Abstract: The disclosure includes systems and methods for bus control. A method comprises receiving a data exchange request, wherein the data exchange request includes a data exchange tag that identifies a data exchange, splitting the data exchange into a plurality of fractional data transactions, providing one or more bus commands to a system bus, receiving, at the bus controller, one or more acceptance notifications indicating that the one or more of the plurality have been accepted by the system bus, assigning transaction identifiers (TIDs) corresponding to the one or more of the plurality of fractional data transactions, receiving one or more completion notifications indicating that the one or more of the plurality have been completed, determining that each of the plurality of fractional data transactions associated with the data exchange tag have been completed, and notifying the processor that the requested data exchange has been completed.

Abstract: Systems and methods for time synchronization for clocks separated by a communication link allow a master clock to be positioned at a downstream-facing port or an upstream-facing port and to send synchronization commands with an associated time stamp embedded in transport layer protocol (TLP) prefixes to a slave clock. The slave clock may update its time value based on the received time stamp. Further, the slave may calculate a round trip delay between the master clock and the slave clock and use this delay calculation to correct the slave clock. The delay calculation may likewise be made using TLP prefixes. By using TLP prefixes in this fashion, the time synchronization can piggyback on existing message traffic, which reduces signaling overhead. Likewise, by using the TLP prefixes, the time synchronization may be initiated from either an upstream-facing port or a downstream-facing port.

Abstract: A system for low-speed Peripheral Component Interconnect (PCI) Express (PCIe) systems, while maintaining both lower level physical layer (PHY) pin requirements and upper layer functionality being capable of both differential and single-ended signaling modes optimized for power savings. An apparatus includes an integrated circuit (IC) adapted to be connected to a Peripheral Component Interconnect (PCI) Express (PCIe) bus. The IC includes a control block selects between differential and single-ended signaling for the PCIe bus. The single-ended signaling is transmitted through existing pins of the IC that are coupled to the PCIe bus for differential signaling when single-ended signaling is selected for the PCIe bus.

Abstract: Extended message signaled interrupts (MSI) data are disclosed. In one aspect, MSI bits are modified to include a system level identifier. In an exemplary aspect, an upper sixteen bits of the MSI message data are modified to be the system level identifier. By providing the system level identifier within the MSI message data, an interrupt controller can verify the interrupt source.

Abstract: Systems and methods for time synchronization for clocks separated by a communication link allow a master clock to be positioned at a downstream-facing port or an upstream-facing port and to send synchronization commands with an associated time stamp embedded in transport layer protocol (TLP) prefixes to a slave clock. The slave clock may update its time value based on the received time stamp. Further, the slave may calculate a round trip delay between the master clock and the slave clock and use this delay calculation to correct the slave clock. The delay calculation may likewise be made using TLP prefixes. By using TLP prefixes in this fashion, the time synchronization can piggyback on existing message traffic, which reduces signaling overhead. Likewise, by using the TLP prefixes, the time synchronization may be initiated from either an upstream-facing port or a downstream-facing port.

Abstract: Systems and methods for time synchronization for clocks separated by a communication link allow a master clock to be positioned at a downstream-facing port or an upstream-facing port and to send synchronization commands with an associated time stamp embedded in transport layer protocol (TLP) prefixes to a slave clock. The slave clock may update its time value based on the received time stamp. Further, the slave may calculate a round trip delay between the master clock and the slave clock and use this delay calculation to correct the slave clock. The delay calculation may likewise be made using TLP prefixes. By using TLP prefixes in this fashion, the time synchronization can piggyback on existing message traffic, which reduces signaling overhead. Likewise, by using the TLP prefixes, the time synchronization may be initiated from either an upstream-facing port or a downstream-facing port.

Abstract: Extended message signaled interrupts (MSI) data are disclosed. In one aspect, MSI bits are modified to include a system level identifier. In an exemplary aspect, an upper sixteen bits of the MSI message data are modified to be the system level identifier. By providing the system level identifier within the MSI message data, an interrupt controller can verify the interrupt source.

