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Code Issues Releases Wiki Activity

spi: davinci: handle DMA completion errors correctly

Browse source 
Do not simply clean the DMA channel on a DMA completion
error. Instead, use wcount and rcount members of davinci_spi
to detecion non-completion of DMA and signal EIO to the
application.

Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Tested-By: Michael Williamson <michael.williamson@criticallink.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
This commit is contained in:
Brian Niebuhr 2010-10-05 11:38:41 +05:30 committed by Sekhar Nori
parent 523c37e700
commit 9b189fd758
1 changed files with 36 additions and 27 deletions
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63
drivers/spi/davinci_spi.c
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@ -388,24 +388,26 @@ static int davinci_spi_setup_transfer(struct spi_device *spi,
static void davinci_spi_dma_rx_callback(unsigned lch, u16 ch_status, void *data)
{
struct davinci_spi_dma *davinci_spi_dma = data;
struct davinci_spi *davinci_spi = data;
struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels;
edma_stop(davinci_spi_dma->dma_rx_channel);
if (ch_status == DMA_COMPLETE)
edma_stop(davinci_spi_dma->dma_rx_channel);
else
edma_clean_channel(davinci_spi_dma->dma_rx_channel);
davinci_spi->rcount = 0;
complete(&davinci_spi_dma->dma_rx_completion);
}
static void davinci_spi_dma_tx_callback(unsigned lch, u16 ch_status, void *data)
{
struct davinci_spi_dma *davinci_spi_dma = data;
struct davinci_spi *davinci_spi = data;
struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels;
edma_stop(davinci_spi_dma->dma_tx_channel);
if (ch_status == DMA_COMPLETE)
edma_stop(davinci_spi_dma->dma_tx_channel);
else
edma_clean_channel(davinci_spi_dma->dma_tx_channel);
davinci_spi->wcount = 0;
complete(&davinci_spi_dma->dma_tx_completion);
}
@ -632,7 +634,6 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
{
struct davinci_spi *davinci_spi;
int int_status = 0;
int count;
unsigned rx_buf_count;
struct davinci_spi_dma *davinci_spi_dma;
int data_type, ret;
@ -648,20 +649,20 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
davinci_spi_dma = &davinci_spi->dma_channels;
/* convert len to words based on bits_per_word */
data_type = davinci_spi->bytes_per_word[spi->chip_select];
tx_reg = (unsigned long)davinci_spi->pbase + SPIDAT1;
rx_reg = (unsigned long)davinci_spi->pbase + SPIBUF;
davinci_spi->tx = t->tx_buf;
davinci_spi->rx = t->rx_buf;
/* convert len to words based on bits_per_word */
data_type = davinci_spi->bytes_per_word[spi->chip_select];
davinci_spi->wcount = t->len / data_type;
davinci_spi->rcount = davinci_spi->wcount;
init_completion(&davinci_spi_dma->dma_rx_completion);
init_completion(&davinci_spi_dma->dma_tx_completion);
count = t->len / data_type; /* the number of elements */
/* disable all interrupts for dma transfers */
clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKALL);
/* Enable SPI */
@ -680,18 +681,18 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
*/
if (t->tx_buf) {
t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf, count,
DMA_TO_DEVICE);
t->tx_dma = dma_map_single(&spi->dev, (void *)t->tx_buf,
davinci_spi->wcount, DMA_TO_DEVICE);
if (dma_mapping_error(&spi->dev, t->tx_dma)) {
dev_dbg(sdev, "Unable to DMA map a %d bytes"
" TX buffer\n", count);
dev_dbg(sdev, "Unable to DMA map %d bytes TX buffer\n",
davinci_spi->wcount);
return -ENOMEM;
}
}
param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_tx_channel);
param.src = t->tx_buf ? t->tx_dma : tx_reg;
param.a_b_cnt = count << 16 | data_type;
param.a_b_cnt = davinci_spi->wcount << 16 | data_type;
param.dst = tx_reg;
param.src_dst_bidx = t->tx_buf ? data_type : 0;
param.link_bcntrld = 0xffff;
@ -715,7 +716,7 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
if (t->rx_buf) {
rx_buf = t->rx_buf;
rx_buf_count = count;
rx_buf_count = davinci_spi->rcount;
} else {
rx_buf = davinci_spi->rx_tmp_buf;
rx_buf_count = sizeof(davinci_spi->rx_tmp_buf);
@ -727,13 +728,14 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
dev_dbg(sdev, "Couldn't DMA map a %d bytes RX buffer\n",
rx_buf_count);
if (t->tx_buf)
dma_unmap_single(NULL, t->tx_dma, count, DMA_TO_DEVICE);
dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount,
DMA_TO_DEVICE);
return -ENOMEM;
}
param.opt = TCINTEN | EDMA_TCC(davinci_spi_dma->dma_rx_channel);
param.src = rx_reg;
param.a_b_cnt = count << 16 | data_type;
param.a_b_cnt = davinci_spi->rcount << 16 | data_type;
param.dst = t->rx_dma;
param.src_dst_bidx = (t->rx_buf ? data_type : 0) << 16;
param.link_bcntrld = 0xffff;
@ -754,7 +756,8 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
wait_for_completion_interruptible(&davinci_spi_dma->dma_rx_completion);
if (t->tx_buf)
dma_unmap_single(NULL, t->tx_dma, count, DMA_TO_DEVICE);
dma_unmap_single(NULL, t->tx_dma, davinci_spi->wcount,
DMA_TO_DEVICE);
dma_unmap_single(NULL, t->rx_dma, rx_buf_count, DMA_FROM_DEVICE);
@ -770,15 +773,21 @@ static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t)
if (ret != 0)
return ret;
if (davinci_spi->rcount != 0 || davinci_spi->wcount != 0) {
dev_err(sdev, "SPI data transfer error\n");
return -EIO;
}
return t->len;
}
static int davinci_spi_request_dma(struct davinci_spi_dma *davinci_spi_dma)
static int davinci_spi_request_dma(struct davinci_spi *davinci_spi)
{
int r;
struct davinci_spi_dma *davinci_spi_dma = &davinci_spi->dma_channels;
r = edma_alloc_channel(davinci_spi_dma->dma_rx_channel,
davinci_spi_dma_rx_callback, davinci_spi_dma,
davinci_spi_dma_rx_callback, davinci_spi,
davinci_spi_dma->eventq);
if (r < 0) {
pr_err("Unable to request DMA channel for SPI RX\n");
@ -787,7 +796,7 @@ static int davinci_spi_request_dma(struct davinci_spi_dma *davinci_spi_dma)
}
r = edma_alloc_channel(davinci_spi_dma->dma_tx_channel,
davinci_spi_dma_tx_callback, davinci_spi_dma,
davinci_spi_dma_tx_callback, davinci_spi,
davinci_spi_dma->eventq);
if (r < 0) {
pr_err("Unable to request DMA channel for SPI TX\n");
@ -929,7 +938,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
davinci_spi->dma_channels.dma_tx_channel = dma_tx_chan;
davinci_spi->dma_channels.eventq = dma_eventq;
ret = davinci_spi_request_dma(&davinci_spi->dma_channels);
ret = davinci_spi_request_dma(davinci_spi);
if (ret)
goto free_clk;