| 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 |