Command replay for non-volatile dual inline memory modules

A method, comprising:

• receiving a plurality of memory access requests including volatile memory reads, volatile memory writes, non-volatile memory reads, and non-volatile memory writes;
• placing memory access commands for fulfilling the memory access requests in a memory interface queue and transmitting the memory access commands from the memory interface queue to a heterogeneous memory channel coupled to a volatile dual in-line memory module (DIMM) and a non-volatile DIMM;
• storing selected memory access commands that are placed in the memory interface queue in a replay queue;
• and
• storing the non-volatile reads that are placed in the memory interface queue in a non-volatile command queue (NV queue);
• and
• detecting, based on information received over the heterogeneous memory channel, that an error has occurred requiring a recovery sequence, and in response to the error, initiating the recovery sequence including (i) transmitting selected memory access commands that are stored in the replay queue, and (ii) transmitting non-volatile reads that are stored in the NV queue.

A data processing system, comprising:

• a central processing unit;
• a data fabric coupled to the central processing unit;
• and
• a memory controller coupled to the data fabric for fulfilling memory access requests made through the data fabric, the memory controller comprising:
• a command queue having a first input for receiving memory access commands including volatile reads, volatile writes, non-volatile reads, and non-volatile writes, and an output, and having a plurality of entries;
• a memory interface queue having an input coupled to the output of the command queue, and an output for coupling to a heterogeneous memory channel to which is coupled a volatile dual in-line memory module (DIMM) and a non-volatile DIMM;
• a non-volatile command queue (NV queue) coupled to the output of the command queue for storing non-volatile reads that are placed in the memory interface queue;
• a replay queue coupled to the output of the command queue for storing selected memory access commands that are placed in the memory interface queue;
• and
• a replay control circuit for detecting, based on information received over the heterogeneous memory channel, that an error has occurred requiring a recovery sequence, and in response to the error, transmitting selected memory access commands that are stored in the replay queue, and transmitting non-volatile reads that are stored in the NV queue.