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yaml
---
r: 307647
b: refs/heads/master
c: a3633fe
h: refs/heads/master
i:
  307645: 1e0e185
  307643: b889e72
  307639: 2bf8269
  307631: ae206e1
  307615: 1cb2d5a
  307583: 08677e7
v: v3
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Shimoda, Yoshihiro authored and Grant Likely committed May 20, 2012
1 parent 0659fe7 commit 9697318
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Showing 3 changed files with 346 additions and 7 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: d195f7bebc14ece71bf11d09f1726ee6f6b4f4b9
refs/heads/master: a3633fe7aa7022e2e9b2b799a0cbf3d6944d8ba5
320 changes: 314 additions & 6 deletions trunk/drivers/spi/spi-rspi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,11 @@
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/sh_dma.h>
#include <linux/spi/spi.h>
#include <linux/spi/rspi.h>

#define RSPI_SPCR 0x00
#define RSPI_SSLP 0x01
Expand Down Expand Up @@ -141,6 +145,16 @@ struct rspi_data {
spinlock_t lock;
struct clk *clk;
unsigned char spsr;

/* for dmaengine */
struct sh_dmae_slave dma_tx;
struct sh_dmae_slave dma_rx;
struct dma_chan *chan_tx;
struct dma_chan *chan_rx;
int irq;

unsigned dma_width_16bit:1;
unsigned dma_callbacked:1;
};

static void rspi_write8(struct rspi_data *rspi, u8 data, u16 offset)
Expand Down Expand Up @@ -265,11 +279,125 @@ static int rspi_send_pio(struct rspi_data *rspi, struct spi_message *mesg,
return 0;
}

static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
struct spi_transfer *t)
static void rspi_dma_complete(void *arg)
{
struct rspi_data *rspi = arg;

rspi->dma_callbacked = 1;
wake_up_interruptible(&rspi->wait);
}

static int rspi_dma_map_sg(struct scatterlist *sg, void *buf, unsigned len,
struct dma_chan *chan,
enum dma_transfer_direction dir)
{
sg_init_table(sg, 1);
sg_set_buf(sg, buf, len);
sg_dma_len(sg) = len;
return dma_map_sg(chan->device->dev, sg, 1, dir);
}

static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
enum dma_transfer_direction dir)
{
dma_unmap_sg(chan->device->dev, sg, 1, dir);
}

static void rspi_memory_to_8bit(void *buf, const void *data, unsigned len)
{
u16 *dst = buf;
const u8 *src = data;

while (len) {
*dst++ = (u16)(*src++);
len--;
}
}

static void rspi_memory_from_8bit(void *buf, const void *data, unsigned len)
{
u8 *dst = buf;
const u16 *src = data;

while (len) {
*dst++ = (u8)*src++;
len--;
}
}

static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
{
struct scatterlist sg;
void *buf = NULL;
struct dma_async_tx_descriptor *desc;
unsigned len;
int ret = 0;

if (rspi->dma_width_16bit) {
/*
* If DMAC bus width is 16-bit, the driver allocates a dummy
* buffer. And, the driver converts original data into the
* DMAC data as the following format:
* original data: 1st byte, 2nd byte ...
* DMAC data: 1st byte, dummy, 2nd byte, dummy ...
*/
len = t->len * 2;
buf = kmalloc(len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
rspi_memory_to_8bit(buf, t->tx_buf, t->len);
} else {
len = t->len;
buf = (void *)t->tx_buf;
}

if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE)) {
ret = -EFAULT;
goto end_nomap;
}
desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
ret = -EIO;
goto end;
}

