From c3341d0ceb4de1680572024f50233403c6a8b10d Mon Sep 17 00:00:00 2001
From: Vimal Singh <vimal.newwork@gmail.com>
Date: Thu, 7 Jan 2010 12:16:26 +0530
Subject: [PATCH] mtd: omap2 fix prefetch mode read issue
There is a bug in nand prefetch read routine, which comes into effect
only if nand device is a 16-bit device (as we have in zoom boards).
This bug is effective only with below combination of conditions:
1. nand deivce, in use, is a 16 bit device
2. nand driver supports 'subpage' read
3. SW ECC is in use
This was not seen old kernel (ex: .23), because when, in early days,
we tested this (nand prefetch read in LDP boards) there was no
'subpage read' support.
Later when we had subpage read in (.27) kernel, we had hw ecc enabled
always in our internal tree. So, we missed this bug.
This patch fixes the issue.
Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
drivers/mtd/nand/omap2.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 16120e2dd4a3d..7df303aed8a44 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -295,11 +295,14 @@ static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len)
u32 *p = (u32 *)buf;
/* take care of subpage reads */
- for (; len % 4 != 0; ) {
- *buf++ = __raw_readb(info->nand.IO_ADDR_R);
- len--;
+ if (len % 4) {
+ if (info->nand.options & NAND_BUSWIDTH_16)
+ omap_read_buf16(mtd, buf, len % 4);
+ else
+ omap_read_buf8(mtd, buf, len % 4);
+ p = (u32 *) (buf + len % 4);
+ len -= len % 4;
}
- p = (u32 *) buf;
/* configure and start prefetch transfer */
ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0);
--
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