From 60c6738245612df9499b340c15edf48b8f3e7981 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Tue, 25 Jun 2013 13:17:59 -0700 Subject: [PATCH] mtd: nand: detect OOB size for Toshiba 24nm raw SLC Toshiba NAND datasheets have not been very forthcoming on OOB size information; they do not provide any bitfields in the ID string for spare area. In their 24nm technology flash, however, Toshiba migrated their NAND to have 32 bytes spare per 512 bytes of page area (up from the traditional 16 bytes), as they now require 8-bit ECC or higher. I have discussed this issue directly with Toshiba representatives, and they acknowledge this problem. They recommend detecting these flash based on their technology node as follows: For 24nm Toshiba SLC raw NAND (not BENAND -- Built-in Ecc NAND), there are 32 bytes of spare area for every 512 bytes of in-band data area. We can implement this rule with the following snippet of a device ID decode table, which applies to all their 43nm, 32nm, and 24nm SLC NAND (this table is not fully in the NAND datasheets, but it was provided directly by Toshiba representatives): - ID byte 5, bit[7]: 1 -> BENAND 0 -> raw SLC - ID byte 6, bits[2:0]: 100b -> 43nm 101b -> 32nm 110b -> 24nm 111b -> Reserved I'm also working with Toshiba on including this bitfield description for their 5th and 6th ID bytes in their public data sheets. I will provide the 8-byte ID strings from the two 24nm Toshiba samples I have; their first 6 bytes match the documentation I received from Toshiba: 24nm SLC 1Gbit TC58NVG0S3HTA00 0x98 0xf1 0x80 0x15 0x72 0x16 0x08 0x00 24nm SLC 2Gbit TC58NVG1S3HTA00 0x98 0xda 0x90 0x15 0x76 0x16 0x08 0x00 I have also tested for regressions with: 43nm SLC 4Gbit TC58NVG2S3ETA00 0x98 0xdc 0x90 0x15 0x76 0x14 0x03 0x10 32nm SLC 8Gbit TC58NVG3SOFA00 0x98 0xd3 0x90 0x26 0x76 0x15 0x02 0x08 Signed-off-by: Brian Norris Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- drivers/mtd/nand/nand_base.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 0980ae3d02aa..158240d5649a 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3081,6 +3081,22 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip, extid >>= 2; /* Get buswidth information */ *busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0; + + /* + * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per + * 512B page. For Toshiba SLC, we decode the 5th/6th byte as + * follows: + * - ID byte 6, bits[2:0]: 100b -> 43nm, 101b -> 32nm, + * 110b -> 24nm + * - ID byte 5, bit[7]: 1 -> BENAND, 0 -> raw SLC + */ + if (id_len >= 6 && id_data[0] == NAND_MFR_TOSHIBA && + !(chip->cellinfo & NAND_CI_CELLTYPE_MSK) && + (id_data[5] & 0x7) == 0x6 /* 24nm */ && + !(id_data[4] & 0x80) /* !BENAND */) { + mtd->oobsize = 32 * mtd->writesize >> 9; + } + } } -- 2.20.1