All,
I'm needing to access the NAND chip on the imx28evk board with the
Linux (Freescale Kernel - FSL). I've compiled a recent version of the
mainstream u-boot with the NAND switches and U-boot works fine. The
U-boot also allows me access to the NAND chip and also boots the FSL
kernel just fine. However, once the kernel is running, it can not "see"
the /dev/mtdX devices.
However, if I boot the *same* kernel directly (no U-boot - and
attach boot-stream to kernel) the FSL kernel works fine and can gets the
/dev/mtdX etc devices. I tracked this down to a couple of differences
that are output during the kernel booting process. I also can replicate
this problem with no NAND chip in the socket. I can do this by using the
script that comes with the imx28evk that is used for formatting the
SDCard for booting. The mk_mx28_sd script writes the uboot, kernel, and
rootfs to an SDcard depending on the parameters. So if I write the
uboot to the card and boot the imx28 from uboot and network boot uImage
I get the error. If I write the kernel to the card and boot the imx28
with it I get no error (Using the same kernel). Here are the steps
1. Setup card for kernel boot
- run mk_mx28_sd -b /dev/sdb (only writes kernel with bootstream on card)
- place card in imx28 and boot it
- the kernel (while booting) outputs these lines:
...
...
i.MX GPMI NFC
NFC: Version 1, 8-chip GPMI and BCH
Boot ROM: Version 1, Single-chip boot area, block mark swapping
supported Scanning for NAND Flash chips...
No NAND device found.
gpmi-nfc gpmi-nfc.0: Chip scan failed
...
...
2. Setup card for uboot
-setup your host ubuntu so uboot can tftp your kernel -use *same* kernel
from #1 (but use uImage) -run mk_mx28_sd -u -b /dev/sdb (only writes
uboot with bootstream on card) -place card in imx28 and boot it -you may
have to edit uboot parms to get your uImage from your host -Allow kernel
to boot, it will output these lines:
...
i.MX GPMI NFC
NFC: Version 1, 8-chip GPMI and BCH
gpmi-nfc: probe of gpmi-nfc.0 failed with error 1 ...
...
So maybe U-boot does some things that prevents kernel from working or
the kernel with the boot stream added on does the right things ?
Thanks,
Bill
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