linux/drivers/spi/coldfire_qspi.c
Steven King 34b8c66173 spi: Add Freescale/Motorola Coldfire QSPI driver
Add support for the QSPI controller found some on Freescale/Motorola
Coldfire MCUs.

Full duplex, active high cs, spi modes 0-3 and word sizes 8-16 bits are
supported.  The hardware drives the MISO, MOSI and SCLK lines, but the chip
selects are managed via GPIO and must be configured by the board code.

The QSPI controller has an 80 byte buffer which allows us to transfer up to 16
words at a time.  For transfers longer than 16 words, we split the buffer in
half so we can update in one half while the controller is operating on the
other half.  Interrupt latencies then ultimately limits our sustained thru-put
to something less than half the maximum speed supported by the part.

Signed-off-by: Steven King <sfking@fdwdc.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2010-01-20 13:49:44 -07:00

641 lines
16 KiB
C

/*
* Freescale/Motorola Coldfire Queued SPI driver
*
* Copyright 2010 Steven King <sfking@fdwdc.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/spi/spi.h>
#include <asm/coldfire.h>
#include <asm/mcfqspi.h>
#define DRIVER_NAME "mcfqspi"
#define MCFQSPI_BUSCLK (MCF_BUSCLK / 2)
#define MCFQSPI_QMR 0x00
#define MCFQSPI_QMR_MSTR 0x8000
#define MCFQSPI_QMR_CPOL 0x0200
#define MCFQSPI_QMR_CPHA 0x0100
#define MCFQSPI_QDLYR 0x04
#define MCFQSPI_QDLYR_SPE 0x8000
#define MCFQSPI_QWR 0x08
#define MCFQSPI_QWR_HALT 0x8000
#define MCFQSPI_QWR_WREN 0x4000
#define MCFQSPI_QWR_CSIV 0x1000
#define MCFQSPI_QIR 0x0C
#define MCFQSPI_QIR_WCEFB 0x8000
#define MCFQSPI_QIR_ABRTB 0x4000
#define MCFQSPI_QIR_ABRTL 0x1000
#define MCFQSPI_QIR_WCEFE 0x0800
#define MCFQSPI_QIR_ABRTE 0x0400
#define MCFQSPI_QIR_SPIFE 0x0100
#define MCFQSPI_QIR_WCEF 0x0008
#define MCFQSPI_QIR_ABRT 0x0004
#define MCFQSPI_QIR_SPIF 0x0001
#define MCFQSPI_QAR 0x010
#define MCFQSPI_QAR_TXBUF 0x00
#define MCFQSPI_QAR_RXBUF 0x10
#define MCFQSPI_QAR_CMDBUF 0x20
#define MCFQSPI_QDR 0x014
#define MCFQSPI_QCR 0x014
#define MCFQSPI_QCR_CONT 0x8000
#define MCFQSPI_QCR_BITSE 0x4000
#define MCFQSPI_QCR_DT 0x2000
struct mcfqspi {
void __iomem *iobase;
int irq;
struct clk *clk;
struct mcfqspi_cs_control *cs_control;
wait_queue_head_t waitq;
struct work_struct work;
struct workqueue_struct *workq;
spinlock_t lock;
struct list_head msgq;
};
static void mcfqspi_wr_qmr(struct mcfqspi *mcfqspi, u16 val)
{
writew(val, mcfqspi->iobase + MCFQSPI_QMR);
}
static void mcfqspi_wr_qdlyr(struct mcfqspi *mcfqspi, u16 val)
{
writew(val, mcfqspi->iobase + MCFQSPI_QDLYR);
}
static u16 mcfqspi_rd_qdlyr(struct mcfqspi *mcfqspi)
{
return readw(mcfqspi->iobase + MCFQSPI_QDLYR);
}
static void mcfqspi_wr_qwr(struct mcfqspi *mcfqspi, u16 val)
{
writew(val, mcfqspi->iobase + MCFQSPI_QWR);
}
static void mcfqspi_wr_qir(struct mcfqspi *mcfqspi, u16 val)
{
writew(val, mcfqspi->iobase + MCFQSPI_QIR);
}
static void mcfqspi_wr_qar(struct mcfqspi *mcfqspi, u16 val)
{
writew(val, mcfqspi->iobase + MCFQSPI_QAR);
}
static void mcfqspi_wr_qdr(struct mcfqspi *mcfqspi, u16 val)
{
writew(val, mcfqspi->iobase + MCFQSPI_QDR);
}
static u16 mcfqspi_rd_qdr(struct mcfqspi *mcfqspi)
{
return readw(mcfqspi->iobase + MCFQSPI_QDR);
}
static void mcfqspi_cs_select(struct mcfqspi *mcfqspi, u8 chip_select,
bool cs_high)
{
mcfqspi->cs_control->select(mcfqspi->cs_control, chip_select, cs_high);
}
static void mcfqspi_cs_deselect(struct mcfqspi *mcfqspi, u8 chip_select,
bool cs_high)
{
mcfqspi->cs_control->deselect(mcfqspi->cs_control, chip_select, cs_high);
}
static int mcfqspi_cs_setup(struct mcfqspi *mcfqspi)
{
return (mcfqspi->cs_control && mcfqspi->cs_control->setup) ?
