// SPDX-License-Identifier: GPL-2.0+
//
// Freescale MXS SPI host driver
//
// Copyright 2012 DENX Software Engineering, GmbH.
// Copyright 2012 Freescale Semiconductor, Inc.
// Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
//
// Rework and transition to new API by:
// Marek Vasut <[email protected]>
//
// Based on previous attempt by:
// Fabio Estevam <[email protected]>
//
// Based on code from U-Boot bootloader by:
// Marek Vasut <[email protected]>
//
// Based on spi-stmp.c, which is:
// Author: Dmitry Pervushin <[email protected]>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/highmem.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/completion.h>
#include <linux/pinctrl/consumer.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/module.h>
#include <linux/stmp_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/mxs-spi.h>
#include <trace/events/spi.h>
#include <linux/dma/mxs-dma.h>
#define DRIVER_NAME "mxs-spi"
/* Use 10S timeout for very long transfers, it should suffice. */
#define SSP_TIMEOUT 10000
#define SG_MAXLEN 0xff00
/*
* Flags for txrx functions. More efficient that using an argument register for
* each one.
*/
#define TXRX_WRITE (1<<0) /* This is a write */
#define TXRX_DEASSERT_CS (1<<1) /* De-assert CS at end of txrx */
struct mxs_spi {
struct mxs_ssp ssp;
struct completion c;
unsigned int sck; /* Rate requested (vs actual) */
};
static int mxs_spi_setup_transfer(struct spi_device *dev,
const struct spi_transfer *t)
{
struct mxs_spi *spi = spi_controller_get_devdata(dev->controller);
struct mxs_ssp *ssp = &spi->ssp;
const unsigned int hz = min(dev->max_speed_hz, t->speed_hz);
if (hz == 0) {
dev_err(&dev->dev, "SPI clock rate of zero not allowed\n");
return -EINVAL;
}
if (hz != spi->sck) {
mxs_ssp_set_clk_rate(ssp, hz);
/*
* Save requested rate, hz, rather than the actual rate,
* ssp->clk_rate. Otherwise we would set the rate every transfer
* when the actual rate is not quite the same as requested rate.
*/
spi->sck = hz;
/*
* Perhaps we should return an error if the actual clock is
* nowhere close to what was requested?
*/
}
writel(BM_SSP_CTRL0_LOCK_CS,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) |
BF_SSP_CTRL1_WORD_LENGTH(BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) |
((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) |
((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0),
ssp->base + HW_SSP_CTRL1(ssp));
writel(0x0, ssp->base + HW_SSP_CMD0);
writel(0x0, ssp->base + HW_SSP_CMD1);
return 0;
}
static u32 mxs_spi_cs_to_reg(unsigned cs)
{
u32 select = 0;
/*
* i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0
*
* The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ
* in HW_SSP_CTRL0 register do have multiple usage, please refer to
* the datasheet for further details. In SPI mode, they are used to
* toggle the chip-select lines (nCS pins).
*/
if (cs & 1)
select |= BM_SSP_CTRL0_WAIT_FOR_CMD;
if (cs & 2)
select |= BM_SSP_CTRL0_WAIT_FOR_IRQ;
return select;
}
static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set)
{
const unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT);
struct mxs_ssp *ssp = &spi->ssp;
u32 reg;
do {
reg = readl_relaxed(ssp->base + offset);
if (!set)
reg = ~reg;
reg &= mask;
if (reg == mask)
return 0;
} while (time_before(jiffies, timeout));
return -ETIMEDOUT;
}
static void mxs_ssp_dma_irq_callback(void *param)
{
struct mxs_spi *spi = param;
complete(&spi->c);
}
static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id)
{
struct mxs_ssp *ssp = dev_id;
dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n",
__func__, __LINE__,
readl(ssp->base + HW_SSP_CTRL1(ssp)),
readl(ssp->base + HW_SSP_STATUS(ssp)));
return IRQ_HANDLED;
}
static int mxs_spi_txrx_dma(struct mxs_spi *spi,
unsigned char *buf, int len,
unsigned int flags)
{
struct mxs_ssp *ssp = &spi->ssp;
struct dma_async_tx_descriptor *desc = NULL;
const bool vmalloced_buf = is_vmalloc_addr(buf);
const int desc_len = vmalloced_buf ? PAGE_SIZE : SG_MAXLEN;
const int sgs = DIV_ROUND_UP(len, desc_len);
int sg_count;
int min, ret;
u32 ctrl0;
struct page *vm_page;
struct {
u32 pio[4];
struct scatterlist sg;
} *dma_xfer;
if (!len)
return -EINVAL;
dma_xfer = kcalloc(sgs, sizeof(*dma_xfer), GFP_KERNEL);
if (!dma_xfer)
return -ENOMEM;
reinit_completion(&spi->c);
/* Chip select was already programmed into CTRL0 */
ctrl0 = readl(ssp->base + HW_SSP_CTRL0);
ctrl0 &= ~(BM_SSP_CTRL0_XFER_COUNT | BM_SSP_CTRL0_IGNORE_CRC |
BM_SSP_CTRL0_READ);
