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>
diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index c8319ab..7281316 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 @@
}
/*
- * 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 @@
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 @@
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 @@
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 @@
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 @@
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);
+ if (rxdesc) {
+ set_bit(RX_BUSY, &dws->dma_chan_busy);
+ dmaengine_submit(rxdesc);
+ dma_async_issue_pending(dws->rxchan);
+ }
- dmaengine_submit(txdesc);
- dma_async_issue_pending(dws->txchan);
+ if (txdesc) {
+ set_bit(TX_BUSY, &dws->dma_chan_busy);
+ dmaengine_submit(txdesc);
+ dma_async_issue_pending(dws->txchan);
+ }
return 0;
}
diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index 83a103a..3d32be6 100644
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -139,7 +139,7 @@
struct scatterlist tx_sgl;
struct dma_chan *rxchan;
struct scatterlist rx_sgl;
- int dma_chan_done;
+ unsigned long dma_chan_busy;
struct device *dma_dev;
dma_addr_t dma_addr; /* phy address of the Data register */
struct dw_spi_dma_ops *dma_ops;