Method and system for efficient framing on addressed buses

• US 20070180173A1
• Filed: 02/01/2006
• Published: 08/02/2007
• Est. Priority Date: 02/01/2006
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Nuckolls, Neal, Jin, Changxi, Loyola, Guillermo, Siener, Stephen
• Granted Patent: US 7,664,898 B2
• Time in Patent Office: Days
• US Class Current: 710/105
• CPC Class Codes: G06F 13/4221 being an input/output bus, e.g. ISA bus, EISA bus, PCI bus, SCSI bus

Abstract

A framing mechanism may be provided that enables passing of messages over an addressed bus. This creates a form of information hiding, which passes information by converting an addressed bus interface to a message-based bus interface. Address-based information in a transaction may be replaced with additional information that specifies framing details comprising, for example, a check pattern and length information. The check pattern provides a mechanism for determining whether frame information may be valid. An end device may utilize this length information to determine an actual length of an incoming frame. The combination of the check pattern and the length information may provide a pattern for resynchronizing a data stream when errors are detected. The framing mechanism may operate over existing addressed buses without requiring host side controller hardware modifications and additional host side software driver may be utilized to add the framing information.

Claims

1. A method for communicating information over a bus interface, the method comprising:

establishing an addressing convention between a host and a device communicatively coupled to said host via a bus, wherein transfer of data between said host and at least one specific address corresponding to said device is interpreted as at least one frame, said frame being compliant with a bus protocol associated with said bus;

configuring a payload portion corresponding to at least a first byte of said frame to indicate length information of said frame; and

communicating said frame to a receiving device via a bus using said bus protocol.

2. The method according to claim 1, wherein said bus protocol is one of:

a PCMCIA/CF bus protocol and a SD bus protocol.

3. The method according to claim 1, wherein said length information comprises a length of said frame, and a checksum of said length information.

4. The method according to claim 1, further comprising processing said frame based on said addressing convention.

5. The method according to claim 1, further comprising processing said frame based on said at least one specific address.

6. The method according to claim 4, further comprising determining a value of a length of said frame from said payload portion.

7. The method according to claim 6, further comprising validating said value of said length based on a checksum in said length information.

8. The method according to claim 7, further comprising processing said frame if said length is correct based on said validating.

9. A machine-readable storage having stored thereon, a computer program having at least one code section for communicating information over a bus interface, the at least one code section being executable by a machine for causing the machine to perform steps comprising:

establishing an addressing convention between a host and a device communicatively coupled to said host via a bus, wherein transfer of data between said host and at least one specific address corresponding to said device is interpreted as at least one frame, said frame being compliant with a bus protocol associated with said bus;

configuring a payload portion corresponding to at least a first byte of said frame to indicate length information of said frame; and

communicating said frame to a receiving device via a bus using said bus protocol.

10. The machine-readable storage according to claim 9, wherein said bus protocol is one of:

a PCMCIA/CF bus protocol and a SD bus protocol.

11. The machine-readable storage according to claim 9, wherein said length information comprises a length of said frame, and a checksum of said length information.

12. The machine-readable storage according to claim 9, further comprising code for processing said frame based on said addressing convention.

13. The machine-readable storage according to claim 9, further comprising code for processing said frame based on said at least one specific address.

14. The machine-readable storage according to claim 12, further comprising code for determining a value of a length of said frame from said payload portion.

15. The machine-readable storage according to claim 14, further comprising code for validating said value of said length based on a checksum in said length information.

16. The machine-readable storage according to claim 15, further comprising code for processing said frame if said length is correct based on said validating.

17. A system for communicating information over a bus interface, the system comprising:

at least one processor that an addressing convention between a host and a device communicatively coupled to said host via a bus, wherein transfer of data between said host and at least one specific address corresponding to said device is interpreted as at least one frame, said frame being compliant with a bus protocol associated with said bus;

the at least one processor configures a payload portion corresponding to at least a first byte of said frame to indicate length information of said frame; and

the at least one processor communicates said frame to a receiving device via a bus using said bus protocol.

18. The system according to claim 17, wherein said bus protocol is one of:

a PCMCIA/CF bus protocol and a SD bus protocol.

19. The system according to claim 17, wherein said length information comprises a length of said frame, and a checksum of said length information.

20. The system according to claim 17, further comprising the at least one processor processes said frame based on said addressing convention.

21. The system according to claim 17, further comprising the at least one processor processes said frame based on said at least one specific address.

22. The system according to claim 20, further comprising the at least one processor determines a value of a length of said frame from said payload portion.

23. The system according to claim 22, further comprising the at least one processor validates said value of said length based on a checksum in said length information.

24. The system according to claim 23, further comprising the at least one processor processes said frame if said length is correct based on said validating.