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mtd: nand/docg4: fix and improve read of factory bbt 

This patch does two things related to reading the factory badblock table during
initialization: (1) fix error where a non-zero return code from
docg4_read_page() is assumed to be an error (it was later changed to be
max_bitflips; thanks to Brian Norris for bringing this to my attention a while
back), and (2) if there is an error reading the factory bbt, it tries reading
another (redundant) factory bbt table.

Signed-off-by: Mike Dunn <mikedunn@newsguy.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
This commit is contained in:
Mike Dunn 2012-12-07 12:07:23 -08:00 committed by Artem Bityutskiy
parent 440b1d73b1
commit 3c9c6d657a
1 changed files with 19 additions and 5 deletions
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24
drivers/mtd/nand/docg4.c
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@ -212,6 +212,7 @@ struct docg4_priv {
#define DOCG4_T 4 /* BCH alg corrects up to 4 bit errors */
#define DOCG4_FACTORY_BBT_PAGE 16 /* page where read-only factory bbt lives */
#define DOCG4_REDUNDANT_BBT_PAGE 24 /* page where redundant factory bbt lives */
/*
* Bytes 0, 1 are used as badblock marker.
@ -1020,16 +1021,15 @@ static int __init read_factory_bbt(struct mtd_info *mtd)
struct docg4_priv *doc = nand->priv;
uint32_t g4_addr = mtd_to_docg4_address(DOCG4_FACTORY_BBT_PAGE, 0);
uint8_t *buf;
int i, block, status;
int i, block;
__u32 eccfailed_stats = mtd->ecc_stats.failed;
buf = kzalloc(DOCG4_PAGE_SIZE, GFP_KERNEL);
if (buf == NULL)
return -ENOMEM;
read_page_prologue(mtd, g4_addr);
status = docg4_read_page(mtd, nand, buf, 0, DOCG4_FACTORY_BBT_PAGE);
if (status)
goto exit;
docg4_read_page(mtd, nand, buf, 0, DOCG4_FACTORY_BBT_PAGE);
/*
* If no memory-based bbt was created, exit. This will happen if module
@ -1041,6 +1041,20 @@ static int __init read_factory_bbt(struct mtd_info *mtd)
if (nand->bbt == NULL) /* no memory-based bbt */
goto exit;
if (mtd->ecc_stats.failed > eccfailed_stats) {
/*
* Whoops, an ecc failure ocurred reading the factory bbt.
* It is stored redundantly, so we get another chance.
*/
eccfailed_stats = mtd->ecc_stats.failed;
docg4_read_page(mtd, nand, buf, 0, DOCG4_REDUNDANT_BBT_PAGE);
if (mtd->ecc_stats.failed > eccfailed_stats) {
dev_warn(doc->dev,
"The factory bbt could not be read!\n");
goto exit;
}
}
/*
* Parse factory bbt and update memory-based bbt. Factory bbt format is
* simple: one bit per block, block numbers increase left to right (msb
@ -1060,7 +1074,7 @@ static int __init read_factory_bbt(struct mtd_info *mtd)
}
exit:
kfree(buf);
return status;
return 0;
}
static int docg4_block_markbad(struct mtd_info *mtd, loff_t ofs)