linux/drivers/spi/dw_spi.c

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/*
* dw_spi.c - Designware SPI core controller driver (refer pxa2xx_spi.c)
*
* Copyright (c) 2009, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/highmem.h>
#include <linux/delay.h>
#include <linux/spi/dw_spi.h>
#include <linux/spi/spi.h>
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#endif
#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
#define MRST_SPI_DEASSERT 0
#define MRST_SPI_ASSERT 1
/* Slave spi_dev related */
struct chip_data {
u16 cr0;
u8 cs; /* chip select pin */
u8 n_bytes; /* current is a 1/2/4 byte op */
u8 tmode; /* TR/TO/RO/EEPROM */
u8 type; /* SPI/SSP/MicroWire */
u8 poll_mode; /* 1 means use poll mode */
u32 dma_width;
u32 rx_threshold;
u32 tx_threshold;
u8 enable_dma;
u8 bits_per_word;
u16 clk_div; /* baud rate divider */
u32 speed_hz; /* baud rate */
int (*write)(struct dw_spi *dws);
int (*read)(struct dw_spi *dws);
void (*cs_control)(u32 command);
};
#ifdef CONFIG_DEBUG_FS
static int spi_show_regs_open(struct inode *inode, struct file *file)
{
file->private_data = inode->i_private;
return 0;
}
#define SPI_REGS_BUFSIZE 1024
static ssize_t spi_show_regs(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct dw_spi *dws;
char *buf;
u32 len = 0;
ssize_t ret;
dws = file->private_data;
buf = kzalloc(SPI_REGS_BUFSIZE, GFP_KERNEL);
if (!buf)
return 0;
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"MRST SPI0 registers:\n");
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"=================================\n");
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"CTRL0: \t\t0x%08x\n", dw_readl(dws, ctrl0));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"CTRL1: \t\t0x%08x\n", dw_readl(dws, ctrl1));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"SSIENR: \t0x%08x\n", dw_readl(dws, ssienr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"SER: \t\t0x%08x\n", dw_readl(dws, ser));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"BAUDR: \t\t0x%08x\n", dw_readl(dws, baudr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"TXFTLR: \t0x%08x\n", dw_readl(dws, txfltr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"RXFTLR: \t0x%08x\n", dw_readl(dws, rxfltr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"TXFLR: \t\t0x%08x\n", dw_readl(dws, txflr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"RXFLR: \t\t0x%08x\n", dw_readl(dws, rxflr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"SR: \t\t0x%08x\n", dw_readl(dws, sr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"IMR: \t\t0x%08x\n", dw_readl(dws, imr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"ISR: \t\t0x%08x\n", dw_readl(dws, isr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"DMACR: \t\t0x%08x\n", dw_readl(dws, dmacr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"DMATDLR: \t0x%08x\n", dw_readl(dws, dmatdlr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"DMARDLR: \t0x%08x\n", dw_readl(dws, dmardlr));
len += snprintf(buf + len, SPI_REGS_BUFSIZE - len,
"=================================\n");
ret = simple_read_from_buffer(user_buf, count, ppos, buf, len);
kfree(buf);
return ret;
}
static const struct file_operations mrst_spi_regs_ops = {
.owner = THIS_MODULE,
.open = spi_show_regs_open,
.read = spi_show_regs,
};
static int mrst_spi_debugfs_init(struct dw_spi *dws)
{
dws->debugfs = debugfs_create_dir("mrst_spi", NULL);
if (!dws->debugfs)
return -ENOMEM;
debugfs_create_file("registers", S_IFREG | S_IRUGO,
dws->debugfs, (void *)dws, &mrst_spi_regs_ops);
return 0;
}
static void mrst_spi_debugfs_remove(struct dw_spi *dws)
{
if (dws->debugfs)
debugfs_remove_recursive(dws->debugfs);
}
#else
static inline int mrst_spi_debugfs_init(struct dw_spi *dws)
