Abstract: A memory controller includes a first arbiter for selecting memory commands for dispatch to a memory over a first channel, a second arbiter for selecting memory commands for dispatch to the memory over a second channel, and a test circuit. The test circuit generates a respective testing sequence of read commands and write commands for each of the first channel and second channel, and causes the testing sequences to be transmitted over the first and second channels at least partially overlapping in time without selection by the first or second arbiters.

Abstract: A memory controller for generating accesses for a memory includes a row hammer logic circuit for providing a sample request. In response to the sample request, the memory controller generates a sample command for dispatch to the memory to cause the memory to capture a current row. In response to a completion of the sample command, the memory controller generates a mitigation command for dispatch to the memory.

Abstract: An arbiter is operable to pick commands from a command queue for dispatch to a memory. The arbiter includes a traffic throttle circuit for mitigating excess power usage increases in coordination with one or more additional arbiters. The traffic throttle circuit includes a monitoring circuit and a throttle circuit. The monitoring circuit is for measuring a number of read and write commands picked by the arbiter and the one or more additional arbiters over a first predetermined period of time. The throttle circuit, responsive to a low activity state, limits a number of read and write commands issued by the arbiter during a second predetermined period of time.

Abstract: A method for performing stutter of dynamic random access memory (DRAM) where a system on a chip (SOC) initiates bursts of requests to the DRAM to fill buffers to allow the DRAM to self-refresh is disclosed. The method includes issuing, by a system management unit (SMU), a ForceZQCal command to the memory controller to initiate the stutter procedure in response to receiving a timeout request, such as an SMU ZQCal timeout request, periodically issuing a power platform threshold (PPT) request, by the SMU, to the memory controller, and sending a ForceZQCal command prior to a PPT request to ensure re-training occurs after ZQ Calibration. The ForceZQCal command issued prior to PPT request may reduce the latency of the stutter. The method may further include issuing a ForceZQCal command prior to each periodic re-training.

Abstract: A memory controller includes a memory channel controller adapted to receive memory access requests and dispatch associated commands addressable in a system memory address space to a non-volatile storage class memory (SCM) module. The non-volatile error reporting circuit identifies error conditions associated with the non-volatile SCM module and maps the error conditions from a first number of possible error conditions associated with the non-volatile SCM module to a second, smaller number of virtual error types for reporting to an error monitoring module of a host operating system, the mapping based at least on a classification that the error condition will or will not have a deleterious effect on an executable process running on the host operating system.

Abstract: A memory controller includes encryption circuits for encrypting write data to be written to an address in a RAM memory. A tweak value is provided based at least on the address. The tweak value is encrypted with Advanced Encryption Standard (AES) encryption using a first key. A first block write data is encrypted by manipulating it based on the encrypted tweak value, AES encrypting with a second key, and then manipulating the result based on the encrypted tweak value again. For subsequent blocks of write data, the encrypted tweak value is modified, and a similar operation is performed.

Abstract: A memory controller selects from among a plurality of memory access commands including volatile memory reads, volatile memory writes, non-volatile memory reads, and non-volatile memory writes. The selected memory access commands are transmitted to a heterogenous memory channel coupled to a non-volatile memory and a volatile memory. The non-volatile read commands that are transmitted are stored in a non-volatile command queue (NV queue). A ready response is received from the non-volatile memory indicating that responsive data is available for an associated one of the non-volatile read commands. In response to receiving the ready response, a send command is transmitted for commanding the non-volatile memory to send the responsive data.

Abstract: A data processor includes provides memory commands to a memory channel according to predetermined criteria. The data processor includes a first error code generation circuit, a second error code generation circuit, and a queue. The first error code generation circuit generates a first type of error code in response to data of a write request. The second error code generation circuit generates a second type of error code for the write request, the second type of error code different from the first type of error code. The queue is coupled to the first error code generation circuit and to the second error code generation circuit, for provides write commands to an interface, the write commands including the data, the first type of error code, and the second type of error code.

Abstract: A memory controller interfaces with a random access memory over a memory channel. A refresh control circuit monitors an activate counter which counts a rolling number of activate commands sent over the memory channel to a memory region of the memory. In response to the activate counter being above an intermediate management threshold value, the refresh control circuit only issue a refresh management (RFM) command if there is no REF command currently held at the refresh command circuit for the memory region.

Abstract: A method and apparatus for performing a simulated write in a computer system includes, responsive to a scheduled memory operation determined by a memory controller, sending a simulated write operation to a physical layer circuitry (PHY) to increase circuit power without enabling the output of the PHY until the memory operation begins. Responsive to the memory operation being complete, sending a simulated write operation to the PHY to decrease circuit power.

Abstract: In one form, a memory controller includes a command queue, an arbiter, and a replay queue. The command queue receives and stores memory access requests. The arbiter is coupled to the command queue for providing a sequence of memory commands to a memory channel. The replay queue stores the sequence of memory commands to the memory channel, and continues to store memory access commands that have not yet received responses from the memory channel. When a response indicates a completion of a corresponding memory command without any error, the replay queue removes the corresponding memory command without taking further action. When a response indicates a completion of the corresponding memory command with an error, the replay queue replays at least the corresponding memory command. In another form, a data processing system includes the memory controller, a memory accessing agent, and a memory system to which the memory controller is coupled.

