Bridge, information processor, and access control method

1. A bridge for connecting a processor unit and a peripheral device, comprising:

a downstream port connected to the peripheral device; and

a router operative to route access from the peripheral device to a memory of the processor unit via the downstream port, to upstream channels each assigned a memory bandwidth available for access to the memory of the processor unit, the upstream channels being virtual channels supported by the processor unit, wherein

the downstream port supports a plurality of downstream channels used for the access by the peripheral device, the downstream channels being virtual channels provided for interfacing with the peripheral device, and

the router is provided with a table storing identifiers of the downstream channels and identifiers of the upstream channels in association with each other, and refers to the table so as to allocate to the peripheral device the upstream channel corresponding to the downstream channel used by the peripheral device, in response to the access from the peripheral device.

2. The bridge according to claim 1 , wherein

the router is provided with a plurality of internal buses,

the table comprises:

a first table operative to store the identifiers of the downstream channels and identifiers of the internal buses in association with each other; and

a second table operative to store the identifiers of the internal buses and the identifiers of the upstream channels in association with each other, and

in response to the access from the peripheral device, the router refers to the first table to allocate to the peripheral device the internal bus corresponding to the downstream channel used by the peripheral device, and refers to the second table to allocate to the peripheral device the upstream channel corresponding to the internal bus allocated to the peripheral device.

3. The bridge according to claim 2 , wherein

the second table stores resource bandwidths in the bridge respectively allocated to the internal buses, in association with the identifiers of the internal buses, and

the router refers to the second table to allocate to the peripheral device the resource bandwidth used by the accessing peripheral device.

4. An information processor comprising:

a processor unit;

a peripheral device; and

a bridge connecting the processor unit and the peripheral device, wherein

the bridge comprises:

a downstream port connected to the peripheral device; and

a router operative to route access from the peripheral device to a memory of the processor unit via the downstream port, to upstream channels each assigned a memory bandwidth available for access to the memory of the processor unit, the upstream channels being virtual channels supported by the processor unit, wherein

the downstream port supports a plurality of downstream channels provided used for the access by the peripheral device, the downstream channels being virtual channels provided for interfacing with the peripheral device,

the router is provided with a table storing identifiers of the downstream channels and identifiers of the upstream channels in association with each other, and refers to the table so as to allocate to the peripheral device the upstream channel corresponding to the downstream channel used by the peripheral device, in response to the access from the peripheral device, and

the processor unit is provided with an access controller operative to route the access, to which one of the upstream channels is allocated, to the memory at the memory bandwidth allocated to the upstream channel.

5. The information processor according to claim 4 , wherein

the router is provided with a plurality of internal buses

the table comprises:

a first table operative to store the identifiers of the downstream channels and identifiers of the internal buses in association with each other; and

a second table operative to store the identifiers of the internal buses and the identifiers of the upstream channels in association with each other, and

in response to the access from the peripheral device, the router refers to the first table to allocate to the peripheral device the internal bus corresponding to the downstream channel used by the peripheral device, and refers to the second table to allocate to the peripheral device the upstream channel corresponding to the internal bus allocated to the peripheral device.

6. The information processor according to claim 5 , wherein

the second table stores resource bandwidths in the bridge respectively allocated to the internal buses, in association with the identifiers of the internal buses, and

the router refers to the second table to allocate to the peripheral device the resource bandwidth used by the accessing peripheral device.

7. An access control method using a bridge connecting a processor unit and a peripheral device, comprising:

acknowledging access from the peripheral device via one of a plurality of downstream channels available for the peripheral device to access a memory of the processor unit, the downstream channels being virtual channels provided between the bridge and the peripheral device;

routing the access to upstream channels each assigned a memory bandwidth available for access to the memory of the processor unit, the upstream channels being virtual channels supported by the processor unit, wherein

the routing refers to a table storing identifiers of the downstream channels and identifiers of the upstream channels in association with each other, so as to allocate to the peripheral device the upstream channel corresponding to the downstream channel used by the peripheral device, in response to the access from the peripheral device.