User Manual

Intel
®
Xeon
®
Processor 5600 Series Datasheet Volume 1 139
Thermal Specifications
7.3.2.4 PCIConfigRd()
The PCIConfigRd() command gives sideband read access to the entire PCI configuration
space maintained in the processor. This capability does not include support for route-
through to downstream devices or sibling processors. The exact listing of supported
devices, functions, and registers can be found in the Intel® Xeon® Processor 5600
Series Datasheet, Volume 2. PECI originators may conduct a device/function/register
enumeration sweep of this space by issuing reads in the same manner that BIOS
would. A response of all 1’s indicates that the device/function/register is
unimplemented.
PCI configuration addresses are constructed as shown in the following diagram. Under
normal in-band procedures, the Bus number (including any reserved bits) would be
used to direct a read or write to the proper device. Since there is a one-to-one mapping
between any given client address and the bus number, any request made with a non-
zero Bus number is ignored and the client will respond with a ‘pass’ completion code
but all 0’s in the data. The only legal bus number is 0x00. The client will return all 1’s in
the data response and ‘pass’ for the completion code for all of the following conditions:
• Unimplemented Device
• Unimplemented Function
• Unimplemented Register
PCI configuration reads may be issued in byte, word, or dword granularities.
7.3.2.4.1 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 7-32)
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
Table 7-21. GetTemp() Response Definition
Response Meaning
General Sensor Error (GSE) Thermal scan did not complete in time. Retry is appropriate.
0x0000 Processor is running at its maximum temperature or is currently being reset.
All other data Valid temperature reading, reported as a negative offset from the TCC
activation temperature.
Figure 7-20. PCI Configuration Address
31
Reserved
2728 20 19 15 1114 12 0
Bus Device Function Register