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In order to perform the operation, the initiator invokes a routine identified by the

set_bus_request_affinity field of the chapi_in descriptor supplying in the parameter brq_handle

the identifier of bus request to set affinity mask for and in the parameter mask the affinity

mask to set. Affinity mask is a bit mask where each particular bit is designated to

particular emulated CPU – lowest bit to the first CPU and so on. The procedure is invoked

as follows:

brq_handle_t brq_handle;

const chapi_in * ci = …;

…

// Connect bus request to the bus getting brq_handle as in previous example

…

// Only first CPU will be allowed to process bus request

// identified by brq_handle

if (ci->set_bus_request_affinity) {

ci->set_bus_request_affinity (ci, brq_handle, 0x01);

}

The example above shows that the CHARON core is not obliged to support the indicated

operation. It also indicates why the device instance should remember the chapi_in

descriptor.

4.9.8 Set bus request affinity callback

The operation of setting bus request affinity callback belongs to the group of operations

previously called “Request for bus interrupt”. Such an operation is initiated by the device

instance and CHARON core is defined as the target of the operation. This routine has

sense only for the case of multi CPU emulated system and defines callback routine which

will notify loadable device that bus request affinity mask is modified for some bus request.

In order to perform the operation, the initiator invokes a routine identified by the set_

affinity_callback field of the chapi_in descriptor supplying in the parameter brq_handle the

identifier of bus request to set affinity callback for, in the parameter sa_callback the pointer

to callback routine to set and in the parameters arg1, arg2 the parameters to be passed to

specified callback routine during its execution. The procedure is invoked as follows:

void sa_procedure(void *arg1, int arg2, int c_no)

{

// Do something here ... c_no is CPU with the lowest number

// among all CPUs specified in affinity mask and used as bus servers

}

…

brq_handle_t brq_handle;

const chapi_in * ci = …;

…

// Connect bus request to the bus getting brq_handle as in previous example

…

// Setup affinity callback routine