mirror of
https://github.com/u-boot/u-boot.git
synced 2024-11-26 05:34:30 +08:00
1cc0a9f496
Spelling corrections for (among other things): * environment * override * variable * ftd (should be "fdt", for flattened device tree) * embedded * FTDI * emulation * controller
291 lines
11 KiB
Plaintext
291 lines
11 KiB
Plaintext
Booting U-Boot on a MXS processor
|
|
=================================
|
|
|
|
This document describes the MXS U-Boot port. This document mostly covers topics
|
|
related to making the module/board bootable.
|
|
|
|
Terminology
|
|
-----------
|
|
|
|
The term "MXS" refers to a family of Freescale SoCs that is composed by MX23
|
|
and MX28.
|
|
|
|
The dollar symbol ($) introduces a snipped of shell code. This shall be typed
|
|
into the unix command prompt in U-Boot source code root directory.
|
|
|
|
The (=>) introduces a snipped of code that should by typed into U-Boot command
|
|
prompt
|
|
|
|
Contents
|
|
--------
|
|
|
|
1) Prerequisites
|
|
2) Compiling U-Boot for a MXS based board
|
|
3) Installation of U-Boot for a MXS based board to SD card
|
|
4) Installation of U-Boot into NAND flash on a MX28 based board
|
|
5) Installation of U-Boot into SPI NOR flash on a MX28 based board
|
|
|
|
1) Prerequisites
|
|
----------------
|
|
|
|
To make a MXS based board bootable, some tools are necessary. The only
|
|
mandatory tool is the "mxsboot" tool found in U-Boot source tree. The
|
|
tool is built automatically when compiling U-Boot for i.MX23 or i.MX28.
|
|
|
|
The production of BootStream image is handled via "mkimage", which is
|
|
also part of the U-Boot source tree. The "mkimage" requires OpenSSL
|
|
development libraries to be installed. In case of Debian and derivates,
|
|
this is installed by running:
|
|
|
|
$ sudo apt-get install libssl-dev
|
|
|
|
NOTE: The "elftosb" tool distributed by Freescale Semiconductor is no
|
|
longer necessary for general use of U-Boot on i.MX23 and i.MX28.
|
|
The mkimage supports generation of BootStream images encrypted
|
|
with a zero key, which is the vast majority of use-cases. In
|
|
case you do need to produce image encrypted with non-zero key
|
|
or other special features, please use the "elftosb" tool,
|
|
otherwise continue to section 2). The installation procedure of
|
|
the "elftosb" is outlined below:
|
|
|
|
Firstly, obtain the elftosb archive from the following location:
|
|
|
|
ftp://ftp.denx.de/pub/tools/elftosb-10.12.01.tar.gz
|
|
|
|
We use a $VER variable here to denote the current version. At the time of
|
|
writing of this document, that is "10.12.01". To obtain the file from command
|
|
line, use:
|
|
|
|
$ VER="10.12.01"
|
|
$ wget ftp://ftp.denx.de/pub/tools/elftosb-${VER}.tar.gz
|
|
|
|
Extract the file:
|
|
|
|
$ tar xzf elftosb-${VER}.tar.gz
|
|
|
|
Compile the file. We need to manually tell the linker to use also libm:
|
|
|
|
$ cd elftosb-${VER}/
|
|
$ make LIBS="-lstdc++ -lm" elftosb
|
|
|
|
Optionally, remove debugging symbols from elftosb:
|
|
|
|
$ strip bld/linux/elftosb
|
|
|
|
Finally, install the "elftosb" binary. The "install" target is missing, so just
|
|
copy the binary by hand:
|
|
|
|
$ sudo cp bld/linux/elftosb /usr/local/bin/
|
|
|
|
Make sure the "elftosb" binary can be found in your $PATH, in this case this
|
|
means "/usr/local/bin/" has to be in your $PATH.
