Host bridge translating non-coherent packets from non-coherent link to coherent packets on conherent link and vice versa

A computer system, comprising:

• a processing subsystem including a first processing node coupled to a second processing node via a coherent communication link on which the first processing node and the second processing node are configured to transmit coherent packets, the coherent packets used to maintain consistency of data stored in memory and in one or more caches included in the processing subsystem, wherein the first processing node comprises a host bridge;
• an input/output (I/O) node coupled to the first processing node via a non-coherent communication link on which the first processing node and the I/O node are configured to transmit only non-coherent packets;
• wherein the coherent and non-coherent communication links are separate and have the same electrical interface and the same signal definition;
• wherein the host bridge is coupled to receive a coherent packet from the second processing node via the coherent communication link and configured to respond to the coherent packet by translating the coherent packet to a non-coherent packet and transmitting the non-coherent packet to the I/O node via the non-coherent communication link;
• and
• wherein the coherent and non-coherent packets have identically located command fields, and wherein said translating comprises copying the contents of the command field of the coherent packet to the command field of the non-coherent packet.

A method for use in a computer system, comprising:

• a host bridge within a first processing node receiving a non-coherent packet from an input/output (I/O) node via a non-coherent communication link on which the first processing node and the I/O node are configured in transmit only non-coherent packets;
• the host bridge translating the non-coherent packet to a coherent packet, wherein the coherent and non-coherent packets have identically located command fields, and wherein said translating comprises copying the contents of the command field of the non-coherent packet to the command field of the coherent packet;
• and
• the host bridge transmitting the coherent packet to a second processing node via a coherent communication link on which the first processing node and the second processing node are configured to transmit coherent packets, the coherent packets used to maintain consistency of data stored in memory and in one or more caches included in the first processing node and the second processing node, wherein the coherent and non-coherent communication links are separate and have the same electrical interface and the same signal definition.

A method for use in a computer system, comprising:

• a host bridge within a first processing node receiving a coherent packet from a second processing node via a coherent communication link on which the first processing node and the second processing node are configured to transmit coherent packets, the coherent packets used to maintain consistency of data stored in memory and in one or more caches included in the first processing node and the second processing node;
• the host bridge translating the coherent packet to a non-coherent packet, wherein the coherent and non-coherent packets have identically located command fields, and wherein said translating comprises copying the contents of the command field of the coherent packet to the command field of the non-coherent packet;
• and
• the host bridge transmitting the non-coherent packet to an input/output (I/O) node via a non-coherent communication link on which the first processing node and the I/O node are configured transmit only non-coherent packets, wherein the coherent and non-coherent communication links are separate and have the same electrical interface and the same signal definition.

A computer system comprising:

• a plurality of coherent nodes interconnected by coherent links on which the plurality of coherent nodes are configured to transmit coherent packets, the coherent packets used to maintain consistency of data stored in memory and in one or more caches included in one or more of the plurality of coherent nodes, wherein at least a first node of the plurality of coherent nodes includes a host bridge and is coupled to a non-coherent link on which the first node is configured to transmit only non-coherent packets;
• and
• an input/output (I/O) node coupled to the non-coherent link and configured to transmit a non-coherent packet on the non-coherent link;
• wherein the host bridge is configured to translate the non-coherent packet to a coherent packet for transmission to one or more of the plurality of coherent nodes, and wherein a command field of the non-coherent and coherent packets is located in a same position within the non-coherent and coherent packets, and wherein the host bridge is configured to copy the command from the command field of the non-coherent packet to the command field of the coherent packet, and wherein the coherent and non-coherent links are separate and have the same electrical interface and the same signal definition.