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- Storage of the board specific values (ethaddr...)
- -------------------------------------------------
- The board specific environment variables that should be unique
- for each individual board, can be stored in the I2C EEPROM. This
- will be done from offset 0x80 with the length of 0x80 bytes. The
- following command can be used to store the values here:
- => setdef de:20:6a:ed:e2:72 de:20:6a:ed:e2:73 AB0001
- ethaddr eth1addr serial#
- Now those 3 values are stored into the I2C EEPROM. A CRC is added
- to make sure that the values get not corrupted.
- SW-Reset Pushbutton handling:
- -----------------------------
- The SW-reset push button is connected to a GPIO input too. This
- way U-Boot can "see" how long the SW-reset was pressed, and a
- specific action can be taken. Two different actions are supported:
- a) Release after more than 5 seconds and less then 10 seconds:
- -> Run POST
- Please note, that the POST test will take a while (approx. 1 min
- on the 128MByte board). This is mainly due to the system memory
- test.
- b) Release after more than 10 seconds:
- -> Restore factory default settings
- The factory default values are restored. The default environment
- variables are restored (ipaddr, serverip...) and the board
- specific values (ethaddr, eth1addr and serial#) are restored
- to the environment from the I2C EEPROM. Also a bootline parameter
- is added to the Linux bootline to signal the Linux kernel upon
- the next startup, that the factory defaults should be restored.
- The command to check this sw-reset status and act accordingly is
- => chkreset
- This command is added to the default "bootcmd", so that it is called
- automatically upon startup.
- Also, the 2 LED's are used to indicate the current status of this
- command (time passed since pushing the button). When the POST test
- will be run, the green LED will be switched off, and when the
- factory restore will be initiated, the reg LED will be switched off.
- Loggin of POST results:
- -----------------------
- The results of the POST tests are logged in a logbuffer located at the end
- of the onboard memory. It can be accessed with the U-Boot command "log":
- => log show
- <4>POST memory PASSED
- <4>POST cache PASSED
- <4>POST cpu PASSED
- <4>POST uart PASSED
- <4>POST ethernet PASSED
- The DENX Linux kernel tree has support for this log buffer included. Exactly
- this buffer is used for logging of all kernel messages too. By enabling the
- compile time option "CONFIG_LOGBUFFER" this support is enabled. This way you
- can access the U-Boot log messages from Linux too.
- 2007-08-10, Stefan Roese <sr@denx.de>
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