Apparatus and method for arbitrating access to a set of resources

Abstract

An apparatus and method are provided for arbitrating access to a set of resources that are to be accessed in response to requests received at an interface. Arbitration circuitry arbitrates amongst the requests received at the interface in order to select, in each arbitration cycle, at least one next request to be processed. Each request identifies an access operation to be performed in response to the request, the access operation being selected from a group of access operations. Further, each access operation in the group has an associated scheduling pattern identifying timing of access to the resources in the set when performing that access operation. In response to a given request being selected by the arbitration circuitry, access control circuitry controls access to the set of resources in accordance with the associated scheduling pattern for the access operation identified by that request. Ordering circuitry determines, for different combinations of requests, an associated ordering of those requests, where the associated ordering is determined taking into account the associated scheduling pattern of each access operation in the group. The arbitration circuitry may employ a bandwidth aware arbitration scheme where a multi-arbitration operation is iteratively performed. Each performance of the multi-arbitration operation comprises sampling the requests currently received at the interface, and employing the ordering circuitry to determine, based on the sampled requests, an order in which the sampled requests should be selected. Then, during each arbitration cycle, at least one next request to be processed is selected from amongst the sampled requests based on the determined order, until each sampled request has been selected.