From: Lars-Peter Clausen <l...@metafoo.de> Avoid sending unnecessary READ commands to the chip.
Signed-off-by: Lars-Peter Clausen <l...@metafoo.de> Signed-off-by: PrasannaKumar Muralidharan <prasannatsmku...@gmail.com> --- This patch is taken from git://projects.qi-hardware.com/qi-kernel.git branch jz-3.16. From [1] and [2] it can be seen that the patch author thinks this can be sent upstream but it never happened so far. This patch is used in OpenWRT as seen from [3]. I have only compile tested the patch. 1. https://www.mail-archive.com/discussion@lists.en.qi-hardware.com/msg04635.html 2. https://www.mail-archive.com/discussion@lists.en.qi-hardware.com/msg04639.html 3. https://git.lede-project.org/?p=source.git;a=blob;f=target/linux/xburst/patches-3.18/002-NAND-Optimize-NAND_ECC_HW_OOB_FIRST-read.patch;h=046da51912de3cd4444779df5de13d2c1999719a;hb=c03d4317a6bc891cb4a5e89cbdd77f37c23aff86 drivers/mtd/nand/nand_base.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 12edaae..4bf3bdb 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -1680,9 +1680,15 @@ static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd, unsigned int max_bitflips = 0; /* Read the OOB area first */ - chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page); - chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); - chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page); + if (mtd->writesize > 512) { + chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page); + chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1); + } else { + chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page); + chip->read_buf(mtd, chip->oob_poi, mtd->oobsize); + chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page); + } ret = mtd_ooblayout_get_eccbytes(mtd, ecc_code, chip->oob_poi, 0, chip->ecc.total); @@ -1902,8 +1908,10 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, __func__, buf); read_retry: - if (nand_standard_page_accessors(&chip->ecc)) + if (nand_standard_page_accessors(&chip->ecc) && + chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) { chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page); + } /* * Now read the page into the buffer. Absent an error, -- 2.10.0
