Hi PrasannaKumar, On Sat, 28 Oct 2017 13:13:51 +0530 PrasannaKumar Muralidharan <prasannatsmku...@gmail.com> wrote:
> 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]. Sounds reasonable, but it's likely to conflict with something I'd like to queue for 4.16 [1]. I'll rebase this patch on nand/next once the ->exec_op() series is merged. Don't hesitate to ping me if I forget. Regards, Boris [1]http://patchwork.ozlabs.org/project/linux-mtd/list/?series=8923 > > 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,
