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pxa2xx_spi.c
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/*
* Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/gpio.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>
#include <mach/dma.h>
#include <mach/regs-ssp.h>
#include <mach/ssp.h>
#include <mach/pxa2xx_spi.h>
MODULE_AUTHOR("Stephen Street");
MODULE_DESCRIPTION("PXA2xx SSP SPI Controller");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pxa2xx-spi");
#define MAX_BUSES 3
#define RX_THRESH_DFLT 8
#define TX_THRESH_DFLT 8
#define TIMOUT_DFLT 1000
#define DMA_INT_MASK (DCSR_ENDINTR | DCSR_STARTINTR | DCSR_BUSERR)
#define RESET_DMA_CHANNEL (DCSR_NODESC | DMA_INT_MASK)
#define IS_DMA_ALIGNED(x) ((((u32)(x)) & 0x07) == 0)
#define MAX_DMA_LEN 8191
#define DMA_ALIGNMENT 8
/*
* for testing SSCR1 changes that require SSP restart, basically
* everything except the service and interrupt enables, the pxa270 developer
* manual says only SSCR1_SCFR, SSCR1_SPH, SSCR1_SPO need to be in this
* list, but the PXA255 dev man says all bits without really meaning the
* service and interrupt enables
*/
#define SSCR1_CHANGE_MASK (SSCR1_TTELP | SSCR1_TTE | SSCR1_SCFR \
| SSCR1_ECRA | SSCR1_ECRB | SSCR1_SCLKDIR \
| SSCR1_SFRMDIR | SSCR1_RWOT | SSCR1_TRAIL \
| SSCR1_IFS | SSCR1_STRF | SSCR1_EFWR \
| SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)
#define DEFINE_SSP_REG(reg, off) \
static inline u32 read_##reg(void const __iomem *p) \
{ return __raw_readl(p + (off)); } \
\
static inline void write_##reg(u32 v, void __iomem *p) \
{ __raw_writel(v, p + (off)); }
DEFINE_SSP_REG(SSCR0, 0x00)
DEFINE_SSP_REG(SSCR1, 0x04)
DEFINE_SSP_REG(SSSR, 0x08)
DEFINE_SSP_REG(SSITR, 0x0c)
DEFINE_SSP_REG(SSDR, 0x10)
DEFINE_SSP_REG(SSTO, 0x28)
DEFINE_SSP_REG(SSPSP, 0x2c)
#define START_STATE ((void*)0)
#define RUNNING_STATE ((void*)1)
#define DONE_STATE ((void*)2)
#define ERROR_STATE ((void*)-1)
#define QUEUE_RUNNING 0
#define QUEUE_STOPPED 1
struct driver_data {
/* Driver model hookup */
struct platform_device *pdev;
/* SSP Info */
struct ssp_device *ssp;
/* SPI framework hookup */
enum pxa_ssp_type ssp_type;
struct spi_master *master;
/* PXA hookup */
struct pxa2xx_spi_master *master_info;
/* DMA setup stuff */
int rx_channel;
int tx_channel;
u32 *null_dma_buf;
/* SSP register addresses */
void __iomem *ioaddr;
u32 ssdr_physical;
/* SSP masks*/
u32 dma_cr1;
u32 int_cr1;
u32 clear_sr;
u32 mask_sr;
/* Driver message queue */
struct workqueue_struct *workqueue;
struct work_struct pump_messages;
spinlock_t lock;
struct list_head queue;
int busy;
int run;
/* Message Transfer pump */
struct tasklet_struct pump_transfers;
/* Current message transfer state info */
struct spi_message* cur_msg;
struct spi_transfer* cur_transfer;
struct chip_data *cur_chip;
size_t len;
void *tx;
void *tx_end;
void *rx;
void *rx_end;
int dma_mapped;
dma_addr_t rx_dma;
dma_addr_t tx_dma;
size_t rx_map_len;
size_t tx_map_len;
u8 n_bytes;
u32 dma_width;
int (*write)(struct driver_data *drv_data);
int (*read)(struct driver_data *drv_data);
irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
void (*cs_control)(u32 command);
};
struct chip_data {
u32 cr0;
u32 cr1;
u32 psp;
u32 timeout;
u8 n_bytes;
u32 dma_width;
