Operation based polling in a memory system

• US 8,904,082 B1
• Filed: 03/25/2008
• Issued: 12/02/2014
• Est. Priority Date: 03/25/2008
• Status: Active Grant

• Current Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Original Assignee: Cadence Design Systems Incorporated (Cadence Group)
• Inventors: Banerjee, Bikram, Brahmadathan, Sandeep
• Primary Examiner(s): Ruiz, Aracelis
• Application Number:
  US12/054,391
• Time in Patent Office: 2,443 Days
• Field of Search: 711/103, 711/156, 710/18, 710/58
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0607 Interleaved addressing
• CPC Class Codes: G06F 13/1647 with interleaved bank access
• CPC Class Codes: G06F 13/4234 being a memory bus
• CPC Class Codes: G11C 7/1042 using interleaving techniques, i.e. read-write of one part of the memory while preparing another part

Abstract

Operation based polling in a memory system. A device manager is provided to perform efficient polling by utilizing the effective bandwidth of the memory system, in a controller coupled to a communication end point. The device manager includes a detection module for detecting a type of operation sent to the communication end point. The device manager also includes a storage module for storing a polling interval value based on a time period of the type of operation in a polling counter of the controller. Further, the device manager includes a controlling module for controlling a polling operation of the controller in such a way that the controller polls the communication end point after a wait period according to the polling interval value.

Claims

1. A device manager comprising:

a detection module for detecting a type of operation sent to two or more communication end points from a controller;

a storage module for storing a polling interval value based on a least time period for completing the type of operation, wherein the least time period is determined by comparing time periods for completing the type of operation for the two or more communication end points; and

a control module for controlling a polling operation of the controller in such a way that the controller polls the two or more communication end points after a wait period according to the polling interval value of the type of operation, wherein the controller operates in an interleaved operation environment, the controller coupled to a plurality of flash memory devices, wherein the controller allows for simultaneous communication with each of the plurality of flash memory devices.

2. The device manager of claim 1 further comprising:

a checking module for checking if the at least one communication end point is ready after the wait period; and

a global interval register for storing a global interval value which specifies a time period at which the controller polls the two or more communication end points periodically if the two or more communication end points are not ready.

3. The device manager of claim 2, wherein the global interval value is a function of the type of operation.

4. The device manager of claim 2, wherein the global interval value is a fraction of the least time period.

5. A method for operating a device manager comprising:

detecting a type of operation;

storing a polling interval value based on a time period for completing the type of operation, wherein the time period is determined by comparing time periods for completing the type of operation for a plurality of devices; and

controlling a polling operation of a controller in such a way that the controller polls two or more communication end points after a wait period according to the polling interval value of the type of operation, wherein the controller operates in an interleaved operation environment, the controller coupled to a plurality of flash memory devices, wherein the controller allows for simultaneous communication with each of the plurality of flash memory devices.

6. The method of claim 5 further comprising:

storing a global interval which specifies a time period for polling periodically if the type of operation is not executed.

7. The method of claim 6, wherein the global interval value is a function of the polling interval value.

8. A memory system comprising:

a controller for initiating a type of operation to two or more flash memory devices coupled to the controller; and

a device manager in the controller for controlling a polling operation of the memory system, the device manager comprising;

a detection module for detecting a type of operation sent to the two or more flash memory devices from the controller, the two or more flash memory devices coupled to the controller;

a storage module for storing a polling interval value based on a least time period for completing the type of operation, wherein the least time period is determined by comparing time periods for completing the type of operation for the two or more flash memory devices;

a polling counter for each of the two or more flash memory devices; and

a controlling module for controlling a polling operation of the controller in such a way that the controller polls the two or more flash memory devices after a wait period according to the polling interval value of the type of operation, wherein the controller operates in an interleaved operation environment, the controller coupled to a plurality of flash memory devices, wherein the controller allows for simultaneous communication with each of the plurality of flash memory devices.

9. The memory system of claim 8, wherein the device manager further comprises:

a checking module for checking if the two or more flash memory devices is are ready after the wait period; and

a global interval register for storing a global interval value which specifies a time period at which the controller polls the two or more flash memory devices periodically if the two or more flash memory devices are not ready.