Abstract: Systems and methods for reducing latency on long distance point-to-point links where the point-to-point link is a Peripheral Component Interconnect (PCI) express (PCIE) link that modifies a receiver to advertise infinite or unlimited credits. A transmitter sends packets to the receiver. If the receiver's buffers fill, the receiver, contrary to PCIE doctrine, drops the packet and returns a negative acknowledgement (NAK) packet to the transmitter. The transmitter, on receipt of the NAK packet, resends packets beginning with the one for which the NAK packet was sent. By the time these resent packets arrive, the receiver will have had time to manage the packets in the buffers and be ready to receive the resent packets.

Abstract: Alternate acknowledgment (ACK) signals in a coalescing Transmission Control Protocol/Internet Protocol (TCP/IP) system are disclosed. In one aspect, a network interface card (NIC) examines packet payloads, and the NIC generates an ACK signal for a sending server before sending a coalesced packet to an internal processor. Further, the NIC may examine incoming packets and send an ACK signal to the internal processor for ACK signals that are received from the sending server before sending the coalesced packet to the internal processor. By extracting and sending the ACK signals before sending the corresponding payloads in the coalesced packet, latency that would otherwise be incurred waiting for the ACK signal is eliminated. Elimination of such latency may improve network performance and may provide power savings.

Abstract: Systems and methods for time synchronization for clocks separated by a communication link allow a master clock to be positioned at a downstream-facing port or an upstream-facing port and to send synchronization commands with an associated time stamp embedded in transport layer protocol (TLP) prefixes to a slave clock. The slave clock may update its time value based on the received time stamp. Further, the slave may calculate a round trip delay between the master clock and the slave clock and use this delay calculation to correct the slave clock. The delay calculation may likewise be made using TLP prefixes. By using TLP prefixes in this fashion, the time synchronization can piggyback on existing message traffic, which reduces signaling overhead. Likewise, by using the TLP prefixes, the time synchronization may be initiated from either an upstream-facing port or a downstream-facing port.

Abstract: Systems and methods for providing split read transactions over an audio communication bus are disclosed. In one aspect, a device that receives a read command informs a requester that data is not yet available and to try again at a future time, potentially outside the traditional response window. In the meantime, the receiving device begins fetching the requested data to have available when the requester makes a subsequent request. By providing a not yet response, data may be fetched from a memory element in a low-power state after it has been taken out of the low-power state or data may be fetched from a remote location or over a slow internal bus.

Abstract: The disclosure includes systems and methods for bus control. A method comprises receiving a data exchange request, wherein the data exchange request includes a data exchange tag that identifies a data exchange, splitting the data exchange into a plurality of fractional data transactions, providing one or more bus commands to a system bus, receiving, at the bus controller, one or more acceptance notifications indicating that the one or more of the plurality have been accepted by the system bus, assigning transaction identifiers (TIDs) corresponding to the one or more of the plurality of fractional data transactions, receiving one or more completion notifications indicating that the one or more of the plurality have been completed, determining that each of the plurality of fractional data transactions associated with the data exchange tag have been completed, and notifying the processor that the requested data exchange has been completed.

Abstract: A replacement physical layer (PHY) for low-speed Peripheral Component Interconnect (PCI) Express (PCIe) systems is disclosed. In one aspect, an analog PHY of a conventional PCIe system is replaced with a digital PHY. The digital PHY is coupled to a media access control (MAC) logic by a PHY interface for PCIe (PIPE) directly. In further exemplary aspects, the digital PHY may be a complementary metal oxide semiconductor (CMOS) PHY that includes a serializer and a deserializer. Replacing the analog PHY with the digital PHY allows entry and exit from low-power modes to occur much quicker, resulting in substantial power savings and reduced latency. Because the digital PHY is operable with low-speed communication, the digital PHY can maintain sufficient bandwidth that communication is not unnecessarily impacted by digital logic of the digital PHY.

Abstract: A system for low-speed Peripheral Component Interconnect (PCI) Express (PCIe) systems, while maintaining both lower level physical layer (PHY) pin requirements and upper layer functionality being capable of both differential and single-ended signaling modes optimized for power savings. An apparatus includes an integrated circuit (IC) adapted to be connected to a Peripheral Component Interconnect (PCI) Express (PCIe) bus. The IC includes a control block selects between differential and single-ended signaling for the PCIe bus. The single-ended signaling is transmitted through existing pins of the IC that are coupled to the PCIe bus for differential signaling when single-ended signaling is selected for the PCIe bus.