|
|
|
|
2) Compiling U-Boot for a MXS based board
|
|
-------------------------------------------
|
|
|
|
Compiling the U-Boot for a MXS board is straightforward and done as compiling
|
|
U-Boot for any other ARM device. For cross-compiler setup, please refer to
|
|
ELDK5.0 documentation. First, clean up the source code:
|
|
|
|
$ make mrproper
|
|
|
|
Next, configure U-Boot for a MXS based board
|
|
|
|
$ make <mxs_based_board_name>_config
|
|
|
|
Examples:
|
|
|
|
1. For building U-Boot for Denx M28EVK board:
|
|
|
|
$ make m28evk_config
|
|
|
|
2. For building U-Boot for Freescale MX28EVK board:
|
|
|
|
$ make mx28evk_config
|
|
|
|
3. For building U-Boot for Freescale MX23EVK board:
|
|
|
|
$ make mx23evk_config
|
|
|
|
4. For building U-Boot for Olimex MX23 Olinuxino board:
|
|
|
|
$ make mx23_olinuxino_config
|
|
|
|
Lastly, compile U-Boot and prepare a "BootStream". The "BootStream" is a special
|
|
type of file, which MXS CPUs can boot. This is handled by the following
|
|
command:
|
|
|
|
$ make u-boot.sb
|
|
|
|
HINT: To speed-up the build process, you can add -j<N>, where N is number of
|
|
compiler instances that'll run in parallel.
|
|
|
|
The code produces "u-boot.sb" file. This file needs to be augmented with a
|
|
proper header to allow successful boot from SD or NAND. Adding the header is
|
|
discussed in the following chapters.
|
|
|
|
NOTE: The process that produces u-boot.sb uses the mkimage to generate the
|
|
BootStream. The BootStream is encrypted with zero key. In case you need
|
|
some special features of the BootStream and plan on using the "elftosb"
|
|
tool instead, the invocation to produce a compatible BootStream with the
|
|
one produced by mkimage is outlined below. For further details, refer to
|
|
the documentation bundled with the "elftosb" package.
|
|
|
|
$ elftosb -zf imx23 -c arch/arm/cpu/arm926ejs/mxs/u-boot-imx23.bd \
|
|
-o u-boot.sb
|
|
$ elftosb -zf imx28 -c arch/arm/cpu/arm926ejs/mxs/u-boot-imx28.bd \
|
|
-o u-boot.sb
|
|
|
|
3) Installation of U-Boot for a MXS based board to SD card
|
|
----------------------------------------------------------
|
|
|
|
To boot a MXS based board from SD, set the boot mode DIP switches according to
|
|
to MX28 manual, section 12.2.1 (Table 12-2) or MX23 manual, section 35.1.2
|
|
(Table 35-3).
|
|
|
|
The SD card used to boot U-Boot must contain a DOS partition table, which in
|
|
turn carries a partition of special type and which contains a special header.
|
|
The rest of partitions in the DOS partition table can be used by the user.
|
|
|
|
To prepare such partition, use your favourite partitioning tool. The partition
|
|
must have the following parameters:
|
|
|
|
* Start sector .......... sector 2048
|
|
* Partition size ........ at least 1024 kb
|
|
* Partition type ........ 0x53 (sometimes "OnTrack DM6 Aux3")
|
|
|
|
For example in Linux fdisk, the sequence for a clear card follows. Be sure to
|
|
run fdisk with the option "-u=sectors" to set units to sectors:
|
|
|
|
* o ..................... create a clear partition table
|
|
* n ..................... create new partition
|
|
* p ............. primary partition
|
|
* 1 ............. first partition
|
|
* 2048 .......... first sector is 2048
|
|
* +1M ........... make the partition 1Mb big
|
|
* t 1 ................... change first partition ID
|
|
* 53 ............ change the ID to 0x53 (OnTrack DM6 Aux3)
|
|
* <create other partitions>
|
|
* w ..................... write partition table to disk
|
|
|
|
The partition layout is ready, next the special partition must be filled with
|
|
proper contents. The contents is generated by running the following command
|
|
(see chapter 2)):
|
|
|
|
$ ./tools/mxsboot sd u-boot.sb u-boot.sd
|
|
|
|
The resulting file, "u-boot.sd", shall then be written to the partition. In this
|
|
case, we assume the first partition of the SD card is /dev/mmcblk0p1:
|
|
|
|
$ dd if=u-boot.sd of=/dev/mmcblk0p1
|
|
|
|
Last step is to insert the card into the MXS based board and boot.
|
|
|
|
NOTE: If the user needs to adjust the start sector, the "mxsboot" tool contains
|
|
a "-p" switch for that purpose. The "-p" switch takes the sector number as
|
|
an argument.
|
|
|
|
4) Installation of U-Boot into NAND flash on a MX28 based board
|
|
---------------------------------------------------------------
|
|
|
|
To boot a MX28 based board from NAND, set the boot mode DIP switches according
|
|
to MX28 manual section 12.2.1 (Table 12-2), PORT=GPMI, NAND 1.8 V.
