mtd: omap: fix subpage ecc issue with prefetch (c5d8c0ca) · Commits · 戴 / test

When reading/writing a subpage (When HW ECC is not available/enabled) for number of bytes not aligned to 4, the mis-aligned bytes are handled first (by cpu copy method) before enabling the Prefetch engine to/from 'p'(start of buffer 'buf'). Then it reads/writes rest of the bytes with the help of Prefetch engine, if available, or again using cpu copy method. Currently, reading/writing of rest of bytes, is not done correctly since its trying to read/write again to/from begining of buffer 'buf', overwriting the mis-aligned bytes. Read & write using prefetch engine got broken in commit ''. We never hit a scenario of not getting 'gpmc_prefetch_enable' call success. So, problem did not get caught up. Signed-off-by:

Kishore Kadiyala <kishore.kadiyala@ti.com> Signed-off-by:

Vimal Singh <vimal.newwork@gmail.com> Reported-by:

Bryan DE FARIA <bdefaria@adeneo-embedded.com> Cc: stable@kernel.org [2.6.35+] Signed-off-by:

Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by:

David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/omap2.c

+5 −7

Original line number	Diff line number	Diff line
		@@ -263,11 +263,10 @@ static void omap_read_buf_pref(struct mtd_info mtd, u_char buf, int len)
		if (ret) {
		/* PFPW engine is busy, use cpu copy method */
		if (info->nand.options & NAND_BUSWIDTH_16)
		omap_read_buf16(mtd, buf, len);
		omap_read_buf16(mtd, (u_char *)p, len);
		else
		omap_read_buf8(mtd, buf, len);
		omap_read_buf8(mtd, (u_char *)p, len);
		} else {
		p = (u32 *) buf;
		do {
		r_count = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT);
		r_count = r_count >> 2;
		@@ -293,7 +292,7 @@ static void omap_write_buf_pref(struct mtd_info *mtd,
		struct omap_nand_info, mtd);
		uint32_t w_count = 0;
		int i = 0, ret = 0;
		u16 *p;
		u16 p = (u16 )buf;
		unsigned long tim, limit;

		/* take care of subpage writes */
		@@ -309,11 +308,10 @@ static void omap_write_buf_pref(struct mtd_info *mtd,
		if (ret) {
		/* PFPW engine is busy, use cpu copy method */
		if (info->nand.options & NAND_BUSWIDTH_16)
		omap_write_buf16(mtd, buf, len);
		omap_write_buf16(mtd, (u_char *)p, len);
		else
		omap_write_buf8(mtd, buf, len);
		omap_write_buf8(mtd, (u_char *)p, len);
		} else {
		p = (u16 *) buf;
		while (len) {
		w_count = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT);
		w_count = w_count >> 1;

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