Commit c3341d0c authored Jan 07, 2010 by Vimal Singh Committed by David Woodhouse Feb 26, 2010

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>

parent f35b6eda

drivers/mtd/nand/omap2.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -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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