META DATA HANDLING WITHIN A FLASH MEDIA CONTROLLER

• US 20130019051A1
• Filed: 12/22/2011
• Published: 01/17/2013
• Est. Priority Date: 07/14/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Somanache, Vinay Ashok, Hicken, Michael S., Hempstead, Pamela S., Swatosh, Timothy W., Ellis, Jackson L., Dell, Martin S.
• Granted Patent: US 8,806,112 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1024 Latency reduction
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/7207 management of metadata or control data

Abstract

A method for handling meta data stored in a page of a flash memory within a flash media controller. The method generally includes (i) defining the meta data on a per context basis, where the context is defined on a per page basis, (ii) when a size of the meta data is less than or equal to a predefined threshold, storing the complete meta data within a structure of the context, and (iii) when the size of the meta data is greater than the predefined threshold, defining meta data pointers within the context.

Claims

1. A method for handling meta data stored in a page of a flash memory within a flash media controller, said method comprising:

defining said meta data on a per context basis, where the context is defined on a per page basis;

when a size of said meta data is less than or equal to a predefined threshold, storing the complete meta data within a structure of the context; and

when the size of the meta data is greater than the predefined threshold, defining meta data pointers within the context.

2. The method according to claim 1, further comprising:

protecting said meta data using an error correction code.

3. The method according to claim 1, wherein said meta data comprises management data.

4. The method according to claim 1, wherein when said predefined threshold specifies a number of bytes per page.

5. The method according to claim 1, wherein during a flash program cycle, said meta data from the context structure is stored in a flash target and during a read cycle, the meta data read from the flash target is stored back in the context structure.

6. The method according to claim 1, wherein the meta data pointers provide address pointers to retrieve the meta data from an external system memory during a flash program cycle and to store the meta data from the flash read command into the external system memory at a location indicated by the meta data pointers specified by the context.

7. The method according to claim 1, wherein:

during a flash program cycle, a first portion of meta data to be stored in a flash target comes from the context structure and a second portion of the meta data to be stored in a flash target comes from a location in an external system memory indicated by the meta data pointers specified by the context; and

during a read cycle, the first portion the meta data read from the flash target is stored back in the context structure and the second portion is stored in the external system memory at a location indicated by the meta data pointers specified by the context.

8. The method according to claim 1, wherein when a page size is a multiple of a host size, the meta data is distributed among each of a plurality of host user data sectors.

9. An apparatus comprising:

a flash memory comprising a plurality of flash media devices, said flash memory being organized as a plurality of pages;

a flash media controller configured to store meta data in one or more pages of said flash memory, wherein (i) said flash media controller defines a context on a per page basis and said meta data on a per context basis, (ii) when a size of said meta data is less than or equal to a predefined threshold, said flash media controller stores the complete meta data within a structure of the context, and (iii) when the size of the meta data is greater than the predefined threshold, said flash media controller defines meta data pointers within the context.

10. The apparatus according to claim 9, wherein said flash media controller protects said meta data using an error correction code.

11. The apparatus according to claim 9, wherein said meta data comprises management data.

12. The apparatus according to claim 9, wherein for a meta data size that is less than or equal to the predefined threshold;

during a flash program cycle, said flash media controller stores the meta data from the context structure in a flash target; and

during a read cycle, said flash media controller stores the meta data read from the flash target back into the context structure.

13. The apparatus according to claim 9, wherein the predefined threshold defines a number of bytes per page.

14. The apparatus according to claim 9, wherein the meta data pointers provide address pointers used by the flash media controller to retrieve the meta data from an external system memory during a flash program cycle and to store the meta data from the flash read command into the external system memory at a location indicated by the meta data pointers specified by the context.

15. The apparatus according to claim 9, wherein

during a flash program cycle, a first portion of meta data to be stored in a flash target comes from the context structure and a second portion of the meta data to be stored in a flash target comes from a location in an external system memory indicated by the meta data pointers specified by the context;

and

during a read cycle, the first portion the meta data read from the flash target is stored back in the context structure and the second portion is stored in the external system memory at a location indicated by the meta data pointers specified by the context.

16. The apparatus according to claim 9, wherein the flash media controller is further configured to distribute the meta data among each of a plurality of host user data sectors when a page size of said flash memory is a multiple of a host size.

17. A flash memory system comprising:

means for defining meta data on a per context basis, where the context is defined on a per page basis;

means for storing the complete meta data within a structure of the context when a size of said meta data is less than or equal to a predefined threshold; and

means for defining meta data pointers within the context when the size of the meta data is greater than the predefined threshold.