UBI IO errors with GPMI NAND

[Vikram Narayanan]

I'm using a i.Mx6 Solo based custom board with the below NAND chip.
<<NAND device: Manufacturer ID: 0x98, Chip ID: 0xac (Toshiba NAND 512MiB 
1,8V 8-bit), page size: 4096, OOB size: 128>>

I'm getting warnings like the one below while attaching the mtd to ubi, 
with a backtrace.

<<UBI warning: ubi_io_read: error -74 (ECC error) while reading 4096 
bytes from PEB 969:4096, read only 4096 bytes, retry>>

According to [1], I ran mtd-tests. But the mtd_oobtest failed to proceed 
as the GPMI-NAND doesn't define a valid nand_ecclayout structure. 
(drivers/mtd/nand/gpmi-nand/gpmi-nand.c) [l2-mtd.git]

I guess that the mtd_oobtest can't be performed without a valid 
nand_ecclayout as the ooblen, oobavail are taken from this struct when 
trying to write to the OOB area in the test.

Did someone try to execute this test with gpmi-nand driver?

The weird behavior is, I see the errors while mounting an empty flash as 
well. I need to do a ubiattach followed by ubiformat. Please see the 
detailed log.

[1] http://www.linux-mtd.infradead.org/faq/ubi.html#L_ecc_error

<Detailed log>
root at BOX:/# ubiattach -m 6 /dev/ubi_ctrl
[   77.053308] UBI: attaching mtd6 to ubi2
[   77.058095] UBI: physical eraseblock size:   262144 bytes (256 KiB)
[   77.066010] UBI: logical eraseblock size:    253952 bytes
[   77.072237] UBI: smallest flash I/O unit:    4096
[   77.077782] UBI: VID header offset:          4096 (aligned 4096)
[   77.085361] UBI: data offset:                8192
[   78.653120] UBI warning: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 714:4096, read only 4096 bytes, retry
[   78.668408] UBI warning: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 714:4096, read only 4096 bytes, retry
[   78.683707] UBI warning: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 714:4096, read only 4096 bytes, retry
[   78.699016] UBI error: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 714:4096, read 4096 bytes
[   78.711264] Backtrace:
[   78.714606] [<80011464>] (dump_backtrace+0x0/0x10c) from [<80414774>] 
(dump_stack+0x18/0x1c)
[   78.724676]  r6:00001000 r5:ffffffb6 r4:8a311800 r3:60000013
[   78.732046] [<8041475c>] (dump_stack+0x0/0x1c) from [<802bb030>] 
(ubi_io_read+0x1fc/0x2d8)
[   78.741991] [<802bae34>] (ubi_io_read+0x0/0x2d8) from [<802bb56c>] 
(ubi_io_read_vid_hdr+0x78/0x220)
[   78.752734] [<802bb4f4>] (ubi_io_read_vid_hdr+0x0/0x220) from 
[<802bfbdc>] (ubi_attach+0x31c/0x1448)
[   78.763593] [<802bf8c0>] (ubi_attach+0x0/0x1448) from [<802b5b6c>] 
(ubi_attach_mtd_dev+0x6a8/0xcf4)
[   78.774390] [<802b54c4>] (ubi_attach_mtd_dev+0x0/0xcf4) from 
[<802b6460>] (ctrl_cdev_ioctl+0xd8/0x184)
[   78.785485] [<802b6388>] (ctrl_cdev_ioctl+0x0/0x184) from 
[<800dbaa4>] (do_vfs_ioctl+0x570/0x5e4)
[   78.796100]  r7:00000003 r6:8a610580 r5:8a21fc58 r4:7e9ccc2c
[   78.803564] [<800db534>] (do_vfs_ioctl+0x0/0x5e4) from [<800dbb58>] 
(sys_ioctl+0x40/0x64)
[   78.813471]  r9:8a616000 r8:8000d944 r7:00000003 r6:40186f40 r5:7e9ccc2c
r4:8a610580
[   78.823947] [<800dbb18>] (sys_ioctl+0x0/0x64) from [<8000d7c0>] 
(ret_fast_syscall+0x0/0x30)
[   78.833987]  r7:00000036 r6:00008b20 r5:00000000 r4:00000000
[   79.467228] UBI warning: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 969:4096, read only 4096 bytes, retry
[   79.482716] UBI warning: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 969:4096, read only 4096 bytes, retry
[   79.498185] UBI warning: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 969:4096, read only 4096 bytes, retry
