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diff --git a/doc/README.imximage b/doc/README.imximage new file mode 100644 index 0000000..9048ef6 --- /dev/null +++ b/doc/README.imximage @@ -0,0 +1,188 @@ +--------------------------------------------- +Imximage Boot Image generation using mkimage +--------------------------------------------- + +This document describes how to set up a U-Boot image +that can be booted by Freescale MX25, MX35 and MX51 +processors via internal boot mode. + +These processors can boot directly from NAND, SPI flash and SD card flash +using its internal boot ROM support. They can boot from an internal +UART, if booting from device media fails. +Booting from NOR flash does not require to use this image type. + +For more details refer Chapter 2 - System Boot and section 2.14 +(flash header description) of the processor's manual. + +This implementation does not use at the moment the secure boot feature +of the processor. The image is generated disabling all security fields. + +Command syntax: +-------------- +./tools/mkimage -l <mx u-boot_file> + to list the imx image file details + +./tools/mkimage -T imximage \ + -n <board specific configuration file> \ + -e <execution address> -d <u-boot binary> <output image file> + +For example, for the mx51evk board: +./tools/mkimage -n ./board/freescale/mx51evk/imximage.cfg \ + -T imximage -e 0x97800000 \ + -d u-boot.bin u-boot.imx + +You can generate directly the image when you compile u-boot with: + +$ make u-boot.imx + +The output image can be flashed on the board SPI flash or on a SD card. +In both cases, you have to copy the image at the offset required for the +chosen media devices (0x400 for both SPI flash or SD card). + +Please check Freescale documentation for further details. + +Board specific configuration file specifications: +------------------------------------------------- +1. This file must present in the $(BOARDDIR) and the name should be + imximage.cfg (since this is used in Makefile). +2. This file can have empty lines and lines starting with "#" as first + character to put comments. +3. This file can have configuration command lines as mentioned below, + any other information in this file is treated as invalid. + +Configuration command line syntax: +--------------------------------- +1. Each command line is must have two strings, first one command or address + and second one data string +2. Following are the valid command strings and associated data strings:- + Command string data string + -------------- ----------- + BOOT_FROM nand/spi/sd/onenand + Example: + BOOT_FROM spi + DATA type address value + + type: word=4, halfword=2, byte=1 + address: physycal register address + value: value to be set in register + All values are in in hexadecimal. + Example (write to IOMUXC): + DATA 4 0x73FA88a0 0x200 + +The processor support up to 60 register programming commands. An error +is generated if more commands are found in the configuration file. + +3. All commands are optional to program. + +Setup a SD Card for booting +-------------------------------- + +The following example prepare a SD card with u-boot and a FAT partition +to be used to stored the kernel to be booted. +I will set the SD in the most compatible mode, setting it with +255 heads and 63 sectors, as suggested from several documentation and +howto on line (I took as reference the preparation of a SD Card for the +Beagleboard, running u-boot as bootloader). + +You should start clearing the partitions table on the SD card. Because +the u-boot image must be stored at the offset 0x400, it must be assured +that there is no partition at that address. A new SD card is already +formatted with FAT filesystem and the partition starts from the first +cylinder, so we need to change it. + +You can do all steps with fdisk. If the device for the SD card is +/dev/mmcblk0, the following commands make the job: + +1. Start the fdisk utility (as superuser) + fdisk /dev/mmcblk0 + +2. Clear the actual partition + +Command (m for help): o + +3. Print card info: + +Command (m for help): p +Disk /dev/mmcblk0: 1981 MB, 1981284352 bytes + +In my case, I have a 2 GB card. I need the size to set later the correct value +for the cylinders. + +4. Go to expert mode: + +Command (m for help): x + +5. Set card geometry + +Expert command (m for help): h +Number of heads (1-256, default 4): 255 + +Expert command (m for help): s +Number of sectors (1-63, default 16): 63 +Warning: setting sector offset for DOS compatiblity + +We have set 255 heads, 63 sector. We have to set the cylinder. +The value to be set can be calculated with: + + cilynder = <total size> / <heads> / <sectors> / <blocksize> + +in this example, + 1981284352 / 255 / 63 / 512 = 239.x = 239 + + +Expert command (m for help): c +Number of cylinders (1-1048576, default 60032): 239 + +6. Leave the expert mode +Expert command (m for help): r + +7. Set up a partition + +Now set a partition table to store the kernel or whatever you want. Of course, +you can set additional partitions to store rootfs, data, etc. +In my example I want to set a single partition. I must take care +to not overwrite the space where I will put u-boot. + +Command (m for help): n +Command action + e extended + p primary partition (1-4) +p +Partition number (1-4): 1 +First cylinder (1-239, default 1): 3 +Last cylinder, +cylinders or +size{K,M,G} (3-239, default 239): +100M + +Command (m for help): p + +Disk /dev/mmcblk0: 1967 MB, 1967128576 bytes +255 heads, 63 sectors/track, 239 cylinders +Units = cylinders of 16065 * 512 = 8225280 bytes +Disk identifier: 0xb712a870 + + Device Boot Start End Blocks Id System +/dev/mmcblk0p1 3 16 112455 83 Linux + +I have set 100MB, leaving the first 2 sectors free. I will copy u-boot +there. + +8. Write the partition table and exit. + +Command (m for help): w +The partition table has been altered! + +Calling ioctl() to re-read partition table. + +9. Copy u-boot.imx on the SD card + +I use dd: + +dd if=u-boot.imx of=/dev/mmcblk0 bs=512 seek=2 + +This command copies the u-boot image at the address 0x400, as required +by the processor. + +Now remove your card from the PC and go to the target. If evrything went right, +the u-boot prompt should come after power on. + +------------------------------------------------ +Author: Stefano babic <sbabic@denx.de> |