CACHE MAINTENANCE OPERATIONS IN A DATA PROCESSING SYSTEM
First Claim
1. An interconnect system comprising:
- a master device;
a cache for temporary storage of data items for low-latency access by the master device;
an intermediate device;
a slave device, wherein the slave device has an associated data storage device for long-term storage of the data items; and
interconnect circuitry connecting the master device, the intermediate device, and the slave device,wherein the master device is capable of initiating a cache maintenance operation in the interconnect system with respect to a data item temporarily stored in the cache, wherein the cache maintenance operation comprises action taken by the slave device with respect to storage of the data item in the data storage device,wherein, when the cache maintenance operation is predetermined as a long-latency operation the master device is capable of issuing to the intermediate device a separated cache maintenance request specifying the data item and the slave device;
the intermediate device is responsive to the separated cache maintenance request to signal an acknowledgment response to the master device indicative that the intermediate device has taken on responsibility for completion of the cache maintenance operation with respect to the data item and to issue the separated cache maintenance request to the slave device; and
the slave device is responsive to receipt of the separated cache maintenance request to signal the acknowledgement response to the intermediate device and is responsive to completion of the cache maintenance operation with respect to the data item stored in the data storage device to signal a completion response to the master device.
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Accused Products
Abstract
An interconnect system and method of operating the system are disclosed. A master device has access to a cache and a slave device has an associated data storage device for long-term storage of data items. The master device can initiate a cache maintenance operation in the interconnect system with respect to a data item temporarily stored in the cache causing action to be taken by the slave device with respect to storage of the data item in the data storage device. For long latency operations the master device can issue a separated cache maintenance request specifying the data item and the slave device. In response an intermediate device signals an acknowledgment response indicating that it has taken on responsibility for completion of the cache maintenance operation and issues the separated cache maintenance request to the slave device. The slave device signals the acknowledgement response to the intermediate device and on completion of the cache maintenance operation with respect to the data item stored in the data storage device signals a completion response to the master device.
6 Citations
20 Claims
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1. An interconnect system comprising:
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a master device; a cache for temporary storage of data items for low-latency access by the master device; an intermediate device; a slave device, wherein the slave device has an associated data storage device for long-term storage of the data items; and interconnect circuitry connecting the master device, the intermediate device, and the slave device, wherein the master device is capable of initiating a cache maintenance operation in the interconnect system with respect to a data item temporarily stored in the cache, wherein the cache maintenance operation comprises action taken by the slave device with respect to storage of the data item in the data storage device, wherein, when the cache maintenance operation is predetermined as a long-latency operation the master device is capable of issuing to the intermediate device a separated cache maintenance request specifying the data item and the slave device; the intermediate device is responsive to the separated cache maintenance request to signal an acknowledgment response to the master device indicative that the intermediate device has taken on responsibility for completion of the cache maintenance operation with respect to the data item and to issue the separated cache maintenance request to the slave device; and the slave device is responsive to receipt of the separated cache maintenance request to signal the acknowledgement response to the intermediate device and is responsive to completion of the cache maintenance operation with respect to the data item stored in the data storage device to signal a completion response to the master device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of operating an interconnect system comprising a master device, a cache for temporary storage of data items for low-latency access by the master device, an intermediate device, a slave device, wherein the slave device has an associated data storage device for long-term storage of the data items, and interconnect circuitry connecting the master device, the intermediate device, and the slave device, the method comprising:
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initiating from the master device a cache maintenance operation in the interconnect system with respect to a data item temporarily stored in the cache, wherein the cache maintenance operation comprises action taken by the slave device with respect to storage of the data item in the data storage device, wherein, when the cache maintenance operation is predetermined as a long-latency operation, the initiating comprises issuing from the master device to the intermediate device a separated cache maintenance request specifying the data item and the slave device, and the method further comprises the steps of; signalling an acknowledgment response to the master device from the intermediate device in response to the separated cache maintenance request indicative that the intermediate device has taken on responsibility for completion of the cache maintenance operation with respect to the data item; issuing the separated cache maintenance request to the slave device; signalling the acknowledgement response to the intermediate device from the slave device in response to receipt of the separated cache maintenance request; and signalling a completion response to the master device from the slave device in response to completion of the cache maintenance operation with respect to the data item stored in the data storage device.
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20. An interconnect system comprising:
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master device means; caching means for temporary storage of data items for low-latency access by the master device means; intermediate device means; slave device means, wherein the slave device means has associated data storage means for long-term storage of the data items; interconnect means for connecting the master device means, the intermediate device means, and the slave device means; means for initiating from the master device means a cache maintenance operation in the interconnect system with respect to a data item temporarily stored in the caching means, wherein the cache maintenance operation comprises action taken by the slave device means with respect to storage of the data item in the data storage means, wherein, when the cache maintenance operation is predetermined as a long-latency operation, the means for initiating comprises means for issuing from the master device to the intermediate device means a separated cache maintenance request specifying the data item and the slave device means, and the interconnect system further comprises; means for signalling an acknowledgment response to the master device means from the intermediate device means in response to the separated cache maintenance request indicative that the intermediate device means has taken on responsibility for completion of the cache maintenance operation with respect to the data item; means for issuing the separated cache maintenance request to the slave device means; means for signalling the acknowledgement response to the intermediate device means from the slave device means in response to receipt of the separated cache maintenance request; and means for signalling a completion response to the master device means from the slave device means in response to completion of the cache maintenance operation with respect to the data item stored in the data storage means.
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Specification