Hi Boris, I've sent v6 of the patch based on your comments.
Thanks. Jane > -----Original Message----- > From: Boris Brezillon [mailto:[email protected]] > Sent: Thursday, May 10, 2018 5:03 AM > To: Wan, Jane (Nokia - US/Sunnyvale) <[email protected]> > Cc: [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; linux- > [email protected]; Bos, Ties (Nokia - US/Sunnyvale) <[email protected]> > Subject: Re: [PATCH v5 2/2] mtd: rawnand: use bit-wise majority to recover the > contents of ONFI parameter > > Hi Jane, > > Subject prefix should be "[PATCH v5] ...", the 2/2 is no longer valid since > you only > have one patch here. > > On Wed, 9 May 2018 19:46:40 -0700 > Jane Wan <[email protected]> wrote: > > > Per ONFI specification (Rev. 4.0), if all parameter pages have invalid > > CRC values, the bit-wise majority may be used to recover the contents > > of the parameter pages from the parameter page copies present. > > > > Signed-off-by: Jane Wan <[email protected]> > > --- > > There should be a changelog here describing what has changed in each version > of the patch. [Jane] Added the changelogs in v6. > > > drivers/mtd/nand/raw/nand_base.c | 46 > +++++++++++++++++++++++++++++++++----- > > 1 file changed, 41 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/mtd/nand/raw/nand_base.c > > b/drivers/mtd/nand/raw/nand_base.c > > index 72f3a89..a7c2507 100644 > > --- a/drivers/mtd/nand/raw/nand_base.c > > +++ b/drivers/mtd/nand/raw/nand_base.c > > @@ -5086,6 +5086,34 @@ static int > nand_flash_detect_ext_param_page(struct nand_chip *chip, > > return ret; > > } > > > > +#define GET_BIT(bit, val) (((val) >> (bit)) & 0x01) > > Not sure we need that macro, see below. [Jane] Removed. > > > + > > +/* > > + * Recover data with bit-wise majority */ static void > > +nand_bit_wise_majority(const void **srcbufs, > > + void *dstbuf, > > + unsigned int nbufs, > > + unsigned int bufsize) > > I'd prefer to have nbufs just after srcbufs and named nsrcbufs: > > static void nand_bit_wise_majority(const void **srcbufs, > unsigned int nsrcbufs, > void *dstbuf, > unsigned int bufsize) [Jane] changed as above in v6. > > > +{ > > + int i, j, k; > > + u8 v, m; > > + u8 *p; > > + > > + p = *(u8 **)srcbufs; > > Nope, I'd like to support the cases where srcbufs are not contiguous, so that > does not work. [Jane] Changed as you suggested to support non-contiguous srcbufs. > > > + for (i = 0; i < bufsize; i++) { > > + v = 0; > > You can declare the v variable here, since its scope is limited to the for > loop. > BTW, v, m, can't we pick better names? I guess v is for val, but I'm not even > sure > what m stands for. [Jane] changed the variables to cnt and val in v6. The "m" was for majority, now changed to cnt (counts for 1s). > > > + for (j = 0; j < 8; j++) { > > + m = 0; > > + for (k = 0; k < nbufs; k++) > > + m += GET_BIT(j, p[k*bufsize + i]); > > for (k = 0; k < nbufs; k++) { > const u8 *srcbuf = srcbufs[j]; > > if (srcbuf[i] & BIT(k)) > m++; > } > > > + if (m > nbufs/2) > > Space between operands and operators please > > if (m > nbufs / 2) [Jane] Changed as suggested in v6. Thanks. > > > + v |= BIT(j); > > + } > > + ((u8 *)dstbuf)[i] = v; > > + } > > +} > > + > > /* > > * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 > > otherwise. > > */ > > @@ -5102,7 +5130,7 @@ static int nand_flash_detect_onfi(struct nand_chip > *chip) > > return 0; > > > > /* ONFI chip: allocate a buffer to hold its parameter page */ > > - p = kzalloc(sizeof(*p), GFP_KERNEL); > > + p = kzalloc((sizeof(*p) * 3), GFP_KERNEL); > > if (!p) > > return -ENOMEM; > > > > @@ -5113,21 +5141,29 @@ static int nand_flash_detect_onfi(struct > nand_chip *chip) > > } > > > > for (i = 0; i < 3; i++) { > > - ret = nand_read_data_op(chip, p, sizeof(*p), true); > > + ret = nand_read_data_op(chip, &p[i], sizeof(*p), true); > > if (ret) { > > ret = 0; > > goto free_onfi_param_page; > > } > > > > - if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) == > > + if (onfi_crc16(ONFI_CRC_BASE, (u8 *)&p[i], 254) == > > le16_to_cpu(p->crc)) { > > + if (i) > > + memcpy(p, &p[i], sizeof(*p)); > > break; > > } > > } > > > > if (i == 3) { > > const void *srcbufs[3] = {p, p + 1, p + 2}; > > > - pr_err("Could not find valid ONFI parameter page; aborting\n"); > > - goto free_onfi_param_page; > > + pr_err("Could not find valid ONFI parameter page\n"); > > + pr_info("Recover ONFI params with bit-wise majority\n"); > > + nand_bit_wise_majority((const void **)&p, p, 3, sizeof(*p)); > > nand_bit_wise_majority(srcbufs, ARRAY_SIZE(srcbufs), p, > sizeof(*p)) [Jane] Changed in v6. Thanks. > > > + if (onfi_crc16(ONFI_CRC_BASE, (u8 *)p, 254) != > > + le16_to_cpu(p->crc)) { > > + pr_err("ONFI parameter recovery failed, aborting\n"); > > + goto free_onfi_param_page; > > + } > > } > > > > /* Check version */ > > Thanks, > > Boris