mcfqspi->cs_control->setup(mcfqspi->cs_control) : 0;
}
static void mcfqspi_cs_teardown(struct mcfqspi *mcfqspi)
{
if (mcfqspi->cs_control && mcfqspi->cs_control->teardown)
mcfqspi->cs_control->teardown(mcfqspi->cs_control);
}
static u8 mcfqspi_qmr_baud(u32 speed_hz)
{
return clamp((MCFQSPI_BUSCLK + speed_hz - 1) / speed_hz, 2u, 255u);
}
static bool mcfqspi_qdlyr_spe(struct mcfqspi *mcfqspi)
{
return mcfqspi_rd_qdlyr(mcfqspi) & MCFQSPI_QDLYR_SPE;
}
static irqreturn_t mcfqspi_irq_handler(int this_irq, void *dev_id)
{
struct mcfqspi *mcfqspi = dev_id;
/* clear interrupt */
mcfqspi_wr_qir(mcfqspi, MCFQSPI_QIR_SPIFE | MCFQSPI_QIR_SPIF);
wake_up(&mcfqspi->waitq);
return IRQ_HANDLED;
}
static void mcfqspi_transfer_msg8(struct mcfqspi *mcfqspi, unsigned count,
const u8 *txbuf, u8 *rxbuf)
{
unsigned i, n, offset = 0;
n = min(count, 16u);
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_CMDBUF);
for (i = 0; i < n; ++i)
mcfqspi_wr_qdr(mcfqspi, MCFQSPI_QCR_BITSE);
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_TXBUF);
if (txbuf)
for (i = 0; i < n; ++i)
mcfqspi_wr_qdr(mcfqspi, *txbuf++);
else
for (i = 0; i < count; ++i)
mcfqspi_wr_qdr(mcfqspi, 0);
count -= n;
if (count) {
u16 qwr = 0xf08;
mcfqspi_wr_qwr(mcfqspi, 0x700);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
do {
wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
mcfqspi_wr_qwr(mcfqspi, qwr);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
if (rxbuf) {
mcfqspi_wr_qar(mcfqspi,
MCFQSPI_QAR_RXBUF + offset);
for (i = 0; i < 8; ++i)
*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
}
n = min(count, 8u);
if (txbuf) {
mcfqspi_wr_qar(mcfqspi,
MCFQSPI_QAR_TXBUF + offset);
for (i = 0; i < n; ++i)
mcfqspi_wr_qdr(mcfqspi, *txbuf++);
}
qwr = (offset ? 0x808 : 0) + ((n - 1) << 8);
offset ^= 8;
count -= n;
} while (count);
wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
mcfqspi_wr_qwr(mcfqspi, qwr);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
if (rxbuf) {
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
for (i = 0; i < 8; ++i)
*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
offset ^= 8;
}
} else {
mcfqspi_wr_qwr(mcfqspi, (n - 1) << 8);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
}
wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
if (rxbuf) {
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
for (i = 0; i < n; ++i)
*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
}
}
static void mcfqspi_transfer_msg16(struct mcfqspi *mcfqspi, unsigned count,
const u16 *txbuf, u16 *rxbuf)
{
unsigned i, n, offset = 0;
n = min(count, 16u);
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_CMDBUF);
for (i = 0; i < n; ++i)
mcfqspi_wr_qdr(mcfqspi, MCFQSPI_QCR_BITSE);
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_TXBUF);
if (txbuf)
for (i = 0; i < n; ++i)
mcfqspi_wr_qdr(mcfqspi, *txbuf++);
else
for (i = 0; i < count; ++i)
mcfqspi_wr_qdr(mcfqspi, 0);
count -= n;
if (count) {
u16 qwr = 0xf08;
mcfqspi_wr_qwr(mcfqspi, 0x700);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