|
|
|
|
There are two possibilities when preparing an image writable to NAND flash.
|
|
|
|
I) The NAND wasn't written at all yet or the BCB is broken
|
|
----------------------------------------------------------
|
|
In this case, both BCB (FCB and DBBT) and firmware needs to be
|
|
written to NAND. To generate NAND image containing all these,
|
|
there is a tool called "mxsboot" in the "tools/" directory. The tool
|
|
is invoked on "u-boot.sb" file from chapter 2):
|
|
|
|
$ ./tools/mxsboot nand u-boot.sb u-boot.nand
|
|
|
|
NOTE: The above invokation works for NAND flash with geometry of
|
|
2048b per page, 64b OOB data, 128kb erase size. If your chip
|
|
has a different geometry, please use:
|
|
|
|
-w <size> change page size (default 2048 b)
|
|
-o <size> change oob size (default 64 b)
|
|
-e <size> change erase size (default 131072 b)
|
|
|
|
The geometry information can be obtained from running U-Boot
|
|
on the MX28 board by issuing the "nand info" command.
|
|
|
|
The resulting file, "u-boot.nand" can be written directly to NAND
|
|
from the U-Boot prompt. To simplify the process, the U-Boot default
|
|
environment contains script "update_nand_full" to update the system.
|
|
|
|
This script expects a working TFTP server containing the file
|
|
"u-boot.nand" in it's root directory. This can be changed by
|
|
adjusting the "update_nand_full_filename" variable.
|
|
|
|
To update the system, run the following in U-Boot prompt:
|
|
|
|
=> run update_nand_full
|
|
|
|
In case you would only need to update the bootloader in future,
|
|
see II) below.
|
|
|
|
II) The NAND was already written with a good BCB
|
|
------------------------------------------------
|
|
This part applies after the part I) above was done at least once.
|
|
|
|
If part I) above was done correctly already, there is no need to
|
|
write the FCB and DBBT parts of NAND again. It's possible to upgrade
|
|
only the bootloader image.
|
|
|
|
To simplify the process of firmware update, the U-Boot default
|
|
environment contains script "update_nand_firmware" to update only
|
|
the firmware, without rewriting FCB and DBBT.
|
|
|
|
This script expects a working TFTP server containing the file
|
|
"u-boot.sb" in it's root directory. This can be changed by
|
|
adjusting the "update_nand_firmware_filename" variable.
|
|
|
|
To update the system, run the following in U-Boot prompt:
|
|
|
|
=> run update_nand_firmware
|
|
|
|
III) Special settings for the update scripts
|
|
--------------------------------------------
|
|
There is a slight possibility of the user wanting to adjust the
|
|
STRIDE and COUNT options of the NAND boot. For description of these,
|
|
see MX28 manual section 12.12.1.2 and 12.12.1.3.
|
|
|
|
The update scripts take this possibility into account. In case the
|
|
user changes STRIDE by blowing fuses, the user also has to change
|
|
"update_nand_stride" variable. In case the user changes COUNT by
|
|
blowing fuses, the user also has to change "update_nand_count"
|
|
variable for the update scripts to work correctly.
|
|
|
|
In case the user needs to boot a firmware image bigger than 1Mb, the
|
|
user has to adjust the "update_nand_firmware_maxsz" variable for the
|
|
update scripts to work properly.
|
|
|
|
5) Installation of U-Boot into SPI NOR flash on a MX28 based board
|
|
------------------------------------------------------------------
|
|
|
|
The u-boot.sb file can be directly written to SPI NOR from U-Boot prompt.
|
|
|
|
Load u-boot.sb into RAM, this can be done in several ways and one way is to use
|
|
tftp:
|
|
=> tftp u-boot.sb 0x42000000
|
|
|
|
Probe the SPI NOR flash:
|
|
=> sf probe
|
|
|
|
(SPI NOR should be succesfully detected in this step)
|
|
|
|
Erase the blocks where U-Boot binary will be written to:
|
|
=> sf erase 0x0 0x80000
|
|
|
|
Write u-boot.sb to SPI NOR:
|
|
=> sf write 0x42000000 0 0x80000
|
|
|
|
Power off the board and set the boot mode DIP switches to boot from the SPI NOR
|
|
according to MX28 manual section 12.2.1 (Table 12-2)
|
|
|
|
Last step is to power up the board and U-Boot should start from SPI NOR.
|