summaryrefslogtreecommitdiff
path: root/drivers/spi/spi-dw-mid.c
diff options
context:
space:
mode:
authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>2014-10-28 19:25:02 +0300
committerMark Brown <broonie@kernel.org>2014-10-29 01:40:38 +0300
commit30c8eb52cc4a7bed59d85243e769ce420f179140 (patch)
tree24f623b6778fcebfdaf8b5c8e30abbedaa600fb4 /drivers/spi/spi-dw-mid.c
parenta5c2db964d3eb26b41bd7abc1b13486f732b3aa2 (diff)
downloadlinux-30c8eb52cc4a7bed59d85243e769ce420f179140.tar.xz
spi: dw-mid: split rx and tx callbacks when DMA
Currently driver wouldn't work properly if user asked for simplex transfer. The patch separates DMA rx and tx callbacks and finishes transfer correctly in any case. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-dw-mid.c')
-rw-r--r--drivers/spi/spi-dw-mid.c53
1 files changed, 39 insertions, 14 deletions
diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index c8319ab0bbdf..7281316a5ecb 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -26,6 +26,9 @@
#include <linux/intel_mid_dma.h>
#include <linux/pci.h>
+#define RX_BUSY 0
+#define TX_BUSY 1
+
struct mid_dma {
struct intel_mid_dma_slave dmas_tx;
struct intel_mid_dma_slave dmas_rx;
@@ -98,15 +101,14 @@ static void mid_spi_dma_exit(struct dw_spi *dws)
}
/*
- * dws->dma_chan_done is cleared before the dma transfer starts,
- * callback for rx/tx channel will each increment it by 1.
- * Reaching 2 means the whole spi transaction is done.
+ * dws->dma_chan_busy is set before the dma transfer starts, callback for tx
+ * channel will clear a corresponding bit.
*/
-static void dw_spi_dma_done(void *arg)
+static void dw_spi_dma_tx_done(void *arg)
{
struct dw_spi *dws = arg;
- if (++dws->dma_chan_done != 2)
+ if (test_and_clear_bit(TX_BUSY, &dws->dma_chan_busy) & BIT(RX_BUSY))
return;
dw_spi_xfer_done(dws);
}
@@ -116,6 +118,9 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws)
struct dma_slave_config txconf;
struct dma_async_tx_descriptor *txdesc;
+ if (!dws->tx_dma)
+ return NULL;
+
txconf.direction = DMA_MEM_TO_DEV;
txconf.dst_addr = dws->dma_addr;
txconf.dst_maxburst = LNW_DMA_MSIZE_16;
@@ -134,17 +139,33 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws)
1,
DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
- txdesc->callback = dw_spi_dma_done;
+ txdesc->callback = dw_spi_dma_tx_done;
txdesc->callback_param = dws;
return txdesc;
}
+/*
+ * dws->dma_chan_busy is set before the dma transfer starts, callback for rx
+ * channel will clear a corresponding bit.
+ */
+static void dw_spi_dma_rx_done(void *arg)
+{
+ struct dw_spi *dws = arg;
+
+ if (test_and_clear_bit(RX_BUSY, &dws->dma_chan_busy) & BIT(TX_BUSY))
+ return;
+ dw_spi_xfer_done(dws);
+}
+
static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws)
{
struct dma_slave_config rxconf;
struct dma_async_tx_descriptor *rxdesc;
+ if (!dws->rx_dma)
+ return NULL;
+
rxconf.direction = DMA_DEV_TO_MEM;
rxconf.src_addr = dws->dma_addr;
rxconf.src_maxburst = LNW_DMA_MSIZE_16;
@@ -163,7 +184,7 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws)
1,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
- rxdesc->callback = dw_spi_dma_done;
+ rxdesc->callback = dw_spi_dma_rx_done;
rxdesc->callback_param = dws;
return rxdesc;
@@ -195,8 +216,6 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
if (cs_change)
dw_spi_dma_setup(dws);
- dws->dma_chan_done = 0;
-
/* 2. Prepare the TX dma transfer */
txdesc = dw_spi_dma_prepare_tx(dws);
@@ -204,11 +223,17 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
rxdesc = dw_spi_dma_prepare_rx(dws);
/* rx must be started before tx due to spi instinct */
- dmaengine_submit(rxdesc);
- dma_async_issue_pending(dws->rxchan);
-
- dmaengine_submit(txdesc);
- dma_async_issue_pending(dws->txchan);
+ if (rxdesc) {
+ set_bit(RX_BUSY, &dws->dma_chan_busy);
+ dmaengine_submit(rxdesc);
+ dma_async_issue_pending(dws->rxchan);
+ }
+
+ if (txdesc) {
+ set_bit(TX_BUSY, &dws->dma_chan_busy);
+ dmaengine_submit(txdesc);
+ dma_async_issue_pending(dws->txchan);
+ }
return 0;
}