From: Ned Forrester Date: Wed, 19 Nov 2008 23:36:21 +0000 (-0800) Subject: pxa2xx_spi: bugfix full duplex dma data corruption X-Git-Tag: v2.6.27.8~93 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=532b2a9f6baf34ab2ce4fa501f76b97be8ab8e85;p=pandora-kernel.git pxa2xx_spi: bugfix full duplex dma data corruption commit 393df744e056ba24e9531d0657d09fc3c7c0dd22 upstream. 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 Cc: Vernon Sauder Cc: J. Scott Merritt Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed