+Peter, who's currently reworking the NAND BBT code. On Wed, 30 Mar 2016 15:13:51 +0200 Boris Brezillon <[email protected]> wrote:
> Hi Kyle, > > On Fri, 25 Mar 2016 17:31:16 -0500 > Kyle Roeschley <[email protected]> wrote: > > > If erasing or writing the BBT fails, we should mark the current BBT > > block as bad and use the BBT descriptor to scan for the next available > > unused block in the BBT. We should only return a failure if there isn't > > any space left. > > > > Based on original code implemented by Jeff Westfahl > > <[email protected]>. > > > > Signed-off-by: Kyle Roeschley <[email protected]> > > Suggested-by: Jeff Westfahl <[email protected]> > > --- > > This v3 is in response to comments from Brian Norris and Bean Ho on 8/26/15: > > http://lists.infradead.org/pipermail/linux-mtd/2015-August/061411.html > > > > v3: Don't overload mtd->priv > > Keep nand_erase_nand from erroring on protected BBT blocks > > > > v2: Mark OOB area in each block as well as BBT > > Avoid marking read-only, bad address, or known bad blocks as bad > > --- > > drivers/mtd/nand/nand_base.c | 4 ++-- > > drivers/mtd/nand/nand_bbt.c | 37 +++++++++++++++++++++++++++++++++++-- > > 2 files changed, 37 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > > index b6facac..9ad8a86 100644 > > --- a/drivers/mtd/nand/nand_base.c > > +++ b/drivers/mtd/nand/nand_base.c > > @@ -2916,8 +2916,8 @@ int nand_erase_nand(struct mtd_info *mtd, struct > > erase_info *instr, > > /* Select the NAND device */ > > chip->select_chip(mtd, chipnr); > > > > - /* Check, if it is write protected */ > > - if (nand_check_wp(mtd)) { > > + /* Check if it is write protected, unless we're erasing BBT */ > > + if (nand_check_wp(mtd) && !allowbbt) { > > Hm, will this really work. Can a write-protected device accept erase > commands? > > > pr_debug("%s: device is write protected!\n", > > __func__); > > instr->state = MTD_ERASE_FAILED; > > diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c > > index 2fbb523..01526e5 100644 > > --- a/drivers/mtd/nand/nand_bbt.c > > +++ b/drivers/mtd/nand/nand_bbt.c > > @@ -662,6 +662,7 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf, > > page = td->pages[chip]; > > goto write; > > } > > + next: > > Please put this label at the beginning of the line and fix all the other > issues reported by checkpatch (I know we already have a 'write' label > which does not follow this rule, but let's try to avoid adding new > ones). > > > > > /* > > * Automatic placement of the bad block table. Search direction > > @@ -787,14 +788,46 @@ static int write_bbt(struct mtd_info *mtd, uint8_t > > *buf, > > einfo.addr = to; > > einfo.len = 1 << this->bbt_erase_shift; > > res = nand_erase_nand(mtd, &einfo, 1); > > - if (res < 0) > > + if (res == -EIO) { > > + /* This block is bad. Mark it as such and see if > > + * there's another block available in the BBT area. */ > > + int block = page >> > > + (this->bbt_erase_shift - this->page_shift); > > + pr_info("nand_bbt: failed to erase block %d when > > writing BBT\n", > > + block); > > + bbt_mark_entry(this, block, BBT_BLOCK_WORN); > > + > > + res = this->block_markbad(mtd, block); > > Not sure we should mark the block bad until we managed to write a new > BBT. ITOH, if we do so and the new BBT write is interrupted, it > will trigger a full BBM scan, which should be harmless on most > platforms (except those overwriting BBM with real data :-/) > > > + if (res) > > + pr_warn("nand_bbt: error %d while marking block > > %d bad\n", > > + res, block); > > + td->pages[chip] = -1; > > + goto next; > > + } else if (res < 0) { > > goto outerr; > > + } > > > > res = scan_write_bbt(mtd, to, len, buf, > > td->options & NAND_BBT_NO_OOB ? NULL : > > &buf[len]); > > - if (res < 0) > > + if (res == -EIO) { > > + /* This block is bad. Mark it as such and see if > > + * there's another block available in the BBT area. */ > > + int block = page >> > > + (this->bbt_erase_shift - this->page_shift); > > + pr_info("nand_bbt: failed to write block %d when > > writing BBT\n", > > + block); > > + bbt_mark_entry(this, block, BBT_BLOCK_WORN); > > + > > + res = this->block_markbad(mtd, block); > > + if (res) > > + pr_warn("nand_bbt: error %d while marking block > > %d bad\n", > > + res, block); > > + td->pages[chip] = -1; > > + goto next; > > + } else if (res < 0) { > > goto outerr; > > + } > > > > pr_info("Bad block table written to 0x%012llx, version > > 0x%02X\n", > > (unsigned long long)to, td->version[chip]); > > Bean, Brian, can you comment on this new version. I haven't followed > the previous iterations, and would like to have your feedback before > taking a decision. > > Thanks, > > Boris > > -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