{
}
static inline void mrst_spi_debugfs_remove(struct dw_spi *dws)
{
}
#endif /* CONFIG_DEBUG_FS */
static void wait_till_not_busy(struct dw_spi *dws)
{
unsigned long end = jiffies + 1 + usecs_to_jiffies(1000);
while (time_before(jiffies, end)) {
if (!(dw_readw(dws, sr) & SR_BUSY))
return;
}
dev_err(&dws->master->dev,
"DW SPI: Stutus keeps busy for 1000us after a read/write!\n");
}
static void flush(struct dw_spi *dws)
{
while (dw_readw(dws, sr) & SR_RF_NOT_EMPT)
dw_readw(dws, dr);
wait_till_not_busy(dws);
}
static void null_cs_control(u32 command)
{
}
static int null_writer(struct dw_spi *dws)
{
u8 n_bytes = dws->n_bytes;
if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
|| (dws->tx == dws->tx_end))
return 0;
dw_writew(dws, dr, 0);
dws->tx += n_bytes;
wait_till_not_busy(dws);
return 1;
}
static int null_reader(struct dw_spi *dws)
{
u8 n_bytes = dws->n_bytes;
while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
&& (dws->rx < dws->rx_end)) {
dw_readw(dws, dr);
dws->rx += n_bytes;
}
wait_till_not_busy(dws);
return dws->rx == dws->rx_end;
}
static int u8_writer(struct dw_spi *dws)
{
if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
|| (dws->tx == dws->tx_end))
return 0;
dw_writew(dws, dr, *(u8 *)(dws->tx));
++dws->tx;
wait_till_not_busy(dws);
return 1;
}
static int u8_reader(struct dw_spi *dws)
{
while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
&& (dws->rx < dws->rx_end)) {
*(u8 *)(dws->rx) = dw_readw(dws, dr);
++dws->rx;
}
wait_till_not_busy(dws);
return dws->rx == dws->rx_end;
}
static int u16_writer(struct dw_spi *dws)
{
if (!(dw_readw(dws, sr) & SR_TF_NOT_FULL)
|| (dws->tx == dws->tx_end))
return 0;
dw_writew(dws, dr, *(u16 *)(dws->tx));
dws->tx += 2;
wait_till_not_busy(dws);
return 1;
}
static int u16_reader(struct dw_spi *dws)
{
u16 temp;
while ((dw_readw(dws, sr) & SR_RF_NOT_EMPT)
&& (dws->rx < dws->rx_end)) {
temp = dw_readw(dws, dr);
*(u16 *)(dws->rx) = temp;
dws->rx += 2;
}
wait_till_not_busy(dws);
return dws->rx == dws->rx_end;
}
static void *next_transfer(struct dw_spi *dws)
{
struct spi_message *msg = dws->cur_msg;
struct spi_transfer *trans = dws->cur_transfer;
/* Move to next transfer */
if (trans->transfer_list.next != &msg->transfers) {
dws->cur_transfer =
list_entry(trans->transfer_list.next,
struct spi_transfer,
transfer_list);
return RUNNING_STATE;
} else
return DONE_STATE;
}
/*
* Note: first step is the protocol driver prepares
* a dma-capable memory, and this func just need translate
* the virt addr to physical
*/
static int map_dma_buffers(struct dw_spi *dws)
{
if (!dws->cur_msg->is_dma_mapped || !dws->dma_inited
|| !dws->cur_chip->enable_dma)
return 0;
if (dws->cur_transfer->tx_dma)
dws->tx_dma = dws->cur_transfer->tx_dma;
if (dws->cur_transfer->rx_dma)
dws->rx_dma = dws->cur_transfer->rx_dma;
return 1;
}
/* Caller already set message->status; dma and pio irqs are blocked */
static void giveback(struct dw_spi *dws)
{
struct spi_transfer *last_transfer;
unsigned long flags;
struct spi_message *msg;
spin_lock_irqsave(&dws->lock, flags);
msg = dws->cur_msg;
dws->cur_msg = NULL;
dws->cur_transfer = NULL;
dws->prev_chip = dws->cur_chip;
dws->cur_chip = NULL;
dws->dma_mapped = 0;
queue_work(dws->workqueue, &dws->pump_messages);
spin_unlock_irqrestore(&dws->lock, flags);
last_transfer = list_entry(msg->transfers.prev,
struct spi_transfer,
transfer_list);
if (!last_transfer->cs_change)
dws->cs_control(MRST_SPI_DEASSERT);
msg->state = NULL;
if (msg->complete)
msg->complete(msg->context);
}
static void int_error_stop(struct dw_spi *dws, const char *msg)
{
/* Stop and reset hw */
flush(dws);
spi_enable_chip(dws, 0);
dev_err(&dws->master->dev, "%s\n", msg);
dws->cur_msg->state = ERROR_STATE;
