diff options
| author | Jan Nikitenko <jan.nikitenko@gmail.com> | 2008-12-01 13:13:56 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-01 19:55:24 -0800 |
| commit | 4e253d23003b54c88d0919d6088be74f00eec3c7 (patch) | |
| tree | 418741f7add461e32f4c2801e8a693f9dbd0455b /drivers | |
| parent | 6a010b56e9bd2fdb32efd153e1a08305949b6b53 (diff) | |
spi: au1550_spi full duplex dma fix
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@gmail.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/spi/au1550_spi.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/spi/au1550_spi.c b/drivers/spi/au1550_spi.c index 87b73e0169c..b02f25c702f 100644 --- a/drivers/spi/au1550_spi.c +++ b/drivers/spi/au1550_spi.c @@ -369,10 +369,23 @@ static int au1550_spi_dma_txrxb(struct spi_device *spi, struct spi_transfer *t) 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 spi_device *spi, struct spi_transfer *t) 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; |