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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
- --------------------------------
- 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).
- If something goes wrong flashing the bootloader, it is always possible to
- recover the board booting from the other device.
- Saving U-Boot in the NOR flash
- ---------------------------------
- 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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