| From foo@baz Wed Feb 28 16:16:23 CET 2018 |
| From: Sascha Hauer <s.hauer@pengutronix.de> |
| Date: Tue, 5 Dec 2017 11:51:40 +0100 |
| Subject: mtd: nand: gpmi: Fix failure when a erased page has a bitflip at BBM |
| |
| From: Sascha Hauer <s.hauer@pengutronix.de> |
| |
| |
| [ Upstream commit fdf2e821052958a114618a95ab18a300d0b080cb ] |
| |
| When erased subpages are read then the BCH decoder returns STATUS_ERASED |
| if they are all empty, or STATUS_UNCORRECTABLE if there are bitflips. |
| When there are bitflips, we have to set these bits again to show the |
| upper layers a completely erased page. When a bitflip happens in the |
| exact byte where the bad block marker is, then this byte is swapped |
| with another byte in block_mark_swapping(). The correction code then |
| detects a bitflip in another subpage and no longer corrects the bitflip |
| where it really happens. |
| |
| Correct this behaviour by calling block_mark_swapping() after the |
| bitflips have been corrected. |
| |
| In our case UBIFS failed with this bug because it expects erased |
| pages to be really empty: |
| |
| UBIFS error (pid 187): ubifs_scan: corrupt empty space at LEB 36:118735 |
| UBIFS error (pid 187): ubifs_scanned_corruption: corruption at LEB 36:118735 |
| UBIFS error (pid 187): ubifs_scanned_corruption: first 8192 bytes from LEB 36:118735 |
| UBIFS error (pid 187): ubifs_scan: LEB 36 scanning failed |
| UBIFS error (pid 187): do_commit: commit failed, error -117 |
| |
| Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> |
| Reviewed-by: Richard Weinberger <richard@nod.at> |
| Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com> |
| Signed-off-by: Richard Weinberger <richard@nod.at> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c |
| +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c |
| @@ -1025,9 +1025,6 @@ static int gpmi_ecc_read_page(struct mtd |
| return ret; |
| } |
| |
| - /* handle the block mark swapping */ |
| - block_mark_swapping(this, payload_virt, auxiliary_virt); |
| - |
| /* Loop over status bytes, accumulating ECC status. */ |
| status = auxiliary_virt + nfc_geo->auxiliary_status_offset; |
| |
| @@ -1043,6 +1040,9 @@ static int gpmi_ecc_read_page(struct mtd |
| max_bitflips = max_t(unsigned int, max_bitflips, *status); |
| } |
| |
| + /* handle the block mark swapping */ |
| + block_mark_swapping(this, buf, auxiliary_virt); |
| + |
| if (oob_required) { |
| /* |
| * It's time to deliver the OOB bytes. See gpmi_ecc_read_oob() |
