blob: 8bacaf8a5e5a19b33b695b7861510bbbdf6edf20 [file] [log] [blame]
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
66Compiling the U-Boot for a MX28 board is straightforward and done as compiling U-Boot
67for any other ARM device. For cross-compiler setup, please refer to ELDK5.0
68documentation. First, clean up the source code:
69
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
103to i.MX28 manual chapter 12.2.1 (Table 12-2), PORT=SSP0, SD/MMC master on
104SSP0, 3.3V.
105
106
107An SD card the i.MX28 CPU can use to boot U-Boot must contain a DOS partition
108table, which in turn carries a partition of special type and which contains a
109special header. The rest of partitions in the DOS partition table can be used
110by the user.
111
112To prepare such partition, use your favourite partitioning tool. The partition
113must have the following parameters:
114
115 * Start sector .......... sector 2048
116 * Partition size ........ at least 1024 kb
117 * Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3")
118
119For example in Linux fdisk, the sequence for a clear card follows. Be sure to
120run fdisk with the option "-u=sectors" to set units to sectors:
121
122 * o ..................... create a clear partition table
123 * n ..................... create new partition
124 * p ............. primary partition
125 * 1 ............. first partition
126 * 2048 .......... first sector is 2048
127 * +1M ........... make the partition 1Mb big
128 * t 1 ................... change first partition ID
129 * 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3)
130 * <create other partitions>
131 * w ..................... write partition table to disk
132
133The partition layout is ready, next the special partition must be filled with
134proper contents. The contents is generated by running the following command
135(see chapter 2)):
136
137 $ ./tools/mxsboot sd u-boot.sb u-boot.sd
138
139The resulting file, "u-boot.sd", shall then be written to the partition. In this
140case, we assume the first partition of the SD card is /dev/mmcblk0p1:
141
142 $ dd if=u-boot.sd of=/dev/mmcblk0p1
143
144Last step is to insert the card into MX28 based board and boot.
145
146NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains
147 a "-p" switch for that purpose. The "-p" switch takes the sector number as
148 an argument.
149
Fabio Estevame9fd0a02012-06-18 05:51:49 +00001504) Installation of U-Boot into NAND flash
151-----------------------------------------
Fabio Estevam419ea2d2012-03-24 12:42:21 +0000152
153To boot a MX28 based board from NAND, set the boot mode DIP switches according to i.MX28
154manual chapter 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V.
155
156There are two possibilities when preparing an image writable to NAND flash.
157
158 I) The NAND wasn't written at all yet or the BCB is broken
159 ----------------------------------------------------------
160 In this case, both BCB (FCB and DBBT) and firmware needs to be
161 written to NAND. To generate NAND image containing all these,
162 there is a tool called "mxsboot" in the "tools/" directory. The tool
163 is invoked on "u-boot.sb" file from chapter 2):
164
165 $ ./tools/mxsboot nand u-boot.sb u-boot.nand
166
167 NOTE: The above invokation works for NAND flash with geometry of
168 2048b per page, 64b OOB data, 128kb erase size. If your chip
169 has a different geometry, please use:
170
171 -w <size> change page size (default 2048 b)
172 -o <size> change oob size (default 64 b)
173 -e <size> change erase size (default 131072 b)
174
175 The geometry information can be obtained from running U-Boot
176 on the MX28 board by issuing the "nand info" command.
177
178 The resulting file, "u-boot.nand" can be written directly to NAND
179 from the U-Boot prompt. To simplify the process, the U-Boot default
180 environment contains script "update_nand_full" to update the system.
181
182 This script expects a working TFTP server containing the file
183 "u-boot.nand" in it's root directory. This can be changed by
184 adjusting the "update_nand_full_filename" varible.
185
186 To update the system, run the following in U-Boot prompt:
187
188 => run update_nand_full
189
190 In case you would only need to update the bootloader in future,
191 see II) below.
192
193 II) The NAND was already written with a good BCB
194 ------------------------------------------------
195 This part applies after the part I) above was done at least once.
196
197 If part I) above was done correctly already, there is no need to
198 write the FCB and DBBT parts of NAND again. It's possible to upgrade
199 only the bootloader image.
200
201 To simplify the process of firmware update, the U-Boot default
202 environment contains script "update_nand_firmware" to update only
203 the firmware, without rewriting FCB and DBBT.
204
205 This script expects a working TFTP server containing the file
206 "u-boot.sb" in it's root directory. This can be changed by
207 adjusting the "update_nand_firmware_filename" varible.
208
209 To update the system, run the following in U-Boot prompt:
210
211 => run update_nand_firmware
212
213 III) Special settings for the update scripts
214 --------------------------------------------
215 There is a slight possibility of the user wanting to adjust the
216 STRIDE and COUNT options of the NAND boot. For description of these,
217 see i.MX28 manual section 12.12.1.2 and 12.12.1.3.
218
219 The update scripts take this possibility into account. In case the
220 user changes STRIDE by blowing fuses, the user also has to change
221 "update_nand_stride" variable. In case the user changes COUNT by
222 blowing fuses, the user also has to change "update_nand_count"
223 variable for the update scripts to work correctly.
224
225 In case the user needs to boot a firmware image bigger than 1Mb, the
226 user has to adjust the "update_nand_firmware_maxsz" variable for the
227 update scripts to work properly.