Abstract: Embodiments relate to out-of-synchronization detection and out-of-order detection in a memory system. One aspect is a system that includes a plurality of channels, each providing communication with a memory buffer chip and a plurality of memory devices. A memory control unit is coupled to the plurality of channels. The memory control unit is configured to perform a method that includes receiving frames on two or more of the channels. The memory control unit identifies alignment logic input in each of the received frames and generates a summarized input to alignment logic for each of the channels of the received frames based on the alignment logic input. The memory control unit adjusts a timing alignment based on a skew value per channel. Each of the timing adjusted summarized inputs is compared. Based on a mismatch between at least two of the timing adjusted summarized inputs, a miscompare signal is asserted.

Abstract: Embodiments relate to performing a memory scrubbing operation that includes injecting an error on a write operation associated with a memory address. One or more errors are detected during a two-pass scrub operation on the memory address. Based on a result of the two-pass scrub operation, one or more of a hard error counter associated with the memory address and a soft error counter associated with the memory address is selected. The one or more selected counters are updated based on the result of the two-pass scrub operation.

Abstract: Embodiments relate to out-of-synchronization detection and out-of-order detection in a memory system. One aspect is a system that includes a plurality of channels, each providing communication with a memory buffer chip and a plurality of memory devices. A memory control unit is coupled to the plurality of channels. The memory control unit is configured to perform a method that includes receiving frames on two or more of the channels. The memory control unit identifies alignment logic input in each of the received frames and generates a summarized input to alignment logic for each of the channels of the received frames based on the alignment logic input. The memory control unit adjusts a timing alignment based on a skew value per channel. Each of the timing adjusted summarized inputs is compared. Based on a mismatch between at least two of the timing adjusted summarized inputs, a miscompare signal is asserted.

Abstract: Embodiments relate to out-of-synchronization detection and out-of-order detection in a memory system. One aspect is a system that includes a plurality of channels, each providing communication with a memory buffer chip and a plurality of memory devices. A memory control unit is coupled to the plurality of channels. The memory control unit is configured to perform a method that includes receiving frames on two or more of the channels. The memory control unit identifies alignment logic input in each of the received frames and generates a summarized input to alignment logic for each of the channels of the received frames based on the alignment logic input. The memory control unit adjusts a timing alignment based on a skew value per channel. Each of the timing adjusted summarized inputs is compared. Based on a mismatch between at least two of the timing adjusted summarized inputs, a miscompare signal is asserted.

Abstract: Embodiments relate to reestablishing synchronization across multiple channels in a memory system. One aspect is a system that includes a plurality of channels, each providing communication with a memory buffer chip and a plurality of memory devices. A memory control unit is coupled to the plurality of channels. The memory control unit is configured to perform a method that includes receiving an out-of-synchronization indication associated with at least one of the channels. The memory control unit performs a first stage of reestablishing synchronization that includes selectively stopping new traffic on the plurality of channels, waiting for a first time period to expire, resuming traffic on the plurality of channels based on the first time period expiring, and verifying that synchronization is reestablished for a second time period.

Abstract: A computer-system implemented method for dual asynchronous and synchronous memory operation in a memory subsystem includes establishing a synchronous channel between a memory controller and a memory buffer chip. A mode selector determines a reference clock source for a memory domain phase-locked loop of the memory buffer chip based on an operating mode of the memory buffer chip. An output of a nest domain phase-locked loop is provided as the reference clock source to the memory domain phase-locked loop in the memory buffer chip based on the operating mode being synchronous. The nest domain phase-locked loop is operable synchronous to a memory controller phase-locked loop of the memory controller. A separate reference clock is provided independent of the nest domain phase-locked loop as the reference clock to the memory domain phase-locked loop based on the operating mode being asynchronous.

Abstract: Embodiments relate to performing a memory scrubbing operation that includes injecting an error on a write operation associated with a memory address. One or more errors are detected during a two-pass scrub operation on the memory address. Based on a result of the two-pass scrub operation, one or more of a hard error counter associated with the memory address and a soft error counter associated with the memory address is selected. The one or more selected counters are updated based on the result of the two-pass scrub operation.

Abstract: Embodiments relate to performing a memory scrubbing operation that includes injecting an error on a write operation associated with a memory address. One or more errors are detected during a two-pass scrub operation on the memory address. Based on a result of the two-pass scrub operation, one or more of a hard error counter associated with the memory address and a soft error counter associated with the memory address is selected. The one or more selected counters are updated based on the result of the two-pass scrub operation.

Abstract: Embodiments relate to address mapping including generic bits. An aspect includes receiving an address including generic bits from a memory control unit (MCU) by a buffer module in a main memory. Another aspect includes mapping the generic bits to an address format corresponding to a type of dynamic random access memory (DRAM) in a memory subsystem associated with the buffer module by the buffer module. Yet another aspect includes accessing a physical location in the DRAM in the memory subsystem by the buffer module based on the mapped generic bits.

Abstract: Embodiments relate to a dual asynchronous and synchronous memory system. One aspect is a system that includes a memory controller and a memory buffer chip coupled to the memory controller via a synchronous channel. The memory buffer chip includes a memory buffer unit configured to synchronously communicate with the memory controller in a nest domain, and a memory buffer adaptor configured to communicate with at least one memory interface port in a memory domain. The at least one memory interface port is operable to access at least one memory device. A boundary layer is connected to the nest domain and the memory domain, where the boundary layer is configurable to operate in a synchronous transfer mode between the nest and memory domains and to operate in an asynchronous transfer mode between the nest and memory domains.