[   79.513668] UBI error: ubi_io_read: error -74 (ECC error) while 
reading 4096 bytes from PEB 969:4096, read 4096 bytes
[   79.526009] Backtrace:
[   79.529352] [<80011464>] (dump_backtrace+0x0/0x10c) from [<80414774>] 
(dump_stack+0x18/0x1c)
[   79.539499]  r6:00001000 r5:ffffffb6 r4:8a311800 r3:60000013
[   79.546945] [<8041475c>] (dump_stack+0x0/0x1c) from [<802bb030>] 
(ubi_io_read+0x1fc/0x2d8)
[   79.556920] [<802bae34>] (ubi_io_read+0x0/0x2d8) from [<802bb56c>] 
(ubi_io_read_vid_hdr+0x78/0x220)
[   79.567730] [<802bb4f4>] (ubi_io_read_vid_hdr+0x0/0x220) from 
[<802bfbdc>] (ubi_attach+0x31c/0x1448)
[   79.578628] [<802bf8c0>] (ubi_attach+0x0/0x1448) from [<802b5b6c>] 
(ubi_attach_mtd_dev+0x6a8/0xcf4)
[   79.589458] [<802b54c4>] (ubi_attach_mtd_dev+0x0/0xcf4) from 
[<802b6460>] (ctrl_cdev_ioctl+0xd8/0x184)
[   79.600529] [<802b6388>] (ctrl_cdev_ioctl+0x0/0x184) from 
[<800dbaa4>] (do_vfs_ioctl+0x570/0x5e4)
[   79.611135]  r7:00000003 r6:8a610580 r5:8a21fc58 r4:7e9ccc2c
[   79.618593] [<800db534>] (do_vfs_ioctl+0x0/0x5e4) from [<800dbb58>] 
(sys_ioctl+0x40/0x64)
[   79.628488]  r9:8a616000 r8:8000d944 r7:00000003 r6:40186f40 r5:7e9ccc2c
r4:8a610580
[   79.638971] [<800dbb18>] (sys_ioctl+0x0/0x64) from [<8000d7c0>] 
(ret_fast_syscall+0x0/0x30)
[   79.649009]  r7:00000036 r6:00008b20 r5:00000000 r4:00000000
[   80.160882] UBI error: scan_peb: bad image sequence number 
-1059128657 in PEB 1168, expected -2128599336
[   80.172534] UBI error: ubi_attach_mtd_dev: failed to attach mtd6, 
error -22
ubiattach: error!: cannot attach mtd6
            error 22 (Invalid argument)
root at BOX:/# ubiformat /dev/mtd6
ubiformat: mtd6 (nand), size 307232768 bytes (293.0 MiB), 1172 
eraseblocks of 262144 bytes (256.0 KiB), min. I/O size 4096 bytes
libscan: scanning eraseblock 1171 -- 100 % complete
ubiformat: 1170 eraseblocks have valid erase counter, mean value is 1
ubiformat: warning!: 2 of 1172 eraseblocks contain non-ubifs data
ubiformat: continue? (yes/no)  yes
ubiformat: formatting eraseblock 1171 -- 100 % complete
root at BOX:/# ubiattach -m 6 /dev/ubi_ctrl
[  112.615497] UBI: attaching mtd6 to ubi2
[  112.620299] UBI: physical eraseblock size:   262144 bytes (256 KiB)
[  112.628266] UBI: logical eraseblock size:    253952 bytes
[  112.634542] UBI: smallest flash I/O unit:    4096
[  112.640071] UBI: VID header offset:          4096 (aligned 4096)
[  112.647673] UBI: data offset:                8192
[  115.211159] UBI: max. sequence number:       0
[  115.231875] UBI: attached mtd6 to ubi2
[  115.236460] UBI: MTD device name:            "user_data2"
[  115.242453] UBI: MTD device size:            293 MiB
[  115.248174] UBI: number of good PEBs:        1172
[  115.253620] UBI: number of bad PEBs:         0
[  115.258763] UBI: number of corrupted PEBs:   0
[  115.263925] UBI: max. allowed volumes:       128
[  115.269230] UBI: wear-leveling threshold:    4096
[  115.274623] UBI: number of internal volumes: 1
[  115.279726] UBI: number of user volumes:     0
[  115.284826] UBI: available PEBs:             1157
[  115.290158] UBI: total number of reserved PEBs: 15
[  115.295582] UBI: number of PEBs reserved for bad PEB handling: 11
[  115.302857] UBI: max/mean erase counter: 3/2
[  115.307752] UBI: image sequence number:  552854966
[  115.313163] UBI: background thread "ubi_bgt2d" started, PID 134
UBI device number 2, total 1172 LEBs (297631744 bytes, 283.8 MiB), 
available 1157 LEBs (293822464 bytes, 280.2 MiB), LEB size 253952 bytes 
(248.0 KiB)
</Detailed log>