240 lines
7.4 KiB
Plaintext
240 lines
7.4 KiB
Plaintext
---------------------------------------------
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Imximage Boot Image generation using mkimage
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---------------------------------------------
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This document describes how to set up a U-Boot image that can be booted
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by Freescale MX25, MX35, MX51, MX53 and MX6 processors via internal boot
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mode.
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These processors can boot directly from NAND, SPI flash and SD card flash
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using its internal boot ROM support. MX6 processors additionally support
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boot from NOR flash and SATA disks. All processors can boot from an internal
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UART, if booting from device media fails.
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Booting from NOR flash does not require to use this image type.
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For more details refer Chapter 2 - System Boot and section 2.14
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(flash header description) of the processor's manual.
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Command syntax:
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--------------
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./tools/mkimage -l <mx u-boot_file>
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to list the imx image file details
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./tools/mkimage -T imximage \
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-n <board specific configuration file> \
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-e <execution address> -d <u-boot binary> <output image file>
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For example, for the mx51evk board:
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./tools/mkimage -n ./board/freescale/mx51evk/imximage.cfg \
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-T imximage -e 0x97800000 \
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-d u-boot.bin u-boot.imx
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You can generate directly the image when you compile u-boot with:
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$ make u-boot.imx
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The output image can be flashed on the board SPI flash or on a SD card.
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In both cases, you have to copy the image at the offset required for the
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chosen media devices (0x400 for both SPI flash or SD card).
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Please check Freescale documentation for further details.
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Board specific configuration file specifications:
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-------------------------------------------------
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1. This file must present in the $(BOARDDIR) and the name should be
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imximage.cfg (since this is used in Makefile).
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2. This file can have empty lines and lines starting with "#" as first
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character to put comments.
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3. This file can have configuration command lines as mentioned below,
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any other information in this file is treated as invalid.
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Configuration command line syntax:
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---------------------------------
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1. Each command line is must have two strings, first one command or address
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and second one data string
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2. Following are the valid command strings and associated data strings:-
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Command string data string
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-------------- -----------
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IMXIMAGE_VERSION 1/2
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1 is for mx25/mx35/mx51 compatible,
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2 is for mx53/mx6 compatible,
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others is invalid and error is generated.
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This command need appear the fist before
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other valid commands in configuration file.
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BOOT_OFFSET value
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This command is parallel to BOOT_FROM and
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is preferred over BOOT_FROM.
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value: Offset of the image header, this
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value shall be set to one of the
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values found in the file:
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arch/arm/include/asm/\
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imx-common/imximage.cfg
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Example:
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BOOT_OFFSET FLASH_OFFSET_STANDARD
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BOOT_FROM nand/spi/sd/onenand/nor/sata
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This command is parallel to BOOT_OFFSET and
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is to be deprecated in favor of BOOT_OFFSET.
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Example:
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BOOT_FROM spi
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CSF value
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Total size of CSF (Command Sequence File)
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used for Secure Boot/ High Assurance Boot
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(HAB).
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Using this command will populate the IVT
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(Initial Vector Table) CSF pointer and adjust
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the length fields only. The CSF itself needs
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to be generated with Freescale tools and
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'manually' appended to the u-boot.imx file.
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The CSF is then simply concatenated
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to the u-boot image, making a signed bootloader,
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that the processor can verify
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if the fuses for the keys are burned.
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Further infos how to configure the SOC to verify
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the bootloader can be found in the "High
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Assurance Boot Version Application Programming
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Interface Reference Manual" as part of the
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Freescale Code Signing Tool, available on the
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manufacturer's website.
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Example:
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CSF 0x2000
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DATA type address value
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type: word=4, halfword=2, byte=1
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address: physycal register address
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value: value to be set in register
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All values are in in hexadecimal.
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Example (write to IOMUXC):
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DATA 4 0x73FA88a0 0x200
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The processor support up to 60 register programming commands for IMXIMAGE_VERSION 1
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and 220 register programming commands for IMXIMAGE_VERSION 2.
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An error is generated if more commands are found in the configuration file.
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3. All commands are optional to program.
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Setup a SD Card for booting
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--------------------------------
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The following example prepare a SD card with u-boot and a FAT partition
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to be used to stored the kernel to be booted.
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I will set the SD in the most compatible mode, setting it with
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255 heads and 63 sectors, as suggested from several documentation and
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howto on line (I took as reference the preparation of a SD Card for the
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Beagleboard, running u-boot as bootloader).
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You should start clearing the partitions table on the SD card. Because
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the u-boot image must be stored at the offset 0x400, it must be assured
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that there is no partition at that address. A new SD card is already
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formatted with FAT filesystem and the partition starts from the first
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cylinder, so we need to change it.
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You can do all steps with fdisk. If the device for the SD card is
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/dev/mmcblk0, the following commands make the job:
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1. Start the fdisk utility (as superuser)
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fdisk /dev/mmcblk0
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2. Clear the actual partition
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Command (m for help): o
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3. Print card info:
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Command (m for help): p
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Disk /dev/mmcblk0: 1981 MB, 1981284352 bytes
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In my case, I have a 2 GB card. I need the size to set later the correct value
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for the cylinders.
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4. Go to expert mode:
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Command (m for help): x
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5. Set card geometry
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Expert command (m for help): h
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Number of heads (1-256, default 4): 255
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Expert command (m for help): s
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Number of sectors (1-63, default 16): 63
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Warning: setting sector offset for DOS compatiblity
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We have set 255 heads, 63 sector. We have to set the cylinder.
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The value to be set can be calculated with:
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cilynder = <total size> / <heads> / <sectors> / <blocksize>
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in this example,
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1981284352 / 255 / 63 / 512 = 239.x = 239
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Expert command (m for help): c
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Number of cylinders (1-1048576, default 60032): 239
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6. Leave the expert mode
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Expert command (m for help): r
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7. Set up a partition
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Now set a partition table to store the kernel or whatever you want. Of course,
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you can set additional partitions to store rootfs, data, etc.
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In my example I want to set a single partition. I must take care
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to not overwrite the space where I will put u-boot.
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Command (m for help): n
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Command action
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e extended
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p primary partition (1-4)
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p
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Partition number (1-4): 1
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First cylinder (1-239, default 1): 3
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Last cylinder, +cylinders or +size{K,M,G} (3-239, default 239): +100M
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Command (m for help): p
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Disk /dev/mmcblk0: 1967 MB, 1967128576 bytes
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255 heads, 63 sectors/track, 239 cylinders
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Units = cylinders of 16065 * 512 = 8225280 bytes
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Disk identifier: 0xb712a870
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Device Boot Start End Blocks Id System
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/dev/mmcblk0p1 3 16 112455 83 Linux
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I have set 100MB, leaving the first 2 sectors free. I will copy u-boot
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there.
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8. Write the partition table and exit.
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Command (m for help): w
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The partition table has been altered!
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Calling ioctl() to re-read partition table.
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9. Copy u-boot.imx on the SD card
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I use dd:
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dd if=u-boot.imx of=/dev/mmcblk0 bs=512 seek=2
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This command copies the u-boot image at the address 0x400, as required
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by the processor.
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Now remove your card from the PC and go to the target. If evrything went right,
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the u-boot prompt should come after power on.
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------------------------------------------------
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Author: Stefano babic <sbabic@denx.de>
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