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>