tasklet_schedule(&dws->pump_transfers);
}
static void transfer_complete(struct dw_spi *dws)
{
/* Update total byte transfered return count actual bytes read */
dws->cur_msg->actual_length += dws->len;
/* Move to next transfer */
dws->cur_msg->state = next_transfer(dws);
/* Handle end of message */
if (dws->cur_msg->state == DONE_STATE) {
dws->cur_msg->status = 0;
giveback(dws);
} else
tasklet_schedule(&dws->pump_transfers);
}
static irqreturn_t interrupt_transfer(struct dw_spi *dws)
{
u16 irq_status, irq_mask = 0x3f;
u32 int_level = dws->fifo_len / 2;
u32 left;
irq_status = dw_readw(dws, isr) & irq_mask;
/* Error handling */
if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
dw_readw(dws, txoicr);
dw_readw(dws, rxoicr);
dw_readw(dws, rxuicr);
int_error_stop(dws, "interrupt_transfer: fifo overrun");
return IRQ_HANDLED;
}
if (irq_status & SPI_INT_TXEI) {
spi_mask_intr(dws, SPI_INT_TXEI);
left = (dws->tx_end - dws->tx) / dws->n_bytes;
left = (left > int_level) ? int_level : left;
while (left--)
dws->write(dws);
dws->read(dws);
/* Re-enable the IRQ if there is still data left to tx */
if (dws->tx_end > dws->tx)
spi_umask_intr(dws, SPI_INT_TXEI);
else
transfer_complete(dws);
}
return IRQ_HANDLED;
}
static irqreturn_t dw_spi_irq(int irq, void *dev_id)
{
struct dw_spi *dws = dev_id;
if (!dws->cur_msg) {
spi_mask_intr(dws, SPI_INT_TXEI);
/* Never fail */
return IRQ_HANDLED;
}
return dws->transfer_handler(dws);
}
/* Must be called inside pump_transfers() */
static void poll_transfer(struct dw_spi *dws)
{
if (dws->tx) {
while (dws->write(dws))
dws->read(dws);
}
dws->read(dws);
transfer_complete(dws);
}
static void dma_transfer(struct dw_spi *dws, int cs_change)
{
}
static void pump_transfers(unsigned long data)
{
struct dw_spi *dws = (struct dw_spi *)data;
struct spi_message *message = NULL;
struct spi_transfer *transfer = NULL;
struct spi_transfer *previous = NULL;
struct spi_device *spi = NULL;
struct chip_data *chip = NULL;
u8 bits = 0;
u8 imask = 0;
u8 cs_change = 0;
u16 txint_level = 0;
u16 clk_div = 0;
u32 speed = 0;
u32 cr0 = 0;
/* Get current state information */
message = dws->cur_msg;
transfer = dws->cur_transfer;
chip = dws->cur_chip;
spi = message->spi;
if (unlikely(!chip->clk_div))
chip->clk_div = dws->max_freq / chip->speed_hz;
if (message->state == ERROR_STATE) {
message->status = -EIO;
goto early_exit;
}
/* Handle end of message */
if (message->state == DONE_STATE) {
message->status = 0;
goto early_exit;
}
/* Delay if requested at end of transfer*/
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);
}
dws->n_bytes = chip->n_bytes;
dws->dma_width = chip->dma_width;
dws->cs_control = chip->cs_control;
dws->rx_dma = transfer->rx_dma;
dws->tx_dma = transfer->tx_dma;
dws->tx = (void *)transfer->tx_buf;
dws->tx_end = dws->tx + transfer->len;
dws->rx = transfer->rx_buf;
dws->rx_end = dws->rx + transfer->len;
dws->write = dws->tx ? chip->write : null_writer;
dws->read = dws->rx ? chip->read : null_reader;
dws->cs_change = transfer->cs_change;
dws->len = dws->cur_transfer->len;
if (chip != dws->prev_chip)
cs_change = 1;
cr0 = chip->cr0;
/* Handle per transfer options for bpw and speed */
if (transfer->speed_hz) {
speed = chip->speed_hz;
if (transfer->speed_hz != speed) {
speed = transfer->speed_hz;
if (speed > dws->max_freq) {
printk(KERN_ERR "MRST SPI0: unsupported"
"freq: %dHz\n", speed);
message->status = -EIO;
goto early_exit;
}
/* clk_div doesn't support odd number */
clk_div = dws->max_freq / speed;
clk_div = (clk_div + 1) & 0xfffe;
chip->speed_hz = speed;
chip->clk_div = clk_div;
}
}
if (transfer->bits_per_word) {
bits = transfer->bits_per_word;
switch (bits) {
case 8:
dws->n_bytes = 1;
dws->dma_width = 1;
dws->read = (dws->read != null_reader) ?