do {
wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
mcfqspi_wr_qwr(mcfqspi, qwr);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
if (rxbuf) {
mcfqspi_wr_qar(mcfqspi,
MCFQSPI_QAR_RXBUF + offset);
for (i = 0; i < 8; ++i)
*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
}
n = min(count, 8u);
if (txbuf) {
mcfqspi_wr_qar(mcfqspi,
MCFQSPI_QAR_TXBUF + offset);
for (i = 0; i < n; ++i)
mcfqspi_wr_qdr(mcfqspi, *txbuf++);
}
qwr = (offset ? 0x808 : 0x000) + ((n - 1) << 8);
offset ^= 8;
count -= n;
} while (count);
wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
mcfqspi_wr_qwr(mcfqspi, qwr);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
if (rxbuf) {
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
for (i = 0; i < 8; ++i)
*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
offset ^= 8;
}
} else {
mcfqspi_wr_qwr(mcfqspi, (n - 1) << 8);
mcfqspi_wr_qdlyr(mcfqspi, MCFQSPI_QDLYR_SPE);
}
wait_event(mcfqspi->waitq, !mcfqspi_qdlyr_spe(mcfqspi));
if (rxbuf) {
mcfqspi_wr_qar(mcfqspi, MCFQSPI_QAR_RXBUF + offset);
for (i = 0; i < n; ++i)
*rxbuf++ = mcfqspi_rd_qdr(mcfqspi);
}
}
static void mcfqspi_work(struct work_struct *work)
{
struct mcfqspi *mcfqspi = container_of(work, struct mcfqspi, work);
unsigned long flags;
spin_lock_irqsave(&mcfqspi->lock, flags);
while (!list_empty(&mcfqspi->msgq)) {
struct spi_message *msg;
struct spi_device *spi;
struct spi_transfer *xfer;
int status = 0;
msg = container_of(mcfqspi->msgq.next, struct spi_message,
queue);
list_del_init(&mcfqspi->msgq);
spin_unlock_irqrestore(&mcfqspi->lock, flags);
spi = msg->spi;
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
bool cs_high = spi->mode & SPI_CS_HIGH;
u16 qmr = MCFQSPI_QMR_MSTR;
if (xfer->bits_per_word)
qmr |= xfer->bits_per_word << 10;
else
qmr |= spi->bits_per_word << 10;
if (spi->mode & SPI_CPHA)
qmr |= MCFQSPI_QMR_CPHA;
if (spi->mode & SPI_CPOL)
qmr |= MCFQSPI_QMR_CPOL;
if (xfer->speed_hz)
qmr |= mcfqspi_qmr_baud(xfer->speed_hz);
else
qmr |= mcfqspi_qmr_baud(spi->max_speed_hz);
mcfqspi_wr_qmr(mcfqspi, qmr);
mcfqspi_cs_select(mcfqspi, spi->chip_select, cs_high);
mcfqspi_wr_qir(mcfqspi, MCFQSPI_QIR_SPIFE);
if ((xfer->bits_per_word ? xfer->bits_per_word :
spi->bits_per_word) == 8)
mcfqspi_transfer_msg8(mcfqspi, xfer->len,
xfer->tx_buf,
xfer->rx_buf);
else
mcfqspi_transfer_msg16(mcfqspi, xfer->len / 2,
xfer->tx_buf,
xfer->rx_buf);
mcfqspi_wr_qir(mcfqspi, 0);
if (xfer->delay_usecs)
udelay(xfer->delay_usecs);
if (xfer->cs_change) {
if (!list_is_last(&xfer->transfer_list,
&msg->transfers))
mcfqspi_cs_deselect(mcfqspi,
spi->chip_select,
cs_high);
} else {
if (list_is_last(&xfer->transfer_list,
&msg->transfers))
mcfqspi_cs_deselect(mcfqspi,
spi->chip_select,
cs_high);
}
msg->actual_length += xfer->len;
}
msg->status = status;
msg->complete(msg->context);
spin_lock_irqsave(&mcfqspi->lock, flags);
}
spin_unlock_irqrestore(&mcfqspi->lock, flags);
}
static int mcfqspi_transfer(struct spi_device *spi, struct spi_message *msg)
