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On Tue, Mar 24, 2015 at 8:04 AM, punnaiah choudary kalluri <punn...@xilinx.com> wrote: > On Fri, Mar 20, 2015 at 4:51 AM, Jeff Lauruhn (jlauruhn) > <jlaur...@micron.com> wrote: >> This device has a Page size x8: 17,600 bytes (16,384 + 1216 bytes) and >> minimum required ECC 24-bit ECC per 1100 bytes of data. Spare area needed >> for ECC would be ECC * M, where M is (codeword <= 2^m-1). In this case >> M=14, because (1100*8)<=2^14-1, therefore minimum spare area needed is 14*24 >> = 336b or 42B per codeword. So for this device a minimum of 672bytes of the >> 1216 need to be used for ECC, the rest can be used for other purposes. >> > > Ok. Does it mean increasing the size to 672 bytes will be enough ? > I see that 672 bytes is the minimum required size for 24 bit ecc. There > may be controllers that may detect errors beyond 24 bit and would require > more number of ecc bytes per codeword. So, i configured the ecc position > value to max oobsize and i believe this change is needed. > > Regards, > Punnaiah >> >> >> Jeff Lauruhn >> NAND Application Engineer >> >> >> -----Original Message----- >> From: linux-mtd [mailto:linux-mtd-boun...@lists.infradead.org] On Behalf Of >> Punnaiah Choudary Kalluri >> Sent: Thursday, March 19, 2015 1:50 AM >> To: dw...@infradead.org; computersforpe...@gmail.com >> Cc: linux-kernel@vger.kernel.org; shak...@xilinx.com; mich...@xilinx.com; >> linux-...@lists.infradead.org; kalluripunnaiahchoud...@gmail.com; Punnaiah >> Choudary Kalluri >> Subject: [PATCH] mtd: Expand the ecc placement locations to 1260 >> >> Device like MT29F32G08ABCDBJ4 have a writesize/oobsize of 16K/1260 Bytes. >> So, increasing the maximum ecc placement locations to 1260 >> >> Signed-off-by: Punnaiah Choudary Kalluri <punn...@xilinx.com> >> --- >> include/linux/mtd/mtd.h | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index >> f17fa75..e73d85b 100644 >> --- a/include/linux/mtd/mtd.h >> +++ b/include/linux/mtd/mtd.h >> @@ -95,7 +95,7 @@ struct mtd_oob_ops { >> }; >> >> #define MTD_MAX_OOBFREE_ENTRIES_LARGE 32 >> -#define MTD_MAX_ECCPOS_ENTRIES_LARGE 640 >> +#define MTD_MAX_ECCPOS_ENTRIES_LARGE 1260 >> /* >> * Internal ECC layout control structure. For historical reasons, there is a >> * similar, smaller struct nand_ecclayout_user (in mtd-abi.h) that is >> retained >> -- >> 1.7.4 >> >> >> ______________________________________________________ >> Linux MTD discussion mailing list >> http://lists.infradead.org/mailman/listinfo/linux-mtd/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
