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Stefano Babic7b07f092010-01-20 18:19:10 +01001---------------------------------------------
2Imximage Boot Image generation using mkimage
3---------------------------------------------
4
5This document describes how to set up a U-Boot image
6that can be booted by Freescale MX25, MX35 and MX51
7processors via internal boot mode.
8
9These processors can boot directly from NAND, SPI flash and SD card flash
10using its internal boot ROM support. They can boot from an internal
11UART, if booting from device media fails.
12Booting from NOR flash does not require to use this image type.
13
14For more details refer Chapter 2 - System Boot and section 2.14
15(flash header description) of the processor's manual.
16
17This implementation does not use at the moment the secure boot feature
18of the processor. The image is generated disabling all security fields.
19
20Command syntax:
21--------------
22./tools/mkimage -l <mx u-boot_file>
23 to list the imx image file details
24
25./tools/mkimage -T imximage \
26 -n <board specific configuration file> \
27 -e <execution address> -d <u-boot binary> <output image file>
28
29For example, for the mx51evk board:
30./tools/mkimage -n ./board/freescale/mx51evk/imximage.cfg \
31 -T imximage -e 0x97800000 \
32 -d u-boot.bin u-boot.imx
33
34You can generate directly the image when you compile u-boot with:
35
36$ make u-boot.imx
37
38The output image can be flashed on the board SPI flash or on a SD card.
39In both cases, you have to copy the image at the offset required for the
40chosen media devices (0x400 for both SPI flash or SD card).
41
42Please check Freescale documentation for further details.
43
44Board specific configuration file specifications:
45-------------------------------------------------
461. This file must present in the $(BOARDDIR) and the name should be
47 imximage.cfg (since this is used in Makefile).
482. This file can have empty lines and lines starting with "#" as first
49 character to put comments.
503. This file can have configuration command lines as mentioned below,
51 any other information in this file is treated as invalid.
52
53Configuration command line syntax:
54---------------------------------
551. Each command line is must have two strings, first one command or address
56 and second one data string
572. Following are the valid command strings and associated data strings:-
58 Command string data string
59 -------------- -----------
60 BOOT_FROM nand/spi/sd/onenand
61 Example:
62 BOOT_FROM spi
63 DATA type address value
64
65 type: word=4, halfword=2, byte=1
66 address: physycal register address
67 value: value to be set in register
68 All values are in in hexadecimal.
69 Example (write to IOMUXC):
70 DATA 4 0x73FA88a0 0x200
71
72The processor support up to 60 register programming commands. An error
73is generated if more commands are found in the configuration file.
74
753. All commands are optional to program.
76
77Setup a SD Card for booting
78--------------------------------
79
80The following example prepare a SD card with u-boot and a FAT partition
81to be used to stored the kernel to be booted.
82I will set the SD in the most compatible mode, setting it with
83255 heads and 63 sectors, as suggested from several documentation and
84howto on line (I took as reference the preparation of a SD Card for the
85Beagleboard, running u-boot as bootloader).
86
87You should start clearing the partitions table on the SD card. Because
88the u-boot image must be stored at the offset 0x400, it must be assured
89that there is no partition at that address. A new SD card is already
90formatted with FAT filesystem and the partition starts from the first
91cylinder, so we need to change it.
92
93You can do all steps with fdisk. If the device for the SD card is
94/dev/mmcblk0, the following commands make the job:
95
961. Start the fdisk utility (as superuser)
97 fdisk /dev/mmcblk0
98
992. Clear the actual partition
100
101Command (m for help): o
102
1033. Print card info:
104
105Command (m for help): p
106Disk /dev/mmcblk0: 1981 MB, 1981284352 bytes
107
108In my case, I have a 2 GB card. I need the size to set later the correct value
109for the cylinders.
110
1114. Go to expert mode:
112
113Command (m for help): x
114
1155. Set card geometry
116
117Expert command (m for help): h
118Number of heads (1-256, default 4): 255
119
120Expert command (m for help): s
121Number of sectors (1-63, default 16): 63
122Warning: setting sector offset for DOS compatiblity
123
124We have set 255 heads, 63 sector. We have to set the cylinder.
125The value to be set can be calculated with:
126
127 cilynder = <total size> / <heads> / <sectors> / <blocksize>
128
129in this example,
130 1981284352 / 255 / 63 / 512 = 239.x = 239
131
132
133Expert command (m for help): c
134Number of cylinders (1-1048576, default 60032): 239
135
1366. Leave the expert mode
137Expert command (m for help): r
138
1397. Set up a partition
140
141Now set a partition table to store the kernel or whatever you want. Of course,
142you can set additional partitions to store rootfs, data, etc.
143In my example I want to set a single partition. I must take care
144to not overwrite the space where I will put u-boot.
145
146Command (m for help): n
147Command action
148 e extended
149 p primary partition (1-4)
150p
151Partition number (1-4): 1
152First cylinder (1-239, default 1): 3
153Last cylinder, +cylinders or +size{K,M,G} (3-239, default 239): +100M
154
155Command (m for help): p
156
157Disk /dev/mmcblk0: 1967 MB, 1967128576 bytes
158255 heads, 63 sectors/track, 239 cylinders
159Units = cylinders of 16065 * 512 = 8225280 bytes
160Disk identifier: 0xb712a870
161
162 Device Boot Start End Blocks Id System
163/dev/mmcblk0p1 3 16 112455 83 Linux
164
165I have set 100MB, leaving the first 2 sectors free. I will copy u-boot
166there.
167
1688. Write the partition table and exit.
169
170Command (m for help): w
171The partition table has been altered!
172
173Calling ioctl() to re-read partition table.
174
1759. Copy u-boot.imx on the SD card
176
177I use dd:
178
179dd if=u-boot.imx of=/dev/mmcblk0 bs=512 seek=2
180
181This command copies the u-boot image at the address 0x400, as required
182by the processor.
183
184Now remove your card from the PC and go to the target. If evrything went right,
185the u-boot prompt should come after power on.
186
187------------------------------------------------
188Author: Stefano babic <sbabic@denx.de>