Datasheet
Interfaces
Intel
®
Xeon
®
Processor C5500/C3500 Series
Datasheet, Volume 1 February 2010
84 Order Number: 323103-001
The 4-byte data defined above is sent in standard PECI ordering with LSB first and MSB
last.
If the MbxSend() response returns a bad Read FCS, the completion code can't be
trusted and the semaphore may or may not be taken. In order to clean out the
interface, an MbxGet() must be issued and the response data should be discarded.
2.2.2.8 MbxGet()
The MbxGet() command is utilized for retrieving response data from the generic
Mailbox interface as well as for unlocking the acquired mailbox. See Section 2.2.2.7 for
details regarding the MbxSend() command. Many of the fundamental concepts of
Mailbox ownership, release, and management are discussed in Section 2.2.2.9.
2.2.2.8.1 Write Data
The MbxGet() command is designed to retrieve response data from a previously
deposited request. In order to guarantee alignment between the temporally separated
request (MbxSend) and response (MbxGet) commands, the originally granted
Transaction ID (sent as part of the passing MbxSend() completion code) must be issued
as part of the MbxGet() request.
Any mailbox request made with an illegal or unlocked Transaction ID will get a failed
completion code response. If the Transaction ID matches an outstanding transaction ID
associated with a locked mailbox, the command will complete successfully and the
response data will be returned to the originator.
Unlike MbxSend(), no Assured Write protocol is necessary for this command because
this is a read-only function.
2.2.2.8.2 Command Format
The MbxGet() format is as follows:
Write Length: 2
Read Length: 5
Command: 0xd5
Multi-Domain Support: Yes (see Table 41)
Description: Retrieves response data from mailbox and unlocks / releases that
mailbox resource.
Table 38. MbxSend() Response Definition
Response Meaning
Bad FCS Electrical error
CC: 0x4X Semaphore is granted with a Transaction ID of ‘X’
CC: 0x80
Error causing a response timeout. Either due to a rare, internal timing condition or a
processor RESET condition or processor S1 state. Retry is appropriate outside of the
RESET or S1 states.
CC: 0x86 Mailbox interface is unavailable or busy