blob: 1848d8cd3846f701d9f0b4a01c811b1d595579a9 [file] [log] [blame]
Stefan Roese779e9752007-08-14 14:44:41 +02001
2Storage of the board specific values (ethaddr...)
3-------------------------------------------------
4
5The board specific environment variables that should be unique
6for each individual board, can be stored in the I2C EEPROM. This
7will be done from offset 0x80 with the length of 0x80 bytes. The
8following command can be used to store the values here:
9
10=> setdef de:20:6a:ed:e2:72 de:20:6a:ed:e2:73 AB0001
11
12 ethaddr eth1addr serial#
13
14Now those 3 values are stored into the I2C EEPROM. A CRC is added
15to make sure that the values get not corrupted.
16
17
18SW-Reset Pushbutton handling:
19-----------------------------
20
21The SW-reset push button is connected to a GPIO input too. This
22way U-Boot can "see" how long the SW-reset was pressed, and a
23specific action can be taken. Two different actions are supported:
24
25a) Release after more than 5 seconds and less then 10 seconds:
26 -> Run POST
27
28 Please note, that the POST test will take a while (approx. 1 min
29 on the 128MByte board). This is mainly due to the system memory
30 test.
31
32b) Release after more than 10 seconds:
33 -> Restore factory default settings
34
35 The factory default values are restored. The default environment
36 variables are restored (ipaddr, serverip...) and the board
37 specific values (ethaddr, eth1addr and serial#) are restored
38 to the environment from the I2C EEPROM. Also a bootline parameter
39 is added to the Linux bootline to signal the Linux kernel upon
40 the next startup, that the factory defaults should be restored.
41
42The command to check this sw-reset status and act accordingly is
43
44=> chkreset
45
46This command is added to the default "bootcmd", so that it is called
47automatically upon startup.
48
49Also, the 2 LED's are used to indicate the current status of this
50command (time passed since pushing the button). When the POST test
51will be run, the green LED will be switched off, and when the
52factory restore will be initiated, the reg LED will be switched off.
53
54
55Loggin of POST results:
56-----------------------
57
58The results of the POST tests are logged in a logbuffer located at the end
59of the onboard memory. It can be accessed with the U-Boot command "log":
60
61=> log show
62<4>POST memory PASSED
63<4>POST cache PASSED
64<4>POST cpu PASSED
65<4>POST uart PASSED
66<4>POST ethernet PASSED
67
68The DENX Linux kernel tree has support for this log buffer included. Exactly
69this buffer is used for logging of all kernel messages too. By enabling the
70compile time option "CONFIG_LOGBUFFER" this support is enabled. This way you
71can access the U-Boot log messages from Linux too.
72
732007-08-10, Stefan Roese <sr@denx.de>