mtd: nand: mxs invalidate dcache before DMA read

Follow linux dma flow:
Before DMA read, be sure to invalidate the cache over the address
range of DMA buffer to prevent cache coherency problems.
After DMA read, invalidate dcache again.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Tim Harvey <tharvey@gateworks.com>

diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
index 33ce8174dc1b8e238770c254f5254cca8374974d..1d689015a5a2294a1b7aa8bc3fe87575e0f5cc7d 100644 (file)
--- a/drivers/mtd/nand/mxs_nand.c
+++ b/drivers/mtd/nand/mxs_nand.c
@@ -462,6 +462,9 @@ static void mxs_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int length)
 
        mxs_dma_desc_append(channel, d);
 
+       /* Invalidate caches */
+       mxs_nand_inval_data_buf(nand_info);
+
        /* Execute the DMA chain. */
        ret = mxs_dma_go(channel);
        if (ret) {
@@ -628,6 +631,9 @@ static int mxs_nand_ecc_read_page(struct mtd_info *mtd, struct nand_chip *nand,
 
        mxs_dma_desc_append(channel, d);
 
+       /* Invalidate caches */
+       mxs_nand_inval_data_buf(nand_info);
+
        /* Execute the DMA chain. */
        ret = mxs_dma_go(channel);
        if (ret) {