u32 dma_burst_size;
u32 threshold;
u32 dma_threshold;
u8 enable_dma;
u8 bits_per_word;
u32 speed_hz;
int gpio_cs;
int gpio_cs_inverted;
int (*write)(struct driver_data *drv_data);
int (*read)(struct driver_data *drv_data);
void (*cs_control)(u32 command);
};
static void pump_messages(struct work_struct *work);
static void cs_assert(struct driver_data *drv_data)
{
struct chip_data *chip = drv_data->cur_chip;
if (chip->cs_control) {
chip->cs_control(PXA2XX_CS_ASSERT);
return;
}
if (gpio_is_valid(chip->gpio_cs))
gpio_set_value(chip->gpio_cs, chip->gpio_cs_inverted);
}
static void cs_deassert(struct driver_data *drv_data)
{
struct chip_data *chip = drv_data->cur_chip;
if (chip->cs_control) {
chip->cs_control(PXA2XX_CS_DEASSERT);
return;
}
if (gpio_is_valid(chip->gpio_cs))
gpio_set_value(chip->gpio_cs, !chip->gpio_cs_inverted);
}
static int flush(struct driver_data *drv_data)
{
unsigned long limit = loops_per_jiffy << 1;
void __iomem *reg = drv_data->ioaddr;
do {
while (read_SSSR(reg) & SSSR_RNE) {
read_SSDR(reg);
}
} while ((read_SSSR(reg) & SSSR_BSY) && --limit);
write_SSSR(SSSR_ROR, reg);
return limit;
}
static int null_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
u8 n_bytes = drv_data->n_bytes;
if (((read_SSSR(reg) & 0x00000f00) == 0x00000f00)
|| (drv_data->tx == drv_data->tx_end))
return 0;
write_SSDR(0, reg);
drv_data->tx += n_bytes;
return 1;
}
static int null_reader(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
u8 n_bytes = drv_data->n_bytes;
while ((read_SSSR(reg) & SSSR_RNE)
&& (drv_data->rx < drv_data->rx_end)) {
read_SSDR(reg);
drv_data->rx += n_bytes;
}
return drv_data->rx == drv_data->rx_end;
}
static int u8_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
if (((read_SSSR(reg) & 0x00000f00) == 0x00000f00)
|| (drv_data->tx == drv_data->tx_end))
return 0;
write_SSDR(*(u8 *)(drv_data->tx), reg);
++drv_data->tx;
return 1;
}
static int u8_reader(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
while ((read_SSSR(reg) & SSSR_RNE)
&& (drv_data->rx < drv_data->rx_end)) {
*(u8 *)(drv_data->rx) = read_SSDR(reg);
++drv_data->rx;
}
return drv_data->rx == drv_data->rx_end;
}
static int u16_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
if (((read_SSSR(reg) & 0x00000f00) == 0x00000f00)
|| (drv_data->tx == drv_data->tx_end))
return 0;
write_SSDR(*(u16 *)(drv_data->tx), reg);
drv_data->tx += 2;
return 1;
}
static int u16_reader(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
while ((read_SSSR(reg) & SSSR_RNE)
&& (drv_data->rx < drv_data->rx_end)) {
*(u16 *)(drv_data->rx) = read_SSDR(reg);
drv_data->rx += 2;
}
return drv_data->rx == drv_data->rx_end;
}
static int u32_writer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
if (((read_SSSR(reg) & 0x00000f00) == 0x00000f00)
|| (drv_data->tx == drv_data->tx_end))
return 0;
write_SSDR(*(u32 *)(drv_data->tx), reg);
drv_data->tx += 4;
return 1;
}
static int u32_reader(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
while ((read_SSSR(reg) & SSSR_RNE)
&& (drv_data->rx < drv_data->rx_end)) {
*(u32 *)(drv_data->rx) = read_SSDR(reg);
drv_data->rx += 4;
}
return drv_data->rx == drv_data->rx_end;
}
static void *next_transfer(struct driver_data *drv_data)
{
struct spi_message *msg = drv_data->cur_msg;
