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CP6924-1-RA-A User Guide
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4.3.1
Power On Self Test
4.3.1.1
Test Routines
Upon power on or system reset, the bootloader performs the following power on self tests (POST):
The POST result is stored in the transient environment variable 'postresult'. If no POST error occurred, postresult is set to
'0', otherwise - depending on the actual POST error - postresult is set as shown in table 4-2 below.
The 'postresult' value is passed to the linux kernel by means of the 'bootargs' environment variable.
The following table shows the POST code values written into the 'postresult' environment variable.
Table 4-1:
POST tests
Test
Description
Serial
Onboard Unit Computer serial controller loopback test
I2C
Check for presence of onboard I2C devices
PCI Express
Check for PCI Express switch device presence
Serviceport
Onboard PPC405EX ethernet internal loopback test
Bootloader environment
Check for valid bootloader environment (CRC correct or both CRCs are
0xFFFFFFFF == not initialized)
VPD area
Check for valid VPD area (CRC is valid)
DDR RAM data/address lines Data/address line test. Checks for stucked or shortened data/address
lines
DDR RAM memory cells
Checkerboard standard test algorithm
Cache
PPC405EX data and instruction cache
KCS
KCS Interface communication
Table 4-2:
POST routines and error codes
Device
Test
0x00
All POST were successful
0x01
Serial POST failed
0x02
I2C POST failed
0x04
PCIe POST failed
0x08
Ethernet POST failed
0x10
Bootloader environment POST failed
0x20
VPD POST failed
0x40
Memory data/address line POST failed
0x80
Memory device cells POST failed
0x100
CPU cache POST failed
0x200
KCS POST failed
