Links having flexible lane allocation

• US 20040088469A1
• Filed: 10/30/2002
• Published: 05/06/2004
• Est. Priority Date: 10/30/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Levy, Paul S.
• Granted Patent: US 7,802,049 B2
• Time in Patent Office: Days
• US Class Current: 710/316
• CPC Class Codes: G06F 13/4265 on a point to point bus G06F13/4247, G06F13/4282 take precedence
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247

Abstract

Machine-readable media, methods, and apparatus are described for flexibly establishing lanes of links. In some embodiments, any port of a device may be connected to another port of another device. Further, the device may determine interconnections of its ports to ports of other devices by issuing requests on its ports.

Claims

1. A device comprising

a plurality of ports to serially transmit symbols over lanes of a plurality of links and to serially receive symbols from lanes of the plurality of links, and

a plurality of agents to control the plurality of links and to support assignment of any port of the plurality of ports to any link of the plurality of links.

2. The device of claim 1 wherein the plurality of agents support defining lanes between any port of the plurality of ports to any port of another device.

3. The device of claim 1 wherein the plurality of agents determine lane ordering of each link of the plurality of links and cause the plurality of ports to serially transmit symbols in a manner that accounts for the lane ordering of the respective link.

4. The device of claim 1 wherein the plurality of agents determine lane ordering of each link of the plurality of links by transmitting identifier requests via each port of the plurality of ports.

5. The device of claim 1 wherein the plurality of agents disable each port of the plurality of ports that is not connected to a port of another device and determine lane ordering of each link of the plurality of links by transmitting identifier requests via each enabled port of the plurality of ports.

6. The device of claim 1 wherein the plurality of agents determine lane ordering of each link of the plurality of links based upon identifier requests received via the plurality of ports.

7. A device comprising

a plurality of ports to serially transmit and receive data over links to other devices,

a mapping table to associate the plurality of ports to lanes of the links, and

a first scatter engine to provide data units to ports associated with lanes of a first link in a first lane order indicated by the mapping table.

8. The device of claim 7 further comprising a first gather engine to order data units received across ports of the first link based upon the first lane order of the mapping table.

9. The device of claim 7 further comprising a second scatter engine to provide data units to ports associated with lanes of a second link in a second lane order indicated by the mapping table.

10. The device of claim 9 further comprising a second gather engine to order data units received across ports of the second link based upon the second lane order of the mapping table.

11. The device of claim 10 wherein the mapping table defines the first lane ordering and the second lane ordering by mapping the plurality of ports to ports of the other devices.

12. The device of claim 7 wherein the first scatter engine is to support any port of the plurality of ports being mapped to the first link and is to support any ordering of the ports mapped to the first link.

13. The device of claim 7 wherein the plurality of ports comprises more than two ports and the scatter engine supports any subset of the plurality of ports to be mapped to the first link.

14. A method comprising

issuing a first request on a first port of a first device,

receiving a first response to the first request that identifies a second device and a first port of the second device, and

identifying a first lane that exists between the first port of the first device and the first port of the second device in response to receiving the first response.

15. The method of claim 14, further comprising

issuing a second request on a second port of the first device, receiving a second response to the second request that identifies the second device and a second port of the second device, and

identifying a second lane that exists between the second port of the first device and the second port of the second device in response to receiving the second response.

16. The method of claim 14, further comprising

defining a link between the first device and the second device to include the first lane and the second lane.

17. The method of claim 14, further comprising

issuing a second request on a second port of the first device,

receiving a second response to the second request that identifies a third device and a first port of the third device, and

identifying a second lane that exists between the second port of the first device and the first port of the third device in response to receiving the second response.

18. The method of claim 17, further comprising

issuing a second request on the second port of the first device,

receiving a second response to the second request that indicates a first port of a third device is connected to the second port of the first device, and

identifying a second lane that exists between the second port of the first device and the first port of the third device in response to receiving the second response.