{
struct mcfqspi *mcfqspi;
struct spi_transfer *xfer;
unsigned long flags;
mcfqspi = spi_master_get_devdata(spi->master);
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
if (xfer->bits_per_word && ((xfer->bits_per_word < 8)
|| (xfer->bits_per_word > 16))) {
dev_dbg(&spi->dev,
"%d bits per word is not supported\n",
xfer->bits_per_word);
goto fail;
}
if (xfer->speed_hz) {
u32 real_speed = MCFQSPI_BUSCLK /
mcfqspi_qmr_baud(xfer->speed_hz);
if (real_speed != xfer->speed_hz)
dev_dbg(&spi->dev,
"using speed %d instead of %d\n",
real_speed, xfer->speed_hz);
}
}
msg->status = -EINPROGRESS;
msg->actual_length = 0;
spin_lock_irqsave(&mcfqspi->lock, flags);
list_add_tail(&msg->queue, &mcfqspi->msgq);
queue_work(mcfqspi->workq, &mcfqspi->work);
spin_unlock_irqrestore(&mcfqspi->lock, flags);
return 0;
fail:
msg->status = -EINVAL;
return -EINVAL;
}
static int mcfqspi_setup(struct spi_device *spi)
{
if ((spi->bits_per_word < 8) || (spi->bits_per_word > 16)) {
dev_dbg(&spi->dev, "%d bits per word is not supported\n",
spi->bits_per_word);
return -EINVAL;
}
if (spi->chip_select >= spi->master->num_chipselect) {
dev_dbg(&spi->dev, "%d chip select is out of range\n",
spi->chip_select);
return -EINVAL;
}
mcfqspi_cs_deselect(spi_master_get_devdata(spi->master),
spi->chip_select, spi->mode & SPI_CS_HIGH);
dev_dbg(&spi->dev,
"bits per word %d, chip select %d, speed %d KHz\n",
spi->bits_per_word, spi->chip_select,
(MCFQSPI_BUSCLK / mcfqspi_qmr_baud(spi->max_speed_hz))
/ 1000);
return 0;
}
static int __devinit mcfqspi_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct mcfqspi *mcfqspi;
struct resource *res;
struct mcfqspi_platform_data *pdata;
int status;
master = spi_alloc_master(&pdev->dev, sizeof(*mcfqspi));
if (master == NULL) {
dev_dbg(&pdev->dev, "spi_alloc_master failed\n");
return -ENOMEM;
}
mcfqspi = spi_master_get_devdata(master);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_dbg(&pdev->dev, "platform_get_resource failed\n");
status = -ENXIO;
goto fail0;
}
if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
dev_dbg(&pdev->dev, "request_mem_region failed\n");
status = -EBUSY;
goto fail0;
}
mcfqspi->iobase = ioremap(res->start, resource_size(res));
if (!mcfqspi->iobase) {
dev_dbg(&pdev->dev, "ioremap failed\n");
status = -ENOMEM;
goto fail1;
}
mcfqspi->irq = platform_get_irq(pdev, 0);
if (mcfqspi->irq < 0) {
dev_dbg(&pdev->dev, "platform_get_irq failed\n");
status = -ENXIO;
goto fail2;
}
status = request_irq(mcfqspi->irq, mcfqspi_irq_handler, IRQF_DISABLED,
pdev->name, mcfqspi);
if (status) {
dev_dbg(&pdev->dev, "request_irq failed\n");
goto fail2;
}
mcfqspi->clk = clk_get(&pdev->dev, "qspi_clk");
if (IS_ERR(mcfqspi->clk)) {
dev_dbg(&pdev->dev, "clk_get failed\n");
status = PTR_ERR(mcfqspi->clk);
goto fail3;
}
clk_enable(mcfqspi->clk);
mcfqspi->workq = create_singlethread_workqueue(dev_name(master->dev.parent));
if (!mcfqspi->workq) {
dev_dbg(&pdev->dev, "create_workqueue failed\n");
status = -ENOMEM;