u8_reader : null_reader;
dws->write = (dws->write != null_writer) ?
u8_writer : null_writer;
break;
case 16:
dws->n_bytes = 2;
dws->dma_width = 2;
dws->read = (dws->read != null_reader) ?
u16_reader : null_reader;
dws->write = (dws->write != null_writer) ?
u16_writer : null_writer;
break;
default:
printk(KERN_ERR "MRST SPI0: unsupported bits:"
"%db\n", bits);
message->status = -EIO;
goto early_exit;
}
cr0 = (bits - 1)
| (chip->type << SPI_FRF_OFFSET)
| (spi->mode << SPI_MODE_OFFSET)
| (chip->tmode << SPI_TMOD_OFFSET);
}
message->state = RUNNING_STATE;
/* Check if current transfer is a DMA transaction */
dws->dma_mapped = map_dma_buffers(dws);
/*
* Interrupt mode
* we only need set the TXEI IRQ, as TX/RX always happen syncronizely
*/
if (!dws->dma_mapped && !chip->poll_mode) {
int templen = dws->len / dws->n_bytes;
txint_level = dws->fifo_len / 2;
txint_level = (templen > txint_level) ? txint_level : templen;
imask |= SPI_INT_TXEI;
dws->transfer_handler = interrupt_transfer;
}
/*
* Reprogram registers only if
* 1. chip select changes
* 2. clk_div is changed
* 3. control value changes
*/
if (dw_readw(dws, ctrl0) != cr0 || cs_change || clk_div || imask) {
spi_enable_chip(dws, 0);
if (dw_readw(dws, ctrl0) != cr0)
dw_writew(dws, ctrl0, cr0);
spi_set_clk(dws, clk_div ? clk_div : chip->clk_div);
spi_chip_sel(dws, spi->chip_select);
/* Set the interrupt mask, for poll mode just diable all int */
spi_mask_intr(dws, 0xff);
if (imask)
spi_umask_intr(dws, imask);
if (txint_level)
dw_writew(dws, txfltr, txint_level);
spi_enable_chip(dws, 1);
if (cs_change)
dws->prev_chip = chip;
}
if (dws->dma_mapped)
dma_transfer(dws, cs_change);
if (chip->poll_mode)
poll_transfer(dws);
return;
early_exit:
giveback(dws);
return;
}
static void pump_messages(struct work_struct *work)
{
struct dw_spi *dws =
container_of(work, struct dw_spi, pump_messages);
unsigned long flags;
/* Lock queue and check for queue work */
spin_lock_irqsave(&dws->lock, flags);
if (list_empty(&dws->queue) || dws->run == QUEUE_STOPPED) {
dws->busy = 0;
spin_unlock_irqrestore(&dws->lock, flags);
return;
}
/* Make sure we are not already running a message */
if (dws->cur_msg) {
spin_unlock_irqrestore(&dws->lock, flags);
return;
}
/* Extract head of queue */
dws->cur_msg = list_entry(dws->queue.next, struct spi_message, queue);
list_del_init(&dws->cur_msg->queue);
/* Initial message state*/
dws->cur_msg->state = START_STATE;
dws->cur_transfer = list_entry(dws->cur_msg->transfers.next,
struct spi_transfer,
transfer_list);
dws->cur_chip = spi_get_ctldata(dws->cur_msg->spi);
/* Mark as busy and launch transfers */
tasklet_schedule(&dws->pump_transfers);
dws->busy = 1;
spin_unlock_irqrestore(&dws->lock, flags);
}
/* spi_device use this to queue in their spi_msg */
static int dw_spi_transfer(struct spi_device *spi, struct spi_message *msg)
{
struct dw_spi *dws = spi_master_get_devdata(spi->master);
unsigned long flags;
spin_lock_irqsave(&dws->lock, flags);
if (dws->run == QUEUE_STOPPED) {
spin_unlock_irqrestore(&dws->lock, flags);
return -ESHUTDOWN;
}
msg->actual_length = 0;
msg->status = -EINPROGRESS;
msg->state = START_STATE;
list_add_tail(&msg->queue, &dws->queue);
if (dws->run == QUEUE_RUNNING && !dws->busy) {
if (dws->cur_transfer || dws->cur_msg)
queue_work(dws->workqueue,
&dws->pump_messages);
else {
/* If no other data transaction in air, just go */
spin_unlock_irqrestore(&dws->lock, flags);
pump_messages(&dws->pump_messages);
return 0;
}
}
spin_unlock_irqrestore(&dws->lock, flags);
return 0;
}
/* This may be called twice for each spi dev */
static int dw_spi_setup(struct spi_device *spi)
{
struct dw_spi_chip *chip_info = NULL;
struct chip_data *chip;
if (spi->bits_per_word != 8 && spi->bits_per_word != 16)
return -EINVAL;
/* Only alloc on first setup */
chip = spi_get_ctldata(spi);
if (!chip) {
chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
if (!chip)
return -ENOMEM;
chip->cs_control = null_cs_control;
chip->enable_dma = 0;
}
/*
* Protocol drivers may change the chip settings, so...
