why can't kernel read from NAND/SMC device?

[Selmeci, Tamas]

Hello!

After spending a few hours examining S3C2410 NAND-code, I could successfully bring to life the NAND subsystem of the S3C2410 processor. (I'm working with 2.6.15-5 kernel). The following appears:

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s3c2410-nand: Tacls=3, 30ns Twrph0=7 70ns, Twrph1=7 70ns
NAND device: Manufacturer ID: 0xec, Chip ID: 0x79 (Samsung NAND 128MiB 3,3V 8-bit)
Scanning device for bad blocks
nand_read_oob: from = 0x00000000, len = 16
...
(media check, not too interesting)
------

After the check has finished, it assigns every partition to an MTD:

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Creating 4 MTD partitions on "NAND 128MiB 3,3V 8-bit":
0x00000000-0x00020000 : "vivi"
mtd: Giving out device 0 to vivi
0x00020000-0x00030000 : "param"
mtd: Giving out device 1 to param
0x00030000-0x000f0000 : "kernel"
mtd: Giving out device 2 to kernel
0x00100000-0x00240000 : "root"
mtd: Giving out device 3 to root
------

(this partition structure is made by vivi to the SMC and compiled in the board's machine file (in s3c2410_nand_set structure) )

cramfs, romfs and jffs2 support is compiled in the kernel, FTL and NFTL not.

If I give the kernel the root=/dev/mtdblock3 parameter, then this can be seen:

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mtdblock_open
ok
mtdblock: read on "root" at 0x0, size 0x200
nand_read_ecc: from = 0x00100000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000800
nand_read_ecc: Failed ECC read, page 0x00000800
end_request: I/O error, dev mtdblock3, sector 0
Buffer I/O error on device mtdblock3, logical block 0
mtdblock: read on "root" at 0x0, size 0x200
nand_read_ecc: from = 0x00100000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000800
nand_read_ecc: Failed ECC read, page 0x00000800
end_request: I/O error, dev mtdblock3, sector 0
Buffer I/O error on device mtdblock3, logical block 0
mtdblock: read on "root" at 0x1000, size 0x200
nand_read_ecc: from = 0x00101000, len = 512
mtdblock: read on "root" at 0x1200, size 0x200
nand_read_ecc: from = 0x00101200, len = 512
nand_read_ecc: Failed ECC read, page 0x00000809
end_request: I/O error, dev mtdblock3, sector 8
Buffer I/O error on device mtdblock3, logical block 1
mtdblock: read on "root" at 0x1000, size 0x200
nand_read_ecc: from = 0x00101000, len = 512
mtdblock: read on "root" at 0x1200, size 0x200
nand_read_ecc: from = 0x00101200, len = 512
nand_read_ecc: Failed ECC read, page 0x00000809
end_request: I/O error, dev mtdblock3, sector 8
Buffer I/O error on device mtdblock3, logical block 1
mtdblock: read on "root" at 0x2000, size 0x200
nand_read_ecc: from = 0x00102000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000810
end_request: I/O error, dev mtdblock3, sector 16
Buffer I/O error on device mtdblock3, logical block 2
mtdblock: read on "root" at 0x2000, size 0x200
nand_read_ecc: from = 0x00102000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000810
end_request: I/O error, dev mtdblock3, sector 16
Buffer I/O error on device mtdblock3, logical block 2
mtdblock: read on "root" at 0x3000, size 0x200
nand_read_ecc: from = 0x00103000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000818
nand_read_ecc: Failed ECC read, page 0x00000818
end_request: I/O error, dev mtdblock3, sector 24
Buffer I/O error on device mtdblock3, logical block 3
mtdblock: read on "root" at 0x3000, size 0x200
nand_read_ecc: from = 0x00103000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000818
nand_read_ecc: Failed ECC read, page 0x00000818
end_request: I/O error, dev mtdblock3, sector 24
Buffer I/O error on device mtdblock3, logical block 3
mtdblock_release
nand_sync: called
ok
VFS: tried fs_name = <cramfs> err= -22
mtdblock_open
ok
mtdblock: read on "root" at 0x0, size 0x200
nand_read_ecc: from = 0x00100000, len = 512
nand_read_ecc: Failed ECC read, page 0x00000800
nand_read_ecc: Failed ECC read, page 0x00000800
end_request: I/O error, dev mtdblock3, sector 0
romfs: unable to read superblock
mtdblock_release
nand_sync: called
ok
VFS: tried fs_name = <romfs> err= -22
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(31,3)
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There are ECC error messages and I/O errors when reading the SmartMedia card, but in the last line (unknown-block(31,3) ) the device ID seems to be OK. The NAND device is recognized but works improperly. Why can't be the partition read?

With root=/dev/mtd3 setting:
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VFS: test name = </dev/root> 
VFS: fs_name = <cramfs> 
VFS: fs_name = <romfs> 
VFS: tried fs_name = <cramfs> err= -6
VFS: Cannot open root device "mtd3" or unknown-block(0,0)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
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There are absolutely no ECC error messages - because /dev/mtd3 refers to no device (unknown-block(0,0) ), I suppose. 

I don't know what's the problem with the NAND card (it's a rather new one, with only one bad eraseblock) or driver... those ECC errors are not too nice (in the kernel I switched off S3C2410 NAND hardware ECC option). Does anybody know what to do now, or any good advices?

Many thanks

Bye
--
Tamas Selmeci