From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: [patch 2.6.28-rc5] SPI -- Freescale iMX SPI controller driver Date: Mon, 17 Nov 2008 12:18:47 -0800 Message-ID: <200811171218.47550.david-b@pacbell.net> References: <49217ACF.7080904@swapp-eng.it> Reply-To: dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: SPI Devel General , Linux ARM Kernel To: Andrea Paterniani Return-path: In-Reply-To: <49217ACF.7080904-03BXCEkGbFHYGGNLXY5/rw@public.gmane.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org On Monday 17 November 2008, Andrea Paterniani wrote: > Fix unsafe order in dma mapping operation. This arrived horribly mangled. Can you verify that the appended patch is an appropriate un-mangled version? ======= CUT HERE From: Andrea Paterniani 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 --- drivers/spi/spi_imx.c | 45 ++++++++++++++++++++++----------------------- 1 file changed, 22 insertions(+), 23 deletions(-) --- a/drivers/spi/spi_imx.c +++ b/drivers/spi/spi_imx.c @@ -506,20 +506,6 @@ static int map_dma_buffers(struct driver 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 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; } ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/