struct spi_transfer *trans = drv_data->cur_transfer;
/* Move to next transfer */
if (trans->transfer_list.next != &msg->transfers) {
drv_data->cur_transfer =
list_entry(trans->transfer_list.next,
struct spi_transfer,
transfer_list);
return RUNNING_STATE;
} else
return DONE_STATE;
}
static int map_dma_buffers(struct driver_data *drv_data)
{
struct spi_message *msg = drv_data->cur_msg;
struct device *dev = &msg->spi->dev;
if (!drv_data->cur_chip->enable_dma)
return 0;
if (msg->is_dma_mapped)
return drv_data->rx_dma && drv_data->tx_dma;
if (!IS_DMA_ALIGNED(drv_data->rx) || !IS_DMA_ALIGNED(drv_data->tx))
return 0;
/* Modify setup if rx buffer is null */
if (drv_data->rx == NULL) {
*drv_data->null_dma_buf = 0;
drv_data->rx = drv_data->null_dma_buf;
drv_data->rx_map_len = 4;
} else
drv_data->rx_map_len = drv_data->len;
/* Modify setup if tx buffer is null */
if (drv_data->tx == NULL) {
*drv_data->null_dma_buf = 0;
drv_data->tx = drv_data->null_dma_buf;
drv_data->tx_map_len = 4;
} else
drv_data->tx_map_len = drv_data->len;
/* Stream map the tx buffer. Always do DMA_TO_DEVICE first
* so we flush the cache *before* invalidating it, in case
* the tx and rx buffers overlap.
*/
drv_data->tx_dma = dma_map_single(dev, drv_data->tx,
drv_data->tx_map_len, DMA_TO_DEVICE);
if (dma_mapping_error(dev, drv_data->tx_dma))
return 0;
/* Stream map the rx buffer */
drv_data->rx_dma = dma_map_single(dev, drv_data->rx,
drv_data->rx_map_len, DMA_FROM_DEVICE);
if (dma_mapping_error(dev, drv_data->rx_dma)) {
dma_unmap_single(dev, drv_data->tx_dma,
drv_data->tx_map_len, DMA_TO_DEVICE);
return 0;
}
return 1;
}
static void unmap_dma_buffers(struct driver_data *drv_data)
{
struct device *dev;
if (!drv_data->dma_mapped)
return;
if (!drv_data->cur_msg->is_dma_mapped) {
dev = &drv_data->cur_msg->spi->dev;
dma_unmap_single(dev, drv_data->rx_dma,
drv_data->rx_map_len, DMA_FROM_DEVICE);
dma_unmap_single(dev, drv_data->tx_dma,
drv_data->tx_map_len, DMA_TO_DEVICE);
}
drv_data->dma_mapped = 0;
}
/* caller already set message->status; dma and pio irqs are blocked */
static void giveback(struct driver_data *drv_data)
{
struct spi_transfer* last_transfer;
unsigned long flags;
struct spi_message *msg;
spin_lock_irqsave(&drv_data->lock, flags);
msg = drv_data->cur_msg;
drv_data->cur_msg = NULL;
drv_data->cur_transfer = NULL;
queue_work(drv_data->workqueue, &drv_data->pump_messages);
spin_unlock_irqrestore(&drv_data->lock, flags);
last_transfer = list_entry(msg->transfers.prev,
struct spi_transfer,
transfer_list);
/* Delay if requested before any change in chip select */
if (last_transfer->delay_usecs)
udelay(last_transfer->delay_usecs);
/* Drop chip select UNLESS cs_change is true or we are returning
* a message with an error, or next message is for another chip
*/
if (!last_transfer->cs_change)
cs_deassert(drv_data);
else {
struct spi_message *next_msg;
/* Holding of cs was hinted, but we need to make sure
* the next message is for the same chip. Don't waste
* time with the following tests unless this was hinted.
*
* We cannot postpone this until pump_messages, because
* after calling msg->complete (below) the driver that
* sent the current message could be unloaded, which
* could invalidate the cs_control() callback...
