u-boot/drivers/spi/mxs_spi.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

362 lines
8.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Freescale i.MX28 SPI driver
*
* Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
* on behalf of DENX Software Engineering GmbH
*
* NOTE: This driver only supports the SPI-controller chipselects,
* GPIO driven chipselects are not supported.
*/
#include <common.h>
#include <malloc.h>
#include <memalign.h>
#include <spi.h>
#include <linux/errno.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/arch/sys_proto.h>
#include <asm/mach-imx/dma.h>
#define MXS_SPI_MAX_TIMEOUT 1000000
#define MXS_SPI_PORT_OFFSET 0x2000
#define MXS_SSP_CHIPSELECT_MASK 0x00300000
#define MXS_SSP_CHIPSELECT_SHIFT 20
#define MXSSSP_SMALL_TRANSFER 512
struct mxs_spi_slave {
struct spi_slave slave;
uint32_t max_khz;
uint32_t mode;
struct mxs_ssp_regs *regs;
};
static inline struct mxs_spi_slave *to_mxs_slave(struct spi_slave *slave)
{
return container_of(slave, struct mxs_spi_slave, slave);
}
void spi_init(void)
{
}
int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
/* MXS SPI: 4 ports and 3 chip selects maximum */
if (!mxs_ssp_bus_id_valid(bus) || cs > 2)
return 0;
else
return 1;
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct mxs_spi_slave *mxs_slave;
if (!spi_cs_is_valid(bus, cs)) {
printf("mxs_spi: invalid bus %d / chip select %d\n", bus, cs);
return NULL;
}
mxs_slave = spi_alloc_slave(struct mxs_spi_slave, bus, cs);
if (!mxs_slave)
return NULL;
if (mxs_dma_init_channel(MXS_DMA_CHANNEL_AHB_APBH_SSP0 + bus))
goto err_init;
mxs_slave->max_khz = max_hz / 1000;
mxs_slave->mode = mode;
mxs_slave->regs = mxs_ssp_regs_by_bus(bus);
return &mxs_slave->slave;
err_init:
free(mxs_slave);
return NULL;
}
void spi_free_slave(struct spi_slave *slave)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
free(mxs_slave);
}
int spi_claim_bus(struct spi_slave *slave)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
struct mxs_ssp_regs *ssp_regs = mxs_slave->regs;
uint32_t reg = 0;
mxs_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
writel((slave->cs << MXS_SSP_CHIPSELECT_SHIFT) |
SSP_CTRL0_BUS_WIDTH_ONE_BIT,
&ssp_regs->hw_ssp_ctrl0);
reg = SSP_CTRL1_SSP_MODE_SPI | SSP_CTRL1_WORD_LENGTH_EIGHT_BITS;
reg |= (mxs_slave->mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0;
reg |= (mxs_slave->mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0;
writel(reg, &ssp_regs->hw_ssp_ctrl1);
writel(0, &ssp_regs->hw_ssp_cmd0);
mxs_set_ssp_busclock(slave->bus, mxs_slave->max_khz);
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
}
static void mxs_spi_start_xfer(struct mxs_ssp_regs *ssp_regs)
{
writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_set);
writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_clr);
}
static void mxs_spi_end_xfer(struct mxs_ssp_regs *ssp_regs)
{
writel(SSP_CTRL0_LOCK_CS, &ssp_regs->hw_ssp_ctrl0_clr);
writel(SSP_CTRL0_IGNORE_CRC, &ssp_regs->hw_ssp_ctrl0_set);
}
static int mxs_spi_xfer_pio(struct mxs_spi_slave *slave,
char *data, int length, int write, unsigned long flags)
{
struct mxs_ssp_regs *ssp_regs = slave->regs;
if (flags & SPI_XFER_BEGIN)
mxs_spi_start_xfer(ssp_regs);
while (length--) {
/* We transfer 1 byte */
#if defined(CONFIG_MX23)
writel(SSP_CTRL0_XFER_COUNT_MASK, &ssp_regs->hw_ssp_ctrl0_clr);
writel(1, &ssp_regs->hw_ssp_ctrl0_set);
#elif defined(CONFIG_MX28)
writel(1, &ssp_regs->hw_ssp_xfer_size);
#endif
if ((flags & SPI_XFER_END) && !length)
mxs_spi_end_xfer(ssp_regs);
if (write)
writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_clr);
else
writel(SSP_CTRL0_READ, &ssp_regs->hw_ssp_ctrl0_set);
writel(SSP_CTRL0_RUN, &ssp_regs->hw_ssp_ctrl0_set);
if (mxs_wait_mask_set(&ssp_regs->hw_ssp_ctrl0_reg,
SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
printf("MXS SPI: Timeout waiting for start\n");
return -ETIMEDOUT;
}
if (write)
writel(*data++, &ssp_regs->hw_ssp_data);
writel(SSP_CTRL0_DATA_XFER, &ssp_regs->hw_ssp_ctrl0_set);
if (!write) {
if (mxs_wait_mask_clr(&ssp_regs->hw_ssp_status_reg,
SSP_STATUS_FIFO_EMPTY, MXS_SPI_MAX_TIMEOUT)) {
printf("MXS SPI: Timeout waiting for data\n");
return -ETIMEDOUT;
}
*data = readl(&ssp_regs->hw_ssp_data);
data++;
}
