摘要:
A data processing apparatus and method of configuration of such an apparatus are provided, the apparatus comprising a plurality of logic elements for processing data, a plurality of storage elements for temporarily storing data, and a plurality of connections from which data is passed between the logic elements. Each connection comprises one or more path portions separated by the storage elements. A number of the storage elements are selectable storage elements having a bypass path associated therewith, and a controller is provided for controlling the selection of each selectable storage element or its associated bypass path based on setup information, in order to enable a change in the number of path portions within one or more of the connections. This hence allows some configurability of the connections within the apparatus post-production, with operating conditions and other aspects affecting operating speed being taken into account when producing the setup information used by the controller to determine which selectable storage elements to use, and which ones to bypass.
摘要:
An on-chip integrated circuit interconnect 16 uses a serialization technique to divide a transaction to be transmitted into a sequence of transmission packets which are serially transmitted over a narrower connection. The order in which bits of the transaction are allocated to transmission packets is selected such that higher priority bits required by a receiving slave device in order that it can commence processing the transaction are sent first. This reduces the latency of the system.
摘要:
An integrated circuit 2 includes a transaction master 4 connected via interconnect circuitry 10 to a transaction slave 12. The transaction slave 12 generates a transfer-complete signal (R Last or B) to indicate completion of a data transfer (either a read or a write). When this transfer-complete signal has been received by the transaction master 4, then the transaction master 4 generates a complete-acknowledgement signal RACK, WACK, which is passed back to the transaction slave so as to acknowledge receipt of the transfer-complete signal.
摘要:
A method of arbitration within a data processing apparatus between a plurality of transfers to be routed over a corresponding plurality of paths provided by an interconnect circuit. The plurality of paths include a shared connection, the data processing apparatus having a plurality of initiator logic elements for initiating transfers and a plurality of recipient logic elements for receiving transfers, for each transfer the corresponding path coupling the initiator logic element responsible for initiating that transfer with the recipient logic element destined to receive that transfer. The method comprises the steps of providing to arbitration logic an indication as to whether the ready signal from a storage element has been asserted, and employing the arbitration logic to select, in dependence on predetermined criteria including at least that indication, one of the plurality of transfers for routing via the shared connection.
摘要:
An integrated circuit 2 includes a transaction master 4 connected via interconnect circuitry 10 to a transaction slave 12. The transaction slave 12 generates a transfer-complete signal (R Last or B) to indicate completion of a data transfer (either a read or a write). When this transfer-complete signal has been received by the transaction master 4, then the transaction master 4 generates a complete-acknowledgement signal RACK, WACK, which is passed back to the transaction slave so as to acknowledge receipt of the transfer-complete signal.
摘要:
A bus master 2, 4 sends write transactions to a bus slave 8 which include separate write addresses AW and write data WD. Write transaction identifiers AWID, WID are associated with these write addresses and write data. The bus slave can accept multiple write addresses such that there can be copending write transactions to the same bus slave. The bus slave uses the write transaction identifiers to correlate interleaved write data for the co-pending write transactions with their write addresses.
摘要:
Interconnect circuitry configured to provide routes for interconnecting several initiator devices and at least one recipient device including a memory. At least one of the initiator devices has a cache for storing a local copy of a subset of data items stored in the memory. The interconnect circuitry includes: a plurality of input ports and at least one output port; a plurality of paths for transmitting the transaction requests between the inputs and the at least one output; coherency control circuitry for maintaining an order in which at least some of the transaction requests to a same data storage location proceed through the interconnect circuitry. The interconnect circuitry is configured not to control the writeback transaction requests with the coherency control circuitry, such that the writeback transaction requests proceed independently of transaction requests routed through the coherency control circuitry.
摘要:
Interconnect circuitry configured to provide routes for interconnecting several initiator devices and at least one recipient device including a memory. At least one of the initiator devices has a cache for storing a local copy of a subset of data items stored in the memory. The interconnect circuitry includes: a plurality of input ports and at least one output port; a plurality of paths for transmitting the transaction requests between the inputs and the at least one output; coherency control circuitry for maintaining an order in which at least some of the transaction requests to a same data storage location proceed through the interconnect circuitry. The interconnect circuitry is configured not to control the writeback transaction requests with the coherency control circuitry, such that the writeback transaction requests proceed independently of transaction requests routed through the coherency control circuitry.
摘要:
An on-chip integrated circuit interconnect 16 uses a serialization technique to divide a transaction to be transmitted into a sequence of transmission packets which are serially transmitted over a narrower connection. The order in which bits of the transaction are allocated to transmission packets is selected such that higher priority bits required by a receiving slave device in order that it can commence processing the transaction are sent first. This reduces the latency of the system.
摘要:
The present invention provides a data processing apparatus and method for managing snoop operations. The data processing apparatus has a plurality of processing units for performing data processing operations requiring access to data in shared memory, with at least two of the processing units having a cache associated therewith for storing a subset of the data for access by that processing unit. A snoop-based cache coherency protocol is employed to ensure data accessed by each processing unit is up-to-date, and when an access request is issued the cache coherency protocol is referenced in order to determine whether a snoop process is required. Snoop control storage is provided which defines a plurality of snoop schemes, each snoop scheme defining a series of snoop phases to be performed to implement the snoop process, and each snoop phase requiring a snoop operation to be performed on either a single cache or multiple caches. When a snoop process is required, a snoop unit is used to reference the snoop control storage in order to identify, having regard to one or more properties of the access request, the snoop scheme to be employed to perform the snoop process. Such an approach provides a great deal of flexibility with regards to how snoop processes are implemented, in particular allowing different snoop schemes to be used dependent on the properties of the access request in question.