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