,
+ "Use Fixed Time Base 100MHz Reference Clock (0=Disable, 1=Enable [default])");
+
+static int cfg_mode_delay = 30;
+module_param(cfg_mode_delay, uint, 0644);
+MODULE_PARM_DESC(cfg_mode_delay,
+ "Delay in micro-seconds for mode change in MPI CFG register (30 [default])");
+
+static void octeontx2_spi_wait_ready(struct octeontx2_spi *p)
+{
+ union mpix_sts mpi_sts;
+ unsigned int loops = 0;
+
+ mpi_sts.u64 = 0;
+ do {
+ if (loops++)
+ __delay(500);
+ mpi_sts.u64 = readq(p->register_base + OCTEONTX2_SPI_STS(p));
+ } while (mpi_sts.s.busy);
+}
+
+static int octeontx2_spi_do_transfer(struct octeontx2_spi *p,
+ struct spi_message *msg,
+ struct spi_transfer *xfer,
+ bool last_xfer,
+ int cs)
+{
+ void __iomem *wbuf_ptr = p->register_base + OCTEONTX2_SPI_WBUF(p);
+ struct spi_device *spi = msg->spi;
+ void __iomem *rx_ptr = wbuf_ptr;
+ unsigned int clkdiv, calc_spd;
+ union mpix_xmit mpi_xmit;
+ union mpix_cfg mpi_cfg;
+ int mode, len, rem, i;
+ const u8 *tx_buf;
+ bool cpha, cpol;
+ u8 *rx_buf;
+
+ mode = spi->mode;
+ cpha = mode & SPI_CPHA;
+ cpol = mode & SPI_CPOL;
+
+ clkdiv = p->sys_freq / (2 * xfer->speed_hz);
+ /* Perform check to not exceed requested speed */
+ while (1) {
+ calc_spd = p->sys_freq / (2 * clkdiv);
+ if (calc_spd <= xfer->speed_hz)
+ break;
+ clkdiv += 1;
+ }
+
+ if (clkdiv > 8191 || (!tbi_clk_en && clkdiv == 1)) {
+ dev_err(&spi->dev,
+ "can't support xfer->speed_hz %d for reference clock %d\n",
+ xfer->speed_hz, p->sys_freq);
+ return -EINVAL;
+ }
+
+ mpi_cfg.u64 = 0;
+ mpi_cfg.s.clkdiv = clkdiv;
+ mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0;
+ mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0;
+ mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0;
+ mpi_cfg.s.idlelo = cpha != cpol;
+ mpi_cfg.s.cslate = cpha ? 1 : 0;
+ mpi_cfg.s.tritx = 1;
+ mpi_cfg.s.enable = 1;
+ mpi_cfg.s.cs_sticky = 1;
+ mpi_cfg.s.legacy_dis = 1;
+ if (tbi_clk_en)
+ mpi_cfg.s.tb100_en = 1;
+
+ /* Set x1 mode as default */
+ mpi_cfg.s.iomode = 0;
+ /* Set x2 mode if either tx or rx request dual */
+ if (xfer->tx_nbits == SPI_NBITS_DUAL ||
+ xfer->rx_nbits == SPI_NBITS_DUAL)
+ mpi_cfg.s.iomode = 2;
+ /* Set x4 mode if either tx or rx request quad */
+ if (xfer->tx_nbits == SPI_NBITS_QUAD ||
+ xfer->rx_nbits == SPI_NBITS_QUAD)
+ mpi_cfg.s.iomode = 3;
+
+ p->cs_enax |= (0xFull << 12);
+ mpi_cfg.u64 |= p->cs_enax;
+
+ if (mpi_cfg.u64 != p->last_cfg) {
+ p->last_cfg = mpi_cfg.u64;
+ writeq(mpi_cfg.u64, p->register_base + OCTEONTX2_SPI_CFG(p));
+ mpi_cfg.u64 = readq(p->register_base + OCTEONTX2_SPI_CFG(p));
