Row hammer refresh command
A memory controller issues a targeted refresh command. A specific row of a memory device can be the target of repeated accesses. When the row is accessed repeatedly within a time threshold (also referred to as “hammered” or a “row hammer event”), physically adjacent row (a “victim” row) may experience data corruption. The memory controller receives an indication of a row hammer event, identifies the row associated with the row hammer event, and sends one or more commands to the memory device to cause the memory device to perform a targeted refresh that will refresh the victim row.
1. An apparatus comprising:
a mode register to store one or more bits to control entry of a memory device into a targeted refresh mode;
multiple rows of memory; and
an interface circuit to couple to a memory controller, the interface circuit to receive a mode register command to trigger entry into the targeted refresh mode in response to a number of activates of a target row of the multiple rows within a time period to meet or exceed a threshold, and to receive one or more commands in the targeted refresh mode to cause refresh of only a limited number of rows physically proximate to the target row including a victim row.
2. The apparatus of claim 1 , wherein the time period comprises a refresh window.
3. The apparatus of claim 1 , wherein the interface to receive the one or more commands further comprises receive an activate command followed by a precharge command.
4. The apparatus of claim 1 , wherein the interface circuit to receive the one or more commands further comprises receive a target row address with target bank group and target bank address from the memory controller.
5. The apparatus of claim 4 , further comprising logic in the memory device to identify the victim row or region associated with the target row address.
6. The apparatus of claim 4 , further comprising logic in the memory device to identify a physical address of one or more victim rows based on a logical address of the target row.
7. The apparatus of claim 1 , wherein the victim row comprises a row physically adjacent to the target row.
8. The apparatus of claim 1 , wherein the memory device includes a dynamic random access memory (DRAM) device compliant with a dual data rate version 4 (DDR4) standard or compliant with a wide input/output (WIO) memory standard.
9. The apparatus of claim 1 , further comprising detector logic in the memory device to determine the number of activates of the target row within the time period meets or exceeds the threshold.
10. The apparatus of claim 9 , wherein the detector logic is to determine a count of the number of activates within the time period of the target row and to indicate when the count meets or exceeds the threshold.
11. The apparatus of claim 1 , wherein the interface circuit to receive the mode register command in response to the number of activates comprises to receive the mode register command from the memory controller, which the memory controller is to issue in response to detection that the number of activates meets or exceeds the threshold by a detector of the memory controller.
12. A system comprising:
a memory controller;
a memory device including
a mode register to store one or more bits to control entry of the memory device into a targeted refresh mode,
multiple rows of memory, and
an interface circuit coupled to the memory controller, the interface circuit to receive a mode register command to trigger entry into the targeted refresh mode in response to a number of activates of a target row of the multiple rows within a time period to meet or exceed a threshold, and to receive one or more commands from the memory controller in the targeted refresh mode to cause refresh of only a limited number of rows physically proximate to the target row including a victim row; and
a detector logic to determine that the number of activates of the target row within the time period meets or exceeds the threshold.
13. The system of claim 12 , wherein the time period comprises a refresh window.
14. The system of claim 12 , wherein the interface to receive the one or more commands further comprises receive an activate command followed by a precharge command.
15. The system of claim 12 , wherein the interface circuit to receive the one or more commands further comprises receive a target row address with target bank group and target bank address from the memory controller.
16. The system of claim 15 , further comprising logic in the memory device to identify the victim row or region associated with the target row address.
17. The system of claim 15 , further comprising logic in the memory device to identify a physical address of one or more victim rows based on a logical address of the target row.
18. The system of claim 12 , wherein the victim row comprises a row physically adjacent to the target row.
19. The system of claim 12 , wherein the memory device includes a dynamic random access memory (DRAM) device compliant with a dual data rate version 4 (DDR4) standard or compliant with a wide input/output (WIO) memory standard.
20. The system of claim 12 , wherein the memory device comprises the detector logic.
21. The system of claim 12 , wherein the memory controller comprises the detector logic.
22. The system of claim 21 , further comprising the memory controller to send the mode register command in response to detection by the detector logic that the number of activates meets or exceeds the threshold.
23. The system of claim 12 , wherein the detector logic is to determine a count of the number of activates within the time period of the target row and to indicate when the count meets or exceeds the threshold.
24. The system of claim 12 , further comprising one or more of:
at least one processor communicatively coupled to the memory controller;
a display communicatively coupled to display data from the memory device;
a battery to power the system; or
a network interface communicatively coupled to exchange data stored in the memory device with a remote device over a network connection.
25. A method comprising:
receiving a mode register set command to set a memory device in a targeted refresh mode in response to a number of activates of a target row within a time period meets or exceeds a threshold;
receiving one or more commands in the targeted refresh mode; and
refreshing only a limited number of rows physically proximate to the target row including a victim row in response to the one or more commands in the targeted refresh mode.
26. The method of claim 25 , wherein the time period comprises a refresh window.
27. The method of claim 25 , wherein receiving the one or more commands further comprises receiving an activate command followed by a precharge command.
28. The method of claim 25 , wherein receiving the one or more commands further comprises receiving a target row address with target bank group and target bank address.
29. The method of claim 28 , further comprising identifying the victim row or region associated with the received target row address.
30. The method of claim 28 , further comprising identifying a physical address of one or more victim rows based on a logical address of the target row.
31. The method of claim 25 , wherein refreshing the victim row comprises refreshing one or more rows physically adjacent to the target row.
32. The method of claim 25 , wherein the memory device includes a dynamic random access memory (DRAM) device compliant with a dual data rate version 4 (DDR4) standard or compliant with a wide input/output (WIO) memory standard.
33. The method of claim 25 , further comprising
determining a count of the number of activates within the time period of the target row; and
indicating when the count meets or exceeds the threshold.
34. An apparatus comprising:
means for receiving a mode register set command to set a memory device in a targeted refresh mode in response to a number of activates of a target row within a time period meets or exceeds a threshold;
means for receiving one or more commands in the targeted refresh mode; and
means for refreshing only a limited number of rows physically proximate to the target row including a victim row in response to the one or more commands in the targeted refresh mode.
35. The apparatus of claim 34 , wherein the time period comprises a refresh window.
36. The apparatus of claim 34 , wherein the means for receiving the one or more commands further comprises means for receiving an activate command followed by a precharge command.
37. The apparatus of claim 34 , wherein the means for receiving the one or more commands further comprises means for receiving a target row address with target bank group and target bank address.
38. The apparatus of claim 37 , further comprising means for identifying the victim row or region associated with the received target row address.
39. The apparatus of claim 37 , further comprising means for identifying a physical address of one or more victim rows based on a logical address of the target row.
40. The apparatus of claim 34 , wherein the means for refreshing the victim row comprises means for refreshing one or more rows physically adjacent to the target row.
41. The apparatus of claim 34 , wherein the memory device includes a dynamic random access memory (DRAM) device compliant with a dual data rate version 4 (DDR4) standard or compliant with a wide input/output (WIO) memory standard.
42. The apparatus of claim 34 , further comprising
means for determining a count of the number of activates within the time period of the target row; and
means for indicating when the count meets or exceeds the threshold.