1--------------------------------------------- 2Imximage Boot Image generation using mkimage 3--------------------------------------------- 4 5This document describes how to set up a U-Boot image that can be booted 6by Freescale MX25, MX35, MX51, MX53 and MX6 processors via internal boot 7mode. 8 9These processors can boot directly from NAND, SPI flash and SD card flash 10using its internal boot ROM support. MX6 processors additionally support 11boot from NOR flash and SATA disks. All processors can boot from an internal 12UART, if booting from device media fails. 13Booting from NOR flash does not require to use this image type. 14 15For more details refer Chapter 2 - System Boot and section 2.14 16(flash header description) of the processor's manual. 17 18This implementation does not use at the moment the secure boot feature 19of the processor. The image is generated disabling all security fields. 20 21Command syntax: 22-------------- 23./tools/mkimage -l <mx u-boot_file> 24 to list the imx image file details 25 26./tools/mkimage -T imximage \ 27 -n <board specific configuration file> \ 28 -e <execution address> -d <u-boot binary> <output image file> 29 30For example, for the mx51evk board: 31./tools/mkimage -n ./board/freescale/mx51evk/imximage.cfg \ 32 -T imximage -e 0x97800000 \ 33 -d u-boot.bin u-boot.imx 34 35You can generate directly the image when you compile u-boot with: 36 37$ make u-boot.imx 38 39The output image can be flashed on the board SPI flash or on a SD card. 40In both cases, you have to copy the image at the offset required for the 41chosen media devices (0x400 for both SPI flash or SD card). 42 43Please check Freescale documentation for further details. 44 45Board specific configuration file specifications: 46------------------------------------------------- 471. This file must present in the $(BOARDDIR) and the name should be 48 imximage.cfg (since this is used in Makefile). 492. This file can have empty lines and lines starting with "#" as first 50 character to put comments. 513. This file can have configuration command lines as mentioned below, 52 any other information in this file is treated as invalid. 53 54Configuration command line syntax: 55--------------------------------- 561. Each command line is must have two strings, first one command or address 57 and second one data string 582. Following are the valid command strings and associated data strings:- 59 Command string data string 60 -------------- ----------- 61 IMXIMAGE_VERSION 1/2 62 1 is for mx25/mx35/mx51 compatible, 63 2 is for mx53/mx6 compatible, 64 others is invalid and error is generated. 65 This command need appear the fist before 66 other valid commands in configuration file. 67 68 BOOT_OFFSET value 69 70 This command is parallel to BOOT_FROM and 71 is preferred over BOOT_FROM. 72 73 value: Offset of the image header, this 74 value shall be set to one of the 75 values found in the file: 76 arch/arm/include/asm/\ 77 imx-common/imximage.cfg 78 Example: 79 BOOT_OFFSET FLASH_OFFSET_STANDARD 80 81 BOOT_FROM nand/spi/sd/onenand/nor/sata 82 83 This command is parallel to BOOT_OFFSET and 84 is to be deprecated in favor of BOOT_OFFSET. 85 86 Example: 87 BOOT_FROM spi 88 89 DATA type address value 90 91 type: word=4, halfword=2, byte=1 92 address: physycal register address 93 value: value to be set in register 94 All values are in in hexadecimal. 95 Example (write to IOMUXC): 96 DATA 4 0x73FA88a0 0x200 97 98The processor support up to 60 register programming commands for IMXIMAGE_VERSION 1 99and 121 register programming commands for IMXIMAGE_VERSION 2. 100An error is generated if more commands are found in the configuration file. 101 1023. All commands are optional to program. 103 104Setup a SD Card for booting 105-------------------------------- 106 107The following example prepare a SD card with u-boot and a FAT partition 108to be used to stored the kernel to be booted. 109I will set the SD in the most compatible mode, setting it with 110255 heads and 63 sectors, as suggested from several documentation and 111howto on line (I took as reference the preparation of a SD Card for the 112Beagleboard, running u-boot as bootloader). 113 114You should start clearing the partitions table on the SD card. Because 115the u-boot image must be stored at the offset 0x400, it must be assured 116that there is no partition at that address. A new SD card is already 117formatted with FAT filesystem and the partition starts from the first 118cylinder, so we need to change it. 119 120You can do all steps with fdisk. If the device for the SD card is 121/dev/mmcblk0, the following commands make the job: 122 1231. Start the fdisk utility (as superuser) 124 fdisk /dev/mmcblk0 125 1262. Clear the actual partition 127 128Command (m for help): o 129 1303. Print card info: 131 132Command (m for help): p 133Disk /dev/mmcblk0: 1981 MB, 1981284352 bytes 134 135In my case, I have a 2 GB card. I need the size to set later the correct value 136for the cylinders. 137 1384. Go to expert mode: 139 140Command (m for help): x 141 1425. Set card geometry 143 144Expert command (m for help): h 145Number of heads (1-256, default 4): 255 146 147Expert command (m for help): s 148Number of sectors (1-63, default 16): 63 149Warning: setting sector offset for DOS compatiblity 150 151We have set 255 heads, 63 sector. We have to set the cylinder. 152The value to be set can be calculated with: 153 154 cilynder = <total size> / <heads> / <sectors> / <blocksize> 155 156in this example, 157 1981284352 / 255 / 63 / 512 = 239.x = 239 158 159 160Expert command (m for help): c 161Number of cylinders (1-1048576, default 60032): 239 162 1636. Leave the expert mode 164Expert command (m for help): r 165 1667. Set up a partition 167 168Now set a partition table to store the kernel or whatever you want. Of course, 169you can set additional partitions to store rootfs, data, etc. 170In my example I want to set a single partition. I must take care 171to not overwrite the space where I will put u-boot. 172 173Command (m for help): n 174Command action 175 e extended 176 p primary partition (1-4) 177p 178Partition number (1-4): 1 179First cylinder (1-239, default 1): 3 180Last cylinder, +cylinders or +size{K,M,G} (3-239, default 239): +100M 181 182Command (m for help): p 183 184Disk /dev/mmcblk0: 1967 MB, 1967128576 bytes 185255 heads, 63 sectors/track, 239 cylinders 186Units = cylinders of 16065 * 512 = 8225280 bytes 187Disk identifier: 0xb712a870 188 189 Device Boot Start End Blocks Id System 190/dev/mmcblk0p1 3 16 112455 83 Linux 191 192I have set 100MB, leaving the first 2 sectors free. I will copy u-boot 193there. 194 1958. Write the partition table and exit. 196 197Command (m for help): w 198The partition table has been altered! 199 200Calling ioctl() to re-read partition table. 201 2029. Copy u-boot.imx on the SD card 203 204I use dd: 205 206dd if=u-boot.imx of=/dev/mmcblk0 bs=512 seek=2 207 208This command copies the u-boot image at the address 0x400, as required 209by the processor. 210 211Now remove your card from the PC and go to the target. If evrything went right, 212the u-boot prompt should come after power on. 213 214------------------------------------------------ 215Author: Stefano babic <sbabic@denx.de> 216