Abstract: Techniques for emulating a configuration space may include emulating a set of configuration registers in an integrated circuit device for a set of functions corresponding to a type of peripheral device. The type of peripheral device represented by the integrated circuit device can be modified by changing the set of configuration registers being emulated in the integrated circuit device. Multiple sets of configuration registers can also be emulated to support different virtual machines or different operating systems.

Abstract: Apparatus and methods are disclosed herein for remote, direct memory access (RDMA) technology that enables direct memory access from one host computer memory to another host computer memory over a physical or virtual computer network according to a number of different RDMA protocols. In one example, a method includes receiving remote direct memory access (RDMA) packets via a network adapter, deriving a protocol index identifying an RDMA protocol used to encode data for an RDMA transaction associated with the RDMA packets, applying the protocol index to a generate RDMA commands from header information in at least one of the received RDMA packets, and performing an RDMA operation using the RDMA commands.

Abstract: A first configurable address decoder can be coupled between a source node and a first interconnect fabric, and a second address decoder can be coupled between the first interconnect fabric and a second interconnect fabric. The first address decoder can be configured with a first address mapping table that can map a first set of address ranges to a first set of target nodes connected to the first interconnect fabric. The second address decoder can be configured with a second address mapping table that can map a second set of address ranges to a second set of target nodes connected to the second interconnect fabric. The second address decoder can be part of the first set of target nodes. The first address decoder and the second address decoder can be configured or re-configured to determine different routes for a transaction from the source node to a target node in the second set of target nodes via the first and second interconnect fabrics.

Abstract: Techniques for cooperative timing alignment using synchronization pulses are described. The techniques can include generating, at an integrated circuit device, a timing signal, controlling a local count value based on the timing signal, monitoring a synchronization signal of a system comprising the integrated circuit device, detecting a synchronization pulse in the synchronization signal, and aligning the local count value with an implied count value associated with the synchronization pulse in order to align the local count value with those of other integrated circuit devices of the system.

Abstract: Techniques are described for maintaining in-order execution when a dependency exists between write transactions. In some embodiments, a write re-order buffer (WROB) is configured to assign the same group ID to an incoming write transaction upon determining that the incoming write transaction is dependent on a pending write transaction. The WROB forwards the incoming write transaction to an interconnect fabric for routing to a completer device. The interconnect fabric enforces in-order execution when write transactions share the same group ID. The WROB can maintain a transaction log of pending write transactions and also track the statuses of responses for such transactions. Transaction responses can include responses sent from a completer to confirm that a transaction has actually been completed. Additionally, the WROB can send a response indicating completion back to the requester of the transaction. In some embodiments, the WROB is configured to send an early response to the requester.

Abstract: Apparatus and methods are disclosed herein for remote, direct memory access (RDMA) technology that enables direct memory access from one host computer memory to another host computer memory over a physical or virtual computer network according to a number of different RDMA protocols. In one example, a method includes receiving remote direct memory access (RDMA) packets via a network adapter, deriving a protocol index identifying an RDMA protocol used to encode data for an RDMA transaction associated with the RDMA packets, applying the protocol index to a generate RDMA commands from header information in at least one of the received RDMA packets, and performing an RDMA operation using the RDMA commands.

Abstract: Techniques for emulating a configuration space may include emulating a set of configuration registers for a set of functions corresponding to a type of peripheral device. The set of functions can include a physical function and a virtual function associated with the physical function. A configuration access request can be processed by retrieving an emulated configuration register from the emulated configuration space, and logging incoming configuration access requests in a configuration transaction log to track configuration accesses.

Abstract: A coherent connection and a non-coherent connection are provided between system-on-chips (SoCs). The coherent connection can be coupled to coherent interconnects on the SoCs, and the non-coherent connection can be coupled to non-coherent interconnects on the SoCs. An input/output (I/O) transaction from an I/O device on a first SoC that is targeted to a second SoC can be transmitted via the non-coherent connection, and a processor transaction from the first SoC that is targeted to the second SoC can be transmitted via the coherent connection.

Abstract: A write cleaner circuit can be used to implement write-through (WT) functionality by a write-back (WB) cache memory for updating the system memory. The write cleaner circuit can intercept memory write transactions issued to the WB cache memory and generate clean requests that can enable the WB cache memory to send update requests to corresponding memory locations in the system memory around the same time as the memory write transactions are performed by the WB cache memory, and clear dirty bits in the cache lines corresponding to those memory write transactions.

Abstract: Apparatus and methods are disclosed herein for remote, direct memory access (RDMA) technology that enables direct memory access from one host computer memory to another host computer memory over a physical or virtual computer network. In one example, RDMA functionality is provided by combining a host executing instructions for RDMA software applications with dedicated hardware accelerator, where the host has access to substantially all RDMA connection context (e.g., configuration, status, state machine, counters, etc.) and a hardware accelerator stores a portion of the context information for a set of currently active transactions. The hardware accelerator derives a transaction identifier from header information in received RDMA packets and performs a local RDMA operation using at least a portion of the received data, a destination address of the location RDMA operation being based at least in part on a memory address determined using the transaction identifier.