Abstract: Alternate acknowledgment (ACK) signals in a coalescing Transmission Control Protocol/Internet Protocol (TCP/IP) system are disclosed. In one aspect, a network interface card (NIC) examines packet payloads, and the NIC generates an ACK signal for a sending server before sending a coalesced packet to an internal processor. Further, the NIC may examine incoming packets and send an ACK signal to the internal processor for ACK signals that are received from the sending server before sending the coalesced packet to the internal processor. By extracting and sending the ACK signals before sending the corresponding payloads in the coalesced packet, latency that would otherwise be incurred waiting for the ACK signal is eliminated. Elimination of such latency may improve network performance and may provide power savings.

Abstract: Aspects disclosed in the detailed description include inline cryptographic engine (ICE) for peripheral component interconnect express (PCIe). In this regard, in one aspect, an ICE is provided in a PCIe root complex (RC) in a host system. The PCIe RC is configured to receive at least one transport layer packet (TLP), which includes a TLP prefix, from a storage device. In a non-limiting example, the TLP prefix includes transaction-specific information that may be used by the ICE to provide data encryption and decryption. By providing the ICE in the PCIe RC and receiving the transaction-specific information in the TLP prefix, it is possible to encrypt and decrypt data in the PCIe RC in compliance with established standards, thus ensuring adequate protection during data exchange between the PCIe RC and the storage device.

Abstract: Communicating transaction-specific attributes in a peripheral component interconnect express (PCIe) system is disclosed. A PCIe system includes a host system and at least one PCIe endpoint. The PCIe endpoint is configured to determine one or more transaction-specific attributes that can improve efficiency and performance of a predefined host transaction. In this regard, in one aspect, the PCIe endpoint encodes the transaction-specific attributes in a transaction layer packet (TLP) prefix of at least one PCIe TLP and provides the PCIe TLP to the host system. In another aspect, a PCIe root complex (RC) in the host system is configured to detect and extract the transaction-specific attributes from the TLP prefix of the PCIe TLP received from the PCIe endpoint. By communicating the transaction-specific attributes in the TLP prefix of the PCIe TLP, it is possible to improve efficiency and performance of the PCIe system without violating the existing PCIe standard.

Abstract: Hardware-based translation lookaside buffer (TLB) invalidation techniques are disclosed. A host system is configured to exchange data with a peripheral component interconnect express PCIE) endpoint (EP). A memory management unit (MMU), which is a hardware element, is included in the host system to provide address translation according to at least one TLB. In one aspect, the MMU is configured to invalidate the at least one TLB in response to receiving at least one TLB invalidation command from the PCIE EP. In another aspect, the PCIE EP is configured to determine that the at least one TLB needs to be invalidated and provide the TLB invalidation command to invalidate the at least one TLB. By implementing hardware-based TLB invalidation in the host system, it is possible to reduce TLB invalidation delay, thus leading to increased data throughput, reduced power consumption, and improved user experience.

Abstract: Hardware-based packet processing circuitry is provided. In this regard, hardware-based packet processing circuitry includes header processing circuitry and payload processing circuitry. The hardware-based packet processing circuitry receives a header portion and a payload portion of an incoming packet in a first packet format. The header processing circuitry and the payload processing circuitry process the header portion and the payload portion to form a processed header portion and a processed payload portion, respectively. The hardware-based packet processing circuitry generates an outgoing packet in a second packet format based on the processed header portion and the processed payload portion. By processing the incoming packet separately in the header processing circuitry and the payload processing circuitry, it is possible to accelerate selected steps (e.g., ciphering/deciphering, compression/de-compression, checksum, etc.

Abstract: A replacement physical layer (PHY) for low-speed Peripheral Component Interconnect (PCI) Express (PCIe) systems is disclosed. In one aspect, an analog PHY of a conventional PCIe system is replaced with a digital PHY. The digital PHY is coupled to a media access control (MAC) logic by a PHY interface for PCIe (PIPE) directly. In further exemplary aspects, the digital PHY may be a complementary metal oxide semiconductor (CMOS) PHY that includes a serializer and a deserializer. Replacing the analog PHY with the digital PHY allows entry and exit from low-power modes to occur much quicker, resulting in substantial power savings and reduced latency. Because the digital PHY is operable with low-speed communication, the digital PHY can maintain sufficient bandwidth that communication is not unnecessarily impacted by digital logic of the digital PHY.