1 Booting U-boot on a MXS processor
2 =================================
4 This document describes the MXS U-Boot port. This document mostly covers topics
5 related to making the module/board bootable.
10 The term "MXS" refers to a family of Freescale SoCs that is composed by MX23
13 The dollar symbol ($) introduces a snipped of shell code. This shall be typed
14 into the unix command prompt in U-Boot source code root directory.
16 The (=>) introduces a snipped of code that should by typed into U-Boot command
23 2) Compiling U-Boot for a MXS based board
24 3) Installation of U-Boot for a MXS based board to SD card
25 4) Installation of U-Boot into NAND flash on a MX28 based board
30 To make a MXS based board bootable, some tools are necessary. The first one is
31 the "elftosb" tool distributed by Freescale Semiconductor. The other one is the
32 "mxsboot" tool found in U-Boot source tree.
34 Firstly, obtain the elftosb archive from the following location:
36 ftp://ftp.denx.de/pub/tools/elftosb-10.12.01.tar.gz
38 We use a $VER variable here to denote the current version. At the time of
39 writing of this document, that is "10.12.01". To obtain the file from command
43 $ wget ftp://ftp.denx.de/pub/tools/elftosb-${VER}.tar.gz
47 $ tar xzf elftosb-${VER}.tar.gz
49 Compile the file. We need to manually tell the linker to use also libm:
52 $ make LIBS="-lstdc++ -lm" elftosb
54 Optionally, remove debugging symbols from elftosb:
56 $ strip bld/linux/elftosb
58 Finally, install the "elftosb" binary. The "install" target is missing, so just
59 copy the binary by hand:
61 $ sudo cp bld/linux/elftosb /usr/local/bin/
63 Make sure the "elftosb" binary can be found in your $PATH, in this case this
64 means "/usr/local/bin/" has to be in your $PATH.
66 Install the 'libssl-dev' package as well. On a Debian-based distribution, this
67 package can be installed as follows:
69 $ sudo apt-get install libssl-dev
71 2) Compiling U-Boot for a MXS based board
72 -------------------------------------------
74 Compiling the U-Boot for a MXS board is straightforward and done as compiling
75 U-Boot for any other ARM device. For cross-compiler setup, please refer to
76 ELDK5.0 documentation. First, clean up the source code:
80 Next, configure U-Boot for a MXS based board
82 $ make <mxs_based_board_name>_config
86 1. For building U-boot for Denx M28EVK board:
90 2. For building U-boot for Freescale MX28EVK board:
94 3. For building U-boot for Freescale MX23EVK board:
98 4. For building U-boot for Olimex MX23 Olinuxino board:
100 $ make mx23_olinuxino_config
102 Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special
103 type of file, which MXS CPUs can boot. This is handled by the following
108 HINT: To speed-up the build process, you can add -j<N>, where N is number of
109 compiler instances that'll run in parallel.
111 The code produces "u-boot.sb" file. This file needs to be augmented with a
112 proper header to allow successful boot from SD or NAND. Adding the header is
113 discussed in the following chapters.
115 3) Installation of U-Boot for a MXS based board to SD card
116 ----------------------------------------------------------
118 To boot a MXS based board from SD, set the boot mode DIP switches according to
119 to MX28 manual, section 12.2.1 (Table 12-2) or MX23 manual, section 35.1.2
122 The SD card used to boot U-Boot must contain a DOS partition table, which in
123 turn carries a partition of special type and which contains a special header.
