From: "Teresa Gámez" <t.gamez@phytec.de>
To: barebox@lists.infradead.org
Cc: Steve Schefter <steve@scheftech.com>
Subject: [PATCH] nand_omap_bch_decoder: Fix up error detection
Date: Fri, 9 Dec 2011 11:00:58 +0100 [thread overview]
Message-ID: <1323424858-14282-1-git-send-email-t.gamez@phytec.de> (raw)
From: Steve Schefter <steve@scheftech.com>
Bit errors in the ECC itself are not beeing taken into account.
In this cases the number of detected errors != number of corrected errors and
chien search returns an error.
This patch adds detection of bit errors in the ECC.
Signed-off-by: Steve Schefter <steve@scheftech.com>
Signed-off-by: Teresa Gámez <t.gamez@phytec.de>
---
drivers/mtd/nand/nand_omap_bch_decoder.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/nand/nand_omap_bch_decoder.c b/drivers/mtd/nand/nand_omap_bch_decoder.c
index 356f71f..d1455e4 100644
--- a/drivers/mtd/nand/nand_omap_bch_decoder.c
+++ b/drivers/mtd/nand/nand_omap_bch_decoder.c
@@ -64,6 +64,7 @@ static int chien(unsigned int select_4_8, int err_nums,
unsigned int err[], unsigned int *location)
{
int i, count; /* Number of dectected errors */
+ int errorsinecc; /* Number of detected errors in ECC bits */
/* Contains accumulation of evaluation at x^i (i:1->8) */
unsigned int gammas[8] = {0};
unsigned int alpha;
@@ -77,7 +78,8 @@ static int chien(unsigned int select_4_8, int err_nums,
gammas[i] = err[i];
count = 0;
- for (i = 1; (i <= nn) && (count < err_nums); i++) {
+ errorsinecc = 0;
+ for (i = 1; (i <= nn) && ((count + errorsinecc) < err_nums); i++) {
/* Result of evaluation at root */
elp_sum = 1 ^ gammas[0] ^ gammas[1] ^
@@ -108,11 +110,13 @@ static int chien(unsigned int select_4_8, int err_nums,
if (i >= 2 * ecc_bits)
location[count++] =
kk_shorten - (bit - 2 * ecc_bits) - 1;
+ else
+ errorsinecc++;
}
}
/* Failure: No. of detected errors != No. or corrected errors */
- if (count != err_nums) {
+ if ((count + errorsinecc) != err_nums) {
count = -1;
printk(KERN_ERR "BCH decoding failed\n");
}
--
1.7.0.4
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next reply other threads:[~2011-12-09 10:01 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-09 10:00 Teresa Gámez [this message]
2011-12-21 13:18 ` Teresa Gamez
2012-01-02 11:45 ` Sascha Hauer
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