/*
* DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
* called. So, this driver disables the IRQ while DMA transfer.
*/
disable_irq(rspi->irq);

rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) | SPCR_TXMD, RSPI_SPCR);
rspi_enable_irq(rspi, SPCR_SPTIE);
rspi->dma_callbacked = 0;

desc->callback = rspi_dma_complete;
desc->callback_param = rspi;
dmaengine_submit(desc);
dma_async_issue_pending(rspi->chan_tx);

ret = wait_event_interruptible_timeout(rspi->wait,
rspi->dma_callbacked, HZ);
if (ret > 0 && rspi->dma_callbacked)
ret = 0;
else if (!ret)
ret = -ETIMEDOUT;
rspi_disable_irq(rspi, SPCR_SPTIE);

enable_irq(rspi->irq);

end:
rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
end_nomap:
if (rspi->dma_width_16bit)
kfree(buf);

return ret;
}

static void rspi_receive_init(struct rspi_data *rspi)
{
int remain = t->len;
u8 *data;
unsigned char spsr;

spsr = rspi_read8(rspi, RSPI_SPSR);
Expand All @@ -278,6 +406,15 @@ static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
if (spsr & SPSR_OVRF)
rspi_write8(rspi, rspi_read8(rspi, RSPI_SPSR) & ~SPSR_OVRF,
RSPI_SPCR);
}

static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
struct spi_transfer *t)
{
int remain = t->len;
u8 *data;

rspi_receive_init(rspi);

data = (u8 *)t->rx_buf;
while (remain > 0) {
Expand Down Expand Up @@ -307,6 +444,120 @@ static int rspi_receive_pio(struct rspi_data *rspi, struct spi_message *mesg,
return 0;
}

static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
{
struct scatterlist sg, sg_dummy;
void *dummy = NULL, *rx_buf = NULL;
struct dma_async_tx_descriptor *desc, *desc_dummy;
unsigned len;
int ret = 0;

if (rspi->dma_width_16bit) {
/*
* If DMAC bus width is 16-bit, the driver allocates a dummy
* buffer. And, finally the driver converts the DMAC data into
* actual data as the following format:
* DMAC data: 1st byte, dummy, 2nd byte, dummy ...
* actual data: 1st byte, 2nd byte ...
*/
len = t->len * 2;
rx_buf = kmalloc(len, GFP_KERNEL);
if (!rx_buf)
return -ENOMEM;
} else {
len = t->len;
rx_buf = t->rx_buf;
}

/* prepare dummy transfer to generate SPI clocks */
dummy = kzalloc(len, GFP_KERNEL);
if (!dummy) {
ret = -ENOMEM;
goto end_nomap;
}
if (!rspi_dma_map_sg(&sg_dummy, dummy, len, rspi->chan_tx,
DMA_TO_DEVICE)) {
ret = -EFAULT;
goto end_nomap;
}
desc_dummy = dmaengine_prep_slave_sg(rspi->chan_tx, &sg_dummy, 1,
DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc_dummy) {
ret = -EIO;
goto end_dummy_mapped;
}

/* prepare receive transfer */
if (!rspi_dma_map_sg(&sg, rx_buf, len, rspi->chan_rx,
DMA_FROM_DEVICE)) {
ret = -EFAULT;
goto end_dummy_mapped;

}
desc = dmaengine_prep_slave_sg(rspi->chan_rx, &sg, 1, DMA_FROM_DEVICE,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
ret = -EIO;
goto end;
}

rspi_receive_init(rspi);

/*
* DMAC needs SPTIE, but if SPTIE is set, this IRQ routine will be
* called. So, this driver disables the IRQ while DMA transfer.
*/
disable_irq(rspi->irq);

rspi_write8(rspi, rspi_read8(rspi, RSPI_SPCR) & ~SPCR_TXMD, RSPI_SPCR);
rspi_enable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE);
rspi->dma_callbacked = 0;

desc->callback = rspi_dma_complete;
desc->callback_param = rspi;
dmaengine_submit(desc);
dma_async_issue_pending(rspi->chan_rx);

desc_dummy->callback = NULL; /* No callback */
dmaengine_submit(desc_dummy);
dma_async_issue_pending(rspi->chan_tx);

ret = wait_event_interruptible_timeout(rspi->wait,
rspi->dma_callbacked, HZ);
if (ret > 0 && rspi->dma_callbacked)
ret = 0;
else if (!ret)
ret = -ETIMEDOUT;
rspi_disable_irq(rspi, SPCR_SPTIE | SPCR_SPRIE);

enable_irq(rspi->irq);