19. A method comprising

receiving a first request on a first port of a first device that identifies a second device and a first port of the second device,

issuing a first response to the first request that identifies the first device and the first port of the first device, and

identifying a first lane that exists between the first port of the first device and the first port of the second device in response to receiving the first request.

20. The method of claim 19, further comprising

receiving a second request on a second port of the first device that identifies the second device and a second port of the second device,

issuing a second response to the second request that identifies the first device and the second port of the first device, and

identifying a second lane that exists between the second port of the first device and the second port of the second device in response to receiving the second request.

21. The method of claim 19, further comprising

receiving a second request on the first port of the first device,

issuing a third request on a second port of the first device in response to determining that the second request comprises a bridge request,

receiving, on the second port of the first device, a third response to the third request that identifies a third device and a first port of the third device, and

identifying a third lane that exists between the second port of the first device and the first port of the third device in response to receiving the third response.

22. The method of claim 21, further comprising

issuing, on the first port of the first device, a second response to the second request that identifies the first device and the second port of the first device.

23. A machine readable medium comprising a plurality of instructions that, in response to being executing, result in a computing device,

issuing a first request on a first port of a first device that identifies the first device and the first port of the first device,

receiving the first request on a first port of a second device,

issuing, on the first port of the second device, a first response to the first request that identifies the second device and the first port of the second device,

receiving, on the first port of the first device, the first response to the first request, and

updating a mapping table to indicate that a first lane exists between the first port of the first device and the first port of the second device in response to the first device receiving the first response.

24. The computer readable medium of claim 23, wherein the plurality of instructions, in response to being executed, result in the computing device

issuing a second request on a second port of the first device that identifies the first device and the second port of the first device,

receiving the second request on a second port of the second device,

issuing, on the second port of the second device, a second response to the second request that identifies the second device and the second port of the second device,

receiving, on the second port of the first device, the second response to the second request, and

updating the mapping table to indicate that the second lane exists between the second port of the first device and the second port of the second device in response to the first device receiving the second response.

25. The computer readable medium of claim 24, wherein the plurality of instructions, in response to being executed, result in the computing device

defining a link between the first device and the second device to include the first lane and the second lane.

26. The computer readable medium of claim 23, wherein the plurality of instructions, in response to being executed, result in the computing device

issuing a bridge request on the first port of the first device,

receiving the bridge request on the first port of the second device,

issuing a second request on a second port of the second device that identifies the second device and the second port of the second device in response to the second device receiving the bridge request,

receiving the second request on a first port of a third device,

issuing, on the first port of the third device, a second response to the second request that identifies the third device and the first port of the third device,

receiving, on the second port of the second device, the second response to the second request, and

issuing, on the first port of the second device, a bridge response to the bridge request that identifies second port of the second device is connected to the first port of the third device, and

updating the mapping table to indicate that the second lane exists between the second port of the second device and the first port of the third device in response to the first device receiving the bridge request,

27. A system comprising

a first device comprising first ports to transfer data,

a second device comprising first ports to transfer data, and

first lanes interconnecting the first ports of the first device with the first ports of the second device to form a first link between the first device and the second device,

wherein the first device is to determine a lane ordering of the first link and is to scatter data units across the first lanes based upon the determined lane ordering.

28. The system of claim 27 wherein the first device scatters the data across the first lanes such that the first ports of the second device receive the data units via a predefined ordering of the first ports of the second device.

29. The system of claim 27 wherein the first device comprises a transmit buffer to store data units in order and a scatter engine to retrieve the data units from the transmit buffer and to scatter the data across the first lanes such that the first ports of the second device receive the data units via a predefined ordering of the first ports of the second device. 30. The system of claim 27, wherein

the first ports of the first device comprise encoders to generate symbols to transmit and decoders to decode received symbols, and

the first ports of the second device comprise encoders to generate symbols to transmit and decoders to decode received symbols.