*/
/* get a pointer to the next message, if any */
spin_lock_irqsave(&drv_data->lock, flags);
if (list_empty(&drv_data->queue))
next_msg = NULL;
else
next_msg = list_entry(drv_data->queue.next,
struct spi_message, queue);
spin_unlock_irqrestore(&drv_data->lock, flags);
/* see if the next and current messages point
* to the same chip
*/
if (next_msg && next_msg->spi != msg->spi)
next_msg = NULL;
if (!next_msg || msg->state == ERROR_STATE)
cs_deassert(drv_data);
}
msg->state = NULL;
if (msg->complete)
msg->complete(msg->context);
drv_data->cur_chip = NULL;
}
static int wait_ssp_rx_stall(void const __iomem *ioaddr)
{
unsigned long limit = loops_per_jiffy << 1;
while ((read_SSSR(ioaddr) & SSSR_BSY) && --limit)
cpu_relax();
return limit;
}
static int wait_dma_channel_stop(int channel)
{
unsigned long limit = loops_per_jiffy << 1;
while (!(DCSR(channel) & DCSR_STOPSTATE) && --limit)
cpu_relax();
return limit;
}
static void dma_error_stop(struct driver_data *drv_data, const char *msg)
{
void __iomem *reg = drv_data->ioaddr;
/* Stop and reset */
DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
write_SSSR(drv_data->clear_sr, reg);
write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg);
if (drv_data->ssp_type != PXA25x_SSP)
write_SSTO(0, reg);
flush(drv_data);
write_SSCR0(read_SSCR0(reg) & ~SSCR0_SSE, reg);
unmap_dma_buffers(drv_data);
dev_err(&drv_data->pdev->dev, "%s\n", msg);
drv_data->cur_msg->state = ERROR_STATE;
tasklet_schedule(&drv_data->pump_transfers);
}
static void dma_transfer_complete(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
struct spi_message *msg = drv_data->cur_msg;
/* Clear and disable interrupts on SSP and DMA channels*/
write_SSCR1(read_SSCR1(reg) & ~drv_data->dma_cr1, reg);
write_SSSR(drv_data->clear_sr, reg);
DCSR(drv_data->tx_channel) = RESET_DMA_CHANNEL;
DCSR(drv_data->rx_channel) = RESET_DMA_CHANNEL;
if (wait_dma_channel_stop(drv_data->rx_channel) == 0)
dev_err(&drv_data->pdev->dev,
"dma_handler: dma rx channel stop failed\n");
if (wait_ssp_rx_stall(drv_data->ioaddr) == 0)
dev_err(&drv_data->pdev->dev,
"dma_transfer: ssp rx stall failed\n");
unmap_dma_buffers(drv_data);
/* update the buffer pointer for the amount completed in dma */
drv_data->rx += drv_data->len -
(DCMD(drv_data->rx_channel) & DCMD_LENGTH);
/* read trailing data from fifo, it does not matter how many
* bytes are in the fifo just read until buffer is full
* or fifo is empty, which ever occurs first */
drv_data->read(drv_data);
/* return count of what was actually read */
msg->actual_length += drv_data->len -
(drv_data->rx_end - drv_data->rx);
/* Transfer delays and chip select release are
* handled in pump_transfers or giveback
*/
/* Move to next transfer */
msg->state = next_transfer(drv_data);
/* Schedule transfer tasklet */
tasklet_schedule(&drv_data->pump_transfers);
}
static void dma_handler(int channel, void *data)
{
struct driver_data *drv_data = data;
u32 irq_status = DCSR(channel) & DMA_INT_MASK;
if (irq_status & DCSR_BUSERR) {
if (channel == drv_data->tx_channel)
dma_error_stop(drv_data,
"dma_handler: "
"bad bus address on tx channel");
else
dma_error_stop(drv_data,
"dma_handler: "
"bad bus address on rx channel");
return;
}
/* PXA255x_SSP has no timeout interrupt, wait for tailing bytes */
if ((channel == drv_data->tx_channel)
&& (irq_status & DCSR_ENDINTR)
&& (drv_data->ssp_type == PXA25x_SSP)) {
/* Wait for rx to stall */
if (wait_ssp_rx_stall(drv_data->ioaddr) == 0)
dev_err(&drv_data->pdev->dev,
