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-rw-r--r--target/linux/ipq806x/patches-4.4/161-mtd-nand-Create-a-BBT-flag-to-access-bad-block-markers-in-raw-mode.patch83
1 files changed, 83 insertions, 0 deletions
diff --git a/target/linux/ipq806x/patches-4.4/161-mtd-nand-Create-a-BBT-flag-to-access-bad-block-markers-in-raw-mode.patch b/target/linux/ipq806x/patches-4.4/161-mtd-nand-Create-a-BBT-flag-to-access-bad-block-markers-in-raw-mode.patch
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--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/161-mtd-nand-Create-a-BBT-flag-to-access-bad-block-markers-in-raw-mode.patch
@@ -0,0 +1,83 @@
+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
+@@ -394,7 +394,11 @@
+ } 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
+@@ -420,7 +420,11 @@
+ 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 +116,12 @@
+ #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.