Thermal Specifications
PCI configuration reads may be issued in byte, word, or dword granularities.
6.3.2.4.1
Command Format
The PCIConfigRd() format is as follows:
Write Length: 5
Read Length: 2 (byte data), 3 (word data), 5 (dword data)
Command: 0xc1
Multi-Domain Support: Yes (see Table 6-15)
Description: Returns the data maintained in the PCI configuration space at the PCI
configuration address sent. The Read Length dictates the desired data return size. This
command supports byte, word, and dword responses as well as a completion code. All
command responses are prepended with a completion code that includes additional
pass/fail status information. Refer to Section 6.3.4.2 for details regarding completion
codes.
Figure 6-14. PCIConfigRd()
Byte #
0
1
2
3
Write Length
0x05
Read Length
{0x02,0x03,0x05}
Cmd Code
0xc1
Client Address
Byte
Definition
4
5
6
7
8
LSB
PCI Configuration Address
MSB
FCS
9
10
8+RL
9+RL
FCS
Completion
Code
Data 0
...
Data N
Note that the 4-byte PCI configuration address defined above is sent in standard PECI
ordering with LSB first and MSB last.
6.3.2.4.2
Supported Responses
The typical client response is a passing FCS, a passing Completion Code (CC) and valid
Data. Under some conditions, the client’s response will indicate a failure.
Table 6-7.
PCIConfigRd() Response Definition
Response
Meaning
Abort FCS
CC: 0x40
CC: 0x80
Illegal command formatting (mismatched RL/WL/Command Code)
Command passed, data is valid
Error causing a response timeout. Either due to a rare, internal timing condition or a
processor RESET or processor S1 state. Retry is appropriate outside of the RESET or
S1 states.
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