Abstract: Apparatus and methods are disclosed herein for remote, direct memory access (RDMA) technology that enables direct memory access from one host computer memory to another host computer memory over a physical or virtual computer network. In one example, RDMA functionality is provided by combining a host executing instructions for RDMA software applications with dedicated hardware accelerator, where the host has access to substantially all RDMA connection context (e.g., configuration, status, state machine, counters, etc.) and a hardware accelerator stores a portion of the context information for a set of currently active transactions. The hardware accelerator derives a transaction identifier from header information in received RDMA packets and performs a local RDMA operation using at least a portion of the received data, a destination address of the location RDMA operation being based at least in part on a memory address determined using the transaction identifier.

Abstract: Systems and methods are provided to differentiate different types of traffic going through the same physical channel such that the traffic flow for different traffic types does not impact each other. The physical channel can be configured to support a plurality of virtual channels. Each transaction that needs to be communicated through the physical channel can be classified into a certain traffic type, and each traffic type can be assigned to a virtual channel. Each transaction can be communicated on a respective virtual channel based on the corresponding traffic type. If the traffic flow through a first virtual channel for a transaction slows down, the traffic flow through a second virtual channel for another transaction can continue without getting impacted by the slow down on the first virtual channel.

Abstract: An integrated circuit design technique utilizes a data structure describing the connections, interconnect routing information of the connections, and bandwidth requirements of the connections in an integrated circuit device to generate an interconnect flow graph having nodes, and edges connecting the nodes. The edges connecting the nodes can reflect the bandwidth requirements of the connections. The interconnect flow graph can be used to optimize and verify the integrated circuit design.

Abstract: Ordering rules, such as those enforced by the peripheral component interconnect express (PCIe) protocol for data communications, can be intelligently enforced for independent transactions. A single device might host or be associated with multiple PCIe devices, such as virtual machines, and treating requests from these separate PCIe devices as coming from separate domains enables the ordering rules to be bypassed for certain transactions. Further, since a virtual machine might host multiple applications or be associated with multiple processors that can submit independent requests, the ordering rules can be bypassed at the transaction level in at least some instances. The ability to intelligently bypass ordering rules can help to improve the performance of the overall system, as requests do not need to be unnecessarily delayed and data storage capacity can be more fully utilized.

Abstract: An address decoder for a source node in a multi-chip system is disclosed, which can perform parallel decoding steps to determine whether a transaction from the source node is addressed to a target node in a local integrated circuit (IC) or a remote IC, and whether the source node is allowed to access that target node. Based on the outcome of both the decoding steps, the transaction can be either blocked by the address decoder, or routed to the target node. If the transaction is addressed to the remote IC, but the source node is not allowed to access the target node on the remote IC, the transaction can be terminated by the address decoder in the local IC.

Abstract: Apparatus and methods are disclosed herein for remote, direct memory access (RDMA) technology that enables direct memory access from one host computer memory to another host computer memory over a physical or virtual computer network according to a number of different RDMA protocols. In one example, a method includes receiving remote direct memory access (RDMA) packets via a network adapter, deriving a protocol index identifying an RDMA protocol used to encode data for an RDMA transaction associated with the RDMA packets, applying the protocol index to a generate RDMA commands from header information in at least one of the received RDMA packets, and performing an RDMA operation using the RDMA commands.

Abstract: Apparatus and methods are disclosed herein for remote, direct memory access (RDMA) technology that enables direct memory access from one host computer memory to another host computer memory over a physical or virtual computer network according to a number of different RDMA protocols. In one example, a method includes receiving remote direct memory access (RDMA) packets via a network adapter, deriving a protocol index identifying an RDMA protocol used to encode data for an RDMA transaction associated with the RDMA packets, applying the protocol index to a generate RDMA commands from header information in at least one of the received RDMA packets, and performing an RDMA operation using the RDMA commands.

Abstract: Techniques for emulating a configuration space may include emulating a set of configuration registers for a set of functions corresponding to a type of peripheral device. The set of functions can include a physical function and a virtual function associated with the physical function. A configuration access request can be processed by retrieving an emulated configuration register from the emulated configuration space, and logging incoming configuration access requests in a configuration transaction log to track configuration accesses.

Abstract: Techniques for emulating a configuration space by a peripheral device may include receiving a access request, determining that the access request is for an emulated configuration space of the peripheral device, and retrieving an emulated configuration from an emulated configuration space. The access request can then be serviced by using the emulated configuration.

Abstract: In a computer comprising a plurality of integrated circuits (ICs), each IC may be connected to all other ICs via a respective point-to-point interconnect. A source IC divides the data to be transmitted to a destination IC for a transaction to generate multiple data cells so that each data cell includes a different portion of the data. The source IC transmits one of the data cells to the destination IC and remaining data cells to intermediate ICs, wherein an intermediate IC is an IC other than the source IC or the destination IC. The intermediate ICs forward the remaining data cells to the destination IC.