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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>
This commit is contained in:
Vimal Singh 2010-01-07 12:16:26 +05:30 committed by David Woodhouse
parent f35b6eda51
commit c3341d0ceb
1 changed files with 7 additions and 4 deletions
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11
drivers/mtd/nand/omap2.c
View File

@ -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);