if (mxs_wait_mask_clr(&ssp_regs->hw_ssp_ctrl0_reg,
SSP_CTRL0_RUN, MXS_SPI_MAX_TIMEOUT)) {
printf("MXS SPI: Timeout waiting for finish\n");
return -ETIMEDOUT;
}
}
return 0;
}
static int mxs_spi_xfer_dma(struct mxs_spi_slave *slave,
char *data, int length, int write, unsigned long flags)
{
const int xfer_max_sz = 0xff00;
const int desc_count = DIV_ROUND_UP(length, xfer_max_sz) + 1;
struct mxs_ssp_regs *ssp_regs = slave->regs;
struct mxs_dma_desc *dp;
uint32_t ctrl0;
uint32_t cache_data_count;
const uint32_t dstart = (uint32_t)data;
int dmach;
int tl;
int ret = 0;
#if defined(CONFIG_MX23)
const int mxs_spi_pio_words = 1;
#elif defined(CONFIG_MX28)
const int mxs_spi_pio_words = 4;
#endif
ALLOC_CACHE_ALIGN_BUFFER(struct mxs_dma_desc, desc, desc_count);
memset(desc, 0, sizeof(struct mxs_dma_desc) * desc_count);
ctrl0 = readl(&ssp_regs->hw_ssp_ctrl0);
ctrl0 |= SSP_CTRL0_DATA_XFER;
if (flags & SPI_XFER_BEGIN)
ctrl0 |= SSP_CTRL0_LOCK_CS;
if (!write)
ctrl0 |= SSP_CTRL0_READ;
if (length % ARCH_DMA_MINALIGN)
cache_data_count = roundup(length, ARCH_DMA_MINALIGN);
else
cache_data_count = length;
/* Flush data to DRAM so DMA can pick them up */
if (write)
flush_dcache_range(dstart, dstart + cache_data_count);
/* Invalidate the area, so no writeback into the RAM races with DMA */
invalidate_dcache_range(dstart, dstart + cache_data_count);
dmach = MXS_DMA_CHANNEL_AHB_APBH_SSP0 + slave->slave.bus;
dp = desc;
while (length) {
dp->address = (dma_addr_t)dp;
dp->cmd.address = (dma_addr_t)data;
/*
* This is correct, even though it does indeed look insane.
* I hereby have to, wholeheartedly, thank Freescale Inc.,
* for always inventing insane hardware and keeping me busy
* and employed ;-)
*/
if (write)
dp->cmd.data = MXS_DMA_DESC_COMMAND_DMA_READ;
else
dp->cmd.data = MXS_DMA_DESC_COMMAND_DMA_WRITE;
/*
* The DMA controller can transfer large chunks (64kB) at
* time by setting the transfer length to 0. Setting tl to
* 0x10000 will overflow below and make .data contain 0.
* Otherwise, 0xff00 is the transfer maximum.
*/
if (length >= 0x10000)
tl = 0x10000;
else
tl = min(length, xfer_max_sz);
dp->cmd.data |=
((tl & 0xffff) << MXS_DMA_DESC_BYTES_OFFSET) |
(mxs_spi_pio_words << MXS_DMA_DESC_PIO_WORDS_OFFSET) |
MXS_DMA_DESC_HALT_ON_TERMINATE |
MXS_DMA_DESC_TERMINATE_FLUSH;
data += tl;
length -= tl;
if (!length) {
dp->cmd.data |= MXS_DMA_DESC_IRQ | MXS_DMA_DESC_DEC_SEM;
if (flags & SPI_XFER_END) {
ctrl0 &= ~SSP_CTRL0_LOCK_CS;
ctrl0 |= SSP_CTRL0_IGNORE_CRC;
}
}
/*
* Write CTRL0, CMD0, CMD1 and XFER_SIZE registers in
* case of MX28, write only CTRL0 in case of MX23 due
* to the difference in register layout. It is utterly
* essential that the XFER_SIZE register is written on
* a per-descriptor basis with the same size as is the
* descriptor!
*/
dp->cmd.pio_words[0] = ctrl0;
#ifdef CONFIG_MX28
dp->cmd.pio_words[1] = 0;
dp->cmd.pio_words[2] = 0;
dp->cmd.pio_words[3] = tl;
#endif
mxs_dma_desc_append(dmach, dp);
dp++;
}
if (mxs_dma_go(dmach))
ret = -EINVAL;
/* The data arrived into DRAM, invalidate cache over them */
if (!write)
invalidate_dcache_range(dstart, dstart + cache_data_count);
return ret;
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
struct mxs_spi_slave *mxs_slave = to_mxs_slave(slave);
struct mxs_ssp_regs *ssp_regs = mxs_slave->regs;
int len = bitlen / 8;
char dummy;
int write = 0;
char *data = NULL;
int dma = 1;
if (bitlen == 0) {
if (flags & SPI_XFER_END) {
din = (void *)&dummy;
len = 1;
} else
return 0;
}
/* Half-duplex only */
if (din && dout)
return -EINVAL;
/* No data */
if (!din && !dout)
return 0;
if (dout) {
data = (char *)dout;
write = 1;
} else if (din) {
data = (char *)din;
write = 0;
}
/*
* Check for alignment, if the buffer is aligned, do DMA transfer,
* PIO otherwise. This is a temporary workaround until proper bounce
* buffer is in place.
*/
if (dma) {
if (((uint32_t)data) & (ARCH_DMA_MINALIGN - 1))
dma = 0;
if (((uint32_t)len) & (ARCH_DMA_MINALIGN - 1))
dma = 0;
}
if (!dma || (len < MXSSSP_SMALL_TRANSFER)) {
writel(SSP_CTRL1_DMA_ENABLE, &ssp_regs->hw_ssp_ctrl1_clr);
return mxs_spi_xfer_pio(mxs_slave, data, len, write, flags);
} else {
writel(SSP_CTRL1_DMA_ENABLE, &ssp_regs->hw_ssp_ctrl1_set);
return mxs_spi_xfer_dma(mxs_slave, data, len, write, flags);
}
}