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spi: rspi: Remove unused 16-bit DMA support

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The 16-bit DMA support doesn't fit well within the SPI core DMA framework,
as it needs to manage its own double-sized temporary buffers, for handling
the interleaved data.
Remove it, as there is no in-tree board code that sets
rspi_plat_data.dma_width_16bit.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Geert Uytterhoeven 2014-06-02 15:38:05 +02:00 • committed by Mark Brown
parent 32c64261c6
commit 9c5de2c175
2 changed files with 6 additions and 80 deletions
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84
drivers/spi/spi-rspi.c
View file

@ -201,7 +201,6 @@ struct rspi_data {
struct dma_chan *chan_tx; struct dma_chan *chan_tx;
struct dma_chan *chan_rx; struct dma_chan *chan_rx;
unsigned dma_width_16bit:1;
unsigned dma_callbacked:1; unsigned dma_callbacked:1;
unsigned byte_access:1; unsigned byte_access:1;
}; };
@ -475,60 +474,17 @@ static void rspi_dma_unmap_sg(struct scatterlist *sg, struct dma_chan *chan,
dma_unmap_sg(chan->device->dev, sg, 1, 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) static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
{ {
struct scatterlist sg; struct scatterlist sg;
const void *buf = NULL; const void *buf = t->tx_buf;
struct dma_async_tx_descriptor *desc; struct dma_async_tx_descriptor *desc;
unsigned int len; unsigned int len = t->len;
int ret = 0; int ret = 0;
if (rspi->dma_width_16bit) { if (!rspi_dma_map_sg(&sg, buf, len, rspi->chan_tx, DMA_TO_DEVICE))
void *tmp; return -EFAULT;
/*
* 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;
tmp = kmalloc(len, GFP_KERNEL);
if (!tmp)
return -ENOMEM;
rspi_memory_to_8bit(tmp, t->tx_buf, t->len);
buf = tmp;
} else {
len = t->len;
buf = 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, desc = dmaengine_prep_slave_sg(rspi->chan_tx, &sg, 1, DMA_TO_DEVICE,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK); DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) { if (!desc) {
@ -563,10 +519,6 @@ static int rspi_send_dma(struct rspi_data *rspi, struct spi_transfer *t)
end: end:
rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE); rspi_dma_unmap_sg(&sg, rspi->chan_tx, DMA_TO_DEVICE);
end_nomap:
if (rspi->dma_width_16bit)
kfree(buf);
return ret; return ret;
} }
@ -603,28 +555,11 @@ static void qspi_receive_init(const struct rspi_data *rspi)
static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t) static int rspi_receive_dma(struct rspi_data *rspi, struct spi_transfer *t)
{ {
struct scatterlist sg, sg_dummy; struct scatterlist sg, sg_dummy;
void *dummy = NULL, *rx_buf = NULL; void *dummy = NULL, *rx_buf = t->rx_buf;
struct dma_async_tx_descriptor *desc, *desc_dummy; struct dma_async_tx_descriptor *desc, *desc_dummy;
unsigned int len; unsigned int len = t->len;
int ret = 0; 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 */ /* prepare dummy transfer to generate SPI clocks */
dummy = kzalloc(len, GFP_KERNEL); dummy = kzalloc(len, GFP_KERNEL);
if (!dummy) { if (!dummy) {
@ -697,11 +632,6 @@ end:
end_dummy_mapped: end_dummy_mapped:
rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE); rspi_dma_unmap_sg(&sg_dummy, rspi->chan_tx, DMA_TO_DEVICE);
end_nomap: 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); kfree(dummy);
return ret; return ret;
@ -1073,8 +1003,6 @@ static int rspi_request_dma(struct rspi_data *rspi,
if (!res || !rspi_pd) if (!res || !rspi_pd)
return 0; /* The driver assumes no error. */ return 0; /* The driver assumes no error. */
rspi->dma_width_16bit = rspi_pd->dma_width_16bit;
/* If the module receives data by DMAC, it also needs TX DMAC */ /* If the module receives data by DMAC, it also needs TX DMAC */
if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) { if (rspi_pd->dma_rx_id && rspi_pd->dma_tx_id) {
dma_cap_zero(mask); dma_cap_zero(mask);

2
include/linux/spi/rspi.h
View file

@ -25,8 +25,6 @@ struct rspi_plat_data {
unsigned int dma_tx_id; unsigned int dma_tx_id;
unsigned int dma_rx_id; unsigned int dma_rx_id;
unsigned dma_width_16bit:1; /* DMAC read/write width = 16-bit */
u16 num_chipselect; u16 num_chipselect;
}; };