Abstract: A memory controller includes an arbiter for selecting memory requests from a command queue for transmission to a dynamic random access memory (DRAM) memory. The arbiter includes a bank group tracking circuit that tracks bank group numbers of three or more prior write requests selected by the arbiter. The arbiter also includes a selection circuit that selects requests to be issued from the command queue, and prevents selection of write requests and associated activate commands to the tracked bank group numbers unless no other write request is eligible in the command queue. The bank group tracking circuit indicates that a prior write request and the associated activate commands are eligible to be issued after a number of clock cycles has passed corresponding to a minimum write-to-write timing period for a bank group of the prior write request.

Abstract: A method for performing stutter of dynamic random access memory (DRAM) where a system on a chip (SOC) initiates bursts of requests to the DRAM to fill buffers to allow the DRAM to self-refresh is disclosed. The method includes issuing, by a system management unit (SMU), a ForceZQCal command to the memory controller to initiate the stutter procedure in response to receiving a timeout request, such as an SMU ZQCal timeout request, periodically issuing a power platform threshold (PPT) request, by the SMU, to the memory controller, and sending a ForceZQCal command prior to a PPT request to ensure re-training occurs after ZQ Calibration. The ForceZQCal command issued prior to PPT request may reduce the latency of the stutter. The method may further include issuing a ForceZQCal command prior to each periodic re-training.

Abstract: A memory controller includes a command queue, a memory interface queue, at least one storage queue, and a replay control circuit. The command queue has a first input for receiving memory access commands. The memory interface queue receives commands selected from the command queue and couples to a heterogeneous memory channel which is coupled to at least one non-volatile storage class memory (SCM) module. The at least one storage queue stores memory access commands that are placed in the memory interface queue. The replay control circuit detects that an error has occurred requiring a recovery sequence, and in response to the error, initiates the recovery sequence. In the recovery sequence, the replay control circuit transmits selected memory access commands from the at least one storage queue by grouping non-volatile read commands together separately from all pending volatile reads, volatile writes, and non-volatile writes.

Abstract: A memory controller includes a memory channel controller that uses multiple groups of command queue and arbiter pairs. Each arbiter is coupled to a respective command queue to select memory access commands from each command queue according to predetermined criteria. Each arbiter selects from among the memory access requests in each command queue independently based on the predetermined criteria and sends selected memory access requests to a selector that serves as a second level arbiter which sends the request to a memory subchannel.

Abstract: A memory controller interfaces with a dynamic random access memory (DRAM). The memory controller selectively places memory commands in a memory interface queue, and transmits the commands from the memory interface queue to a memory channel connected to at least one dynamic random access memory (DRAM). The transmitted commands are stored in a replay queue. A number of activate commands to a memory region of the DRAM is counted. Based on this count, a refresh control circuit signals that an urgent refresh command should be sent to the memory region. In response to detecting a designated type of error, a recovery sequence initiates to re-transmit memory commands from the replay queue. Designated error conditions can cause the recovery sequence to restart. If an urgent refresh command is pending when such a restart occurs, the recovery sequence is interrupted to allow the urgent refresh command to be sent.

Abstract: A memory controller includes a memory channel controller adapted to receive memory access requests and dispatch associated commands addressable in a system memory address space to a non-volatile storage class memory (SCM) module. The non-volatile error reporting circuit identifies error conditions associated with the non-volatile SCM module and maps the error conditions from a first number of possible error conditions associated with the non-volatile SCM module to a second, smaller number of virtual error types for reporting to an error monitoring module of a host operating system, the mapping based at least on a classification that the error condition will or will not have a deleterious effect on an executable process running on the host operating system.

Abstract: A memory controller includes a command queue having an input for receiving memory access commands for a memory channel, and a number of entries for holding a predetermined number of memory access commands, and an arbiter that selects memory commands from the command queue for dispatch to one of a persistent memory and a DRAM memory coupled to the memory channel. The arbiter includes a first-tier sub-arbiter circuit coupled to the command queue for selecting candidate commands from among DRAM commands and persistent memory commands, and a second-tier sub-arbiter circuit coupled to the first-tier sub-arbiter circuit for receiving the candidate commands and selecting at least one command from among the candidate commands.

Abstract: A memory controller includes a command queue, a memory interface queue, at least one storage queue, and a replay control circuit. The command queue has a first input for receiving memory access commands. The memory interface queue receives commands selected from the command queue and couples to a heterogeneous memory channel which is coupled to at least one non-volatile storage class memory (SCM) module. The at least one storage queue stores memory access commands that are placed in the memory interface queue. The replay control circuit detects that an error has occurred requiring a recovery sequence, and in response to the error, initiates the recovery sequence. In the recovery sequence, the replay control circuit transmits selected memory access commands from the at least one storage queue by grouping non-volatile read commands together separately from all pending volatile reads, volatile writes, and non-volatile writes.

Abstract: Systems, apparatuses, and methods for performing efficient memory accesses for a computing system are disclosed. In various embodiments, a computing system includes one or more computing resources and a memory controller coupled to a memory device. The memory controller determines a memory access request targets a given bank of multiple banks. An access history is updated for the given bank based on whether the memory access request hits on an open page within the given bank and a page hit rate for the given bank is determined. The memory controller sets an idle cycle limit based on the page hit rate. The idle cycle limit is a maximum amount of time the given bank will be held open before closing the given bank while the bank is idle. The idle cycle limit is based at least in part on a page hit rate for the bank.