ctrl0 |= BM_SSP_CTRL0_DATA_XFER;
if (!(flags & TXRX_WRITE))
ctrl0 |= BM_SSP_CTRL0_READ;
/* Queue the DMA data transfer. */
for (sg_count = 0; sg_count < sgs; sg_count++) {
/* Prepare the transfer descriptor. */
min = min(len, desc_len);
/*
* De-assert CS on last segment if flag is set (i.e., no more
* transfers will follow)
*/
if ((sg_count + 1 == sgs) && (flags & TXRX_DEASSERT_CS))
ctrl0 |= BM_SSP_CTRL0_IGNORE_CRC;
if (ssp->devid == IMX23_SSP) {
ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
ctrl0 |= min;
}
dma_xfer[sg_count].pio[0] = ctrl0;
dma_xfer[sg_count].pio[3] = min;
if (vmalloced_buf) {
vm_page = vmalloc_to_page(buf);
if (!vm_page) {
ret = -ENOMEM;
goto err_vmalloc;
}
sg_init_table(&dma_xfer[sg_count].sg, 1);
sg_set_page(&dma_xfer[sg_count].sg, vm_page,
min, offset_in_page(buf));
} else {
sg_init_one(&dma_xfer[sg_count].sg, buf, min);
}
ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
(flags & TXRX_WRITE) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
len -= min;
buf += min;
/* Queue the PIO register write transfer. */
desc = dmaengine_prep_slave_sg(ssp->dmach,
(struct scatterlist *)dma_xfer[sg_count].pio,
(ssp->devid == IMX23_SSP) ? 1 : 4,
DMA_TRANS_NONE,
sg_count ? DMA_PREP_INTERRUPT : 0);
if (!desc) {
dev_err(ssp->dev,
"Failed to get PIO reg. write descriptor.\n");
ret = -EINVAL;
goto err_mapped;
}
desc = dmaengine_prep_slave_sg(ssp->dmach,
&dma_xfer[sg_count].sg, 1,
(flags & TXRX_WRITE) ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | MXS_DMA_CTRL_WAIT4END);
if (!desc) {
dev_err(ssp->dev,
"Failed to get DMA data write descriptor.\n");
ret = -EINVAL;
goto err_mapped;
}
}
/*
* The last descriptor must have this callback,
* to finish the DMA transaction.
*/
desc->callback = mxs_ssp_dma_irq_callback;
desc->callback_param = spi;
/* Start the transfer. */
dmaengine_submit(desc);
dma_async_issue_pending(ssp->dmach);
if (!wait_for_completion_timeout(&spi->c,
msecs_to_jiffies(SSP_TIMEOUT))) {
dev_err(ssp->dev, "DMA transfer timeout\n");
ret = -ETIMEDOUT;
dmaengine_terminate_all(ssp->dmach);
goto err_vmalloc;
}
ret = 0;
err_vmalloc:
while (--sg_count >= 0) {
err_mapped:
dma_unmap_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
(flags & TXRX_WRITE) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
}
kfree(dma_xfer);
return ret;
}
static int mxs_spi_txrx_pio(struct mxs_spi *spi,
unsigned char *buf, int len,
unsigned int flags)
{
struct mxs_ssp *ssp = &spi->ssp;
writel(BM_SSP_CTRL0_IGNORE_CRC,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
while (len--) {
if (len == 0 && (flags & TXRX_DEASSERT_CS))
writel(BM_SSP_CTRL0_IGNORE_CRC,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
if (ssp->devid == IMX23_SSP) {
writel(BM_SSP_CTRL0_XFER_COUNT,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
writel(1,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
} else {
writel(1, ssp->base + HW_SSP_XFER_SIZE);
}
if (flags & TXRX_WRITE)
writel(BM_SSP_CTRL0_READ,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
else
writel(BM_SSP_CTRL0_READ,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
writel(BM_SSP_CTRL0_RUN,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1))
return -ETIMEDOUT;
if (flags & TXRX_WRITE)
writel(*buf, ssp->base + HW_SSP_DATA(ssp));
writel(BM_SSP_CTRL0_DATA_XFER,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
if (!(flags & TXRX_WRITE)) {
if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp),
BM_SSP_STATUS_FIFO_EMPTY, 0))
return -ETIMEDOUT;
*buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff);
}
if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0))
return -ETIMEDOUT;
buf++;
}
if (len <= 0)
return 0;
return -ETIMEDOUT;
}
static int mxs_spi_transfer_one(struct spi_controller *host,
struct spi_message *m)
{
struct mxs_spi *spi = spi_controller_get_devdata(host);
struct mxs_ssp *ssp = &spi->ssp;
struct spi_transfer *t;
unsigned int flag;
int status = 0;
/* Program CS register bits here, it will be used for all transfers. */
writel(BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ,
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
writel(mxs_spi_cs_to_reg(spi_get_chipselect(m->spi, 0)),
ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
list_for_each_entry(t, &m->transfers, transfer_list) {
trace_spi_transfer_start(m, t);
status = mxs_spi_setup_transfer(m->spi, t);
if (status)
break;
/* De-assert on last transfer, inverted by cs_change flag */
flag = (&t->transfer_list == m->transfers.prev) ^ t->cs_change ?
