Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 1 | Booting U-boot on a MX28 processor |
| 2 | ================================== |
| 3 | |
| 4 | This document describes the MX28 U-Boot port. This document mostly |
| 5 | covers topics related to making the module/board bootable. |
| 6 | |
| 7 | Terminology |
| 8 | ----------- |
| 9 | |
| 10 | The dollar symbol ($) introduces a snipped of shell code. This shall be typed |
| 11 | into the unix command prompt in U-Boot source code root directory. |
| 12 | |
| 13 | The (=>) introduces a snipped of code that should by typed into U-Boot command |
| 14 | prompt |
| 15 | |
| 16 | Contents |
| 17 | -------- |
| 18 | |
| 19 | 1) Prerequisites |
| 20 | 2) Compiling U-Boot for a MX28 based board |
| 21 | 3) Installation of U-Boot for a MX28 based board to SD card |
Fabio Estevam | de73282 | 2012-06-18 05:51:49 +0000 | [diff] [blame] | 22 | 4) Installation of U-Boot into NAND flash |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 23 | |
| 24 | 1) Prerequisites |
| 25 | ---------------- |
| 26 | |
| 27 | To make a MX28 based board bootable, some tools are necessary. The first one |
| 28 | is the "elftosb" tool distributed by Freescale Semiconductor. The other one |
| 29 | is the "mxsboot" tool found in U-Boot source tree. |
| 30 | |
| 31 | Firstly, obtain the elftosb archive from the following location: |
| 32 | |
Anatolij Gustschin | 7528a65 | 2012-06-27 04:14:29 +0000 | [diff] [blame] | 33 | ftp://ftp.denx.de/pub/tools/elftosb-10.12.01.tar.gz |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 34 | |
| 35 | We use a $VER variable here to denote the current version. At the time of |
| 36 | writing of this document, that is "10.12.01". To obtain the file from command |
| 37 | line, use: |
| 38 | |
| 39 | $ VER="10.12.01" |
Anatolij Gustschin | 7528a65 | 2012-06-27 04:14:29 +0000 | [diff] [blame] | 40 | $ wget ftp://ftp.denx.de/pub/tools/elftosb-${VER}.tar.gz |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 41 | |
| 42 | Extract the file: |
| 43 | |
| 44 | $ tar xzf elftosb-${VER}.tar.gz |
| 45 | |
| 46 | Compile 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 | |
| 51 | Optionally, remove debugging symbols from elftosb: |
| 52 | |
| 53 | $ strip bld/linux/elftosb |
| 54 | |
| 55 | Finally, install the "elftosb" binary. The "install" target is missing, so just |
| 56 | copy the binary by hand: |
| 57 | |
| 58 | $ sudo cp bld/linux/elftosb /usr/local/bin/ |
| 59 | |
| 60 | Make sure the "elftosb" binary can be found in your $PATH, in this case this |
| 61 | means "/usr/local/bin/" has to be in your $PATH. |
| 62 | |
| 63 | 2) Compiling U-Boot for a MX28 based board |
| 64 | ------------------------------------------- |
| 65 | |
Fabio Estevam | dc7cfd6 | 2013-05-03 15:07:57 -0300 | [diff] [blame] | 66 | Compiling the U-Boot for a MX28 board is straightforward and done as compiling |
| 67 | U-Boot for any other ARM device. For cross-compiler setup, please refer to |
| 68 | ELDK5.0 documentation. First, clean up the source code: |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 69 | |
| 70 | $ make mrproper |
| 71 | |
| 72 | Next, configure U-Boot for a MX28 based board |
| 73 | |
| 74 | $ make <mx28_based_board_name>_config |
| 75 | |
| 76 | Examples: |
| 77 | |
| 78 | 1. For building U-boot for Denx M28EVK board: |
| 79 | |
| 80 | $ make m28evk_config |
| 81 | |
| 82 | 2. For building U-boot for Freescale MX28EVK board: |
| 83 | |
| 84 | $ make mx28evk_config |
| 85 | |
| 86 | Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special |
| 87 | type of file, which the i.MX28 CPU can boot. This is handled by the following |
| 88 | command: |
| 89 | |
| 90 | $ make u-boot.sb |
| 91 | |
| 92 | HINT: 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 | |
| 95 | The code produces "u-boot.sb" file. This file needs to be augmented with a |
| 96 | proper header to allow successful boot from SD or NAND. Adding the header is |
| 97 | discussed in the following chapters. |
| 98 | |
| 99 | 3) Installation of U-Boot for a MX28 based board to SD card |
| 100 | ----------------------------------------------------------- |
| 101 | |
| 102 | To boot a MX28 based board from SD, set the boot mode DIP switches according |
Fabio Estevam | e0747ef | 2013-05-03 15:07:58 -0300 | [diff] [blame] | 103 | to i.MX28 manual chapter 12.2.1 (Table 12-2). |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 104 | |
Fabio Estevam | 7891f78 | 2013-05-03 15:07:59 -0300 | [diff] [blame^] | 105 | The SD card used to boot U-Boot must contain a DOS partition table, which in |
| 106 | turn carries a partition of special type and which contains a special header. |
| 107 | The rest of partitions in the DOS partition table can be used by the user. |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 108 | |
| 109 | To prepare such partition, use your favourite partitioning tool. The partition |
| 110 | must 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 | |
| 116 | For example in Linux fdisk, the sequence for a clear card follows. Be sure to |
| 117 | run 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 | |
| 130 | The partition layout is ready, next the special partition must be filled with |
| 131 | proper 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 | |
| 136 | The resulting file, "u-boot.sd", shall then be written to the partition. In this |
| 137 | case, we assume the first partition of the SD card is /dev/mmcblk0p1: |
| 138 | |
| 139 | $ dd if=u-boot.sd of=/dev/mmcblk0p1 |
| 140 | |
| 141 | Last step is to insert the card into MX28 based board and boot. |
| 142 | |
| 143 | NOTE: 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 Estevam | de73282 | 2012-06-18 05:51:49 +0000 | [diff] [blame] | 147 | 4) Installation of U-Boot into NAND flash |
| 148 | ----------------------------------------- |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 149 | |
Fabio Estevam | dc7cfd6 | 2013-05-03 15:07:57 -0300 | [diff] [blame] | 150 | To boot a MX28 based board from NAND, set the boot mode DIP switches according |
| 151 | to i.MX28 manual chapter 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V. |
Fabio Estevam | b671647 | 2012-03-24 12:42:21 +0000 | [diff] [blame] | 152 | |
| 153 | There 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. |