Abstract: There is provided an apparatus comprising bridge circuitry to couple processing circuitry to an allocated subset of a plurality of port controllers for connecting the processing circuitry to link partners. The bridge circuitry is configured to perform a data transfer between the processing circuitry and the allocated subset according to a bandwidth quota. The apparatus is provided with control circuitry to receive configuration information identifying the allocated subset, and to allocate a bandwidth share to each port controller identified in the allocated subset. The control circuitry is configured to determine the bandwidth share based on the configuration information. The control circuitry is configured, for each given port controller identified in the allocated subset, to implement a restriction to limit the data transfer between the given port controller and the processing circuitry according to the bandwidth share allocated to the given port controller.

Abstract: An apparatus comprises bridge circuitry configured to bridge between a memory system interconnect and a port controller. In a first state, the bridge circuitry is configured to control the internal communication link interface to transmit a given type of packet to the port controller using a first type of credit. In a second state, the bridge circuitry is configured to control the internal communication link interface to transmit the given type of packet to the port controller without using the first type of credit. The first type of credit represents availability of buffer storage at the link partner.

Abstract: There is provided an apparatus, a method, and a storage medium. The apparatus comprises one or more requestor devices to issue transaction requests, and one or more target devices to service those requests. The requestor devices and the target devices are configured to fulfil the requests according to a request ordering protocol specifying an ordered write observation behaviour in which, for each write transaction in a group of ordered write transactions, at least a deferred portion of the write transaction is deferred until all data specified in the group of ordered write transactions preceding the write transaction are observable. When implementing the request ordering protocol, the target devices are responsive to control information taking a first value to dynamically enable the ordered write observation behaviour, and the one or more target devices are responsive to the control information taking a second value to dynamically disable the ordered write observation behaviour.

Abstract: There is provided an apparatus, a method, and a storage medium. The apparatus comprises one or more requestor devices to issue transaction requests, and one or more target devices to service those requests. The requestor devices and the target devices are configured to fulfil the requests according to a request ordering protocol specifying an ordered write observation behaviour in which, for each write transaction in a group of ordered write transactions, at least a deferred portion of the write transaction is deferred until all data specified in the group of ordered write transactions preceding the write transaction are observable. When implementing the request ordering protocol, the target devices are responsive to control information taking a first value to dynamically enable the ordered write observation behaviour, and the one or more target devices are responsive to the control information taking a second value to dynamically disable the ordered write observation behaviour.

Abstract: A method and apparatus is disclosed for minimizing power virus in a network on chip. The method includes an operational metric related to a node with at least one threshold, the node configured to manage communication of a first number of outbound transactions; determining, based on the comparison, a second number of outbound transactions from the first number of outbound transactions that are allowed from the node; and communicating the second number of outbound transactions. An apparatus for minimizing power virus in a network on chip is also disclosed.

Abstract: Aspects disclosed herein include avoiding deadlocks in processor-based systems employing retry and in-order-response non-retry bus coherency protocols. In this regard, an interface bridge circuit is communicatively coupled to a first core device that implements a retry bus coherency protocol, and a second core device that implements an in-order-response non-retry bus coherency protocol. The interface bridge circuit receives a snoop command from the first core device, and forwards the snoop command to the second core device. While the snoop command is pending, the interface bridge circuit detects a potential deadlock condition between the first core device and the second core device. In response to detecting the potential deadlock condition, the interface bridge circuit is configured to send a retry response to the first core device. This enables the first core device to continue processing, thereby eliminating the potential deadlock condition.

Abstract: Maintaining cache coherency using conditional intervention among multiple master devices is disclosed. In one aspect, a conditional intervention circuit is configured to receive intervention responses from multiple snooping master devices. To select a snooping master device to provide intervention data, the conditional intervention circuit determines how many snooping master devices have a cache line granule size the same as or larger than a requesting master device. If one snooping master device has a same or larger cache line granule size, that snooping master device is selected. If more than one snooping master device has a same or larger cache line granule size, a snooping master device is selected based on an alternate criteria. The intervention responses provided by the unselected snooping master devices are canceled by the conditional intervention circuit, and intervention data from the selected snooping master device is provided to the requesting master device.

Abstract: Aspects disclosed herein include avoiding deadlocks in processor-based systems employing retry and in-order-response non-retry bus coherency protocols. In this regard, an interface bridge circuit is communicatively coupled to a first core device that implements a retry bus coherency protocol, and a second core device that implements an in-order-response non-retry bus coherency protocol. The interface bridge circuit receives a snoop command from the first core device, and forwards the snoop command to the second core device. While the snoop command is pending, the interface bridge circuit detects a potential deadlock condition between the first core device and the second core device. In response to detecting the potential deadlock condition, the interface bridge circuit is configured to send a retry response to the first core device. This enables the first core device to continue processing, thereby eliminating the potential deadlock condition.

Abstract: Maintaining cache coherency using conditional intervention among multiple master devices is disclosed. In one aspect, a conditional intervention circuit is configured to receive intervention responses from multiple snooping master devices. To select a snooping master device to provide intervention data, the conditional intervention circuit determines how many snooping master devices have a cache line granule size the same as or larger than a requesting master device. If one snooping master device has a same or larger cache line granule size, that snooping master device is selected. If more than one snooping master device has a same or larger cache line granule size, a snooping master device is selected based on an alternate criteria. The intervention responses provided by the unselected snooping master devices are canceled by the conditional intervention circuit, and intervention data from the selected snooping master device is provided to the requesting master device.