Tunneling of peripheral-bus protocol traffic over coherent fabric
A peripheral device includes two or more peripheral-bus modules, a coherent interconnect, and two or more tunnel adapters coupled between the peripheral-bus modules and the coherent interconnect. The peripheral-bus modules are to exchange peripheral-bus packets with one another in accordance with a peripheral-bus protocol. The coherent interconnect is to connect electronic components of the peripheral device in accordance with a coherent interconnect protocol. The tunnel adapters are to convey the peripheral-bus packets between the peripheral-bus modules over the coherent interconnect, by translating between the peripheral-bus packets and messages of the coherent interconnect protocol.
1 . A peripheral device, comprising:
two or more peripheral-bus modules, to exchange peripheral-bus packets with one another in accordance with a peripheral-bus protocol;
a coherent interconnect, to connect electronic components of the peripheral device in accordance with a coherent interconnect protocol; and
two or more tunnel adapters, which are coupled between the peripheral-bus modules and the coherent interconnect, and which are to convey the peripheral-bus packets between the peripheral-bus modules over the coherent interconnect, by translating between the peripheral-bus packets and messages of the coherent interconnect protocol.
2 . The peripheral device according to claim 1 , wherein a given peripheral-bus module among the peripheral-bus modules is to communicate with a host over a peripheral bus in accordance with the peripheral-bus protocol.
3 . The peripheral device according to claim 1 , wherein the messages of the coherent interconnect protocol are smaller in data size than the peripheral-bus packets, and wherein a given tunnel adapter among the tunnel adapters is to translate a peripheral-bus packet into a plurality of the messages.
4 . The peripheral device according to claim 1 , wherein the messages of the coherent interconnect protocol are smaller in data size than the peripheral-bus packets, and wherein a given tunnel adapter among the tunnel adapters is to identify a plurality of the messages corresponding to a peripheral-bus packet, and to reconstruct the peripheral-bus packet from the identified plurality of messages.
5 . The peripheral device according to claim 1 , wherein the coherent interconnect protocol does not guarantee unconditional in-order delivery of the messages, and wherein, in translating the peripheral-bus packets into the messages, a given tunnel adapter among the tunnel adapters is to select two or more of the messages, and to cause the coherent interconnect to deliver the selected messages in-order.
6 . The peripheral device according to claim 5 , wherein the given tunnel adapter is to cause the coherent interconnect to deliver the selected messages in-order by assigning to the selected messages a same hash value, thereby causing the coherent interconnect to route the selected messages over a same route.
7 . The peripheral device according to claim 1 , wherein a given tunnel adapter among the tunnel adapters is to:
receive messages corresponding to peripheral-bus packets originating from multiple different peripheral-bus modules;
maintain a respective context for each of the multiple different peripheral-bus modules; and
reconstruct the peripheral-bus packets originating from each of the multiple different peripheral-bus modules using the respective context.
8 . The peripheral device according to claim 1 , wherein at least two of the tunnel adapters are to control a flow of the messages therebetween by applying credit-based flow control.
9 . A method, comprising:
exchanging peripheral-bus packets between two or more peripheral-bus modules in a peripheral device, in accordance with a peripheral-bus protocol;
communicating among electronic components of the peripheral device using a coherent interconnect, in accordance with a coherent interconnect protocol; and
conveying the peripheral-bus packets between the peripheral-bus modules over the coherent interconnect, by translating between the peripheral-bus packets and messages of the coherent interconnect protocol.
10 . The method according to claim 9 , further comprising, using a given peripheral-bus module among the peripheral-bus modules, communicating with a host over a peripheral bus in accordance with the peripheral-bus protocol.
11 . The method according to claim 9 , wherein the messages of the coherent interconnect protocol are smaller in data size than the peripheral-bus packets, and wherein translating between the peripheral-bus packets and the messages of the coherent interconnect protocol comprises translating a peripheral-bus packet into a plurality of the messages.
12 . The method according to claim 9 , wherein the messages of the coherent interconnect protocol are smaller in data size than the peripheral-bus packets, and wherein translating between the peripheral-bus packets and the messages of the coherent interconnect protocol comprises identifying a plurality of the messages corresponding to a peripheral-bus packet, and reconstructing the peripheral-bus packet from the identified plurality of messages.
13 . The method according to claim 9 , wherein the coherent interconnect protocol does not guarantee unconditional in-order delivery of the messages, and wherein translating the peripheral-bus packets into the messages comprises selecting two or more of the messages, and causing the coherent interconnect to deliver the selected messages in-order.
14 . The method according to claim 13 , wherein causing the coherent interconnect to deliver the selected messages in-order comprises assigning to the selected messages a same hash value, thereby causing the coherent interconnect to route the selected messages over a same route.
15 . The method according to claim 9 , wherein translating the messages into the peripheral-bus packets comprises:
receiving messages corresponding to peripheral-bus packets originating from multiple different peripheral-bus modules;
maintaining a respective context for each of the multiple different peripheral-bus modules; and
reconstructing the peripheral-bus packets originating from each of the multiple different peripheral-bus modules using the respective context.
16 . The method according to claim 9 , and comprising controlling a flow of the messages by applying credit-based flow control.