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| author | Andrea Paterniani <a.paterniani@swapp-eng.it> | 2008-11-19 15:36:26 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-11-19 18:49:58 -0800 |
| commit | 3b45d6380c392e402adc460e4ccf7d41e0caf82a (patch) | |
| tree | 39526d9c921330fbdd57c864364b5ce3cdbd8751 /drivers | |
| parent | b3b4dc8840a8fdbe495723d35cd976d781fd42fa (diff) | |
| download | lwn-3b45d6380c392e402adc460e4ccf7d41e0caf82a.tar.gz lwn-3b45d6380c392e402adc460e4ccf7d41e0caf82a.zip | |
spi_imx: full duplex dma corruption bugfix
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.
Signed-off-by: Andrea Paterniani <a.paterniani@swapp-eng.it>
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/spi_imx.c | 45 |
1 files changed, 22 insertions, 23 deletions
diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c index 61ba147e384d..0b4db0ce78d6 100644 --- a/drivers/spi/spi_imx.c +++ b/drivers/spi/spi_imx.c @@ -506,20 +506,6 @@ static int map_dma_buffers(struct driver_data *drv_data) if (!IS_DMA_ALIGNED(drv_data->rx) || !IS_DMA_ALIGNED(drv_data->tx)) return -1; - /* NULL rx means write-only transfer and no map needed - since rx DMA will not be used */ - if (drv_data->rx) { - buf = drv_data->rx; - drv_data->rx_dma = dma_map_single( - dev, - buf, - drv_data->len, - DMA_FROM_DEVICE); - if (dma_mapping_error(dev, drv_data->rx_dma)) - return -1; - drv_data->rx_dma_needs_unmap = 1; - } - if (drv_data->tx == NULL) { /* Read only message --> use drv_data->dummy_dma_buf for dummy writes to achive reads */ @@ -533,18 +519,31 @@ static int map_dma_buffers(struct driver_data *drv_data) buf, drv_data->tx_map_len, DMA_TO_DEVICE); - if (dma_mapping_error(dev, drv_data->tx_dma)) { - if (drv_data->rx_dma) { - dma_unmap_single(dev, - drv_data->rx_dma, - drv_data->len, - DMA_FROM_DEVICE); - drv_data->rx_dma_needs_unmap = 0; - } + if (dma_mapping_error(dev, drv_data->tx_dma)) return -1; - } drv_data->tx_dma_needs_unmap = 1; + /* NULL rx means write-only transfer and no map needed + * since rx DMA will not be used */ + if (drv_data->rx) { + buf = drv_data->rx; + drv_data->rx_dma = dma_map_single(dev, + buf, + drv_data->len, + DMA_FROM_DEVICE); + if (dma_mapping_error(dev, drv_data->rx_dma)) { + if (drv_data->tx_dma) { + dma_unmap_single(dev, + drv_data->tx_dma, + drv_data->tx_map_len, + DMA_TO_DEVICE); + drv_data->tx_dma_needs_unmap = 0; + } + return -1; + } + drv_data->rx_dma_needs_unmap = 1; + } + return 0; } |