"dma_handler: ssp rx stall failed\n");
/* finish this transfer, start the next */
dma_transfer_complete(drv_data);
}
}
static irqreturn_t dma_transfer(struct driver_data *drv_data)
{
u32 irq_status;
void __iomem *reg = drv_data->ioaddr;
irq_status = read_SSSR(reg) & drv_data->mask_sr;
if (irq_status & SSSR_ROR) {
dma_error_stop(drv_data, "dma_transfer: fifo overrun");
return IRQ_HANDLED;
}
/* Check for false positive timeout */
if ((irq_status & SSSR_TINT)
&& (DCSR(drv_data->tx_channel) & DCSR_RUN)) {
write_SSSR(SSSR_TINT, reg);
return IRQ_HANDLED;
}
if (irq_status & SSSR_TINT || drv_data->rx == drv_data->rx_end) {
/* Clear and disable timeout interrupt, do the rest in
* dma_transfer_complete */
if (drv_data->ssp_type != PXA25x_SSP)
write_SSTO(0, reg);
/* finish this transfer, start the next */
dma_transfer_complete(drv_data);
return IRQ_HANDLED;
}
/* Opps problem detected */
return IRQ_NONE;
}
static void int_error_stop(struct driver_data *drv_data, const char* msg)
{
void __iomem *reg = drv_data->ioaddr;
/* Stop and reset SSP */
write_SSSR(drv_data->clear_sr, reg);
write_SSCR1(read_SSCR1(reg) & ~drv_data->int_cr1, reg);
if (drv_data->ssp_type != PXA25x_SSP)
write_SSTO(0, reg);
flush(drv_data);
write_SSCR0(read_SSCR0(reg) & ~SSCR0_SSE, reg);
dev_err(&drv_data->pdev->dev, "%s\n", msg);
drv_data->cur_msg->state = ERROR_STATE;
tasklet_schedule(&drv_data->pump_transfers);
}
static void int_transfer_complete(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
/* Stop SSP */
write_SSSR(drv_data->clear_sr, reg);
write_SSCR1(read_SSCR1(reg) & ~drv_data->int_cr1, reg);
if (drv_data->ssp_type != PXA25x_SSP)
write_SSTO(0, reg);
/* Update total byte transfered return count actual bytes read */
drv_data->cur_msg->actual_length += drv_data->len -
(drv_data->rx_end - drv_data->rx);
/* Transfer delays and chip select release are
* handled in pump_transfers or giveback
*/
/* Move to next transfer */
drv_data->cur_msg->state = next_transfer(drv_data);
/* Schedule transfer tasklet */
tasklet_schedule(&drv_data->pump_transfers);
}
static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
{
void __iomem *reg = drv_data->ioaddr;
u32 irq_mask = (read_SSCR1(reg) & SSCR1_TIE) ?
drv_data->mask_sr : drv_data->mask_sr & ~SSSR_TFS;
u32 irq_status = read_SSSR(reg) & irq_mask;
if (irq_status & SSSR_ROR) {
int_error_stop(drv_data, "interrupt_transfer: fifo overrun");
return IRQ_HANDLED;
}
if (irq_status & SSSR_TINT) {
write_SSSR(SSSR_TINT, reg);
if (drv_data->read(drv_data)) {
int_transfer_complete(drv_data);
return IRQ_HANDLED;
}
}
/* Drain rx fifo, Fill tx fifo and prevent overruns */
do {
if (drv_data->read(drv_data)) {
int_transfer_complete(drv_data);
return IRQ_HANDLED;
}
} while (drv_data->write(drv_data));
if (drv_data->read(drv_data)) {
int_transfer_complete(drv_data);
return IRQ_HANDLED;
}
if (drv_data->tx == drv_data->tx_end) {
write_SSCR1(read_SSCR1(reg) & ~SSCR1_TIE, reg);
/* PXA25x_SSP has no timeout, read trailing bytes */
if (drv_data->ssp_type == PXA25x_SSP) {
if (!wait_ssp_rx_stall(reg))
{
int_error_stop(drv_data, "interrupt_transfer: "
"rx stall failed");
return IRQ_HANDLED;
}
if (!drv_data->read(drv_data))
{
int_error_stop(drv_data,
"interrupt_transfer: "
"trailing byte read failed");
return IRQ_HANDLED;
}
int_transfer_complete(drv_data);
}
}
/* We did something */
return IRQ_HANDLED;
}
static irqreturn_t ssp_int(int irq, void *dev_id)
{
struct driver_data *drv_data = dev_id;
void __iomem *reg = drv_data->ioaddr;