goto fail4;
}
INIT_WORK(&mcfqspi->work, mcfqspi_work);
spin_lock_init(&mcfqspi->lock);
INIT_LIST_HEAD(&mcfqspi->msgq);
init_waitqueue_head(&mcfqspi->waitq);
pdata = pdev->dev.platform_data;
if (!pdata) {
dev_dbg(&pdev->dev, "platform data is missing\n");
goto fail5;
}
master->bus_num = pdata->bus_num;
master->num_chipselect = pdata->num_chipselect;
mcfqspi->cs_control = pdata->cs_control;
status = mcfqspi_cs_setup(mcfqspi);
if (status) {
dev_dbg(&pdev->dev, "error initializing cs_control\n");
goto fail5;
}
master->mode_bits = SPI_CS_HIGH | SPI_CPOL | SPI_CPHA;
master->setup = mcfqspi_setup;
master->transfer = mcfqspi_transfer;
platform_set_drvdata(pdev, master);
status = spi_register_master(master);
if (status) {
dev_dbg(&pdev->dev, "spi_register_master failed\n");
goto fail6;
}
dev_info(&pdev->dev, "Coldfire QSPI bus driver\n");
return 0;
fail6:
mcfqspi_cs_teardown(mcfqspi);
fail5:
destroy_workqueue(mcfqspi->workq);
fail4:
clk_disable(mcfqspi->clk);
clk_put(mcfqspi->clk);
fail3:
free_irq(mcfqspi->irq, mcfqspi);
fail2:
iounmap(mcfqspi->iobase);
fail1:
release_mem_region(res->start, resource_size(res));
fail0:
spi_master_put(master);
dev_dbg(&pdev->dev, "Coldfire QSPI probe failed\n");
return status;
}
static int __devexit mcfqspi_remove(struct platform_device *pdev)
{
struct spi_master *master = platform_get_drvdata(pdev);
struct mcfqspi *mcfqspi = spi_master_get_devdata(master);
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
/* disable the hardware (set the baud rate to 0) */
mcfqspi_wr_qmr(mcfqspi, MCFQSPI_QMR_MSTR);
platform_set_drvdata(pdev, NULL);
mcfqspi_cs_teardown(mcfqspi);
destroy_workqueue(mcfqspi->workq);
clk_disable(mcfqspi->clk);
clk_put(mcfqspi->clk);
free_irq(mcfqspi->irq, mcfqspi);
iounmap(mcfqspi->iobase);
release_mem_region(res->start, resource_size(res));
spi_unregister_master(master);
spi_master_put(master);
return 0;
}
#ifdef CONFIG_PM
static int mcfqspi_suspend(struct device *dev)
{
struct mcfqspi *mcfqspi = platform_get_drvdata(to_platform_device(dev));
clk_disable(mcfqspi->clk);
return 0;
}
static int mcfqspi_resume(struct device *dev)
{
struct mcfqspi *mcfqspi = platform_get_drvdata(to_platform_device(dev));
clk_enable(mcfqspi->clk);
return 0;
}
static struct dev_pm_ops mcfqspi_dev_pm_ops = {
.suspend = mcfqspi_suspend,
.resume = mcfqspi_resume,
};
#define MCFQSPI_DEV_PM_OPS (&mcfqspi_dev_pm_ops)
#else
#define MCFQSPI_DEV_PM_OPS NULL
#endif
static struct platform_driver mcfqspi_driver = {
.driver.name = DRIVER_NAME,
.driver.owner = THIS_MODULE,
.driver.pm = MCFQSPI_DEV_PM_OPS,
.remove = __devexit_p(mcfqspi_remove),
};
static int __init mcfqspi_init(void)
{
return platform_driver_probe(&mcfqspi_driver, mcfqspi_probe);
}
module_init(mcfqspi_init);
static void __exit mcfqspi_exit(void)
{
platform_driver_unregister(&mcfqspi_driver);
}
module_exit(mcfqspi_exit);
MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
MODULE_DESCRIPTION("Coldfire QSPI Controller Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);