* if chip_info exists, use it
*/
chip_info = spi->controller_data;
/* chip_info doesn't always exist */
if (chip_info) {
if (chip_info->cs_control)
chip->cs_control = chip_info->cs_control;
chip->poll_mode = chip_info->poll_mode;
chip->type = chip_info->type;
chip->rx_threshold = 0;
chip->tx_threshold = 0;
chip->enable_dma = chip_info->enable_dma;
}
if (spi->bits_per_word <= 8) {
chip->n_bytes = 1;
chip->dma_width = 1;
chip->read = u8_reader;
chip->write = u8_writer;
} else if (spi->bits_per_word <= 16) {
chip->n_bytes = 2;
chip->dma_width = 2;
chip->read = u16_reader;
chip->write = u16_writer;
} else {
/* Never take >16b case for MRST SPIC */
dev_err(&spi->dev, "invalid wordsize\n");
return -EINVAL;
}
chip->bits_per_word = spi->bits_per_word;
if (!spi->max_speed_hz) {
dev_err(&spi->dev, "No max speed HZ parameter\n");
return -EINVAL;
}
chip->speed_hz = spi->max_speed_hz;
chip->tmode = 0; /* Tx & Rx */
/* Default SPI mode is SCPOL = 0, SCPH = 0 */
chip->cr0 = (chip->bits_per_word - 1)
| (chip->type << SPI_FRF_OFFSET)
| (spi->mode << SPI_MODE_OFFSET)
| (chip->tmode << SPI_TMOD_OFFSET);
spi_set_ctldata(spi, chip);
return 0;
}
static void dw_spi_cleanup(struct spi_device *spi)
{
struct chip_data *chip = spi_get_ctldata(spi);
kfree(chip);
}
static int __devinit init_queue(struct dw_spi *dws)
{
INIT_LIST_HEAD(&dws->queue);
spin_lock_init(&dws->lock);
dws->run = QUEUE_STOPPED;
dws->busy = 0;
tasklet_init(&dws->pump_transfers,
pump_transfers, (unsigned long)dws);
INIT_WORK(&dws->pump_messages, pump_messages);
dws->workqueue = create_singlethread_workqueue(
dev_name(dws->master->dev.parent));
if (dws->workqueue == NULL)
return -EBUSY;
return 0;
}
static int start_queue(struct dw_spi *dws)
{
unsigned long flags;
spin_lock_irqsave(&dws->lock, flags);
if (dws->run == QUEUE_RUNNING || dws->busy) {
spin_unlock_irqrestore(&dws->lock, flags);
return -EBUSY;
}
dws->run = QUEUE_RUNNING;
dws->cur_msg = NULL;
dws->cur_transfer = NULL;
dws->cur_chip = NULL;
dws->prev_chip = NULL;
spin_unlock_irqrestore(&dws->lock, flags);
queue_work(dws->workqueue, &dws->pump_messages);
return 0;
}
static int stop_queue(struct dw_spi *dws)
{
unsigned long flags;
unsigned limit = 50;
int status = 0;
spin_lock_irqsave(&dws->lock, flags);
dws->run = QUEUE_STOPPED;
while (!list_empty(&dws->queue) && dws->busy && limit--) {
spin_unlock_irqrestore(&dws->lock, flags);
msleep(10);
spin_lock_irqsave(&dws->lock, flags);
}
if (!list_empty(&dws->queue) || dws->busy)
status = -EBUSY;
spin_unlock_irqrestore(&dws->lock, flags);
return status;
}
static int destroy_queue(struct dw_spi *dws)
{
int status;
status = stop_queue(dws);
if (status != 0)
return status;
destroy_workqueue(dws->workqueue);
return 0;
}
/* Restart the controller, disable all interrupts, clean rx fifo */
static void spi_hw_init(struct dw_spi *dws)
