1Booting U-boot on a MXS processor 2================================= 3 4This document describes the MXS U-Boot port. This document mostly covers topics 5related to making the module/board bootable. 6 7Terminology 8----------- 9 10The term "MXS" refers to a family of Freescale SoCs that is composed by MX23 11and MX28. 12 13The dollar symbol ($) introduces a snipped of shell code. This shall be typed 14into the unix command prompt in U-Boot source code root directory. 15 16The (=>) introduces a snipped of code that should by typed into U-Boot command 17prompt 18 19Contents 20-------- 21 221) Prerequisites 232) Compiling U-Boot for a MXS based board 243) Installation of U-Boot for a MXS based board to SD card 254) Installation of U-Boot into NAND flash on a MX28 based board 26 271) Prerequisites 28---------------- 29 30To make a MXS based board bootable, some tools are necessary. The first one is 31the "elftosb" tool distributed by Freescale Semiconductor. The other one is the 32"mxsboot" tool found in U-Boot source tree. 33 34Firstly, obtain the elftosb archive from the following location: 35 36 ftp://ftp.denx.de/pub/tools/elftosb-10.12.01.tar.gz 37 38We use a $VER variable here to denote the current version. At the time of 39writing of this document, that is "10.12.01". To obtain the file from command 40line, use: 41 42 $ VER="10.12.01" 43 $ wget ftp://ftp.denx.de/pub/tools/elftosb-${VER}.tar.gz 44 45Extract the file: 46 47 $ tar xzf elftosb-${VER}.tar.gz 48 49Compile the file. We need to manually tell the linker to use also libm: 50 51 $ cd elftosb-${VER}/ 52 $ make LIBS="-lstdc++ -lm" elftosb 53 54Optionally, remove debugging symbols from elftosb: 55 56 $ strip bld/linux/elftosb 57 58Finally, install the "elftosb" binary. The "install" target is missing, so just 59copy the binary by hand: 60 61 $ sudo cp bld/linux/elftosb /usr/local/bin/ 62 63Make sure the "elftosb" binary can be found in your $PATH, in this case this 64means "/usr/local/bin/" has to be in your $PATH. 65 662) Compiling U-Boot for a MXS based board 67------------------------------------------- 68 69Compiling the U-Boot for a MXS board is straightforward and done as compiling 70U-Boot for any other ARM device. For cross-compiler setup, please refer to 71ELDK5.0 documentation. First, clean up the source code: 72 73 $ make mrproper 74 75Next, configure U-Boot for a MXS based board 76 77 $ make <mxs_based_board_name>_config 78 79Examples: 80 811. For building U-boot for Denx M28EVK board: 82 83 $ make m28evk_config 84 852. For building U-boot for Freescale MX28EVK board: 86 87 $ make mx28evk_config 88 893. For building U-boot for Freescale MX23EVK board: 90 91 $ make mx23evk_config 92 934. For building U-boot for Olimex MX23 Olinuxino board: 94 95 $ make mx23_olinuxino_config 96 97Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special 98type of file, which MXS CPUs can boot. This is handled by the following 99command: 100 101 $ make u-boot.sb 102 103HINT: To speed-up the build process, you can add -j<N>, where N is number of 104 compiler instances that'll run in parallel. 105 106The code produces "u-boot.sb" file. This file needs to be augmented with a 107proper header to allow successful boot from SD or NAND. Adding the header is 108discussed in the following chapters. 109 1103) Installation of U-Boot for a MXS based board to SD card 111---------------------------------------------------------- 112 113To boot a MXS based board from SD, set the boot mode DIP switches according to 114to MX28 manual, section 12.2.1 (Table 12-2) or MX23 manual, section 35.1.2 115(Table 35-3). 116 117The SD card used to boot U-Boot must contain a DOS partition table, which in 118turn carries a partition of special type and which contains a special header. 119The rest of partitions in the DOS partition table can be used by the user. 120 121To prepare such partition, use your favourite partitioning tool. The partition 122must have the following parameters: 123 124 * Start sector .......... sector 2048 125 * Partition size ........ at least 1024 kb 126 * Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3") 127 128For example in Linux fdisk, the sequence for a clear card follows. Be sure to 129run fdisk with the option "-u=sectors" to set units to sectors: 130 131 * o ..................... create a clear partition table 132 * n ..................... create new partition 133 * p ............. primary partition 134 * 1 ............. first partition 135 * 2048 .......... first sector is 2048 136 * +1M ........... make the partition 1Mb big 137 * t 1 ................... change first partition ID 138 * 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3) 139 * <create other partitions> 140 * w ..................... write partition table to disk 141 142The partition layout is ready, next the special partition must be filled with 143proper contents. The contents is generated by running the following command 144(see chapter 2)): 145 146 $ ./tools/mxsboot sd u-boot.sb u-boot.sd 147 148The resulting file, "u-boot.sd", shall then be written to the partition. In this 149case, we assume the first partition of the SD card is /dev/mmcblk0p1: 150 151 $ dd if=u-boot.sd of=/dev/mmcblk0p1 152 153Last step is to insert the card into the MXS based board and boot. 154 155NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains 156 a "-p" switch for that purpose. The "-p" switch takes the sector number as 157 an argument. 158 1594) Installation of U-Boot into NAND flash on a MX28 based board 160--------------------------------------------------------------- 161 162To boot a MX28 based board from NAND, set the boot mode DIP switches according 163to MX28 manual section 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V. 164 165There are two possibilities when preparing an image writable to NAND flash. 166 167 I) The NAND wasn't written at all yet or the BCB is broken 168 ---------------------------------------------------------- 169 In this case, both BCB (FCB and DBBT) and firmware needs to be 170 written to NAND. To generate NAND image containing all these, 171 there is a tool called "mxsboot" in the "tools/" directory. The tool 172 is invoked on "u-boot.sb" file from chapter 2): 173 174 $ ./tools/mxsboot nand u-boot.sb u-boot.nand 175 176 NOTE: The above invokation works for NAND flash with geometry of 177 2048b per page, 64b OOB data, 128kb erase size. If your chip 178 has a different geometry, please use: 179 180 -w <size> change page size (default 2048 b) 181 -o <size> change oob size (default 64 b) 182 -e <size> change erase size (default 131072 b) 183 184 The geometry information can be obtained from running U-Boot 185 on the MX28 board by issuing the "nand info" command. 186 187 The resulting file, "u-boot.nand" can be written directly to NAND 188 from the U-Boot prompt. To simplify the process, the U-Boot default 189 environment contains script "update_nand_full" to update the system. 190 191 This script expects a working TFTP server containing the file 192 "u-boot.nand" in it's root directory. This can be changed by 193 adjusting the "update_nand_full_filename" varible. 194 195 To update the system, run the following in U-Boot prompt: 196 197 => run update_nand_full 198 199 In case you would only need to update the bootloader in future, 200 see II) below. 201 202 II) The NAND was already written with a good BCB 203 ------------------------------------------------ 204 This part applies after the part I) above was done at least once. 205 206 If part I) above was done correctly already, there is no need to 207 write the FCB and DBBT parts of NAND again. It's possible to upgrade 208 only the bootloader image. 209 210 To simplify the process of firmware update, the U-Boot default 211 environment contains script "update_nand_firmware" to update only 212 the firmware, without rewriting FCB and DBBT. 213 214 This script expects a working TFTP server containing the file 215 "u-boot.sb" in it's root directory. This can be changed by 216 adjusting the "update_nand_firmware_filename" varible. 217 218 To update the system, run the following in U-Boot prompt: 219 220 => run update_nand_firmware 221 222 III) Special settings for the update scripts 223 -------------------------------------------- 224 There is a slight possibility of the user wanting to adjust the 225 STRIDE and COUNT options of the NAND boot. For description of these, 226 see MX28 manual section 12.12.1.2 and 12.12.1.3. 227 228 The update scripts take this possibility into account. In case the 229 user changes STRIDE by blowing fuses, the user also has to change 230 "update_nand_stride" variable. In case the user changes COUNT by 231 blowing fuses, the user also has to change "update_nand_count" 232 variable for the update scripts to work correctly. 233 234 In case the user needs to boot a firmware image bigger than 1Mb, the 235 user has to adjust the "update_nand_firmware_maxsz" variable for the 236 update scripts to work properly. 237