+ udelay(cfg_mode_delay); /* allow CS change to settle */
+ }
+ tx_buf = xfer->tx_buf;
+ rx_buf = xfer->rx_buf;
+ len = xfer->len;
+
+ if (!mpi_cfg.s.iomode && p->rcvd_present)
+ rx_ptr = p->register_base + OCTEONTX2_SPI_RCVD(p);
+
+ while (len > OCTEONTX2_SPI_MAX_BYTES) {
+ if (tx_buf) {
+ /* 8 bytes per iteration */
+ for (i = 0; i < OCTEONTX2_SPI_MAX_BYTES / 8; i++) {
+ u64 data = *(uint64_t *)tx_buf;
+
+ tx_buf += 8;
+ writeq(data, wbuf_ptr + (8 * i));
+ }
+ }
+ mpi_xmit.u64 = 0;
+ mpi_xmit.s.csid = cs;
+ mpi_xmit.s.leavecs = 1;
+ mpi_xmit.s.txnum = tx_buf ? OCTEONTX2_SPI_MAX_BYTES : 0;
+ mpi_xmit.s.totnum = OCTEONTX2_SPI_MAX_BYTES;
+ writeq(mpi_xmit.u64, p->register_base + OCTEONTX2_SPI_XMIT(p));
+
+ octeontx2_spi_wait_ready(p);
+ if (rx_buf) {
+ /* 8 bytes per iteration */
+ for (i = 0; i < OCTEONTX2_SPI_MAX_BYTES / 8; i++) {
+ u64 v;
+
+ v = readq(rx_ptr + (8 * i));
+ *(uint64_t *)rx_buf = v;
+ rx_buf += 8;
+ }
+ }
+ len -= OCTEONTX2_SPI_MAX_BYTES;
+ }
+
+ rem = len % 8;
+
+ if (tx_buf) {
+ u64 data;
+ /* 8 bytes per iteration */
+ for (i = 0; i < len / 8; i++) {
+ data = *(uint64_t *)tx_buf;
+ tx_buf += 8;
+ writeq(data, wbuf_ptr + (8 * i));
+ }
+ /* remaining <8 bytes */
+ if (rem) {
+ data = 0;
+ memcpy(&data, tx_buf, rem);
+ writeq(data, wbuf_ptr + (8 * i));
+ }
+ }
+
+ mpi_xmit.u64 = 0;
+ mpi_xmit.s.csid = cs;
+ if (last_xfer)
+ mpi_xmit.s.leavecs = xfer->cs_change;
+ else
+ mpi_xmit.s.leavecs = !xfer->cs_change;
+ mpi_xmit.s.txnum = tx_buf ? len : 0;
+ mpi_xmit.s.totnum = len;
+ writeq(mpi_xmit.u64, p->register_base + OCTEONTX2_SPI_XMIT(p));
+
+ octeontx2_spi_wait_ready(p);
+ if (rx_buf) {
+ u64 v;
+ /* 8 bytes per iteration */
+ for (i = 0; i < len / 8; i++) {
+ v = readq(rx_ptr + (8 * i));
+ *(uint64_t *)rx_buf = v;
+ rx_buf += 8;
+ }
+ /* remaining <8 bytes */
+ if (rem) {
+ v = readq(rx_ptr + (8 * i));
+ memcpy(rx_buf, &v, rem);
+ rx_buf += rem;
+ }
+ }
+
+ spi_transfer_delay_exec(xfer);
+
+ return xfer->len;
+}
+
+int octeontx2_spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg)
+{
+ struct octeontx2_spi *p = spi_master_get_devdata(master);
+ int cs = msg->spi->chip_select;
+ unsigned int total_len = 0;
+ struct spi_transfer *xfer;
+ int status = 0;
+
+ list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+ bool last_xfer = list_is_last(&xfer->transfer_list,
+ &msg->transfers);
+ int r = octeontx2_spi_do_transfer(p, msg, xfer, last_xfer, cs);
+
+ if (r < 0) {
+ status = r;
+ goto err;
+ }
+ total_len += r;
+ }
+err:
+ msg->status = status;
+ msg->actual_length = total_len;
+ spi_finalize_current_message(master);
+ return status;
+}
