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Fabio Estevam419ea2d2012-03-24 12:42:21 +00001Booting U-boot on a MX28 processor
2==================================
3
4This document describes the MX28 U-Boot port. This document mostly
5covers topics related to making the module/board bootable.
6
7Terminology
8-----------
9
10The dollar symbol ($) introduces a snipped of shell code. This shall be typed
11into the unix command prompt in U-Boot source code root directory.
12
13The (=>) introduces a snipped of code that should by typed into U-Boot command
14prompt
15
16Contents
17--------
18
191) Prerequisites
202) Compiling U-Boot for a MX28 based board
213) Installation of U-Boot for a MX28 based board to SD card
Fabio Estevame9fd0a02012-06-18 05:51:49 +0000224) Installation of U-Boot into NAND flash
Fabio Estevam419ea2d2012-03-24 12:42:21 +000023
241) Prerequisites
25----------------
26
27To make a MX28 based board bootable, some tools are necessary. The first one
28is the "elftosb" tool distributed by Freescale Semiconductor. The other one
29is the "mxsboot" tool found in U-Boot source tree.
30
31Firstly, obtain the elftosb archive from the following location:
32
Anatolij Gustschin9de1c222012-06-27 04:14:29 +000033 ftp://ftp.denx.de/pub/tools/elftosb-10.12.01.tar.gz
Fabio Estevam419ea2d2012-03-24 12:42:21 +000034
35We use a $VER variable here to denote the current version. At the time of
36writing of this document, that is "10.12.01". To obtain the file from command
37line, use:
38
39 $ VER="10.12.01"
Anatolij Gustschin9de1c222012-06-27 04:14:29 +000040 $ wget ftp://ftp.denx.de/pub/tools/elftosb-${VER}.tar.gz
Fabio Estevam419ea2d2012-03-24 12:42:21 +000041
42Extract the file:
43
44 $ tar xzf elftosb-${VER}.tar.gz
45
46Compile the file. We need to manually tell the linker to use also libm:
47
48 $ cd elftosb-${VER}/
49 $ make LIBS="-lstdc++ -lm" elftosb
50
51Optionally, remove debugging symbols from elftosb:
52
53 $ strip bld/linux/elftosb
54
55Finally, install the "elftosb" binary. The "install" target is missing, so just
56copy the binary by hand:
57
58 $ sudo cp bld/linux/elftosb /usr/local/bin/
59
60Make sure the "elftosb" binary can be found in your $PATH, in this case this
61means "/usr/local/bin/" has to be in your $PATH.
62
632) Compiling U-Boot for a MX28 based board
64-------------------------------------------
65
Fabio Estevam84286c22013-05-03 15:07:57 -030066Compiling the U-Boot for a MX28 board is straightforward and done as compiling
67U-Boot for any other ARM device. For cross-compiler setup, please refer to
68ELDK5.0 documentation. First, clean up the source code:
Fabio Estevam419ea2d2012-03-24 12:42:21 +000069
70 $ make mrproper
71
72Next, configure U-Boot for a MX28 based board
73
74 $ make <mx28_based_board_name>_config
75
76Examples:
77
781. For building U-boot for Denx M28EVK board:
79
80 $ make m28evk_config
81
822. For building U-boot for Freescale MX28EVK board:
83
84 $ make mx28evk_config
85
86Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special
87type of file, which the i.MX28 CPU can boot. This is handled by the following
88command:
89
90 $ make u-boot.sb
91
92HINT: To speed-up the build process, you can add -j<N>, where N is number of
93 compiler instances that'll run in parallel.
94
95The code produces "u-boot.sb" file. This file needs to be augmented with a
96proper header to allow successful boot from SD or NAND. Adding the header is
97discussed in the following chapters.
98
993) Installation of U-Boot for a MX28 based board to SD card
100-----------------------------------------------------------
101
102To boot a MX28 based board from SD, set the boot mode DIP switches according
Fabio Estevam3f5e2e22013-05-03 15:07:58 -0300103to i.MX28 manual chapter 12.2.1 (Table 12-2).
Fabio Estevam419ea2d2012-03-24 12:42:21 +0000104
Fabio Estevam7333eca2013-05-03 15:07:59 -0300105The SD card used to boot U-Boot must contain a DOS partition table, which in
106turn carries a partition of special type and which contains a special header.
107The rest of partitions in the DOS partition table can be used by the user.
