Abstract: A method and circuit for implementing lane shuffle for fault-tolerant communication links, and a design structure on which the subject circuit resides are provided. Shuffle hardware logic steers a set of virtual data lanes onto a set of physical optical lanes, steering around all lanes that are detected as bad during link initialization training. A mask status register is loaded with a mask of lane fail information during link training, which flags the bad lanes, if any. The shuffle hardware logic uses a shift template, where each position in the starting template is a value representing the corresponding lane position. The shift template is cascaded through a set of shifters controlled by the fail mask.

Abstract: A method and circuit for implementing exchange of failing lane information for fault-tolerant communication links, and a design structure on which the subject circuit resides are provided. An ordered set for lane and link training includes a novel lane mask field for lane and link training. Ordered sets are exchanged during lane and link training for a fault-tolerant communication link to establish synchronization between a transmitter and a receiver. In a link training step, the bus link layer exchanges an ordered set with a plurality of bits of lane mask information included in predefined bytes, such as bytes 8 and 9 of the lane mask field. Upon receiving the ordered set with the plurality of bits of lane mask information, the transmitter lanes are reconfigured to align with the received mask information.

Abstract: A method and circuit for implementing lane shuffle for fault-tolerant communication links, and a design structure on which the subject circuit resides are provided. Shuffle hardware logic steers a set of virtual data lanes onto a set of physical optical lanes, steering around all lanes that are detected as bad during link initialization training. A mask status register is loaded with a mask of lane fail information during link training, which flags the bad lanes, if any. The shuffle hardware logic uses a shift template, where each position in the starting template is a value representing the corresponding lane position. The shift template is cascaded through a set of shifters controlled by the fail mask.

Abstract: A method and circuit for implementing exchange of failing lane information for fault-tolerant communication links, and a design structure on which the subject circuit resides are provided. An ordered set for lane and link training includes a novel lane mask field for lane and link training. Ordered sets are exchanged during lane and link training for a fault-tolerant communication link to establish synchronization between a transmitter and a receiver. In a link training step, the bus link layer exchanges an ordered set with a plurality of bits of lane mask information included in predefined bytes, such as bytes 8 and 9 of the lane mask field. Upon receiving the ordered set with the plurality of bits of lane mask information, the transmitter lanes are reconfigured to align with the received mask information.

Abstract: Managing write-to-read turnarounds in an early read after write memory system is presented. Memory controller logic identifies a write operation's bank set, allows a different bank set read operation to issue prior to the write operation's completion, and allows a same bank set read operation to issue once the write operation completes. The memory controller includes operation counter logic, operation selection logic, operation acceptance logic, command formatting logic, and memory interface logic. The operation counter logic receives new-operation-related signals from the operation acceptance logic and, in turn, provides signals to the operation selection logic and the operation acceptance logic as to when to issue a read operation that corresponds to either an even DRAM bank or an odd DRAM bank.

Abstract: A memory system employs calibrations to ensure the precise transmission of data. During calibrations, memory refreshes can occur; however, these refreshes can interfere with calibration streams. Therefore, to alleviate collisions and interferences, refreshes are deferred to periods where no calibrations are taking place. The number of deferred refreshes is also tracked such that the overall loss of refreshes is prevented.

Abstract: A structure of sequencers, a method, and a computer program are provided for performing initial and periodic calibrations in an XDR™ memory system. A memory controller that performs these calibrations is divided into identical, independent halves, with each half containing a Current/Impedance Calibration (i/z Cal) sequencer and six Bank sequencers. The i/z Cal sequencer contains three pathways that perform the XIO current and termination calibrations, and the XDR™ DRAM current and termination impedance calibrations. Each Bank sequencer contains normal read and write operation pathways that are reused to accomplish receive setup, receive hold, transmit setup, transmit hold, XIO receive, and XIO transmit timing calibrations. Initial and periodic calibrations are necessary to ensure the precise transfer of data between the XIOs and the XDR™ DRAMs.

Abstract: Managing write-to-read turnarounds in an early read after write memory system is presented. Memory controller logic identifies a write operation's bank set, allows a different bank set read operation to issue prior to the write operation's completion, and allows a same bank set read operation to issue once the write operation completes. The memory controller includes operation counter logic, operation selection logic, operation acceptance logic, command formatting logic, and memory interface logic. The operation counter logic receives new-operation-related signals from the operation acceptance logic and, in turn, provides signals to the operation selection logic and the operation acceptance logic as to when to issue a read operation that corresponds to either an even DRAM bank or an odd DRAM bank.

Abstract: A memory controller design tool retrieves parameter ranges supported by a memory controller, and identifies troublesome parameter value combinations. The memory controller design tool suggests to 1) add logic to the memory controller to resolve the conflict, 2) incorporate a constraint that reduces/eliminates command collisions, data conflicts, and/or the need to check particular timing parameters, or 3) a combination of both. The memory controller design tool may work in conjunction with a memory controller designer to define and use the constraints.