+
+static int octeontx2_spi_probe(struct pci_dev *pdev,
+ const struct pci_device_id *ent)
+{
+ struct device *dev = &pdev->dev;
+ struct spi_master *master;
+ struct octeontx2_spi *p;
+ union mpix_sts mpi_sts;
+ int ret = -ENOENT;
+
+ /* may need to hunt for devtree entry */
+ if (!pdev->dev.of_node) {
+ struct device_node *np = of_find_node_by_name(NULL, "spi");
+
+ if (IS_ERR(np)) {
+ ret = PTR_ERR(np);
+ goto error;
+ }
+ pdev->dev.of_node = np;
+ of_node_put(np);
+ }
+
+ master = spi_alloc_master(dev, sizeof(struct octeontx2_spi));
+ if (!master) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ p = spi_master_get_devdata(master);
+
+ ret = pcim_enable_device(pdev);
+ if (ret)
+ goto error_put;
+
+ ret = pci_request_regions(pdev, DRV_NAME);
+ if (ret)
+ goto error_disable;
+
+ p->register_base = pcim_iomap(pdev, 0, pci_resource_len(pdev, 0));
+ if (!p->register_base) {
+ ret = -EINVAL;
+ goto error_disable;
+ }
+
+ p->regs.config = 0x1000;
+ p->regs.status = 0x1008;
+ p->regs.xmit = 0x1018;
+ p->regs.wbuf = 0x1800;
+ p->regs.rcvd = 0x2800;
+ p->last_cfg = 0x0;
+
+ mpi_sts.u64 = readq(p->register_base + OCTEONTX2_SPI_STS(p));
+ p->rcvd_present = mpi_sts.u64 & 0x4 ? true : false;
+
+ p->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(p->clk)) {
+ p->clk = devm_clk_get(dev, "sclk");
+ p->sys_freq = 0;
+ } else {
+ ret = clk_prepare_enable(p->clk);
+ if (!ret)
+ p->sys_freq = clk_get_rate(p->clk);
+ }
+
+ if (!p->sys_freq)
+ p->sys_freq = SYS_FREQ_DEFAULT;
+ if (tbi_clk_en)
+ p->sys_freq = TBI_FREQ;
+ dev_info(dev, "Reference clock is %u\n", p->sys_freq);
+
+ master->num_chipselect = 4;
+ master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH |
+ SPI_LSB_FIRST | SPI_3WIRE |
+ SPI_TX_DUAL | SPI_RX_DUAL |
+ SPI_TX_QUAD | SPI_RX_QUAD;
+ master->transfer_one_message = octeontx2_spi_transfer_one_message;
+ master->bits_per_word_mask = SPI_BPW_MASK(8);
+ master->max_speed_hz = OCTEONTX2_SPI_MAX_CLOCK_HZ;
+ master->dev.of_node = pdev->dev.of_node;
+
+ pci_set_drvdata(pdev, master);
+
+ ret = devm_spi_register_master(dev, master);
+ if (ret)
+ goto error_disable;
+
+ return 0;
+
+error_disable:
+ clk_disable_unprepare(p->clk);
+error_put:
+ spi_master_put(master);
+error:
+ return ret;
+}
+
+static void octeontx2_spi_remove(struct pci_dev *pdev)
+{
+ struct spi_master *master = pci_get_drvdata(pdev);
+ struct octeontx2_spi *p;
+
+ p = spi_master_get_devdata(master);
+ /* Put everything in a known state. */
+ if (p) {
+ clk_disable_unprepare(p->clk);
+ writeq(0, p->register_base + OCTEONTX2_SPI_CFG(p));
+ }
+
+ pci_disable_device(pdev);
