mtd: nand: fix generating over-boundary ECC data when writing

When mtk_ecc_encode() is writing the ECC parity data to the OOB
region,because each register is 4 bytes in length,but the len's unit is
in bytes,the operation in the for loop will cross the ECC's boundary.

Signed-off-by: RogerCC Lin <rogercc.lin@mediatek.com>
Fixes: 1d6b1e464950 ("mtd: mediatek: driver for MTK Smart Device")
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

diff --git a/drivers/mtd/nand/mtk_ecc.c b/drivers/mtd/nand/mtk_ecc.c
index 25a4fbd..d54f666 100644 (file)
--- a/drivers/mtd/nand/mtk_ecc.c
+++ b/drivers/mtd/nand/mtk_ecc.c
@@ -366,7 +366,8 @@ int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config,
                   u8 *data, u32 bytes)
 {
        dma_addr_t addr;
-       u32 *p, len, i;
+       u8 *p;
+       u32 len, i, val;
        int ret = 0;
 
        addr = dma_map_single(ecc->dev, data, bytes, DMA_TO_DEVICE);
@@ -392,11 +393,14 @@ int mtk_ecc_encode(struct mtk_ecc *ecc, struct mtk_ecc_config *config,
 
        /* Program ECC bytes to OOB: per sector oob = FDM + ECC + SPARE */
        len = (config->strength * ECC_PARITY_BITS + 7) >> 3;
-       p = (u32 *)(data + bytes);
+       p = data + bytes;
 
        /* write the parity bytes generated by the ECC back to the OOB region */
-       for (i = 0; i < len; i++)
-               p[i] = readl(ecc->regs + ECC_ENCPAR(i));
+       for (i = 0; i < len; i++) {
+               if ((i % 4) == 0)
+                       val = readl(ecc->regs + ECC_ENCPAR(i / 4));
+               p[i] = (val >> ((i % 4) * 8)) & 0xff;
+       }
 timeout:
 
        dma_unmap_single(ecc->dev, addr, bytes, DMA_TO_DEVICE);