124 The rest of partitions in the DOS partition table can be used by the user.
126 To prepare such partition, use your favourite partitioning tool. The partition
127 must have the following parameters:
129 * Start sector .......... sector 2048
130 * Partition size ........ at least 1024 kb
131 * Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3")
133 For example in Linux fdisk, the sequence for a clear card follows. Be sure to
134 run fdisk with the option "-u=sectors" to set units to sectors:
136 * o ..................... create a clear partition table
137 * n ..................... create new partition
138 * p ............. primary partition
139 * 1 ............. first partition
140 * 2048 .......... first sector is 2048
141 * +1M ........... make the partition 1Mb big
142 * t 1 ................... change first partition ID
143 * 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3)
144 * <create other partitions>
145 * w ..................... write partition table to disk
147 The partition layout is ready, next the special partition must be filled with
148 proper contents. The contents is generated by running the following command
151 $ ./tools/mxsboot sd u-boot.sb u-boot.sd
153 The resulting file, "u-boot.sd", shall then be written to the partition. In this
154 case, we assume the first partition of the SD card is /dev/mmcblk0p1:
156 $ dd if=u-boot.sd of=/dev/mmcblk0p1
158 Last step is to insert the card into the MXS based board and boot.
160 NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains
161 a "-p" switch for that purpose. The "-p" switch takes the sector number as
164 4) Installation of U-Boot into NAND flash on a MX28 based board
165 ---------------------------------------------------------------
167 To boot a MX28 based board from NAND, set the boot mode DIP switches according
168 to MX28 manual section 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V.
170 There are two possibilities when preparing an image writable to NAND flash.
172 I) The NAND wasn't written at all yet or the BCB is broken
173 ----------------------------------------------------------
174 In this case, both BCB (FCB and DBBT) and firmware needs to be
175 written to NAND. To generate NAND image containing all these,
176 there is a tool called "mxsboot" in the "tools/" directory. The tool
177 is invoked on "u-boot.sb" file from chapter 2):
179 $ ./tools/mxsboot nand u-boot.sb u-boot.nand
181 NOTE: The above invokation works for NAND flash with geometry of
182 2048b per page, 64b OOB data, 128kb erase size. If your chip
183 has a different geometry, please use:
185 -w <size> change page size (default 2048 b)
186 -o <size> change oob size (default 64 b)
187 -e <size> change erase size (default 131072 b)
189 The geometry information can be obtained from running U-Boot
190 on the MX28 board by issuing the "nand info" command.
192 The resulting file, "u-boot.nand" can be written directly to NAND
193 from the U-Boot prompt. To simplify the process, the U-Boot default
194 environment contains script "update_nand_full" to update the system.
196 This script expects a working TFTP server containing the file
197 "u-boot.nand" in it's root directory. This can be changed by
198 adjusting the "update_nand_full_filename" varible.
200 To update the system, run the following in U-Boot prompt:
202 => run update_nand_full
204 In case you would only need to update the bootloader in future,
207 II) The NAND was already written with a good BCB
208 ------------------------------------------------
209 This part applies after the part I) above was done at least once.
211 If part I) above was done correctly already, there is no need to
212 write the FCB and DBBT parts of NAND again. It's possible to upgrade
213 only the bootloader image.
215 To simplify the process of firmware update, the U-Boot default
216 environment contains script "update_nand_firmware" to update only
217 the firmware, without rewriting FCB and DBBT.
219 This script expects a working TFTP server containing the file
220 "u-boot.sb" in it's root directory. This can be changed by
221 adjusting the "update_nand_firmware_filename" varible.
223 To update the system, run the following in U-Boot prompt:
225 => run update_nand_firmware
227 III) Special settings for the update scripts
228 --------------------------------------------
229 There is a slight possibility of the user wanting to adjust the
230 STRIDE and COUNT options of the NAND boot. For description of these,
231 see MX28 manual section 12.12.1.2 and 12.12.1.3.
233 The update scripts take this possibility into account. In case the
234 user changes STRIDE by blowing fuses, the user also has to change
235 "update_nand_stride" variable. In case the user changes COUNT by
236 blowing fuses, the user also has to change "update_nand_count"
237 variable for the update scripts to work correctly.
239 In case the user needs to boot a firmware image bigger than 1Mb, the
240 user has to adjust the "update_nand_firmware_maxsz" variable for the
241 update scripts to work properly.