Abstract: Managing write-to-read turnarounds in an early read after write memory system is presented. Memory controller logic identifies a write operation's bank set, allows a different bank set read operation to issue prior to the write operation's completion, and allows a same bank set read operation to issue once the write operation completes. The memory controller includes operation counter logic, operation selection logic, operation acceptance logic, command formatting logic, and memory interface logic. The operation counter logic receives new-operation-related signals from the operation acceptance logic and, in turn, provides signals to the operation selection logic and the operation acceptance logic as to when to issue a read operation that corresponds to either an even DRAM bank or an odd DRAM bank.

Abstract: In a first aspect, a first method of interfacing a processor and memory is provided. The first method includes the steps of (1) providing a processor adapted to issue a command complying with a first protocol; (2) providing a memory coupled to the processor and accessible by a command complying with a second protocol; (3) employing a plurality of scrub commands complying with the second protocol to check respective portions of the memory for errors, wherein each scrub command complying with the second protocol is a converted version of a scrub command complying with the first protocol issued by the processor and the respective portions are non-sequential; and (4) refreshing bits stored in the entire memory within a predetermined time period. Numerous other aspects are provided.

Abstract: In a first aspect, a first method of interfacing a processor and memory is provided. The first method includes the steps of (1) providing a computer system including (a) a first memory; (b) a processor adapted to issue a functional command to the first memory; (c) a translation chip; (d) a cache memory coupled to the translation chip; (e) a first link adapted to couple the processor to the translation chip; and (f) a second link adapted to couple the translation chip to the first memory; and (2) calibrating the first link to transmit data between the processor and cache memory. Numerous other aspects are provided.

Abstract: A memory system employs calibrations to ensure the precise transmission of data. During calibrations, memory refreshes can occur; however, these refreshes can interfere with calibration streams. Therefore, to alleviate collisions and interferences, refreshes are deferred to periods where no calibrations are taking place. The number of deferred refreshes is also tracked such that the overall loss of refreshes is prevented.

Abstract: A method, an apparatus, and a computer program are provided to control refreshes in Extreme Data Rate (XDR™) memory systems. XDR™ memory systems employ calibrations to ensure the precise transmission of data. During calibrations, memory refreshes can occur; however, these refreshes can interfere with calibration streams. Therefore, to alleviate collisions and interferences, refreshes are deferred to periods where no calibrations are taking place. The number of deferred refreshes is also tracked such that the overall loss of refreshes is prevented.

Abstract: A method and apparatus for managing write-to-read turnarounds in an early read after write memory system are presented. Memory controller logic identifies a write operation's bank set, allows a different bank set read operation to issue prior to the write operation's completion, and allows a same bank set read operation to issue once the write operation completes. The memory controller includes operation counter logic, operation selection logic, operation acceptance logic, command formatting logic, and memory interface logic. The operation counter logic receives new-operation-related signals from the operation acceptance logic and, in turn, provides signals to the operation selection logic and the operation acceptance logic as to when to issue a read operation that corresponds to either an even DRAM bank or an odd DRAM bank.

Abstract: A method and apparatus to avoid collisions between row activate and column read or column write commands is presented. A memory controller includes control logic, activate allowed logic, and last column counter logic. The control logic sends particular values to the activate allowed logic and the last column counter logic at the beginning of a read or write operation, such as a new command load value, a read count value, and a write count value. In turn, the control logic receives an activate allowed signal from the activate allowed logic, which indicates the times at which a new activate command may be issued. As a result, the memory controller allows an activate command to commence on “even” command cycles or anytime after the last outstanding column command has been issued.

Abstract: A structure of sequencers, a method, and a computer program are provided for performing initial and periodic calibrations in an XDR™ memory system. A memory controller that performs these calibrations is divided into identical, independent halves, with each half containing a Current/Impedance Calibration (i/z Cal) sequencer and six Bank sequencers. The i/z Cal sequencer contains three pathways that perform the XIO current and termination calibrations, and the XDR™ DRAM current and termination impedance calibrations. Each Bank sequencer contains normal read and write operation pathways that are reused to accomplish receive setup, receive hold, transmit setup, transmit hold, XIO receive, and XIO transmit timing calibrations. Initial and periodic calibrations are necessary to ensure the precise transfer of data between the XIOs and the XDR™ DRAMs.

Abstract: A method, a computer program, and an apparatus are provided for flexible SC to SR mapping to enable sub-page activation in an XDR™ memory system. An XDR™ memory system may allow system page size to reduced by a factor of two (half-page activation) or four (quarter-page activation). In an XDR™ memory system there are five different SCs and two different SRs. This scheme allows any one of the five SCs (or none) to be mapped to any one of the two SRs. Overall, this invention provides a flexible mapping scheme that can be utilized for any possible XDR memory system.