Host-based flash memory maintenance techniques
Devices and techniques are disclosed herein for allowing host-based maintenance of a flash memory device. In certain examples, memory write information can be encrypted at the memory device and provided to the host for updating and maintaining memory device maintenance statistics.
1. A method comprising:
providing mapping table information to a host from a memory device;
receiving a write command and write data from the host at the memory device;
executing the write command at the memory device to store the write data in a physical block of the memory device; and
encrypting reply information at the memory device to provide encrypted reply information, the encrypted reply information configured to reveal an address of a first block when decrypted at the host, wherein the address of the first block does not indicate an address of a true physical block of the memory device to the host; and
sending a reply message, including the encrypted reply information, to the host in response to the write command.
2. The method of claim 1 , including receiving a memory maintenance command from the host at the memory device, wherein the memory maintenance command includes at least a portion of the encrypted reply information.
3. The method of claim 2 , including decrypting the encrypted reply information at the memory device to provide a first physical address of the memory device.
4. The method of claim 3 , wherein the memory maintenance command is a garbage collection command.
5. The method of claim 4 , wherein the method includes executing garbage collection at a physical block of memory of the memory device represented by the first physical address.
6. The method of claim 4 , determining the first physical address is not a valid physical address of the memory device; and
not executing a garbage collection procedure in response to the garbage collection command.
7. The method of claim 3 , wherein the memory maintenance command is a wear-leveling command.
8. The method of claim 7 , including executing a wear-leveling procedure at a physical block of memory of the memory device represented by the first physical address.
9. The method of claim 7 , including determining the first physical address is not a valid physical address of the memory device; and
not executing a wear-leveling procedure in reply to the wear-leveling command.
10. The method of claim 1 , wherein the reply information includes a secret; and
wherein decrypting the reply information includes decrypting the reply information using the secret.
11. The method of claim 1 , wherein the physical block includes flash memory.
12. The method of claim 11 , wherein the flash memory includes NAND memory.
13. A method comprising:
maintaining mapping table information and memory statistics of an external flash memory system at a host;
sending a write command and write data to the external flash memory system from the host;
receiving encrypted reply information including a first encrypted portion from the external flash memory system in response to the write command;
decrypting the first encrypted portion at the host to get an address of a first block associated with the write data, wherein the address of the first block does not indicate an address of a true physical block of the memory device;
updating the memory statistics of the external flash memory system at the host using the address of the first block; and
sending a memory maintenance command when a memory statistic associated with the address of the first block satisfies a maintenance threshold; and
wherein the memory maintenance command includes the first encrypted portion of the encrypted reply information.
14. The method of claim 13 , wherein the encrypted reply information includes a secret.
15. The method of claim 14 , wherein maintaining memory statistics of the external flash memory system includes decrypting the encrypted reply information using the secret to provide a first physical address of the external flash memory system, wherein the first physical address is not a true physical address of the external flash memory.
16. The method of claim 15 , wherein maintaining memory statistics of the external flash memory system includes updating the mapping table information using the first physical address.
17. The method of claim 15 , wherein maintaining memory statistics of the external flash memory system includes maintain a valid data count statistic using the first physical address.
18. The method of claim 15 , wherein maintaining memory statistics of the external flash memory system includes maintaining a full/empty status statistic using the first physical address.
19. The method of claim 15 , wherein maintaining memory statistics of the external flash memory system includes maintaining a time since last write statistic using the first physical address.
20. The method of claim 13 , wherein the memory maintenance command is a garbage collection command.
21. The method of claim 13 , wherein the memory maintenance command is a wear-leveling command.