Abstract: Embodiments relate to replay suspension in a memory system. One aspect is a system that includes a replay buffer coupled to a memory controller interface, and a replay control coupled to the replay buffer and a memory controller. The replay control is configured to receive an error indication associated with sending data from the memory controller interface to a memory subsystem as part of an operation. A replay pending signal is provided to the memory controller based on the error indication. Based on waiting for a period of time sufficient for the memory controller to provide remaining data associated with the operation to the replay buffer, a replay signal is asserted.

Abstract: A computer implemented method for early data delivery prior to error detection completion in a memory system includes receiving a frame of a multi-frame data block at a memory control unit interface. A controller writes the frame to a buffer control block in a memory controller nest domain. The frame is read from the buffer control block by a cache subsystem interface in a system domain prior to completion of error detection of the multi-frame data block. Error detection is performed on the frame by an error detector in the memory controller nest domain. Based on detecting an error in the frame, an intercept signal is sent from the memory controller nest domain to a correction pipeline in the system domain. The intercept signal indicates that error correction is needed prior to writing data in the frame to a cache subsystem.

Abstract: Embodiments relate to early data delivery prior to error detection completion in a memory system. One aspect is a system that includes a cache subsystem interface with a correction pipeline in a system domain. The system includes a memory control unit interface in a memory controller nest domain and a buffer control block providing an asynchronous boundary layer between the system domain and the memory controller nest domain. A controller is configured to receive a frame of a multi-frame data block and write the frame to the buffer control block. The frame is read by the cache subsystem interface prior to completion of error detection of the multi-frame data block. Error detection is performed on the frame in the memory controller nest domain. Based on detecting an error in the frame, an intercept signal is sent from the memory controller nest domain to the correction pipeline in the system domain.

Abstract: Embodiments relate to tagging in a MCU. An aspect includes assigning a command tag to a command by a tag allocation logic of the MCU. Another aspect includes sending the command and the command tag on a plurality of channels that are in communication with the MCU. Another aspect includes receiving a response tag comprising one of a data tag and a done tag corresponding to the command tag from each of the plurality of channels. Another aspect includes, based on receiving a data tag from each of the plurality of channels, determining that read data corresponding to the command is available.

Abstract: A computer-system implemented method for dual asynchronous and synchronous memory operation in a memory subsystem includes establishing a synchronous channel between a memory controller and a memory buffer chip. A mode selector determines a reference clock source for a memory domain phase-locked loop of the memory buffer chip based on an operating mode of the memory buffer chip. An output of a nest domain phase-locked loop is provided as the reference clock source to the memory domain phase-locked loop in the memory buffer chip based on the operating mode being synchronous. The nest domain phase-locked loop is operable synchronous to a memory controller phase-locked loop of the memory controller. A separate reference clock is provided independent of the nest domain phase-locked loop as the reference clock to the memory domain phase-locked loop based on the operating mode being asynchronous.

Abstract: A computer implemented method for early data delivery prior to error detection completion in a memory system includes receiving a frame of a multi-frame data block at a memory control unit interface. A controller writes the frame to a buffer control block in a memory controller nest domain. The frame is read from the buffer control block by a cache subsystem interface in a system domain prior to completion of error detection of the multi-frame data block. Error detection is performed on the frame by an error detector in the memory controller nest domain. Based on detecting an error in the frame, an intercept signal is sent from the memory controller nest domain to a correction pipeline in the system domain. The intercept signal indicates that error correction is needed prior to writing data in the frame to a cache subsystem.

Abstract: Embodiments relate to early data delivery prior to error detection completion in a memory system. One aspect is a system that includes a cache subsystem interface with a correction pipeline in a system domain. The system includes a memory control unit interface in a memory controller nest domain and a buffer control block providing an asynchronous boundary layer between the system domain and the memory controller nest domain. A controller is configured to receive a frame of a multi-frame data block and write the frame to the buffer control block. The frame is read by the cache subsystem interface prior to completion of error detection of the multi-frame data block. Error detection is performed on the frame in the memory controller nest domain. Based on detecting an error in the frame, an intercept signal is sent from the memory controller nest domain to the correction pipeline in the system domain.

Abstract: Embodiments relate to a dual asynchronous and synchronous memory system. One aspect is a system that includes a memory controller and a memory buffer chip coupled to the memory controller via a synchronous channel. The memory buffer chip includes a memory buffer unit configured to synchronously communicate with the memory controller in a nest domain, and a memory buffer adaptor configured to communicate with at least one memory interface port in a memory domain. The at least one memory interface port is operable to access at least one memory device. A boundary layer is connected to the nest domain and the memory domain, where the boundary layer is configurable to operate in a synchronous transfer mode between the nest and memory domains and to operate in an asynchronous transfer mode between the nest and memory domains.

Abstract: Embodiments relate to tagging in a MCU. An aspect includes assigning a command tag to a command by a tag allocation logic of the MCU. Another aspect includes sending the command and the command tag on a plurality of channels that are in communication with the MCU. Another aspect includes receiving a response tag comprising one of a data tag and a done tag corresponding to the command tag from each of the plurality of channels. Another aspect includes, based on receiving a data tag from each of the plurality of channels, determining that read data corresponding to the command is available.

Abstract: Embodiments relate to replay suspension in a memory system. One aspect is a system that includes a replay buffer coupled to a memory controller interface, and a replay control coupled to the replay buffer and a memory controller. The replay control is configured to receive an error indication associated with sending data from the memory controller interface to a memory subsystem as part of an operation. A replay pending signal is provided to the memory controller based on the error indication. Based on waiting for a period of time sufficient for the memory controller to provide remaining data associated with the operation to the replay buffer, a replay signal is asserted.