Method and apparatus for response modes in pipelined environment

• US 6,785,753 B2
• Filed: 06/01/2001
• Issued: 08/31/2004
• Est. Priority Date: 06/01/2001
• Status: Active Grant

• Current Assignee: META Platforms Technologies LLC (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Original Assignee: Sonics Incorporated (Meta Platforms, Inc. (f/k/a Facebook, Inc.))
• Inventors: Weber, Wolf-Dietrich, Wingard, Drew E., Tomlinson, Jay S.
• Primary Examiner(s): Dang, Khanh
• Application Number:
  US09/872,126
• Publication Number:
  US 20020184421A1
• Time in Patent Office: 1,187 Days
• Field of Search: 710/1, 710/26, 710/29, 710/104, 710/105, 710/107, 710/110, 710/267, 710/268, 710/266, 710/305
• US Class Current: 710/105
• CPC Class Codes: G06F 13/4226 with asynchronous protocol

Abstract

A pipelined network is disclosed which provides for at least one mode to control the state of a response flag and when the target device is unable to respond to an initiator device request.

Claims

1. A pipelined network, comprising:

at least one initiator device configured to issue requests;

a target device configured to receive requests; and

bus signal lines comprising lines to issue requests and responses to requests between initiator devices and the target device and a response flag coupled between the target device and at least one of the initiator devices;

the target device having logic to respond to the request in different modes of operation comprising

a first mode wherein a no-response-available (NRA) response is selectively issued and a response flag is set to a first state if space is available in the target device to service the request;

a second mode wherein an NRA response is selectively issued and the response flag is set to the first state if space is available in the target device to service the request and a port of the target device is not busy;

a third mode wherein an NRA response is selectively issued and the response flag is set to the first state; and

control logic to direct the logic which mode of operation to utilize when issuing the NRA response and setting the state of the response flag to a first initiator device when the target device is unavailable to service the request of the first initiator device.

2. The pipelined network as set forth in claim 1, wherein the control logic is selected from the group consisting of static control, program controlled, software controlled and hardwired controlled.

3. The pipeline as set forth in claim 1, wherein the logic comprises response logic configured to issue a NRA response and a response flag logic configured to selectively place the response flag in the first state or the second state.

4. The pipeline as set forth in claim 3, wherein the logic further comprises a fourth mode wherein the NRA response is selectively issued and the response flag is set to the first state when an early-flow-control indication occurs.

5. The pipeline as set forth in claim 4, wherein the control logic selects one of the first, second, third, and fourth modes and logically combines the states of the response flag corresponding to the selected mode to generate a response flag received by the at least one initiator device.

6. A pipelined network, comprising:

at least one initiator device configured to issue requests;

a target device configured to receive requests; and

bus signal lines comprising lines to issue requests and responses to requests between initiator devices and the target device and a response flag coupled between the target device and at least one of the initiator devices;

the target device having logic to respond to the request in different modes of operation comprising

a first mode wherein a NRA response is selectively issued and a response flag is set to a first state if an early-flow-control indication is in an inactive state;

a second mode wherein an NRA response is selectively issued and the response flag is set to the first state; and

control logic to direct the logic which mode of operation to utilize when issuing the NRA response and setting the state of the response flag to a first initiator device when the target device is unavailable to service the request of the first initiator device.

7. The pipelined network as set forth in claim 6, wherein the control logic is selected from the group consisting of static control, program controlled, software controlled and hardwired controlled.

8. The pipeline as set forth in claim 6, wherein the logic comprises response logic configured to issue the NRA response and a response flag logic configured to selectively place the response flag in the first state or the second state.

9. A pipelined network comprising:

at least one initiator device configured to issue requests;

a target device configured to receive requests; and

bus signal lines comprising lines to issue requests and responses to requests between initiator devices and the target device and a response flag coupled between the target device and at least one of the initiator devices;

the target device having logic to respond to the request in different modes of operation comprising

a first mode wherein a NRA response is selectively issued and a response flag is set to a first state if a first condition exists;

a second mode wherein an NRA response is selectively issued and the response flag is set to the first state if a second condition exists; and

control logic to direct the logic which mode of operation to utilize when issuing the NRA response and setting the state of the response flag to a first initiator device when the target device is unavailable to service the request of the first initiator device.

10. The pipeline as set forth in claim 9, wherein the control logic logically combines the states of the response flag corresponding to the first and second modes to generate a response flag to be received by the at least one initiator device.

11. The pipeline as set forth in claim 9, wherein the first condition comprises space availability in the target device to service the request and whether the target device is busy.

12. The pipeline as set forth in claim 9, wherein the second condition comprises a state of an early-flow-control.

13. In a pipelined network comprising at least one initiator device configured to issue requests and at least one target device coupled to receive requests from at least one initiator device, a method for notifying initiator devices that a target device is unavailable to service an initiator device request, the method comprising:

directing the target to operate in a first mode of operation or in a second mode of operation;

wherein if the target operates in the first mode, then

selectively issuing a NRA response and setting a response flag to a first state if space is available in the target device to service the request and the target device is busy;

selectively issuing an NRA response and setting the response flag to the first state if space is available in the target device to service the request and a port of the target device is not busy;

wherein if the target operates in the second mode, then

selecting a response to issue to an initiator device when a target device is unavailable to service the initiator device request.

14. The method as set forth in claim 13, wherein selecting is performed at a time selected from the group consisting of at run-time and at network configuration.

15. The method as set forth in claim 13, further comprising selectively issuing an NRA response and setting the response flag to the first state if an early-flow-control indication is in a first state and the target operates in either the first or the second mode.

16. The method as set forth in claim 15, further comprising logically combining response flag states of selected responses and to generate a response flag received by the at least one initiator device.

17. In a pipelined network comprising at least one initiator device configured to issue requests and at least one target device coupled to receive requests from at least one initiator device, a method for notifying initiator devices that a target device is unavailable to service an initiator device request, the method comprising:

directing the target to operate in a first mode of operation or in a second mode of operation;

wherein if the target operates in the first mode, then

selectively issuing a NRA response and setting the response flag to the first state if an early-flow-control indication is in a first state;

selectively issuing the NRA response and setting the response flag to the first state; and

selecting a response to issue to an initiator device when a target device is unavailable to service the initiator device request.

18. The method as set forth in claim 17, wherein selecting is performed at a time selected from the group consisting of at run-time and at network configuration.

20. The method as set forth in claim 18, further comprising logically combining the states of the response flag corresponding to the first and second conditions to generate a response flag to be received by the at least one initiator device.

21. The method as set forth in claim 18, wherein the first condition comprises space availability in the target device to service the request and whether the target device is busy.

22. The method as set forth in claim 18, wherein the second condition comprises a state of an early-flow-control.

19. In a pipelined network comprising at least one initiator device configured to issue requests and at least one target device coupled to receive requests from at least one initiator device, a method for notifying initiator devices that a target device is unavailable to service an initiator device request, the method comprising:

directing the target to operate in a first mode of operation or in a second mode of operation;

wherein if the target operates in the first mode, then

selectively issuing a NRA response and setting a response flag to a first state if a first condition exists;

selectively issuing the NRA response and setting the response flag to the first state if a second condition exists; and

selecting a response to issue to an initiator device when the target device is unavailable to service the initiator device request.