Advanced Micro Devices Corporation

Kedarnath Balakrishnan

James Raymond Magro

Jing Wang

Kevin M Brandl

Guanhao Shen

Ravindra Nath Bhargava

Vilas K Sridharan

Kevin Michael Lepak

Hideki Kanayama

Brendan T Mangan

Anthony Asaro

Mark Fowler

Ruihua Peng

Thomas H Hamilton

Scott P Murphy

YuBin Yao

Jean J Chittilappilly

Shriram Ravichandran

Jackson Peng

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.

Directed refresh management for DRAM

Systems, apparatuses, and methods for performing efficient memory accesses for a computing system are disclosed. When a memory controller in a computing system determines a threshold number of memory access requests have not been sent to the memory device in a current mode of a read mode and a write mode, a first cost corresponding to a latency associated with sending remaining requests in either the read queue or the write queue associated with the current mode is determined. If the first cost exceeds the cost of a data bus turnaround, the cost of a data bus turnaround comprising a latency incurred when switching a transmission direction of the data bus from one direction to an opposite direction, then a second cost is determined for sending remaining memory access requests to the memory device. If the second cost does not exceed the cost of the data bus turnaround, then a time for the data bus turnaround is indicated and the current mode of the memory controller is changed.

Dynamic page state aware scheduling of read/write burst transactions

A data processor that is operable to be coupled to a memory includes a memory operation array, a controller, a refresh logic circuit, and a selector. The memory operation array is for storing memory operations for a first power state of the memory. The controller is responsive to a power state change request to execute a plurality of memory operations from the memory operation array when the first power state is selected. The refresh logic circuit generates refresh cycles periodically for the memory. The selector is for multiplexing the refresh cycles with the memory operations during a power state change to the first power state.

Refresh during power state changes

Staging memory access requests includes receiving a memory access request directed to Dynamic Random Access Memory; storing the memory access request in a staging buffer; and moving the memory access request from the staging buffer to a command queue.

Staging memory access requests

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.

Memory calibration system and method

Systems, apparatuses, and methods for performing scheduling memory requests for issue to two different memory types are disclosed. A computing system includes one or more clients for processing applications. A heterogeneous memory channel within a memory controller transfers memory traffic between the memory controller and a memory bus connected to each of a first memory and a second memory different from the first memory. The memory controller determines a next given point in time that does not already have read response data scheduled to be driven on the memory bus. The memory controller determines whether there is time to schedule a first memory access command for accessing the first memory and a second memory access command for accessing the second memory. If there is sufficient time for each, then one of the access commands is selected based on weighted criteria.

Scheduling memory requests with non-uniform latencies

A memory controller includes a command queue, an arbiter, and a controller. The controller is responsive to a repair signal for migrating data from a failing region of a memory to a buffer, generating at least one command to perform a post-package repair operation of the failing region, and migrating the data from the buffer to a substitute region of the memory. The controller migrates the data to and from the buffer by providing migration read requests and migration write requests, respectively, to the command queue. The arbiter uses the plurality of arbitration rules for both the read migration requests and the write migration requests, and the read access requests and the write access requests.

Full dynamic post-package repair

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.

Channel and sub-channel throttling for memory controllers

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.

Error recovery for non-volatile memory modules

A memory controller includes an arbiter. The arbiter is configured to elevate a priority of memory access requests that generate row activate commands in response to receiving a same-bank refresh request, and to send a same-bank refresh command in response to receiving the same-bank refresh request.

Performance of bank refresh

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.

Memory controller with a plurality of command sub-queues and corresponding arbiters

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.

Memory controller with hybrid DRAM/persistent memory channel arbitration

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.

Error reporting for non-volatile memory modules

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.

Signalling for heterogeneous memory systems

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.

Growing community of inventors

Bengaluru, India

Kedarnath Balakrishnan