TXRX_DEASSERT_CS : 0;
/*
* Small blocks can be transfered via PIO.
* Measured by empiric means:
*
* dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1
*
* DMA only: 2.164808 seconds, 473.0KB/s
* Combined: 1.676276 seconds, 610.9KB/s
*/
if (t->len < 32) {
writel(BM_SSP_CTRL1_DMA_ENABLE,
ssp->base + HW_SSP_CTRL1(ssp) +
STMP_OFFSET_REG_CLR);
if (t->tx_buf)
status = mxs_spi_txrx_pio(spi,
(void *)t->tx_buf,
t->len, flag | TXRX_WRITE);
if (t->rx_buf)
status = mxs_spi_txrx_pio(spi,
t->rx_buf, t->len,
flag);
} else {
writel(BM_SSP_CTRL1_DMA_ENABLE,
ssp->base + HW_SSP_CTRL1(ssp) +
STMP_OFFSET_REG_SET);
if (t->tx_buf)
status = mxs_spi_txrx_dma(spi,
(void *)t->tx_buf, t->len,
flag | TXRX_WRITE);
if (t->rx_buf)
status = mxs_spi_txrx_dma(spi,
t->rx_buf, t->len,
flag);
}
trace_spi_transfer_stop(m, t);
if (status) {
stmp_reset_block(ssp->base);
break;
}
m->actual_length += t->len;
}
m->status = status;
spi_finalize_current_message(host);
return status;
}
static int mxs_spi_runtime_suspend(struct device *dev)
{
struct spi_controller *host = dev_get_drvdata(dev);
struct mxs_spi *spi = spi_controller_get_devdata(host);
struct mxs_ssp *ssp = &spi->ssp;
int ret;
clk_disable_unprepare(ssp->clk);
ret = pinctrl_pm_select_idle_state(dev);
if (ret) {
int ret2 = clk_prepare_enable(ssp->clk);
if (ret2)
dev_warn(dev, "Failed to reenable clock after failing pinctrl request (pinctrl: %d, clk: %d)\n",
ret, ret2);
}
return ret;
}
static int mxs_spi_runtime_resume(struct device *dev)
{
struct spi_controller *host = dev_get_drvdata(dev);
struct mxs_spi *spi = spi_controller_get_devdata(host);
struct mxs_ssp *ssp = &spi->ssp;
int ret;
ret = pinctrl_pm_select_default_state(dev);
if (ret)
return ret;
ret = clk_prepare_enable(ssp->clk);
if (ret)
pinctrl_pm_select_idle_state(dev);
return ret;
}
static int __maybe_unused mxs_spi_suspend(struct device *dev)
{
struct spi_controller *host = dev_get_drvdata(dev);
int ret;
ret = spi_controller_suspend(host);
if (ret)
return ret;
if (!pm_runtime_suspended(dev))
return mxs_spi_runtime_suspend(dev);
else
return 0;
}
static int __maybe_unused mxs_spi_resume(struct device *dev)
{
struct spi_controller *host = dev_get_drvdata(dev);
int ret;
if (!pm_runtime_suspended(dev))
ret = mxs_spi_runtime_resume(dev);
else
ret = 0;
if (ret)
return ret;
ret = spi_controller_resume(host);
if (ret < 0 && !pm_runtime_suspended(dev))
mxs_spi_runtime_suspend(dev);
return ret;
}
static const struct dev_pm_ops mxs_spi_pm = {
SET_RUNTIME_PM_OPS(mxs_spi_runtime_suspend,
mxs_spi_runtime_resume, NULL)
SET_SYSTEM_SLEEP_PM_OPS(mxs_spi_suspend, mxs_spi_resume)
};
static const struct of_device_id mxs_spi_dt_ids[] = {
{ .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, },
{ .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids);
static int mxs_spi_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(mxs_spi_dt_ids, &pdev->dev);
struct device_node *np = pdev->dev.of_node;
struct spi_controller *host;
struct mxs_spi *spi;
struct mxs_ssp *ssp;
struct clk *clk;
void __iomem *base;
int devid, clk_freq;
int ret = 0, irq_err;
/*
* Default clock speed for the SPI core. 160MHz seems to
* work reasonably well with most SPI flashes, so use this
* as a default. Override with "clock-frequency" DT prop.
