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| Started by | Yanjiantao <yanjiantao@hisilicon.com> |
|---|---|
| First post | 2015-10-13 13:40 +0200 |
| Last post | 2015-10-13 20:00 +0200 |
| Articles | 2 — 2 participants |
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questions about [PATCH]mtd: nand: fix SCAN2NDPAGE check for BBM Yanjiantao <yanjiantao@hisilicon.com> - 2015-10-13 13:40 +0200
Re: questions about [PATCH]mtd: nand: fix SCAN2NDPAGE check for BBM Brian Norris <computersforpeace@gmail.com> - 2015-10-13 20:00 +0200
| From | Yanjiantao <yanjiantao@hisilicon.com> |
|---|---|
| Date | 2015-10-13 13:40 +0200 |
| Subject | questions about [PATCH]mtd: nand: fix SCAN2NDPAGE check for BBM |
| Message-ID | <qj65X-5h7-15@gated-at.bofh.it> |
Dear Brian,
i read the patch: " mtd: nand: fix SCAN2NDPAGE check for BBM "
And i am confused about the markbad flows.
xxxxx;
if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
ofs += mtd->erasesize - mtd->writesize;
xxxxx;
do {
if (chip->options & NAND_BUSWIDTH_16) {
chip->cmdfunc(mtd, NAND_CMD_READOOB,
chip->badblockpos & 0xFE, page);
bad = cpu_to_le16(chip->read_word(mtd));
if (chip->badblockpos & 0x1)
bad >>= 8;
else
bad &= 0xFF;
} else {
chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos,
page);
bad = chip->read_byte(mtd);
}
if (likely(chip->badblockbits == 8))
res = bad != 0xFF;
else
res = hweight8(bad) < chip->badblockbits;
ofs += mtd->writesize;
page = (int)(ofs >> chip->page_shift) & chip->pagemask;
i++;
} while (!res && i < 2 && (chip->bbt_options & NAND_BBT_SCAN2NDPAGE));
mark bad flows is the same.
If I understand the patch right, then I think that:
1. when NAND_BBT_SCANLASTPAGE is set, markbad and checkbad on the last page only.
2. when NAND_BBT_SCAN2NDPAGE is set, markbad and checkbad on the 1st and 2nd page.
I checked some datasheets of different manufacturers(such as SAMSUNG/HYNIX/MICRON/TOSHIBA), they claim that bad block marker is on 1st/2nd, or 1st/last, or 1st/2nd/last(for spansion).
the checkbad method may check fail in some cases:
for example,:
1. for spansion nand(bad block marker is on 1st or 2nd or last page), set NAND_BBT_SCAN2NDPAGE while badblock marker is on last page or set NAND_BBT_SCANLASTPAGE while badblock marker is on 1st/2nd page may cause badblock chech failed.
2. for HYNIX (H27UBG8T2CTR) nand (bad block marker is on 1st or last page), check may failed whether NAND_BBT_SCANLASTPAGE is set or not.
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| From | Brian Norris <computersforpeace@gmail.com> |
|---|---|
| Date | 2015-10-13 20:00 +0200 |
| Message-ID | <qjc1K-5sd-47@gated-at.bofh.it> |
| In reply to | #1245616 |
On Tue, Oct 13, 2015 at 11:33:54AM +0000, Yanjiantao wrote:
> Dear Brian,
>
> i read the patch: " mtd: nand: fix SCAN2NDPAGE check for BBM "
> And i am confused about the markbad flows.
>
> xxxxx;
> if (chip->bbt_options & NAND_BBT_SCANLASTPAGE)
> ofs += mtd->erasesize - mtd->writesize;
>
> xxxxx;
>
> do {
> if (chip->options & NAND_BUSWIDTH_16) {
> chip->cmdfunc(mtd, NAND_CMD_READOOB,
> chip->badblockpos & 0xFE, page);
> bad = cpu_to_le16(chip->read_word(mtd));
> if (chip->badblockpos & 0x1)
> bad >>= 8;
> else
> bad &= 0xFF;
> } else {
> chip->cmdfunc(mtd, NAND_CMD_READOOB, chip->badblockpos,
> page);
> bad = chip->read_byte(mtd);
> }
>
> if (likely(chip->badblockbits == 8))
> res = bad != 0xFF;
> else
> res = hweight8(bad) < chip->badblockbits;
> ofs += mtd->writesize;
> page = (int)(ofs >> chip->page_shift) & chip->pagemask;
> i++;
> } while (!res && i < 2 && (chip->bbt_options & NAND_BBT_SCAN2NDPAGE));
> mark bad flows is the same.
>
> If I understand the patch right, then I think that:
> 1. when NAND_BBT_SCANLASTPAGE is set, markbad and checkbad on the last page only.
> 2. when NAND_BBT_SCAN2NDPAGE is set, markbad and checkbad on the 1st and 2nd page.
>
> I checked some datasheets of different manufacturers(such as SAMSUNG/HYNIX/MICRON/TOSHIBA), they claim that bad block marker is on 1st/2nd, or 1st/last, or 1st/2nd/last(for spansion).
> the checkbad method may check fail in some cases:
> for example,:
> 1. for spansion nand(bad block marker is on 1st or 2nd or last page), set NAND_BBT_SCAN2NDPAGE while badblock marker is on last page or set NAND_BBT_SCANLASTPAGE while badblock marker is on 1st/2nd page may cause badblock chech failed.
> 2. for HYNIX (H27UBG8T2CTR) nand (bad block marker is on 1st or last page), check may failed whether NAND_BBT_SCANLASTPAGE is set or not.
Are you repeating the question from here [1]? The refer to my response
here [2].
Brian
[1] http://lists.infradead.org/pipermail/linux-mtd/2015-October/062486.html
[2] http://lists.infradead.org/pipermail/linux-mtd/2015-October/062509.html
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