if (!drv_data->cur_msg) {
write_SSCR0(read_SSCR0(reg) & ~SSCR0_SSE, reg);
write_SSCR1(read_SSCR1(reg) & ~drv_data->int_cr1, reg);
if (drv_data->ssp_type != PXA25x_SSP)
write_SSTO(0, reg);
write_SSSR(drv_data->clear_sr, reg);
dev_err(&drv_data->pdev->dev, "bad message state "
"in interrupt handler\n");
/* Never fail */
return IRQ_HANDLED;
}
return drv_data->transfer_handler(drv_data);
}
static int set_dma_burst_and_threshold(struct chip_data *chip,
struct spi_device *spi,
u8 bits_per_word, u32 *burst_code,
u32 *threshold)
{
struct pxa2xx_spi_chip *chip_info =
(struct pxa2xx_spi_chip *)spi->controller_data;
int bytes_per_word;
int burst_bytes;
int thresh_words;
int req_burst_size;
int retval = 0;
/* Set the threshold (in registers) to equal the same amount of data
* as represented by burst size (in bytes). The computation below
* is (burst_size rounded up to nearest 8 byte, word or long word)
* divided by (bytes/register); the tx threshold is the inverse of
* the rx, so that there will always be enough data in the rx fifo
* to satisfy a burst, and there will always be enough space in the
* tx fifo to accept a burst (a tx burst will overwrite the fifo if
* there is not enough space), there must always remain enough empty
* space in the rx fifo for any data loaded to the tx fifo.
* Whenever burst_size (in bytes) equals bits/word, the fifo threshold
* will be 8, or half the fifo;
* The threshold can only be set to 2, 4 or 8, but not 16, because
* to burst 16 to the tx fifo, the fifo would have to be empty;
* however, the minimum fifo trigger level is 1, and the tx will
* request service when the fifo is at this level, with only 15 spaces.
*/
/* find bytes/word */
if (bits_per_word <= 8)
bytes_per_word = 1;
else if (bits_per_word <= 16)
bytes_per_word = 2;
else
bytes_per_word = 4;
/* use struct pxa2xx_spi_chip->dma_burst_size if available */
if (chip_info)
req_burst_size = chip_info->dma_burst_size;
else {
switch (chip->dma_burst_size) {
default:
/* if the default burst size is not set,
* do it now */
chip->dma_burst_size = DCMD_BURST8;
case DCMD_BURST8:
req_burst_size = 8;
break;
case DCMD_BURST16:
req_burst_size = 16;
break;
case DCMD_BURST32:
req_burst_size = 32;
break;
}
}
if (req_burst_size <= 8) {
*burst_code = DCMD_BURST8;
burst_bytes = 8;
} else if (req_burst_size <= 16) {
if (bytes_per_word == 1) {
/* don't burst more than 1/2 the fifo */
*burst_code = DCMD_BURST8;
burst_bytes = 8;
retval = 1;
} else {
*burst_code = DCMD_BURST16;
burst_bytes = 16;
}
} else {
if (bytes_per_word == 1) {
/* don't burst more than 1/2 the fifo */
*burst_code = DCMD_BURST8;
burst_bytes = 8;
retval = 1;
} else if (bytes_per_word == 2) {
/* don't burst more than 1/2 the fifo */
*burst_code = DCMD_BURST16;
burst_bytes = 16;
retval = 1;
} else {
*burst_code = DCMD_BURST32;
burst_bytes = 32;
}
}
thresh_words = burst_bytes / bytes_per_word;
/* thresh_words will be between 2 and 8 */
*threshold = (SSCR1_RxTresh(thresh_words) & SSCR1_RFT)
| (SSCR1_TxTresh(16-thresh_words) & SSCR1_TFT);
return retval;
}
static unsigned int ssp_get_clk_div(struct ssp_device *ssp, int rate)
{
unsigned long ssp_clk = clk_get_rate(ssp->clk);
if (ssp->type == PXA25x_SSP)
return ((ssp_clk / (2 * rate) - 1) & 0xff) << 8;
else
return ((ssp_clk / rate - 1) & 0xfff) << 8;
}
static void pump_transfers(unsigned long data)
{
struct driver_data *drv_data = (struct driver_data *)data;
struct spi_message *message = NULL;
struct spi_transfer *transfer = NULL;
