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mx28evk: Add documentation on how to boot from SPI NOR 

Explain the necessary steps in order to boot from SPI NOR.

Based on a earlier submission from Mårten Wikman.

Signed-off-by: Mårten Wikman <marten.wikman@novia.fi>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
This commit is contained in:
Fabio Estevam 2014-06-10 00:03:59 -03:00 committed by Stefano Babic
parent d4c8258812
commit a81c90f4c8
2 changed files with 45 additions and 3 deletions
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22
board/freescale/mx28evk/README
View File

@ -23,11 +23,19 @@ To boot MX28EVK from an SD card, set the boot mode DIP switches as:
* VDD 5V: To the left (off)
* Hold Button: Down (off)
To boot MX28EVK from SPI NOR flash, set the boot mode DIP switches as:
* Boot Mode Select: 0 0 1 0 (Boot from SSP2)
* JTAG PSWITCH RESET: To the right (reset disabled)
* Battery Source: Down
* Wall 5V: Up
* VDD 5V: To the left (off)
* Hold Button: Down (off)
Environment Storage
-------------------
There are two targets for mx28evk:
There are three targets for mx28evk:
"make mx28evk_config" - store environment variables into MMC
@ -35,12 +43,20 @@ or
"make mx28evk_nand_config" - store environment variables into NAND flash
or
"make mx28evk_spi_config" - store enviroment variables into SPI NOR flash
Choose the target accordingly.
Note: The mx28evk board does not come with a NAND flash populated from the
factory. It comes with an empty slot (U23), which allows the insertion of a
48-pin TSOP flash device.
Follow the instructions from doc/README.mxs to generate a bootable SD card.
mx28evk does not come with SPI NOR flash populated from the factory either.
It is possible to solder a SOIC memory on U49 or use a DIP8 on J89.
To get SPI communication to work R320, R321,R322 and C178 need to be populated.
Look in the schematics for the proper component values.
Insert the SD card in slot 0, power up the board and U-boot will boot.
Follow the instructions from doc/README.mxs to generate a bootable SD card or
to generate a binary to be flashed into SPI NOR.

26
doc/README.mxs
View File

@ -23,6 +23,7 @@ Contents
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
----------------
@ -262,3 +263,28 @@ There are two possibilities when preparing an image writable to NAND flash.
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.