mx35pdk: README: Remove NAND references

Booting from NAND is currently not supported, so remove its references.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
This commit is contained in:
Fabio Estevam 2012-09-14 12:14:54 +00:00 committed by Stefano Babic
parent f994dc5ecf
commit 1d9b033269

View File

@ -71,91 +71,17 @@ exec -c "noinitrd console=ttymxc0,115200 root=/dev/nfsroot rootfstype=nfsroot nf
Flashing U-Boot
--------------------------------
There are two options: the original bootloader in NAND can be replaced with
u-boot, or u-boot can be stored on the NOR flash without erasing
the delivered bootloader.
U-boot should be stored on the NOR flash.
The boot storage can be select using the switches on the personality board
(SW1-SW2) and on the DEBUG board (SW4-SW10).
The second option is to be preferred if you have not a JTAG debugger.
If something goes wrong flashing the bootloader, it is always possible to
recover the board booting from the other device.
Replacing the bootloader on the NAND
--------------------------------------
To replace RedBoot with U-Boot, the easy way is to do this in linux.
Start the kernel with the suggested options. Make sure to have set the
mtdparts exactly as described, because this matches the layout on the
mx35pdk.
You should see in your boot log the following entries for the NAND
flash:
5 cmdlinepart partitions found on MTD device mxc_nand
Creating 5 MTD partitions on "mxc_nand":
0x000000000000-0x000000100000 : "boot"
0x000000100000-0x000000600000 : "linux"
0x000000600000-0x000006600000 : "root"
0x000006600000-0x000006e00000 : "cfg"
0x000006e00000-0x000080000000 : "user"
You can use the utilities flash_eraseall and nandwrite to put
u-boot on the NAND. The bootloader is marked as "boot", and 1MB is
reserved. If everything is correct, this partition is accessed as
/dev/mtd4. However, check if it is correct with "cat /proc/mtd" and
get the device node from the partition name:
$ cat /proc/mtd | grep boot
I suggest you try the utilities on a different partition to be sure
if everything works correctly. If not, and you remove RedBoot, you have to
reinstall it using the ATK tool as suggested by Freescale, or using a
JTAG debugger.
I report the versions of the utilities I used (they are provided with ELDK):
-bash-3.2# nandwrite --version
nandwrite $Revision: 1.32 $
flash_eraseall --version
flash_eraseall $Revision: 1.22 $
nandwrite reports a warning if the file to be saved is not sector aligned.
This should have no consequences, but I preferred to pad u-boot.bin
to get no problem at all.
$ dd if=/dev/zero of=zeros bs=1 count=74800
$ cat u-boot.bin zeros > u-boot-padded.bin
To erase the partition:
$ flash_eraseall /dev/mtd4
Writing u-boot:
$ nandwrite /dev/mtd4 u-boot-padded.bin
Now U-Boot is stored on the booting partition.
To boot from NAND, you have to select the switches as follows:
Personality board
SW2 1, 4, 5 on
2, 3, 6, 7, 8 off
SW1 all off
Debug Board:
SW5 0
SW6 0
SW7 0
SW8 1
SW9 1
SW10 0
Saving U-Boot in the NOR flash
---------------------------------
The procedure to save in the NOR flash is quite the same as to write into the NAND.
Check the partition for boot in the NOR flash. Setting the mtdparts as reported,
the boot partition should be /dev/mtd0.