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 @@ 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 @@ -420,7 +420,11 @@ 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 +116,12 @@ 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.