Messages in this thread | | | Date | Thu, 2 May 2013 16:39:40 -0700 | Subject | Re: [PATCH V4 4/9] mtd: get the ECC info from the Extended Parameter Page | From | Brian Norris <> |
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Hi Huang,
On Fri, Apr 26, 2013 at 2:08 AM, Huang Shijie <b32955@freescale.com> wrote: > Since the ONFI 2.1, the onfi spec adds the Extended Parameter Page > to store the ECC info. > > The onfi spec tells us that if the nand chip's recommended ECC codeword > size is not 512 bytes, then the @ecc_bits is 0xff. The host _SHOULD_ then > read the Extended ECC information that is part of the extended parameter > page to retrieve the ECC requirements for this device. > > This patch implement the reading of the Extended Parameter Page, and parses > the sections for ECC type, and get the ECC info from the ECC section. > > Tested this patch with Micron MT29F64G08CBABAWP. > > Signed-off-by: Huang Shijie <b32955@freescale.com> > --- > drivers/mtd/nand/nand_base.c | 77 ++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 77 insertions(+), 0 deletions(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index beff911..abec615 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -2846,6 +2846,68 @@ static u16 onfi_crc16(u16 crc, u8 const *p, size_t len) > return crc; > } > > +/* Parse the Extended Parameter Page. */ > +static int nand_flash_detect_ext_param_page(struct mtd_info *mtd, > + struct nand_chip *chip, struct nand_onfi_params *p) > +{ > + struct onfi_ext_param_page *ep; > + struct onfi_ext_section *s; > + struct onfi_ext_ecc_info *ecc; > + uint8_t *cursor; > + int len; > + int ret; > + int i; > + > + len = le16_to_cpu(p->ext_param_page_length) * 16; > + ep = kmalloc(len, GFP_KERNEL); > + if (!ep) { > + ret = -ENOMEM; > + goto ext_out; > + } > + > + /* Send our own NAND_CMD_PARAM. */ > + chip->cmdfunc(mtd, NAND_CMD_PARAM, 0, -1); > + > + /* Use the Change Read Column command to skip the ONFI param pages. */ > + chip->cmdfunc(mtd, NAND_CMD_RNDOUT, > + sizeof(*p) * p->num_of_param_pages , -1); > + > + /* Read out the Extended Parameter Page. */ > + chip->read_buf(mtd, (uint8_t *)ep, len); > + if ((onfi_crc16(ONFI_CRC_BASE, ((uint8_t *)ep) + 2, len - 2) > + != le16_to_cpu(ep->crc)) || strncmp(ep->sig, "EPPS", 4)) { > + pr_debug("fail in the CRC.\n"); > + ret = -EINVAL; > + goto ext_out; > + } > + > + /* find the ECC section. */ > + cursor = (uint8_t *)(ep + 1); > + for (i = 0; i < ONFI_EXT_SECTION_MAX; i++) { > + s = ep->sections + i; > + if (s->type == ONFI_SECTION_TYPE_2) > + break; > + cursor += s->length * 16; > + } > + if (i == ONFI_EXT_SECTION_MAX) { > + pr_debug("We can not find the ECC section.\n"); > + ret = -EINVAL; > + goto ext_out; > + } > + > + /* get the info we want. */ > + ecc = (struct onfi_ext_ecc_info *)cursor; > + chip->ecc_strength = ecc->ecc_bits; > + chip->ecc_size = 1 << ecc->codeword_size; > + > + pr_info("ONFI extended param page detected.\n"); > + return 0; > + > +ext_out: > + kfree(ep); > + return ret; > +} > + > /* > * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise. > */ > @@ -2914,6 +2976,21 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, > if (p->ecc_bits != 0xff) { > chip->ecc_strength = p->ecc_bits; > chip->ecc_size = 512; > + } else if (chip->onfi_version >= 21 && > + (onfi_feature(chip) & ONFI_FEATURE_EXT_PARAM_PAGE)) { > + > + /* > + * The nand_flash_detect_ext_param_page() uses the > + * Change Read Column command which maybe not supported > + * by the chip->cmdfunc. So try to update the chip->cmdfunc > + * now. We do not replace user supplied command function. > + */ > + if (mtd->writesize > 512 && chip->cmdfunc == nand_command) > + chip->cmdfunc = nand_command_lp;
I don't think we want to assign chip->cmdfunc within the 'detect_onfi' function. We already have several places from which the default functions may be assigned. Rather, we should only code the above statement *once* (where it already is, in nand_get_flash_type()) and only run the extended parameter page function after that point.
If that's too cumbersome, then maybe it's fine as-is. Or I'll take a crack at rewriting it myself.
> + /* The Extended Parameter Page is supported since ONFI 2.1. */ > + if (nand_flash_detect_ext_param_page(mtd, chip, p)) > + pr_info("Failed to detect the extended param page.\n"); > } > > pr_info("ONFI flash detected\n"); > -- > 1.7.1 > >
Brian
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