end:
rspi_dma_unmap_sg(&sg, rspi->chan_rx, DMA_FROM_DEVICE);
end_dummy_mapped:
rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE);
end_nomap:
if (rspi->dma_width_16bit) {
if (!ret)
rspi_memory_from_8bit(t->rx_buf, rx_buf, t->len);
kfree(rx_buf);
}
kfree(dummy);

return ret;
}

static int rspi_is_dma(struct rspi_data *rspi, struct spi_transfer *t)
{
if (t->tx_buf && rspi->chan_tx)
return 1;
/* If the module receives data by DMAC, it also needs TX DMAC */
if (t->rx_buf && rspi->chan_tx && rspi->chan_rx)
return 1;

return 0;
}

static void rspi_work(struct work_struct *work)
{
struct rspi_data *rspi = container_of(work, struct rspi_data, ws);
Expand All @@ -325,12 +576,18 @@ static void rspi_work(struct work_struct *work)

list_for_each_entry(t, &mesg->transfers, transfer_list) {
if (t->tx_buf) {
ret = rspi_send_pio(rspi, mesg, t);
if (rspi_is_dma(rspi, t))
ret = rspi_send_dma(rspi, t);
else
ret = rspi_send_pio(rspi, mesg, t);
if (ret < 0)
goto error;
}
if (t->rx_buf) {
ret = rspi_receive_pio(rspi, mesg, t);
if (rspi_is_dma(rspi, t))
ret = rspi_receive_dma(rspi, t);
else
ret = rspi_receive_pio(rspi, mesg, t);
if (ret < 0)
goto error;
}
Expand Down Expand Up @@ -406,11 +663,58 @@ static irqreturn_t rspi_irq(int irq, void *_sr)
return ret;
}

static bool rspi_filter(struct dma_chan *chan, void *filter_param)
{
chan->private = filter_param;
return true;
}

static void __devinit rspi_request_dma(struct rspi_data *rspi,
struct platform_device *pdev)
{
struct rspi_plat_data *rspi_pd = pdev->dev.platform_data;
dma_cap_mask_t mask;

if (!rspi_pd)
return;

rspi->dma_width_16bit = rspi_pd->dma_width_16bit;

/* If the module receives data by DMAC, it also needs TX DMAC */
if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
rspi->dma_rx.slave_id = rspi_pd->dma_rx_id;
rspi->chan_rx = dma_request_channel(mask, rspi_filter,
&rspi->dma_rx);
if (rspi->chan_rx)
dev_info(&pdev->dev, "Use DMA when rx.\n");
}
if (rspi_pd->dma_tx_id) {
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
rspi->dma_tx.slave_id = rspi_pd->dma_tx_id;
rspi->chan_tx = dma_request_channel(mask, rspi_filter,
&rspi->dma_tx);
if (rspi->chan_tx)
dev_info(&pdev->dev, "Use DMA when tx\n");
}
}

static void __devexit rspi_release_dma(struct rspi_data *rspi)
{
if (rspi->chan_tx)
dma_release_channel(rspi->chan_tx);
if (rspi->chan_rx)
dma_release_channel(rspi->chan_rx);
}

static int __devexit rspi_remove(struct platform_device *pdev)
{
struct rspi_data *rspi = dev_get_drvdata(&pdev->dev);

spi_unregister_master(rspi->master);
rspi_release_dma(rspi);
free_irq(platform_get_irq(pdev, 0), rspi);
clk_put(rspi->clk);
iounmap(rspi->addr);
Expand Down Expand Up @@ -483,6 +787,9 @@ static int __devinit rspi_probe(struct platform_device *pdev)
goto error3;
}

rspi->irq = irq;
rspi_request_dma(rspi, pdev);

ret = spi_register_master(master);
if (ret < 0) {
dev_err(&pdev->dev, "spi_register_master error.\n");
Expand All @@ -494,6 +801,7 @@ static int __devinit rspi_probe(struct platform_device *pdev)
return 0;

error4:
rspi_release_dma(rspi);
free_irq(irq, rspi);
error3:
clk_put(rspi->clk);
Expand Down
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