Communicating message request transaction types between agents in a computer system using multiple message groups

Abstract

A transmitting device and a receiving device are coupled via a high-speed serial interface within a computer system. The transmitting device transmits a packet header for a message request transaction that include a message group sub-field that indicates one of a plurality of message groups. The packet header also includes a format field that indicates whether the message request packet includes data. The packet header further includes a message code field to indicate a specific message type.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a protocol stack including layers to communicate data over an interconnect; and   a transmitter to transmit data on a point to point interconnect;   wherein the protocol stack including layers comprises a physical layer, a data link layer, and a transactions layer;   wherein the physical layer is to determine whether received data contains errors;   wherein the physical layer is to send the received data to the data link layer based upon whether the received data contains errors; and   wherein the data link layer is to send the received data from the physical layer to the transaction layer based upon whether the received data is to contain errors.   
     
     
         2 . The apparatus of  claim 1 , wherein the received data sent from the physical layer to the data link layer is in the form of a data link layer frame. 
     
     
         3 . The apparatus of  claim 2 , wherein the data link layer frame includes along with the received data a sequence number and a cyclical redundancy check (CRC) symbol. 
     
     
         4 . The apparatus of  claim 1 , wherein the received data sent from the data link layer to the transaction layer is in the form of a transaction frame. 
     
     
         5 . The apparatus of  claim 4 , wherein the transaction frame includes a header, footer, and a CRC symbol. 
     
     
         6 . The apparatus of  claim 1 , wherein the physical layer comprises a transmitter and a receiver. 
     
     
         7 . The apparatus of  claim 6 , wherein the transmitter is to be notified by Negative Acknowledgement (NAK) frames of errors of data received by a remote receiver. 
     
     
         8 . The apparatus of  claim 7 , wherein the errors are at least one of CRC symbol and sequence number errors. 
     
     
         9 . The apparatus of  claim 6 , wherein the transmitter enables 8b/10b encoding. 
     
     
         10 . The apparatus of  claim 9 , wherein the data received by the physical layer and the data link layer are framed using special symbols consistent with 8b/10b encoding. 
     
     
         11 . The apparatus of  claim 9 , wherein the data received by the physical layer and the data link layer are framed using special symbols consistent with 8b/10b encoding. 
     
     
         12 . A method, comprising:
 utilizing a protocol stack including layers to communicate data over an interconnect;   utilizing a transmitter to transmit data on a point to point interconnect;   wherein the protocol stack including layers comprises a physical layer, a data link layer, and a transactions layer;   utilizing the physical layer to determine whether received data contains errors;   utilizing the physical layer to send the received data to the data link layer based upon whether the received data is to contain errors; and   utilizing the data link layer to send the received data received from the physical layer to the transaction layer based upon whether the received data contains errors.   
     
     
         13 . The method of  claim 12  further comprising framing the data received at the physical layer and sending the framed data to the data link layer. 
     
     
         14 . The method of  claim 13 , wherein the framing includes appending a sequence number and a CRC symbol to the data received at the physical layer. 
     
     
         15 . The method of  claim 12  further comprising notifying the transmitter by NAK frames of errors present in data received at a remote receiver. 
     
     
         16 . The method of  claim 12  further comprising framing the data received by the physical layer and the data link layer using special symbols consistent with 8b/10b encoding. 
     
     
         17 . A non-transitory computer readable medium storing computer readable instructions for machine execution of a method for:
 utilizing a protocol stack including layers to communicate data over an interconnect;   utilizing a transmitter to transmit data on a point to point interconnect;   wherein the protocol stack including layers comprises a physical layer, a data link layer, and a transactions layer;   utilizing the physical layer to determine whether received data contains errors;   utilizing the physical layer to send the received data to the data link layer based upon whether the received data is to contain errors; and   utilizing the data link layer to send the received data received from the physical layer to the transaction layer based upon whether the received data contains errors.   
     
     
         18 . The non-transitory computer readable medium of  claim 17  further comprising framing the received data at the data link layer prior to sending the framed data to the transactions layer. 
     
     
         19 . A system-on-a-chip (SoC) embedded within a mobile device, comprising:
 a protocol stack including layers to communicate data over an interconnect; and   a transmitter to transmit data on a point to point interconnect;   wherein the protocol stack including layers comprises a physical layer, a data link layer, and a transactions layer;   wherein the physical layer a transmitter to enable 8b/10b encoding and to send data to a remote receiver and a receiver to decode 8b/10b encoded data and to receive data from a remote transmitter;   wherein the physical layer is to determine whether received data contains errors;   wherein the physical layer is to send the received data to the data link layer based upon whether the received data contains errors;   wherein the data link layer is to send the received data from the physical layer to the transaction layer based upon whether the received data contains errors.   
     
     
         20 . The SoC of  claim 19  is an embedded component within a cellular phone.