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 <iws@ovro.caltech.edu>
Signed-off-by: Li Yang <leoli@freescale.com>

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,