David,
> -----Original Message----- > From: davinci-linux-open-source-boun...@linux.davincidsp.com > [mailto:davinci-linux-open-source-boun...@linux.davincidsp.com] On Behalf > Of David Brownell > Sent: Monday, February 09, 2009 3:43 PM > To: DaVinci > Subject: [patch davinci-git 2/3] NAND: Fix "raw" reads with ECC syndrome > layouts > > From: David Brownell <dbrown...@users.sourceforge.net> > > The syndrome based page read/write routines store ECC, and possibly > other "OOB" data, right after each chunk of ECC'd data. With ECC > chunk size of 512 bytes and a large page (2KB) NAND, the layout is: > > data-0 OOB-0 data-1 OOB-1 data-2 OOB-2 data-3 OOB-3 OOB-leftover Shouldn't this be data-0 data-1 data-2 data-3 OOB-0 OOB-1 OOB-2 OOB-3? We used to have the "data-0 OOB-0 ..." layout in the Montavista based LSP releases. This layout can cause to place real data in the spare area and erase NAND manufacturer's meta-data -- bad block information. The standard layout should be 2048 bytes data + 64 bytes OOB. 2048 bytes of data should still be read in 512 byte chunks. Given that we have the boards with uboot and other Bootloader components loaded with the old legacy layout, we may still have to support both the layouts. BTW, I am actually working on the support for standard layout! Thanks Sneha > > Where OOBx is (prepad, ECC, postpad). However, the current "raw" > routines use a traditional layout -- data OOB, disregarding the > prepad and postpad values -- so when they're used with that type of > ECC hardware, those calls mix up the data and OOB. Which means, > in particular, that bad block tables won't be found on startup, > with data corruption and related chaos ensuing. > > The current syndrome-based drivers in mainline all seem to use one > chunk per page; presumably they haven't noticed such bugs. > > Fix this, by adding read/write page_raw_syndrome() routines as > siblings of the existing non-raw routines; "raw" just means to > bypass the ECC computations, not change data and OOB layout. > > Signed-off-by: David Brownell <dbrown...@users.sourceforge.net> > --- > Observed when trying to get this working with the DaVinci NAND > driver in 4-bit ECC mode with a large page chip. > > drivers/mtd/nand/nand_base.c | 113 > +++++++++++++++++++++++++++++++++++++---- > 1 file changed, 103 insertions(+), 10 deletions(-) > > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -748,6 +748,8 @@ static int nand_wait(struct mtd_info *mt > * @mtd: mtd info structure > * @chip: nand chip info structure > * @buf: buffer to store read data > + * > + * Not for syndrome calculating ecc controllers, which use a special oob > layout > */ > static int nand_read_page_raw(struct mtd_info *mtd, struct nand_chip > *chip, > uint8_t *buf) > @@ -758,6 +760,48 @@ static int nand_read_page_raw(struct mtd > } > > /** > + * nand_read_page_raw_syndrome - [Intern] read raw page data without ecc > + * @mtd: mtd info structure > + * @chip: nand chip info structure > + * @buf: buffer to store read data > + * > + * We need a special oob layout and handling even when OOB isn't used. > + */ > +static int nand_read_page_raw_syndrome(struct mtd_info *mtd, struct > nand_chip *chip, > + uint8_t *buf) > +{ > + int eccsize = chip->ecc.size; > + int eccbytes = chip->ecc.bytes; > + uint8_t *oob = chip->oob_poi; > + int temp; > + > + temp = chip->ecc.steps; > + do { > + chip->read_buf(mtd, buf, eccsize); > + buf += eccsize; > + > + if (chip->ecc.prepad) { > + chip->read_buf(mtd, oob, chip->ecc.prepad); > + oob += chip->ecc.prepad; > + } > + > + chip->read_buf(mtd, oob, eccbytes); > + oob += eccbytes; > + > + if (chip->ecc.postpad) { > + chip->read_buf(mtd, oob, chip->ecc.postpad); > + oob += chip->ecc.postpad; > + } > + } while (--temp); > + > + temp = mtd->oobsize - (oob - chip->oob_poi); > + if (temp) > + chip->read_buf(mtd, oob, temp); > + > + return 0; > +} > + > +/** > * nand_read_page_swecc - [REPLACABLE] software ecc based page read > function > * @mtd: mtd info structure > * @chip: nand chip info structure > @@ -1482,6 +1526,8 @@ static int