+ spi_master_put(master);
+}
+
+static const struct pci_device_id octeontx2_spi_pci_id_table[] = {
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM,
+ PCI_DEVID_OCTEONTX2_SPI,
+ PCI_VENDOR_ID_CAVIUM,
+ PCI_SUBSYS_DEVID_OTX2_98XX) },
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM,
+ PCI_DEVID_OCTEONTX2_SPI,
+ PCI_VENDOR_ID_CAVIUM,
+ PCI_SUBSYS_DEVID_OTX2_96XX) },
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM,
+ PCI_DEVID_OCTEONTX2_SPI,
+ PCI_VENDOR_ID_CAVIUM,
+ PCI_SUBSYS_DEVID_OTX2_95XX) },
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM,
+ PCI_DEVID_OCTEONTX2_SPI,
+ PCI_VENDOR_ID_CAVIUM,
+ PCI_SUBSYS_DEVID_OTX2_LOKI) },
+ { PCI_DEVICE_SUB(PCI_VENDOR_ID_CAVIUM,
+ PCI_DEVID_OCTEONTX2_SPI,
+ PCI_VENDOR_ID_CAVIUM,
+ PCI_SUBSYS_DEVID_OTX2_95MM) },
+ { 0, }
+};
+
+MODULE_DEVICE_TABLE(pci, octeontx2_spi_pci_id_table);
+
+static struct pci_driver octeontx2_spi_driver = {
+ .name = DRV_NAME,
+ .id_table = octeontx2_spi_pci_id_table,
+ .probe = octeontx2_spi_probe,
+ .remove = octeontx2_spi_remove,
+};
+
+module_pci_driver(octeontx2_spi_driver);
+
+MODULE_DESCRIPTION("OcteonTX2 SPI bus driver");
+MODULE_AUTHOR("Marvell Inc.");
+MODULE_LICENSE("GPL");
diff --git a/drivers/spi/spi-octeontx2.h b/drivers/spi/spi-octeontx2.h
new file mode 100644
index 0000000000000000000000000000000000000000..3b09a735e8575faaf59a4562ee16632754764c09
--- /dev/null
+++ b/drivers/spi/spi-octeontx2.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __SPI_OCTEONTX2_H
+#define __SPI_OCTEONTX2_H
+
+#include <linux/clk.h>
+
+#define PCI_DEVID_OCTEONTX2_SPI 0xA00B
+#define PCI_SUBSYS_DEVID_OTX2_98XX 0xB100
+#define PCI_SUBSYS_DEVID_OTX2_96XX 0xB200
+#define PCI_SUBSYS_DEVID_OTX2_95XX 0xB300
+#define PCI_SUBSYS_DEVID_OTX2_LOKI 0xB400
+#define PCI_SUBSYS_DEVID_OTX2_95MM 0xB500
+
+#define OCTEONTX2_SPI_MAX_BYTES 1024
+#define OCTEONTX2_SPI_MAX_CLOCK_HZ 25000000
+
+struct octeontx2_spi_regs {
+ int config;
+ int status;
+ int xmit;
+ int wbuf;
+ int rcvd;
+};
+
+struct octeontx2_spi {
+ void __iomem *register_base;
+ u64 last_cfg;
+ u64 cs_enax;
+ int sys_freq;
+ bool rcvd_present;
+ struct octeontx2_spi_regs regs;
+ struct clk *clk;
+};
+
+#define OCTEONTX2_SPI_CFG(x) ((x)->regs.config)
+#define OCTEONTX2_SPI_STS(x) ((x)->regs.status)
+#define OCTEONTX2_SPI_XMIT(x) ((x)->regs.xmit)
+#define OCTEONTX2_SPI_WBUF(x) ((x)->regs.wbuf)
+#define OCTEONTX2_SPI_RCVD(x) ((x)->regs.rcvd)
+
+int octeontx2_spi_transfer_one_message(struct spi_master *master,
+ struct spi_message *msg);
+
+union mpix_cfg {
+ u64 u64;
+ struct mpix_cfg_s {
+#ifdef __BIG_ENDIAN_BITFIELD
