The patch titled
spi: au1550_spi full duplex dma fix
has been added to the -mm tree. Its filename is
spi-au1550_spi-full-duplex-dma-fix.patch
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------------------------------------------------------
Subject: spi: au1550_spi full duplex dma fix
From: Jan Nikitenko <jan.nikitenko@xxxxxxxxx>
Fix unsafe order in dma mapping operation: always flush data from the
cache *BEFORE* invalidating it, to allow full duplex transfers where the
same buffer may be used for both writes and reads. Tested with mmc-spi.
Signed-off-by: Jan Nikitenko <jan.nikitenko@xxxxxxxxx>
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/spi/au1550_spi.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
diff -puN drivers/spi/au1550_spi.c~spi-au1550_spi-full-duplex-dma-fix drivers/spi/au1550_spi.c
--- a/drivers/spi/au1550_spi.c~spi-au1550_spi-full-duplex-dma-fix
+++ a/drivers/spi/au1550_spi.c
@@ -369,10 +369,23 @@ static int au1550_spi_dma_txrxb(struct s
dma_rx_addr = t->rx_dma;
/*
- * check if buffers are already dma mapped, map them otherwise
+ * check if buffers are already dma mapped, map them otherwise:
+ * - first map the TX buffer, so cache data gets written to memory
+ * - then map the RX buffer, so that cache entries (with
+ * soon-to-be-stale data) get removed
* use rx buffer in place of tx if tx buffer was not provided
* use temp rx buffer (preallocated or realloc to fit) for rx dma
*/
+ if (t->tx_buf) {
+ if (t->tx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
+ dma_tx_addr = dma_map_single(hw->dev,
+ (void *)t->tx_buf,
+ t->len, DMA_TO_DEVICE);
+ if (dma_mapping_error(hw->dev, dma_tx_addr))
+ dev_err(hw->dev, "tx dma map error\n");
+ }
+ }
+
if (t->rx_buf) {
if (t->rx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
dma_rx_addr = dma_map_single(hw->dev,
@@ -396,15 +409,8 @@ static int au1550_spi_dma_txrxb(struct s
dma_sync_single_for_device(hw->dev, dma_rx_addr,
t->len, DMA_FROM_DEVICE);
}
- if (t->tx_buf) {
- if (t->tx_dma == 0) { /* if DMA_ADDR_INVALID, map it */
- dma_tx_addr = dma_map_single(hw->dev,
- (void *)t->tx_buf,
- t->len, DMA_TO_DEVICE);
- if (dma_mapping_error(hw->dev, dma_tx_addr))
- dev_err(hw->dev, "tx dma map error\n");
- }
- } else {
+
+ if (!t->tx_buf) {
dma_sync_single_for_device(hw->dev, dma_rx_addr,
t->len, DMA_BIDIRECTIONAL);
hw->tx = hw->rx;
_
Patches currently in -mm which might be from jan.nikitenko@xxxxxxxxx are
spi-au1550_spi-full-duplex-dma-fix.patch
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