Fabio Estevam419ea2d2012-03-24 12:42:21 +0000108
109To prepare such partition, use your favourite partitioning tool. The partition
110must have the following parameters:
111
112 * Start sector .......... sector 2048
113 * Partition size ........ at least 1024 kb
114 * Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3")
115
116For example in Linux fdisk, the sequence for a clear card follows. Be sure to
117run fdisk with the option "-u=sectors" to set units to sectors:
118
119 * o ..................... create a clear partition table
120 * n ..................... create new partition
121 * p ............. primary partition
122 * 1 ............. first partition
123 * 2048 .......... first sector is 2048
124 * +1M ........... make the partition 1Mb big
125 * t 1 ................... change first partition ID
126 * 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3)
127 * <create other partitions>
128 * w ..................... write partition table to disk
129
130The partition layout is ready, next the special partition must be filled with
131proper contents. The contents is generated by running the following command
132(see chapter 2)):
133
134 $ ./tools/mxsboot sd u-boot.sb u-boot.sd
135
136The resulting file, "u-boot.sd", shall then be written to the partition. In this
137case, we assume the first partition of the SD card is /dev/mmcblk0p1:
138
139 $ dd if=u-boot.sd of=/dev/mmcblk0p1
140
141Last step is to insert the card into MX28 based board and boot.
142
143NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains
144 a "-p" switch for that purpose. The "-p" switch takes the sector number as
145 an argument.
146
Fabio Estevame9fd0a02012-06-18 05:51:49 +00001474) Installation of U-Boot into NAND flash
148-----------------------------------------
Fabio Estevam419ea2d2012-03-24 12:42:21 +0000149
Fabio Estevam84286c22013-05-03 15:07:57 -0300150To boot a MX28 based board from NAND, set the boot mode DIP switches according
151to i.MX28 manual chapter 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V.
Fabio Estevam419ea2d2012-03-24 12:42:21 +0000152
153There are two possibilities when preparing an image writable to NAND flash.
154
155 I) The NAND wasn't written at all yet or the BCB is broken
156 ----------------------------------------------------------
157 In this case, both BCB (FCB and DBBT) and firmware needs to be
158 written to NAND. To generate NAND image containing all these,
159 there is a tool called "mxsboot" in the "tools/" directory. The tool
160 is invoked on "u-boot.sb" file from chapter 2):
161
162 $ ./tools/mxsboot nand u-boot.sb u-boot.nand
163
164 NOTE: The above invokation works for NAND flash with geometry of
165 2048b per page, 64b OOB data, 128kb erase size. If your chip
166 has a different geometry, please use:
167
168 -w <size> change page size (default 2048 b)
169 -o <size> change oob size (default 64 b)
170 -e <size> change erase size (default 131072 b)
171
172 The geometry information can be obtained from running U-Boot
173 on the MX28 board by issuing the "nand info" command.
174
175 The resulting file, "u-boot.nand" can be written directly to NAND
176 from the U-Boot prompt. To simplify the process, the U-Boot default
177 environment contains script "update_nand_full" to update the system.
178
179 This script expects a working TFTP server containing the file
180 "u-boot.nand" in it's root directory. This can be changed by
181 adjusting the "update_nand_full_filename" varible.
182
183 To update the system, run the following in U-Boot prompt:
184
185 => run update_nand_full
186
187 In case you would only need to update the bootloader in future,
188 see II) below.
189
190 II) The NAND was already written with a good BCB
191 ------------------------------------------------
192 This part applies after the part I) above was done at least once.
193
194 If part I) above was done correctly already, there is no need to
195 write the FCB and DBBT parts of NAND again. It's possible to upgrade
196 only the bootloader image.
197
198 To simplify the process of firmware update, the U-Boot default
199 environment contains script "update_nand_firmware" to update only
200 the firmware, without rewriting FCB and DBBT.
201
202 This script expects a working TFTP server containing the file
203 "u-boot.sb" in it's root directory. This can be changed by
204 adjusting the "update_nand_firmware_filename" varible.
205
206 To update the system, run the following in U-Boot prompt:
207
208 => run update_nand_firmware
209
210 III) Special settings for the update scripts
211 --------------------------------------------
212 There is a slight possibility of the user wanting to adjust the
213 STRIDE and COUNT options of the NAND boot. For description of these,
214 see i.MX28 manual section 12.12.1.2 and 12.12.1.3.
215
216 The update scripts take this possibility into account. In case the
217 user changes STRIDE by blowing fuses, the user also has to change
218 "update_nand_stride" variable. In case the user changes COUNT by
219 blowing fuses, the user also has to change "update_nand_count"
220 variable for the update scripts to work correctly.
221
222 In case the user needs to boot a firmware image bigger than 1Mb, the
223 user has to adjust the "update_nand_firmware_maxsz" variable for the
224 update scripts to work properly.