Messages in this thread | | | Date | Tue, 19 Dec 2017 12:56:24 +0100 | From | Boris Brezillon <> | Subject | Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID |
| |
On Tue, 19 Dec 2017 20:42:36 +0900 KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> On 2017/12/07 0:08, Boris Brezillon wrote: > > On Wed, 6 Dec 2017 23:04:57 +0900 > > KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote: > > > >> This patch enables support to read the ECC strength and size from the > >> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is > >> based on the information of the 6th ID byte of the Toshiba Memory SLC > >> NAND. > >> > >> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> > >> --- > >> drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++ > >> 1 file changed, 28 insertions(+) > >> > >> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c > >> index 57df857..c2c141b 100644 > >> --- a/drivers/mtd/nand/nand_toshiba.c > >> +++ b/drivers/mtd/nand/nand_toshiba.c > >> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip) > >> (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ && > >> !(chip->id.data[4] & 0x80) /* !BENAND */) > >> mtd->oobsize = 32 * mtd->writesize >> 9; > >> + > >> + /* > >> + * Extract ECC requirements from 6th id byte. > >> + * For Toshiba SLC, ecc requrements are as follows: > >> + * - 43nm: 1 bit ECC for each 512Byte is required. > >> + * - 32nm: 4 bit ECC for each 512Byte is required. > >> + * - 24nm: 8 bit ECC for each 512Byte is required. > >> + */ > >> + if (chip->id.len >= 6 && nand_is_slc(chip)) { > >> + chip->ecc_step_ds = 512; > >> + switch (chip->id.data[5] & 0x7) { > >> + case 0x4: > >> + chip->ecc_strength_ds = 1; > >> + break; > >> + case 0x5: > >> + chip->ecc_strength_ds = 4; > >> + break; > >> + case 0x6: > >> + chip->ecc_strength_ds = 8; > >> + break; > >> + default: > >> + WARN(1, "Could not get ECC info"); > >> + chip->ecc_step_ds = 0; > >> + break; > >> + } > >> + } else if (chip->id.len < 6 && nand_is_slc(chip)) { > >> + WARN(1, "Could not get ECC info, 6th nand id byte does not exist."); > > > > I'm pretty sure you have old NAND chips that do not have 6bytes ids > > (see the table here [1]), and printing a huge backtrace in this case is > > probably not what you want. > > > > If you're okay with dropping this else block, I'll do the change when > > applying, no need to send a new version. > > Some controllers may have limitation in reading ids beyond 5 bytes, > considering such scenario we think it is better to keep this warning. > However if you feel huge backtrace is an issue, how about we using pr_warn() instead? >
Toshiba NANDs with an id smaller than 6 bytes exist, so no, we should not complain at all. If the controller is broken and can't read the 8 id bytes the core is asking for, then it should be detected at the core level not in the NAND manufacturer driver.
| |