-Booting U-boot on a MXS processor
+Booting U-Boot on a MXS processor
=================================
This document describes the MXS U-Boot port. This document mostly covers topics
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 first one is
-the "elftosb" tool distributed by Freescale Semiconductor. The other one is the
-"mxsboot" tool found in U-Boot source tree.
+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:
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.
-Install the 'libssl-dev' package as well. On a Debian-based distribution, this
-package can be installed as follows:
-
- $ sudo apt-get install libssl-dev
-
2) Compiling U-Boot for a MXS based board
-------------------------------------------
Examples:
-1. For building U-boot for Denx M28EVK board:
+1. For building U-Boot for Aries M28EVK board:
$ make m28evk_config
-2. For building U-boot for Freescale MX28EVK board:
+2. For building U-Boot for Freescale MX28EVK board:
$ make mx28evk_config
-3. For building U-boot for Freescale MX23EVK board:
+3. For building U-Boot for Freescale MX23EVK board:
$ make mx23evk_config
-4. For building U-boot for Olimex MX23 Olinuxino board:
+4. For building U-Boot for Olimex MX23 Olinuxino board:
$ make mx23_olinuxino_config
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
----------------------------------------------------------
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" varible.
+ adjusting the "update_nand_full_filename" variable.
To update the system, run the following in U-Boot prompt:
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" varible.
+ adjusting the "update_nand_firmware_filename" variable.
To update the system, run the following in U-Boot prompt:
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.
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