10. The memory system of claim 9, wherein the device manager is implemented as software instruction code and stored in each of the two or more flash memory devices.

11. The memory system of claim 8, wherein the two or more flash memory devices comprises a NAND flash memory device.

12. The memory system of claim 8, wherein the type of operation is selected from the group comprising a load operation, a program operation and an erase operation.

13. A method comprising:

initiating a type of operation to two or more flash memory devices coupled to a controller;

determining a time period for completing the type of operation by comparing time periods for completing the type of operation for the two or more flash memory devices; and

performing a polling operation of the controller on the two or more flash memory devices based on the type of operation, wherein performing a polling operation comprises;

detecting the type of operation sent to the two or more flash memory devices from the controller, the two or more flash memory devices coupled to the controller;

storing a polling interval value based on a time period for completing the type of operation in a polling counter of the controller; and

controlling a polling operation of the controller in such a way that the controller polls the two or more flash memory devices after a wait period according to the polling interval value of the type of operation, wherein the controller operates in an interleaved operation environment the controller coupled to a plurality of flash memory devices, wherein the controller allows for simultaneous communication with each of the plurality of flash memory devices.

14. The method of claim 13, wherein performing a polling operation further comprises:

checking if the two or more flash memory devices is ready after the wait period; and

storing a global interval value which specifies a time period at which the controller polls the two or more flash memory devices periodically if the two or more flash memory devices are not ready.

15. The method of claim 14, wherein checking if the at least one flash memory device is ready comprises:

checking a status register of the at least one flash memory device; and

polling the at least one flash memory device periodically until the at least one flash memory device is ready.

16. An interleaved operation method in a memory system comprising:

sending a first type of operation to a first flash memory device from a controller, the first flash memory device coupled to the controller;

sending a second type of operation to a second flash memory device from the controller, the second flash memory device coupled to the controller; and

polling the second flash memory device after a wait period so that the controller can efficiently communicate with the first flash memory device by utilizing the effective bandwidth of the memory system, polling the second flash memory device after a wait period comprising;

detecting the second type of operation sent to the second flash memory device;

storing a polling interval value based on a least time period for completing the second type of operation in a polling counter of the controller, wherein the least time period is determined by comparing time periods for completing the second type of operation for the first and the second flash memory devices; and

controlling a polling operation of the controller in such a way that the controller polls the second flash memory device after a wait period according to the polling interval value of the type of operation, wherein the controller operates in an interleaved operation environment, the controller coupled to a plurality of flash memory devices, wherein the controller allows for simultaneous communication with each of the plurality of flash memory devices.

17. The interleaved operation method of claim 16, wherein polling the second flash memory device comprises:

checking if the second flash memory device is ready after the wait period; and

storing a global interval value which specifies a time period at which the controller polls the second flash memory device periodically if the second flash memory device is not ready.

18. The interleaved operation method of claim 17, wherein checking if the second flash memory device is ready comprises:

checking a status register of the second flash memory device; and

polling the at least one flash memory device periodically until the second flash memory device is ready.

19. The interleaved operation method of claim 17, wherein the global interval value is a function of the type of operation.

20. An initialization method in a memory system comprising:

initiating a type of operation;

determining a least time period for completing the type of operation, wherein the least time period is determined by comparing time periods for completing the type of operation for a plurality of memory devices;

storing a polling interval value according to the least time period for completing the type of operation; and

controlling a polling operation of a controller in such a way that the controller polls two or more communication end points after a wait period according to the polling interval value of the type of operation, wherein the controller operates in an interleaved operation environment, the controller coupled to a plurality of flash memory devices, wherein the controller allows for simultaneous communication with each of the plurality of flash memory devices.

21. The initialization method of claim 20 further comprising:

polling after a wait period according to the polling interval value; and

storing a global interval value which specifies a time period for polling periodically, if the type of operation is not executed.

22. The initialization method of claim 21, wherein the global interval value is a fraction of the least time period.

23. The initialization method of claim 21, wherein storing a global interval value comprises storing a value that is a function of the polling interval value as the global interview value.