Processing Host Transfer Requests for Direct Block Access Storage Devices

• US 20110072173A1
• Filed: 09/01/2010
• Published: 03/24/2011
• Est. Priority Date: 09/23/2009
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Williams, Jeffrey L., Forhan, Carl, Hicken, Michael, Holty, Bryan
• Granted Patent: US 8,458,381 B2
• Time in Patent Office: Days
• US Class Current: 710/52
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/1027 using associative or pseudo-associative address translation means, e.g. translation look-aside buffer [TLB]
• CPC Class Codes: G06F 13/14 Handling requests for interconnection or transfer
• CPC Class Codes: G06F 13/24 using interrupt G06F13/32 takes precedence
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 2212/7203 Temporary buffering, e.g. using volatile buffer or dedicated buffer blocks
• CPC Class Codes: G06F 2213/0028 Serial attached SCSI [SAS]
• CPC Class Codes: G06F 3/00 Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements

Abstract

Described embodiments provide a host subsystem that generates a host context corresponding to a received host data transfer request. A programmable sequencer generates one or more sequencer contexts based on the host context. Each of the sequencer contexts corresponds to at least part of the host data transfer request. The sequencer contexts are provided to a buffer subsystem of the media controller. For host read requests, the buffer subsystem retrieves the data associated with the sequencer contexts of the read request from a corresponding buffer or a storage media and transmits the data associated with the sequencer contexts to the host device. For host write requests, the buffer subsystem receives the data associated with the host context from the host device and stores the data associated with the sequencer contexts of the write request to a corresponding buffer or the storage media.

Claims

1. A method of processing, by a media controller, a transfer request from a host device, the method comprising:

generating, by a host subsystem, a host context corresponding to a received host transfer request;

generating, by a programmable sequencer based on the host context, one or more sequencer contexts, each of the one or more sequencer contexts corresponding to at least part of the host transfer request;

providing, by the programmable sequencer, the one or more sequencer contexts to a buffer subsystem of the media controller;

if the host transfer request is a read request;

retrieving, by the buffer subsystem, the data associated with the one or more sequencer contexts of the read request, from at least one of i) a corresponding buffer of the media controller and ii) a storage media coupled to the media controller; and

transmitting, by the host subsystem, the data associated with the one or more sequencer contexts to the host device;

otherwise, if the host transfer request is a write request;

receiving, by the buffer subsystem, the data associated with the host context from the host device; and

storing the data associated with the one or more sequencer contexts of the write request to at least one of i) a corresponding buffer of the media controller and ii) the storage media.

2. The method of claim 1, further comprising:

if the host transfer request is a read request;

combining, by the host subsystem, the data corresponding to the one or more sequencer contexts into at least one host transfer to the host device; and

transmitting each host transfer to the host device;

otherwise, if the host transfer request is a write request;

splitting, by the host subsystem, the data corresponding to the host context into data portions corresponding to the one or more sequencer contexts; and

storing the data portions corresponding to the one or more sequencer contexts.

3. The method of claim 2, wherein the size of the at least one host transfer corresponds to a maximum frame size of a communication link coupled between the media controller and the host device.

4. The method of claim 1, wherein the host context corresponds to a starting address of the host transfer request and a length of the host transfer request.

5. The method of claim 4, wherein

the starting address of the transfer is at least one of a logical block address (LBA) of the storage media and an address of the corresponding buffer of the media controller;

and

the length of the host transfer request is a number of logical blocks included in the data transfer.

6. The method of claim 4, wherein the size of a sequencer context corresponds to a storage unit size of the media controller.

7. The method of claim 1, comprising performing, in parallel, host-side context processing and storage media-side context processing.

21. The method of claim 1, wherein the storage media is a Redundant Array of Independent Disks (RAID) system comprising a plurality of storage devices and at least one media controller coupled to at least one corresponding storage device.

