189 lines
5.9 KiB
Plaintext
189 lines
5.9 KiB
Plaintext
Overview
|
|
--------------
|
|
|
|
mx35pdk (known als as mx35_3stack) is a development board by Freescale.
|
|
It consists of three pluggable board:
|
|
- CPU module, with CPU, RAM, flash
|
|
- Personality board, with most interfaces (USB, Network,..)
|
|
- Debug board with JTAG header.
|
|
|
|
The board is usually delivered with redboot. This howto explains how to boot
|
|
a linux kernel and how to replace the original bootloader with U-Boot.
|
|
|
|
The board is delivered with Redboot on the NAND flash. It is possible to
|
|
switch the boot device with the switches SW1-SW2 on the Personality board,
|
|
and with SW5-SW10 on the Debug board.
|
|
|
|
Delivered Redboot script to start the kernel
|
|
---------------------------------------------------
|
|
|
|
In redboot the following script is stored:
|
|
|
|
fis load kernel
|
|
exec -c "noinitrd console=ttymxc0,115200 root=/dev/mtdblock8 rw rootfstype=jffs2 ip=dhcp fec_mac=00:04:9F:00:E7:76"
|
|
|
|
Kernel is taken from flash. The image is in zImage format.
|
|
|
|
Booting from NET, rootfs on NFS:
|
|
-----------------------------------
|
|
|
|
To change the script in redboot:
|
|
|
|
load -r -b 0x100000 <path_to_zImage>
|
|
exec -c "noinitrd console=ttymxc0,115200 root=/dev/nfsroot rootfstype=nfsroot nfsroot=192.168.1.1:/opt/eldk-4.2-arm/armVFP rw ip=dhcp"
|
|
|
|
If the ip address is not set, you can set it with :
|
|
|
|
ip_address -l <board_ip/netmask> -h <server_ip>
|
|
|
|
Linux partitions:
|
|
---------------------------
|
|
|
|
As default, the board is shipped with these partition tables for NAND
|
|
and for NOR:
|
|
|
|
Creating 5 MTD partitions on "NAND 2GiB 3,3V 8-bit":
|
|
0x00000000-0x00100000 : "nand.bootloader"
|
|
0x00100000-0x00600000 : "nand.kernel"
|
|
0x00600000-0x06600000 : "nand.rootfs"
|
|
0x06600000-0x06e00000 : "nand.configure"
|
|
0x06e00000-0x80000000 : "nand.userfs"
|
|
|
|
Creating 6 MTD partitions on "mxc_nor_flash.0":
|
|
0x00000000-0x00080000 : "Bootloader"
|
|
0x00080000-0x00480000 : "nor.Kernel"
|
|
0x00480000-0x02280000 : "nor.userfs"
|
|
0x02280000-0x03e80000 : "nor.rootfs"
|
|
0x01fe0000-0x01fe3000 : "FIS directory"
|
|
0x01fff000-0x04000000 : "Redboot config"
|
|
|
|
NAND partitions can be recognized enabling in kernel CONFIG_MTD_REDBOOT_PARTS.
|
|
For this board, CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK should be set to 2.
|
|
|
|
However, the setup in redboot is not correct and does not use the whole flash.
|
|
|
|
Better solution is to use the kernel parameter mtdparts.
|
|
Here the resulting script to be defined in RedBoot with fconfig:
|
|
|
|
load -r -b 0x100000 sbabic/mx35pdk/zImage.2.6.37
|
|
exec -c "noinitrd console=ttymxc0,115200 root=/dev/nfsroot rootfstype=nfsroot nfsroot=192.168.1.1:/opt/eldk-4.2-arm/arm rw ip=dhcp mtdparts=mxc_nand:1m(boot),5m(linux),96m(root),8m(cfg),1938m(user);physmap-flash.0:512k(b),4m(k),30m(u),28m(r)"
|
|
|
|
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.
|
|
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.
|
|
|
|
Creating 6 MTD partitions on "mxc_nor_flash.0":
|
|
0x00000000-0x00080000 : "Bootloader"
|
|
0x00080000-0x00480000 : "nor.Kernel"
|
|
0x00480000-0x02280000 : "nor.userfs"
|
|
0x02280000-0x03e80000 : "nor.rootfs"
|
|
0x01fe0000-0x01fe3000 : "FIS directory"
|
|
0x01fff000-0x04000000 : "Redboot config"
|
|
|
|
To erase the whole partition:
|
|
$ flash_eraseall /dev/mtd0
|
|
|
|
Writing u-boot:
|
|
dd if=u-boot.bin of=/dev/mtd0
|
|
|
|
To boot from NOR, you have to select the switches as follows:
|
|
|
|
Personality board
|
|
SW2 all off
|
|
SW1 all off
|
|
|
|
Debug Board:
|
|
SW5 0
|
|
SW6 0
|
|
SW7 0
|
|
SW8 1
|
|
SW9 1
|
|
SW10 0
|