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diff --git a/doc/README.mx35pdk b/doc/README.mx35pdk new file mode 100644 index 0000000..3d69ed5 --- /dev/null +++ b/doc/README.mx35pdk @@ -0,0 +1,188 @@ +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 |