| 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 |