| |
| 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> |