{
spi_enable_chip(dws, 0);
spi_mask_intr(dws, 0xff);
spi_enable_chip(dws, 1);
flush(dws);
/*
* Try to detect the FIFO depth if not set by interface driver,
* the depth could be from 2 to 256 from HW spec
*/
if (!dws->fifo_len) {
u32 fifo;
for (fifo = 2; fifo <= 257; fifo++) {
dw_writew(dws, txfltr, fifo);
if (fifo != dw_readw(dws, txfltr))
break;
}
dws->fifo_len = (fifo == 257) ? 0 : fifo;
dw_writew(dws, txfltr, 0);
}
}
int __devinit dw_spi_add_host(struct dw_spi *dws)
{
struct spi_master *master;
int ret;
BUG_ON(dws == NULL);
master = spi_alloc_master(dws->parent_dev, 0);
if (!master) {
ret = -ENOMEM;
goto exit;
}
dws->master = master;
dws->type = SSI_MOTO_SPI;
dws->prev_chip = NULL;
dws->dma_inited = 0;
dws->dma_addr = (dma_addr_t)(dws->paddr + 0x60);
ret = request_irq(dws->irq, dw_spi_irq, 0,
"dw_spi", dws);
if (ret < 0) {
dev_err(&master->dev, "can not get IRQ\n");
goto err_free_master;
}
master->mode_bits = SPI_CPOL | SPI_CPHA;
master->bus_num = dws->bus_num;
master->num_chipselect = dws->num_cs;
master->cleanup = dw_spi_cleanup;
master->setup = dw_spi_setup;
master->transfer = dw_spi_transfer;
dws->dma_inited = 0;
/* Basic HW init */
spi_hw_init(dws);
/* Initial and start queue */
ret = init_queue(dws);
if (ret) {
dev_err(&master->dev, "problem initializing queue\n");
goto err_diable_hw;
}
ret = start_queue(dws);
if (ret) {
dev_err(&master->dev, "problem starting queue\n");
goto err_diable_hw;
}
spi_master_set_devdata(master, dws);
ret = spi_register_master(master);
if (ret) {
dev_err(&master->dev, "problem registering spi master\n");
goto err_queue_alloc;
}
mrst_spi_debugfs_init(dws);
return 0;
err_queue_alloc:
destroy_queue(dws);
err_diable_hw:
spi_enable_chip(dws, 0);
free_irq(dws->irq, dws);
err_free_master:
spi_master_put(master);
exit:
return ret;
}
EXPORT_SYMBOL(dw_spi_add_host);
void __devexit dw_spi_remove_host(struct dw_spi *dws)
{
int status = 0;
if (!dws)
return;
mrst_spi_debugfs_remove(dws);
/* Remove the queue */
status = destroy_queue(dws);
if (status != 0)
dev_err(&dws->master->dev, "dw_spi_remove: workqueue will not "
"complete, message memory not freed\n");
spi_enable_chip(dws, 0);
/* Disable clk */
spi_set_clk(dws, 0);
free_irq(dws->irq, dws);
/* Disconnect from the SPI framework */
spi_unregister_master(dws->master);
}
int dw_spi_suspend_host(struct dw_spi *dws)
{
int ret = 0;
ret = stop_queue(dws);
if (ret)
return ret;
spi_enable_chip(dws, 0);
spi_set_clk(dws, 0);
return ret;
}
EXPORT_SYMBOL(dw_spi_suspend_host);
int dw_spi_resume_host(struct dw_spi *dws)
{
int ret;
spi_hw_init(dws);
ret = start_queue(dws);
if (ret)
dev_err(&dws->master->dev, "fail to start queue (%d)\n", ret);
return ret;
}
EXPORT_SYMBOL(dw_spi_resume_host);
MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
MODULE_LICENSE("GPL v2");