The patch titled pxa2xx_spi: bugfix full duplex dma data corruption has been removed from the -mm tree. Its filename was pxa2xx_spi-bugfix-full-duplex-dma-data-corruption.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: pxa2xx_spi: bugfix full duplex dma data corruption From: Ned Forrester <nforrester@xxxxxxxx> Fixes a data corruption bug in pxa2xx_spi.c when operating in full duplex mode with DMA and using buffers that overlap. SPI transmit and receive buffers are allowed to be the same or to overlap. However, this driver fails if such overlap is attempted in DMA mode because it maps the rx and tx buffers in the wrong order. By mapping DMA_FROM_DEVICE (read) before DMA_TO_DEVICE (write), it invalidates the cache before flushing it, thus discarding data which should have been transmitted. The patch corrects the order of mapping. This bug exists in all versions of pxa2xx_spi.c; similar bugs are in the drivers for two other SPI controllers (au1500, imx). A version of this patch has been tested on kernel 2.6.20 using verification of loopback data with: random transfer length, random bits-per-word, random positive offsets (both larger and smaller than transfer length) between the start of the rx and tx buffers, and varying clock rates. Signed-off-by: Ned Forrester <nforrester@xxxxxxxx> Cc: Vernon Sauder <vernoninhand@xxxxxxxxx> Cc: J. Scott Merritt <merrij3@xxxxxxx> Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxx> [2.6.27.x] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/spi/pxa2xx_spi.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff -puN drivers/spi/pxa2xx_spi.c~pxa2xx_spi-bugfix-full-duplex-dma-data-corruption drivers/spi/pxa2xx_spi.c --- a/drivers/spi/pxa2xx_spi.c~pxa2xx_spi-bugfix-full-duplex-dma-data-corruption +++ a/drivers/spi/pxa2xx_spi.c @@ -352,21 +352,21 @@ static int map_dma_buffers(struct driver } else drv_data->tx_map_len = drv_data->len; - /* Stream map the rx buffer */ - drv_data->rx_dma = dma_map_single(dev, drv_data->rx, - drv_data->rx_map_len, - DMA_FROM_DEVICE); - if (dma_mapping_error(dev, drv_data->rx_dma)) - return 0; - - /* Stream map the tx buffer */ + /* Stream map the tx buffer. Always do DMA_TO_DEVICE first + * so we flush the cache *before* invalidating it, in case + * the tx and rx buffers overlap. + */ drv_data->tx_dma = dma_map_single(dev, drv_data->tx, - drv_data->tx_map_len, - DMA_TO_DEVICE); + drv_data->tx_map_len, DMA_TO_DEVICE); + if (dma_mapping_error(dev, drv_data->tx_dma)) + return 0; - if (dma_mapping_error(dev, drv_data->tx_dma)) { - dma_unmap_single(dev, drv_data->rx_dma, + /* Stream map the rx buffer */ + drv_data->rx_dma = dma_map_single(dev, drv_data->rx, drv_data->rx_map_len, DMA_FROM_DEVICE); + if (dma_mapping_error(dev, drv_data->rx_dma)) { + dma_unmap_single(dev, drv_data->tx_dma, + drv_data->tx_map_len, DMA_TO_DEVICE); return 0; } _ Patches currently in -mm which might be from nforrester@xxxxxxxx are origin.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html