+ uint64_t reserved_50_63:14;
+ uint64_t tb100_en:1;
+ uint64_t reserved_48:1;
+ uint64_t cs_espi_en:4;
+ uint64_t reserved_36_43:8;
+ uint64_t iomode:2;
+ uint64_t reserved_32_33:2;
+ uint64_t legacy_dis:1;
+ uint64_t reserved_29_30:2;
+ uint64_t clkdiv:13;
+ uint64_t csena3:1;
+ uint64_t csena2:1;
+ uint64_t csena1:1;
+ uint64_t csena0:1;
+ uint64_t cslate:1;
+ uint64_t tritx:1;
+ uint64_t idleclks:2;
+ uint64_t cshi:1;
+ uint64_t reserved_6:1;
+ uint64_t cs_sticky:1;
+ uint64_t lsbfirst:1;
+ uint64_t wireor:1;
+ uint64_t clk_cont:1;
+ uint64_t idlelo:1;
+ uint64_t enable:1;
+#else
+ uint64_t enable:1;
+ uint64_t idlelo:1;
+ uint64_t clk_cont:1;
+ uint64_t wireor:1;
+ uint64_t lsbfirst:1;
+ uint64_t cs_sticky:1;
+ uint64_t reserved_6:1;
+ uint64_t cshi:1;
+ uint64_t idleclks:2;
+ uint64_t tritx:1;
+ uint64_t cslate:1;
+ uint64_t csena0:1;
+ uint64_t csena1:1;
+ uint64_t csena2:1;
+ uint64_t csena3:1;
+ uint64_t clkdiv:13;
+ uint64_t reserved_29_30:2;
+ uint64_t legacy_dis:1;
+ uint64_t reserved_32_33:2;
+ uint64_t iomode:2;
+ uint64_t reserved_36_43:8;
+ uint64_t cs_espi_en:4;
+ uint64_t reserved_48:1;
+ uint64_t tb100_en:1;
+ uint64_t reserved_50_63:14;
+#endif
+ } s;
+};
+
+union mpix_sts {
+ u64 u64;
+ struct mpix_sts_s {
+#ifdef __BIG_ENDIAN_BITFIELD
+ uint64_t reserved_40_63:24;
+ uint64_t crc:8;
+ uint64_t reserved_27_31:5;
+ uint64_t crc_err:1;
+ uint64_t reserved_19_25:7;
+ uint64_t rxnum:11;
+ uint64_t reserved_2_7:6;
+ uint64_t mpi_intr:1;
+ uint64_t busy:1;
+#else
+ uint64_t busy:1;
+ uint64_t mpi_intr:1;
+ uint64_t reserved_2_7:6;
+ uint64_t rxnum:11;
+ uint64_t reserved_19_25:7;
+ uint64_t crc_err:1;
+ uint64_t reserved_27_31:5;
+ uint64_t crc:8;
+ uint64_t reserved_40_63:24;
+#endif
+ } s;
+};
+
+union mpix_xmit {
+ u64 u64;
+ struct mpix_xmit_s {
+#ifdef __BIG_ENDIAN_BITFIELD
+ uint64_t reserved_63:1;
+ uint64_t csid:2;
+ uint64_t leavecs:1;
+ uint64_t reserved_31_59:29;
+ uint64_t txnum:11;
+ uint64_t reserved_11_19:9;
+ uint64_t totnum:11;
+#else
+ uint64_t totnum:11;
+ uint64_t reserved_11_19:9;
+ uint64_t txnum:11;
+ uint64_t reserved_31_59:29;
+ uint64_t leavecs:1;
+ uint64_t csid:2;
+ uint64_t reserved_63:1;
+#endif
+ } s;
+};
+#endif /* __SPI_OCTEONTX2_H */
--
2.17.1
Hi Suneel,
[...]
> +static int tbi_clk_en = 1;
bool?
> +module_param(tbi_clk_en, uint, 0644);
> +MODULE_PARM_DESC(tbi_clk_en,
> + "Use Fixed Time Base 100MHz Reference Clock (0=Disable, 1=Enable [default])");
can we avoid using module parameters? You can have these defined
in device tree and you can also make sysfs interfaces, as well.