struct spi_transfer *previous = NULL;
struct chip_data *chip = NULL;
struct ssp_device *ssp = drv_data->ssp;
void __iomem *reg = drv_data->ioaddr;
u32 clk_div = 0;
u8 bits = 0;
u32 speed = 0;
u32 cr0;
u32 cr1;
u32 dma_thresh = drv_data->cur_chip->dma_threshold;
u32 dma_burst = drv_data->cur_chip->dma_burst_size;
/* Get current state information */
message = drv_data->cur_msg;
transfer = drv_data->cur_transfer;
chip = drv_data->cur_chip;
/* Handle for abort */
if (message->state == ERROR_STATE) {
message->status = -EIO;
giveback(drv_data);
return;
}
/* Handle end of message */
if (message->state == DONE_STATE) {
message->status = 0;
giveback(drv_data);
return;
}
/* Delay if requested at end of transfer before CS change */
if (message->state == RUNNING_STATE) {
previous = list_entry(transfer->transfer_list.prev,
struct spi_transfer,
transfer_list);
if (previous->delay_usecs)
udelay(previous->delay_usecs);
/* Drop chip select only if cs_change is requested */
if (previous->cs_change)
cs_deassert(drv_data);
}
/* Check for transfers that need multiple DMA segments */
if (transfer->len > MAX_DMA_LEN && chip->enable_dma) {
/* reject already-mapped transfers; PIO won't always work */
if (message->is_dma_mapped
|| transfer->rx_dma || transfer->tx_dma) {
dev_err(&drv_data->pdev->dev,
"pump_transfers: mapped transfer length "
"of %u is greater than %d\n",
transfer->len, MAX_DMA_LEN);
message->status = -EINVAL;
giveback(drv_data);
return;
}
/* warn ... we force this to PIO mode */
if (printk_ratelimit())
dev_warn(&message->spi->dev, "pump_transfers: "
"DMA disabled for transfer length %ld "
"greater than %d\n",
(long)drv_data->len, MAX_DMA_LEN);
}
/* Setup the transfer state based on the type of transfer */
if (flush(drv_data) == 0) {
dev_err(&drv_data->pdev->dev, "pump_transfers: flush failed\n");
message->status = -EIO;
giveback(drv_data);
return;
}
drv_data->n_bytes = chip->n_bytes;
drv_data->dma_width = chip->dma_width;
drv_data->tx = (void *)transfer->tx_buf;
drv_data->tx_end = drv_data->tx + transfer->len;
drv_data->rx = transfer->rx_buf;
drv_data->rx_end = drv_data->rx + transfer->len;
drv_data->rx_dma = transfer->rx_dma;
drv_data->tx_dma = transfer->tx_dma;
drv_data->len = transfer->len & DCMD_LENGTH;
drv_data->write = drv_data->tx ? chip->write : null_writer;
drv_data->read = drv_data->rx ? chip->read : null_reader;
/* Change speed and bit per word on a per transfer */
cr0 = chip->cr0;
if (transfer->speed_hz || transfer->bits_per_word) {
bits = chip->bits_per_word;
speed = chip->speed_hz;
if (transfer->speed_hz)
speed = transfer->speed_hz;
if (transfer->bits_per_word)
bits = transfer->bits_per_word;
clk_div = ssp_get_clk_div(ssp, speed);
if (bits <= 8) {
drv_data->n_bytes = 1;
drv_data->dma_width = DCMD_WIDTH1;
drv_data->read = drv_data->read != null_reader ?
u8_reader : null_reader;
drv_data->write = drv_data->write != null_writer ?
u8_writer : null_writer;
} else if (bits <= 16) {
drv_data->n_bytes = 2;
drv_data->dma_width = DCMD_WIDTH2;
drv_data->read = drv_data->read != null_reader ?
u16_reader : null_reader;
drv_data->write = drv_data->write != null_writer ?
u16_writer : null_writer;
} else if (bits <= 32) {
drv_data->n_bytes = 4;
drv_data->dma_width = DCMD_WIDTH4;
drv_data->read = drv_data->read != null_reader ?
u32_reader : null_reader;
drv_data->write = drv_data->write != null_writer ?
u32_writer : null_writer;
}
/* if bits/word is changed in dma mode, then must check the
* thresholds and burst also */