[PATCH] fix root cause of NAND trouble
Werner Almesberger
werner at openmoko.org
Sat Nov 1 22:50:54 CET 2008
Ben Dooks wrote:
> My only comment would be
> that a slightly better solution would be to do:
Oh, that's much better, thanks ! I hadn't realized at first that
once could read the FIFO one byte at a time.
The revised patch is below.
- Werner
---------------------------------- cut here -----------------------------------
fix-s3c-nand-read-bytes.patch
With the introduction of optimized OOB reads in nand_read_subpage,
the length of the data requested may not be a multiple of four bytes.
This caused a partial read on the 2440, leading to false ECC errors
and, worse, attempts to "correct" them.
Note that there is a similar issue in s3c2440_nand_write_buf, which
doesn't seem to cause trouble yet.
Signed-off-by: Werner Almesberger <werner at openmoko.org>
---
Index: ktrack/drivers/mtd/nand/s3c2410.c
===================================================================
--- ktrack.orig/drivers/mtd/nand/s3c2410.c 2008-11-01 19:25:11.000000000 -0200
+++ ktrack/drivers/mtd/nand/s3c2410.c 2008-11-01 19:38:07.000000000 -0200
@@ -530,7 +530,12 @@
static void s3c2440_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
struct s3c2410_nand_info *info = s3c2410_nand_mtd_toinfo(mtd);
+ u8 *ptr = buf + (len & ~3);
+ int i;
+
readsl(info->regs + S3C2440_NFDATA, buf, len / 4);
+ for (i = 0; i != (len & 3); i++)
+ ptr[i] = readb(info->regs + S3C2440_NFDATA);
}
static void s3c2410_nand_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
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