US 2010/0064071 A1 · DMA device having plural buffers storing transfer request information and DMA transfer method

Abstract

A Direct Memory Access (DMA) device includes a first buffer which holds a first transfer information required for a first transfer request, and a second buffer which holds a second transfer information required for a second transfer request, and a transfer request comparison circuit which determines whether or not a current transfer request, which is newly inputted, matches with the first transfer request or the second transfer request. The DMA device includes a priority determination circuit that, in case where the transfer request comparison circuit determines that the current transfer request is not matched with the first transfer request or the second transfer request, updates the second transfer information to a transfer information for the current transfer request when a priority of the current transfer request is higher than a priority of the second transfer request, and updates the first transfer information to the transfer information for the current transfer request when the priority of the current transfer request is lower than the priority of the second transfer request.

Claims16

Dependent claims

A Direct Memory Access (DMA) device, comprising:

a first buffer which holds a first transfer information required for a first transfer request;
a second buffer which holds a second transfer information required for a second transfer request;
a transfer request comparison circuit which determines whether or not a current transfer request, which is newly inputted, matches with the first transfer request or the second transfer request;
a priority determination circuit that, in case where the transfer request comparison circuit determines that the current transfer request is not matched with the first transfer request or the second transfer request, updates the second transfer information to a transfer information for the current transfer request when a priority of the current transfer request is higher than a priority of the second transfer request, and updates the first transfer information to the transfer information for the current transfer request when the priority of the current transfer request is lower than the priority of the second transfer request;
and
a DMA transfer control circuit which carries out a DMA transfer using the transfer information held in the first buffer or the second buffer updated by the priority determination circuit.

3 more elements

A DMA transfer method using a DMA device equipped with a first buffer holding a first transfer information required for a first transfer request and a second buffer holding a second transfer information required for a second transfer request, the method comprising:

determining whether or not a current transfer request, which is a newly inputted transfer request, matches with the first transfer request or the second transfer request;
in case where the current transfer request does not match with the first transfer request or the second transfer request,
updating the second transfer information to the transfer information for the current transfer request when a priority of the current transfer request is higher than a priority of the second transfer request;
updating the first transfer information to the transfer information for the current transfer request when the priority of the current transfer request is lower than the priority of the second transfer request;
and
carrying out a DMA transfer using the transfer information held in the updated first buffer or second buffer.

3 more elements

A DMA transfer method, comprising:

updating a transfer information stored in a first buffer to a transfer information for a newly inputted transfer request when a priority level of a newly inputted transfer request is higher than the priority level of the transfer request held in the first buffer;
and
updating a transfer information stored in a second buffer to the transfer information for the newly inputted transfer request when the priority level of the newly inputted transfer request is lower than the priority level of the transfer request held in the first buffer.

Dependencies are inferred from the claim text.

DMA device having plural buffers storing transfer request information and DMA transfer method

Life of this patent

DMA device having plural buffers storing transfer request information and DMA transfer method

Life of this patent

Abstract

Claims16