nand_read_oob(struct mtd_info > * @mtd: mtd info structure > * @chip: nand chip info structure > * @buf: data buffer > + * > + * Not for syndrome calculating ecc controllers, which use a special oob > layout > */ > static void nand_write_page_raw(struct mtd_info *mtd, struct nand_chip > *chip, > const uint8_t *buf) > @@ -1491,6 +1537,45 @@ static void nand_write_page_raw(struct m > } > > /** > + * nand_write_page_raw_syndrome - [Intern] raw page write function > + * @mtd: mtd info structure > + * @chip: nand chip info structure > + * @buf: data buffer > + * > + * We need a special oob layout and handling even when ECC isn't used. > + */ > +static void nand_write_page_raw_syndrome(struct mtd_info *mtd, struct > nand_chip *chip, > + const uint8_t *buf) > +{ > + int eccsize = chip->ecc.size; > + int eccbytes = chip->ecc.bytes; > + uint8_t *oob = chip->oob_poi; > + int temp; > + > + temp = chip->ecc.steps; > + do { > + chip->write_buf(mtd, buf, eccsize); > + buf += eccsize; > + > + if (chip->ecc.prepad) { > + chip->write_buf(mtd, oob, chip->ecc.prepad); > + oob += chip->ecc.prepad; > + } > + > + chip->read_buf(mtd, oob, eccbytes); > + oob += eccbytes; > + > + if (chip->ecc.postpad) { > + chip->write_buf(mtd, oob, chip->ecc.postpad); > + oob += chip->ecc.postpad; > + } > + } while (--temp); > + > + temp = mtd->oobsize - (oob - chip->oob_poi); > + if (temp) > + chip->write_buf(mtd, oob, temp); > +} > +/** > * nand_write_page_swecc - [REPLACABLE] software ecc based page write > function > * @mtd: mtd info structure > * @chip: nand chip info structure > @@ -2564,10 +2649,6 @@ int nand_scan_tail(struct mtd_info *mtd) > * check ECC mode, default to software if 3byte/512byte hardware ECC > is > * selected and we have 256 byte pagesize fallback to software ECC > */ > - if (!chip->ecc.read_page_raw) > - chip->ecc.read_page_raw = nand_read_page_raw; > - if (!chip->ecc.write_page_raw) > - chip->ecc.write_page_raw = nand_write_page_raw; > > switch (chip->ecc.mode) { > #ifdef CONFIG_NAND_FLASH_HW_ECC > @@ -2583,6 +2664,10 @@ int nand_scan_tail(struct mtd_info *mtd) > chip->ecc.read_page = nand_read_page_hwecc; > if (!chip->ecc.write_page) > chip->ecc.write_page = nand_write_page_hwecc; > + if (!chip->ecc.read_page_raw) > + chip->ecc.read_page_raw = nand_read_page_raw; > + if (!chip->ecc.write_page_raw) > + chip->ecc.write_page_raw = nand_write_page_raw; > if (!chip->ecc.read_oob) > chip->ecc.read_oob = nand_read_oob_std; > if (!chip->ecc.write_oob) > @@ -2604,6 +2689,10 @@ int nand_scan_tail(struct mtd_info *mtd) > chip->ecc.read_page = nand_read_page_syndrome; > if (!chip->ecc.write_page) > chip->ecc.write_page = nand_write_page_syndrome; > + if (!chip->ecc.read_page_raw) > + chip->ecc.read_page_raw = nand_read_page_raw_syndrome; > + if (!chip->ecc.write_page_raw) > + chip->ecc.write_page_raw = nand_write_page_raw_syndrome; > if (!chip->ecc.read_oob) > chip->ecc.read_oob = nand_read_oob_syndrome; > if (!chip->ecc.write_oob) > @@ -2622,6 +2711,8 @@ int nand_scan_tail(struct mtd_info *mtd) > chip->ecc.read_page = nand_read_page_swecc; > chip->ecc.read_subpage = nand_read_subpage; > chip->ecc.write_page = nand_write_page_swecc; > + chip->ecc.read_page_raw = nand_read_page_raw; > + chip->ecc.write_page_raw = nand_write_page_raw; > chip->ecc.read_oob = nand_read_oob_std; > chip->ecc.write_oob = nand_write_oob_std; > chip->ecc.size = 256; > @@ -2634,6 +2725,8 @@ int nand_scan_tail(struct mtd_info *mtd) > chip->ecc.read_page = nand_read_page_raw; > chip->ecc.write_page = nand_write_page_raw; > chip->ecc.read_oob = nand_read_oob_std; > + chip->ecc.read_page_raw = nand_read_page_raw; > + chip->ecc.write_page_raw = nand_write_page_raw; > chip->ecc.write_oob = nand_write_oob_std; > chip->ecc.size = mtd->writesize; > chip->ecc.bytes = 0; > > _______________________________________________ > Davinci-linux-open-source mailing list > Davinci-linux-open-source@linux.davincidsp.com > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source _______________________________________________ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
