Abstract: The present invention provides a transaction interface to be used between semiconductor intellectual property cores. The urgency attribute of pending transactions can be changed by a special type of transaction at the interface. The urgency can be incremented, raised to at least an indicated value, or changed to a value as specified. For an interface with multiple pending transactions, a mask can be used to indicate one or more IDs, the transactions of which should be changed.

Abstract: The optimal configuration of a number of optional pipeline stages within the data paths of systems-on-chip is determined by application of a solver. The solver includes variables such as: the placement of modules physically within the floorplan of the chip; the signal propagation time; the logic gate switching time; the arrival time, after a clock edge, of a signal at each module port; the arrival time at each pipeline stage; and the Boolean value of the state of activation of each optional pipeline stage. The optimal configuration ensures that a timing constraint is met, if possible, with the lowest possible cost of pipeline stages.

Abstract: A system and method are disclosed for error corrected data transmission using an error detection and retry scheme. Data frames are sent from a transmitting chip to a receiving chip either formatted as PHITs or combined, compressed, and formatted as ePHITs. The ePHIT formatting includes hashing one or more CRC with a sequence number that is generated in the receiver. Upon error detection, a retry operation may retransmit the data in a different format than the original transmission.

Abstract: A simplified coherency controller supports multiple exclusively active fully coherent agent interfaces and any number of active I/O (partially) coherent agent interfaces. A state controller determines which fully coherent agent is active. Multiple fully coherent agents can be simultaneously active during a short period of a transition of processing from one to another processor. Multiple fully coherent agents can be simultaneously active, though without a mutually consistent view of memory, which is practical in cases such as when running multiple operating systems on different processors.

Abstract: A coherency controller, such as one used within a system-on-chip, is capable of issuing different types of snoops to coherent caches. The coherency controller chooses the type of snoop based on the type of request that caused the snoops or the state of the system or both. By so doing, coherent caches provide data when they have sufficient throughput, and are not required to provide data when they do not have insufficient throughput.

Abstract: The invention is a transaction interface protocol wherein the interface protocol has a transaction identifier signal in each of the request and response channels. It is used between a target network interface unit (NIU) master and an initiator NIU slave that are directly connected through a transaction interface. The target NIU response channel uses the transaction ID signal to identify the entry in a context array associated with the corresponding request. The coupling of target NIU and initiator NIU enable the formation of an on-chip interconnect comprising multiple network-on-chip (NoCs) wherein the topology of the interconnect is simpler, smaller, faster, and has lower latency.

Abstract: The invention is a transaction interface protocol wherein the interface protocol has a transaction identifier signal in each of the request and response channels. It is used between a target network interface unit (NIU) master and an initiator NIU slave that are directly connected through a transaction interface. The target NIU response channel uses the transaction ID signal to identify the entry in a context array associated with the corresponding request. The coupling of target NIU and initiator NIU enable the formation of an on-chip interconnect comprising multiple network-on-chip (NoCs) wherein the topology of the interconnect is simpler, smaller, faster, and has lower latency.

Abstract: A system with a prefetch address generator coupled to a system translation look-aside buffer that comprises a translation cache. Prefetch requests are sent for page address translations for predicted future normal requests. Prefetch requests are filtered to only be issued for address translations that are unlikely to be in the translation cache. Pending prefetch requests are limited to a configurable or programmable number. Such a system is simulated from a hardware description language representation.

Abstract: A system TLB accepts translation prefetch requests from initiators. Misses generate external translation requests to a walker port. Attributes of the request such as ID, address, and class, as well as the state of the TLB affect the allocation policy of translations within multiple levels of translation tables. Translation tables are implemented with SRAM, and organized in groups.

Abstract: A multi-dimension engine, connected to a system TLB, generates sequences of addresses to request page address translation prefetch requests in advance of predictable accesses to elements within data arrays. Prefetch requests are filtered to avoid redundant requests of translations to the same page. Prefetch requests run ahead of data accesses but are tethered to within a reasonable range. The number of pending prefetches are limited. A system TLB stores a number of translations, the number being relative to the dimensions of the range of elements accessed from within the data array.

Abstract: System TLBs are integrated within an interconnect, use a and share a transport network to connect to a shared walker port. Transactions are able to pass STLB allocation information through a second initiator side interconnect, in a way that interconnects can be cascaded, so as to allow initiators to control a shared STLB within the first interconnect. Within the first interconnect, multiple STLBs share an intermediate-level translation cache that improves performance when there is locality between requests to the two STLBs.

Abstract: A Network-on-Chip (NoC) is provided that performs reordering of transaction responses such as those with requests that cross address mapping boundaries. Ordering is ensured by filtering logic in reorder buffers, some of which include storage to allow multiple simultaneously pending transactions. Transactions are transported by a packet-based transport protocol. The reorder buffering is done at packet level, within the transport topology. Reorder buffers are distributed physically throughout the floorplan of the chip, they have localized connectivity to initiators, and they operate in separate power and clock domains.

Abstract: The disclosed invention gives an estimation of the placement location of the units comprising a NoC within the floorplan of a chip. From that, and with knowledge of the number of wires of links within the NoC topology, an estimation of the wire density at each point is calculated. Furthermore, an estimate is made of the locations of the critical timing paths within the chip. The timing path calculation is also used to generate IO constraints for the synthesis of modules comprising different parts of the NoC. Further still, a scenario of traffic through the NoC is combined with the wire map and information about the width of links within the topology to generate an estimation of power consumption.

Abstract: A system and method is disclosed for multiple chips in which the connection between chips is made with registered inputs and registered outputs. This is achieved using a credit-based flow control protocol between the chips. The connection is made as part of a single packet-based on-chip and between-chip network with a common address space between the two chips.

Abstract: A system and method are disclosed for connecting PCI-ordered agents based on fully independent networks. The system and method are free of PCI topology constraints, so that the system and method can be implemented in an inexpensive and scalable way. The method disclosed is used to handle and transport PCI-ordered traffic on a fabric. Based on the actual ordering requirement of the set of PCI agents, the fabric includes two, three, or four independent networks.

Abstract: An improved cache coherency controller, method of operation, and system of such is provided. Traffic from coherent agents to shared targets can flow on different channels through the coherency controller. This improves quality of service for performance sensitive agents. Furthermore, data transfer is performed on a separate network from coherency control. This minimizes the distance of data movement, reducing congestion for the physical routing of wires on the chip and reduces the power consumption for data transfers.

Abstract: A system and method are disclosed for communicating coherency information between initiator and target agents on semiconductor chips. Sufficient information communication to support full coherency is performed through a socket interface using only three channels. Transaction requests are issued on one channel with responses given on a second. Intervention requests are issued on the same channel as transaction responses. Intervention responses are given on a third channel. Such an approach drastically reduces the complexity of cache coherent socket interfaces compared to conventional approaches. The net effect is faster logic, smaller silicon area, improved architecture performance, and a reduced probability of bugs by the designers of coherent initiators and targets.