*/
const int clk_freq_default = 160000000;
irq_err = platform_get_irq(pdev, 0);
if (irq_err < 0)
return irq_err;
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk))
return PTR_ERR(clk);
devid = (enum mxs_ssp_id) of_id->data;
ret = of_property_read_u32(np, "clock-frequency",
&clk_freq);
if (ret)
clk_freq = clk_freq_default;
host = spi_alloc_host(&pdev->dev, sizeof(*spi));
if (!host)
return -ENOMEM;
platform_set_drvdata(pdev, host);
host->transfer_one_message = mxs_spi_transfer_one;
host->bits_per_word_mask = SPI_BPW_MASK(8);
host->mode_bits = SPI_CPOL | SPI_CPHA;
host->num_chipselect = 3;
host->dev.of_node = np;
host->flags = SPI_CONTROLLER_HALF_DUPLEX;
host->auto_runtime_pm = true;
spi = spi_controller_get_devdata(host);
ssp = &spi->ssp;
ssp->dev = &pdev->dev;
ssp->clk = clk;
ssp->base = base;
ssp->devid = devid;
init_completion(&spi->c);
ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0,
dev_name(&pdev->dev), ssp);
if (ret)
goto out_host_free;
ssp->dmach = dma_request_chan(&pdev->dev, "rx-tx");
if (IS_ERR(ssp->dmach)) {
dev_err(ssp->dev, "Failed to request DMA\n");
ret = PTR_ERR(ssp->dmach);
goto out_host_free;
}
pm_runtime_enable(ssp->dev);
if (!pm_runtime_enabled(ssp->dev)) {
ret = mxs_spi_runtime_resume(ssp->dev);
if (ret < 0) {
dev_err(ssp->dev, "runtime resume failed\n");
goto out_dma_release;
}
}
ret = pm_runtime_resume_and_get(ssp->dev);
if (ret < 0) {
dev_err(ssp->dev, "runtime_get_sync failed\n");
goto out_pm_runtime_disable;
}
clk_set_rate(ssp->clk, clk_freq);
ret = stmp_reset_block(ssp->base);
if (ret)
goto out_pm_runtime_put;
ret = devm_spi_register_controller(&pdev->dev, host);
if (ret) {
dev_err(&pdev->dev, "Cannot register SPI host, %d\n", ret);
goto out_pm_runtime_put;
}
pm_runtime_put(ssp->dev);
return 0;
out_pm_runtime_put:
pm_runtime_put(ssp->dev);
out_pm_runtime_disable:
pm_runtime_disable(ssp->dev);
out_dma_release:
dma_release_channel(ssp->dmach);
out_host_free:
spi_controller_put(host);
return ret;
}
static void mxs_spi_remove(struct platform_device *pdev)
{
struct spi_controller *host;
struct mxs_spi *spi;
struct mxs_ssp *ssp;
host = platform_get_drvdata(pdev);
spi = spi_controller_get_devdata(host);
ssp = &spi->ssp;
pm_runtime_disable(&pdev->dev);
if (!pm_runtime_status_suspended(&pdev->dev))
mxs_spi_runtime_suspend(&pdev->dev);
dma_release_channel(ssp->dmach);
}
static struct platform_driver mxs_spi_driver = {
.probe = mxs_spi_probe,
.remove_new = mxs_spi_remove,
.driver = {
.name = DRIVER_NAME,
.of_match_table = mxs_spi_dt_ids,
.pm = &mxs_spi_pm,
},
};
module_platform_driver(mxs_spi_driver);
MODULE_AUTHOR("Marek Vasut <[email protected]>");
MODULE_DESCRIPTION("MXS SPI host driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mxs-spi");
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