From: Ira Snyder Date: Fri, 15 May 2009 18:33:20 +0000 (-0700) Subject: fsldma: snooping is not enabled for last entry in descriptor chain X-Git-Tag: firefly_0821_release~14064^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=776c8943f2766f2819fafd88fdfbaf418ecd6e41;p=firefly-linux-kernel-4.4.55.git fsldma: snooping is not enabled for last entry in descriptor chain On the 83xx controller, snooping is necessary for the DMA controller to ensure cache coherence with the CPU when transferring to/from RAM. The last descriptor in a chain will always have the End-of-Chain interrupt bit set, so we can set the snoop bit while adding the End-of-Chain interrupt bit. Signed-off-by: Ira W. Snyder Signed-off-by: Li Yang --- diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index 7313a1ae5f83..ff9194d7ebb7 100644 --- a/drivers/dma/fsldma.c +++ b/drivers/dma/fsldma.c @@ -179,9 +179,14 @@ static void dma_halt(struct fsl_dma_chan *fsl_chan) static void set_ld_eol(struct fsl_dma_chan *fsl_chan, struct fsl_desc_sw *desc) { + u64 snoop_bits; + + snoop_bits = ((fsl_chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_83XX) + ? FSL_DMA_SNEN : 0; + desc->hw.next_ln_addr = CPU_TO_DMA(fsl_chan, - DMA_TO_CPU(fsl_chan, desc->hw.next_ln_addr, 64) | FSL_DMA_EOL, - 64); + DMA_TO_CPU(fsl_chan, desc->hw.next_ln_addr, 64) | FSL_DMA_EOL + | snoop_bits, 64); } static void append_ld_queue(struct fsl_dma_chan *fsl_chan,