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Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: [v3,
1/5] mtd: nand: Create a BBT flag to access bad block markers in raw
mode
From: Archit Taneja <architt@codeaurora.org>
X-Patchwork-Id: 6927081
Message-Id: <1438578498-32254-2-git-send-email-architt@codeaurora.org>
To: linux-mtd@lists.infradead.org, dehrenberg@google.com,
cernekee@gmail.com, computersforpeace@gmail.com
Cc: linux-arm-msm@vger.kernel.org, agross@codeaurora.org,
sboyd@codeaurora.org, linux-kernel@vger.kernel.org,
Archit Taneja <architt@codeaurora.org>
Date: Mon, 3 Aug 2015 10:38:14 +0530
Some controllers can access the factory bad block marker from OOB only
when they read it in raw mode. When ECC is enabled, these controllers
discard reading/writing bad block markers, preventing access to them
altogether.
The bbt driver assumes MTD_OPS_PLACE_OOB when scanning for bad blocks.
This results in the nand driver's ecc->read_oob() op to be called, which
works with ECC enabled.
Create a new BBT option flag that tells nand_bbt to force the mode to
MTD_OPS_RAW. This would result in the correct op being called for the
underlying nand controller driver.
Reviewed-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
---
drivers/mtd/nand/nand_base.c | 6 +++++-
drivers/mtd/nand/nand_bbt.c | 6 +++++-
include/linux/mtd/bbm.h | 7 +++++++
3 files changed, 17 insertions(+), 2 deletions(-)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -395,7 +395,11 @@ static int nand_default_block_markbad(st
} else {
ops.len = ops.ooblen = 1;
}
- ops.mode = MTD_OPS_PLACE_OOB;
+
+ if (unlikely(chip->bbt_options & NAND_BBT_ACCESS_BBM_RAW))
+ ops.mode = MTD_OPS_RAW;
+ else
+ ops.mode = MTD_OPS_PLACE_OOB;
/* Write to first/last page(s) if necessary */
if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
--- a/drivers/mtd/nand/nand_bbt.c
+++ b/drivers/mtd/nand/nand_bbt.c
@@ -423,7 +423,11 @@ static int scan_block_fast(struct mtd_in
ops.oobbuf = buf;
ops.ooboffs = 0;
ops.datbuf = NULL;
- ops.mode = MTD_OPS_PLACE_OOB;
+
+ if (unlikely(bd->options & NAND_BBT_ACCESS_BBM_RAW))
+ ops.mode = MTD_OPS_RAW;
+ else
+ ops.mode = MTD_OPS_PLACE_OOB;
for (j = 0; j < numpages; j++) {
/*
--- a/include/linux/mtd/bbm.h
+++ b/include/linux/mtd/bbm.h
@@ -116,6 +116,13 @@ struct nand_bbt_descr {
#define NAND_BBT_NO_OOB_BBM 0x00080000
/*
+ * Force MTD_OPS_RAW mode when trying to access bad block markes from OOB. To
+ * be used by controllers which can access BBM only when ECC is disabled, i.e,
+ * when in RAW access mode
+ */
+#define NAND_BBT_ACCESS_BBM_RAW 0x00100000
+
+/*
* Flag set by nand_create_default_bbt_descr(), marking that the nand_bbt_descr
* was allocated dynamicaly and must be freed in nand_release(). Has no meaning
* in nand_chip.bbt_options.
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