> +static int cfg_mode_delay = 30;
> +module_param(cfg_mode_delay, uint, 0644);
> +MODULE_PARM_DESC(cfg_mode_delay,
> + "Delay in micro-seconds for mode change in MPI CFG register (30 [default])");
> +
> +static void octeontx2_spi_wait_ready(struct octeontx2_spi *p)
> +{
> + union mpix_sts mpi_sts;
> + unsigned int loops = 0;
> +
> + mpi_sts.u64 = 0;
> + do {
> + if (loops++)
> + __delay(500);
mmhhh... why have you chosen __delay() ?
> + mpi_sts.u64 = readq(p->register_base + OCTEONTX2_SPI_STS(p));
> + } while (mpi_sts.s.busy);
[...]
> + if (mpi_cfg.u64 != p->last_cfg) {
> + p->last_cfg = mpi_cfg.u64;
> + writeq(mpi_cfg.u64, p->register_base + OCTEONTX2_SPI_CFG(p));
> + mpi_cfg.u64 = readq(p->register_base + OCTEONTX2_SPI_CFG(p));
> + udelay(cfg_mode_delay); /* allow CS change to settle */
before "udelaying" anything that the user gives you, I would
check what cfg_mode_delay is.
Andi
On Mon, Mar 27, 2023 at 11:07:52AM -0700, Piyush Malgujar wrote:
> +static int tbi_clk_en = 1;
> +module_param(tbi_clk_en, uint, 0644);
> +MODULE_PARM_DESC(tbi_clk_en,
> + "Use Fixed Time Base 100MHz Reference Clock (0=Disable, 1=Enable [default])");
> +
> +static int cfg_mode_delay = 30;
> +module_param(cfg_mode_delay, uint, 0644);
> +MODULE_PARM_DESC(cfg_mode_delay,
> + "Delay in micro-seconds for mode change in MPI CFG register (30 [default])");
These don't look like they should be configurable at runtime,
either DT or (especially in the second case) just have the driver
do the right thing.
> +static void octeontx2_spi_wait_ready(struct octeontx2_spi *p)
> +{
> + union mpix_sts mpi_sts;
> + unsigned int loops = 0;
> +
> + mpi_sts.u64 = 0;
> + do {
> + if (loops++)
> + __delay(500);
> + mpi_sts.u64 = readq(p->register_base + OCTEONTX2_SPI_STS(p));
> + } while (mpi_sts.s.busy);
Might want a cpu_relax() in there.
> + p->cs_enax |= (0xFull << 12);
> + mpi_cfg.u64 |= p->cs_enax;
> +
> + if (mpi_cfg.u64 != p->last_cfg) {
> + p->last_cfg = mpi_cfg.u64;
> + writeq(mpi_cfg.u64, p->register_base + OCTEONTX2_SPI_CFG(p));
> + mpi_cfg.u64 = readq(p->register_base + OCTEONTX2_SPI_CFG(p));
> + udelay(cfg_mode_delay); /* allow CS change to settle */
> + }
It looks like the hardware has independent control of chip select
so should just implement a set_cs() operation. That seems to be
the only thing stopping the driver using transfer_one() instead
of transfer_one_message() so it should do that too and save more
code.
> + p->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(p->clk)) {
> + p->clk = devm_clk_get(dev, "sclk");
> + p->sys_freq = 0;
> + } else {
> + ret = clk_prepare_enable(p->clk);
> + if (!ret)
> + p->sys_freq = clk_get_rate(p->clk);
> + }
We don't need to enable sclk or care about errors? That seems
buggy. The driver should just rely on the clock API here.
> + if (!p->sys_freq)
> + p->sys_freq = SYS_FREQ_DEFAULT;
> + if (tbi_clk_en)
> + p->sys_freq = TBI_FREQ;
We never seem to do anything to actually configure this in the
hardware.