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PECI Interface
PCI configuration reads may be issued in byte, word or dword granularities.
7.1.4.10.1
Command Format
The RdPCIConfig() format is as follows:
Write Length: 0x06
Read Length: 0x05 (dword)
Command: 0x61
Description: Returns the data maintained in the PCI configuration space at the
requested PCI configuration address. The Read Length dictates the desired data return
size. This command supports only dword responses with a completion code on the
processor PECI clients. All command responses are prepended with a completion code
that includes additional pass/fail status information. Refer to
regarding completion codes.
Figure 7-40. RdPCIConfig()
0
Byte #
Client Address
Byte
Definition
4
Host ID[7:1] &
Retry[0]
10
Completion
LSB
Code
Note that the 4-byte PCI configuration address and read data field defined in
Figure 7-40
7.1.4.10.2
Supported Responses
The typical client response is a passing FCS, a passing Completion Code and valid data.
Under some conditions, the client's response will indicate a failure.
The PECI client response can also vary depending on the address and data. It will
respond with a passing completion code if it successfully submits the request to the
appropriate location and gets a response. Exactly what the receiving agent does with
the data or how it responds is up to that agent and is outside the scope of PECI 3.0.
Table 7-13. RdPCIConfig() Response Definition (Sheet 1 of 2)
Response
Bad FCS
Abort FCS
CC: 0x40
Thermal/Mechanical Specifications and Design Guide
1
Write Length
0x06
{0x02,0x03,0x05}
5
6
LSB
PCI Configuration Address
11
12
Data (1, 2 or 4 bytes)
are sent in standard PECI ordering with LSB first and MSB last.
Electrical error
Invalid command formatting (mismatched RL/WL/Command Code)
Command passed, data is valid.
2
Read Length
Cmd Code
0x61
7
13
Meaning
Section 7.1.7.2
for details
3
8
9
MSB
FCS
14
15
MSB
FCS
83
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