8. A media controller for processing a transfer request from a host device, the media controller comprising:

a host subsystem for generating a host context corresponding to a received host transfer request;

a buffer subsystem for buffering data transferred between the host subsystem and a storage media;

a programmable sequencer for i) generating, based on the host context, one or more sequencer contexts, each of the one or more sequencer contexts corresponding to at least part of the host transfer request, and ii) providing the one or more sequencer contexts to the buffer subsystem;

wherein, if the host transfer request is a read request;

the buffer subsystem is adapted to retrieve the data associated with the one or more sequencer contexts, from at least one of a corresponding buffer and the storage media; and

the host subsystem is adapted to transmit the retrieved data to the host device;

otherwise, if the host transfer request is a write request;

the buffer subsystem is adapted to i) receive the data associated with the host context from the host device, and ii) store the data associated with the one or more sequencer contexts to at least one of a corresponding buffer and the storage media.

9. The media controller of claim 8, further comprising:

if the host transfer request is a read request;

the host subsystem is adapted to i) combine the data associated with the one or more sequencer contexts into at least one host transfer to the host device, and ii) transmit each host transfer to the host device;

otherwise, if the host transfer request is a write request;

the host subsystem is adapted to i) split the data associated with the host context into data corresponding to the one or more sequencer contexts, and ii) store the data corresponding to the one or more sequencer contexts.

10. The media controller of claim 9, wherein the size of the at least one host transfer corresponds to a maximum frame size of a communication link coupled between the media controller and the host device.

11. The media controller of claim 8, wherein the host context corresponds to a starting address of the host transfer request and a length of the host transfer request.

12. The media controller of claim 11, wherein

the starting address of the transfer is at least one of a logical block address (LBA) of the storage media and an address of the buffer of the media controller;

the length of the host data transfer request is a number of logical blocks to be included in the transfer; and

the size of a sequencer context corresponds to a storage unit size of the media controller.

13. The media controller of claim 8, wherein host-side context processing and storage media-side context processing occurs in parallel.

14. The media controller of claim 8, wherein the apparatus is implemented in a monolithic integrated circuit chip.

15. A machine-readable storage medium, having encoded thereon program code, wherein, when the program code is executed by a machine, the machine implements a method of processing a data transfer request from a host device, by a media controller, the method comprising:

generating, by a host subsystem, a host context corresponding to a received host data transfer request;

generating, by a programmable sequencer based on the host context, one or more sequencer contexts, each of the one or more sequencer contexts corresponding to at least part of the host data transfer request;

providing, by the programmable sequencer, the one or more sequencer contexts to a buffer subsystem of the media controller;

if the host data transfer request is a read request;

retrieving, by the buffer subsystem, the data associated with the one or more sequencer contexts of the read request, from at least one of i) a corresponding buffer of the media controller and ii) a storage media coupled to the media controller; and

transmitting, by the host subsystem, the data associated with the one or more sequencer contexts to the host device;

otherwise, if the host data transfer request is a write request;

receiving, by the buffer subsystem, the data associated with the host context from the host device; and

storing the data associated with the one or more sequencer contexts of the write request to at least one of i) a corresponding buffer of the media controller and ii) the storage media.

16. The machine-readable storage medium of claim 15, further comprising:

if the host data transfer request is a read request;

combining, by the host subsystem, the data associated with the one or more sequencer contexts into at least one host data transfer to the host device; and

transmitting each host data transfer to the host device;

otherwise, if the host data transfer request is a write request;

splitting, by the host subsystem, the data associated with the host context into data portions corresponding to the one or more sequencer contexts; and

storing the data portions associated with the one or more sequencer contexts.

17. The machine-readable storage medium of claim 16, wherein the size of the at least one host data transfer corresponds to a maximum frame size of a communication link coupled between the media controller and the host device.

18. The machine-readable storage medium of claim 15, wherein the host context corresponds to a starting address of the host data transfer request and a length of the host data transfer request.

19. The machine-readable storage medium of claim 18, wherein

the starting address of the transfer is at least one of a logical block address (LBA) of the storage media and an address of the buffer of the media controller;

the length of the host data transfer request is a number of logical blocks to be included in the data transfer; and

the size of a sequencer context corresponds to a storage unit size of the media controller.

20. The machine-readable storage medium of claim 15, comprising performing, in parallel, host-side context processing and storage media-side context processing.