Hi Detlev,
I have tried to create a jffs2-image of the linux-filesystem I wish to use, and then write it to my flash using "nand write.jffs2 100000 0 $(filesize)". But with no luck... Then I began to investigate the fundamental "ls" and "nand erase" commands, but neither there did I have any success. Below is a trace of what I've tried in order to get something working.
Are you really sure, your NAND gets accessed correctly both under U-Boot and Linux? Can you erase / write / readback some data under U-Boot by hand?
I'm sure it works under Linux - there I can both write and read - boot and use the flash-data again. No problems.
Under u-boot I've just tried the following:
=============== 8< 8< 8< 8< ===============
=> md.b 100000
00100000: 7f a3 eb 78 38 a0 00 00 4b ff fa b1 7c 7f 1b 78 ...x8...K...|..x 00100010: 3d 40 c0 18 39 2a 14 60 81 69 00 08 39 6b ff ff =@..9*.`.i..9k.. 00100020: 91 69 00 08 2c 0b 00 00 40 82 00 10 80 0a 14 60 .i..,...@......` 00100030: 2c 00 00 00 40 82 00 0c 7f e3 fb 78 4b ff fe a0 ,...@......xK...
=> nand write 100000 0 40
NAND write: device 0 offset 0, size 64 ... Warning block writes should be at lea st 512 bytes and start on a 512 byte boundry 64 bytes written: OK
=> nand read 200000 0 40
NAND read: device 0 offset 0, size 64 ... Warning block writes should be at leas t 512 bytes and start on a 512 byte boundry 64 bytes read: OK
=> md.b 200000
00200000: 7f a3 eb 78 38 a0 00 00 4b ff fa b1 7c 7f 1b 78 ...x8...K...|..x 00200010: 3d 40 c0 18 39 2a 14 60 81 69 00 08 39 6b ff ff =@..9*.`.i..9k.. 00200020: 91 69 00 08 2c 0b 00 00 40 82 00 10 80 0a 14 60 .i..,...@......` 00200030: 2c 00 00 00 40 82 00 0c 7f e3 fb 78 4b ff fe a0 ,...@......xK...
=>
=============== 8< 8< 8< 8< ===============
In short: the giberish-data present at memory 0x100000 is written to flash, and reread again to memory at 0x200000. The flash does still contain the data after reboot.
Next, I tried reading the data from my Linux:
# dd if=/dev/mtd0 of=/ftp/dump bs=8 count=8
=== /ftp/dump contains: ===
00000000: 7fa3 eb78 38a0 0000 4bff fab1 7c7f 1b78 ...x8...K...|..x 00000010: 3d40 c018 392a 1460 8169 0008 396b ffff =@..9*.`.i..9k.. 00000020: 9169 0008 2c0b 0000 4082 0010 800a 1460 .i..,...@......` 00000030: 2c00 0000 4082 000c 7fe3 fb78 4bff fea0 ,...@......xK...
Hence, the same data is available from Linux at the beginning at the device.
That made me wonder... Aaaaand, then I tried mounting the flash-root-filesystem under Linux after what I thought would have corrupted it (the above writing of giberish to the system). And the root-filesystem still worked! Hence, I tried dumping the entire flash to a file. And I discovered that the filesystem-data was positioned at the "end" of the flash... That may be the reason that "ls" in u-boot does not work with the image in flash - or what?
Best regards, Martin Egholm