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- 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
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