Links having flexible lane allocation

• US 7,802,049 B2
• Filed: 10/30/2002
• Issued: 09/21/2010
• Est. Priority Date: 10/30/2002
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Levy, Paul S.
• Primary Examiner(s): Rinehart; Mark
• Assistant Examiner(s): DALEY, CHRISTOPHER ANTHONY
• Application Number:
  US10/284,847
• Publication Number:
  US 20040088469A1
• Time in Patent Office: 2,883 Days
• Field of Search: 710/52, 710/316, 710/306, 710/29, 710/117, 710/72, 710/73, 710/71, 710/302, 710/66, 710/36, 370/389, 370/412, 370/395, 715/812, 715/815
• 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 comprising a first port, a second port, a third port, and a fourth port to serially transmit symbols over lanes of a plurality of links and to serially receive symbols from lanes of the plurality of links,

a mapping table coupled to the plurality of ports, wherein the mapping table is to provide control information including port mappings and lane order to support assignment of any combination of the plurality of ports to any link of the plurality of links, and

a plurality of agents coupled to the plurality of ports, a first agent of the plurality of agents further comprises,

a first scatter engine to provide symbols for serial transmission to the plurality of ports associated with lanes of a first link in a first lane order indicated by the mapping table, and

a first gather engine to reorder symbols serially received over the plurality of ports based upon port mappings indicated by the mapping table and,

wherein the plurality of agents are to control the plurality of links and support assignment of any combination 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 comprising a first port, a second port, a third port and a fourth port to serially transmit and receive data over links to other devices,

a mapping table to associate any permutation of the plurality of ports to the links,

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, and

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.

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 gather engine to order data units received across ports of the second link based upon the second lane order of the mapping table.

10. The device of claim 9 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.

11. 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.

12. 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.

13. 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,

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,

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.

14. The computer readable medium of claim 13, wherein the plurality of instructions, in response to being executed, result in the computing device

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

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

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

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

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

15. The computer readable medium of claim 14, 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 third lane, and

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

16. A system comprising

a first device comprising at least a first port, a second port, a third port and a fourth port to transfer data units,

a second device comprising ports to transfer data units,

a third device comprising ports to transfer data units,

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

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

the first device further comprises,

a mapping table to associate any permutation of a first plurality of ports to the first link and any permutation of a second plurality of ports to the second link,

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

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

17. The system of claim 16 the first device further comprises a transmit buffer, wherein the first scatter engine is to retrieve the data units from the transmit buffer before scattering the data across the first lanes such that ports of the second device receive the data units via a predefined ordering of the ports of the second device.

18. The system of claim 16 wherein the first device comprises,

a gather engine to generate the data units in order by reordering the data units received from the second device over the first link,

a receive buffer to store data units in order, and

a controller to retrieve the data units from the receive buffer before providing the data units in a predefined order to the first device for further processing.

19. The system of claim 16, wherein

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

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

20. A method in a network device, comprising:

storing control information including port mappings and lane order in a mapping table to support assignment of any combination of a plurality of ports to any link of a plurality of links, serially transmitting symbols over lanes of the plurality of links, wherein symbols are transmitted over the plurality of ports associated with the lanes of a first link in a first lane order indicated by the port mappings, serially receiving symbols from lanes of the plurality of links and reordering the symbols received over the lanes coupled to a plurality of ports based upon port mappings indicated by the port mappings, and controlling the plurality of links and supporting assignment of any combination of the plurality of ports to any link of the plurality of links;

wherein the mapping table is coupled to the plurality of ports, wherein the mapping table is to provide control information including port mappings and lane order to support assignment of any combination of the plurality of ports to any link of the plurality of links, and a plurality of agents coupled to the plurality of ports, a first agent of the plurality of agents further comprises, a first scatter engine to provide symbols for serial transmission to the plurality of ports associated with lanes of a first link in a first lane order indicated by the mapping table, and a first, gather engine to reorder symbols serially received over the plurality of ports based upon port mappings indicated by the mapping table.

21. The method of claim 20 further comprises defining lanes between any port of the plurality of ports to any port of another device.

22. The method of claim 20 further comprises,

determining lane ordering of each link of the plurality of links, and

causing the plurality of ports to serially transmit symbols in a manner that accounts for the lane ordering of the respective link.

23. The method of claim 22 comprises determining the lane ordering of each link of the plurality of links by transmitting identifier requests via each port of the plurality of ports.

24. The method of claim 22 comprises determining the lane ordering of each link of the plurality of links based upon identifier requests received via the plurality of ports.

25. The method of claim 20 further comprises disabling 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.

26. A method in a network device, comprising:

storing mappings that indicate associations of any permutation of the plurality of ports to the links, serially transmitting data units over a link from a plurality of ports of the network device to other devices, receiving data units over links from the other devices over the plurality of ports of the network device, wherein the plurality of ports are coupled to the links, and wherein the data units are provided by a first scatter engine to the plurality of ports associated with lanes of a first link in a first lane order indicated by the mappings, and wherein the data units are provided by a second scatter engine to the plurality of ports associated with lanes of a second link in a second lane order indicated by the mapping table;

wherein the mapping table is coupled to the plurality of ports, wherein the mapping table is to provide control information including port mappings and lane order to support assignment of any combination of the plurality of ports to any link of the plurality of links, and a plurality of agents coupled to the plurality of ports, a first agent of the plurality of agents further comprises, a first scatter engine to provide symbols for serial transmission to the plurality of ports associated with lanes of a first link in a first lane order indicated by the mapping table, and a first, gather engine to reorder symbols serially received over the plurality of ports based upon port mappings indicated by the mapping table.

27. The method of claim 26 further comprises ordering data units received across the plurality of ports of the first link based upon the first lane order before the first scatter engine provides the data units to the plurality of ports.

28. The method of claim 26 further comprises ordering data units received across the plurality of ports of the second link based upon the second lane order before the second scatter engine provides the data units to the plurality of ports.

29. The method of claim 26 further comprises defining the first lane ordering and the second lane ordering in the mappings by mapping the plurality of ports of the network device to ports of the other devices.

30. The method of claim 26 further comprises supporting any port of the plurality of ports being mapped to the first link and any ordering of the plurality of ports mapped to the first link.