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Commit 776c8943 authored by Ira Snyder's avatar Ira Snyder Committed by Li Yang
Browse files

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: default avatarIra W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: default avatarLi Yang <leoli@freescale.com>
parent bcfb7465

drivers/dma/fsldma.c

+7 −2
Original line number Diff line number Diff line
@@ -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,