Frame Scheduler Initialization Function

Frame Scheduler Initialization Function

The device driver must provide a function with the following prototype:

void pfx_frs_func_set ( intrgroup_t* intrgroup ) ;

A skeleton of an initialization function is shown in Example 7-9. The function is called by a new master Frame Scheduler that is created with an interrupt source parameter of FRS_INTRSOURCE_DRIVER and an interrupt qualifier specifying this device driver's number (see "Device Driver Interrupt"). A device driver is used by only one Frame Scheduler at a time.

The argument intrgroup is passed by the Frame Scheduler to identify the interrupt group it has allocated. A VME device driver must set the hardware devices it manages so that interrupts are directed to this interrupt group (see the paper "Group Interrupts on Challenge and Onyx Systems" distributed with REACT/Pro). The actual group identifier may be obtained using the macro:

intrgroup_get_groupid(intrgroup)

The effective destination may be obtained using the following macro:

EVINTR_GROUPDEST(intrgroup_get_groupid(intrgroup))

Example 7-9 : Device Driver Initialization Function

/*
** Frame Scheduler initialization function
** for the External Interrupts Driver
*/
int FRS_is_active = 0;
int FRS_vme_install = 0;
void
example_frs_func_set(intrgroup_t* intrgroup)
{
   int s;
   ASSERT(intrgroup != 0);
   /*
   ** Step 1 (VME only):
   ** In a VME device driver, set up the hardware to send
   ** the interrupt to the appropriate destination.
   ** This is done with vme_frs_install() which takes:
   ** * (int) the VME adapter number
   ** * (int) the VME IPL level
   ** * the intrgroup as passed to this function.
   */
   FRS_vme_install = vme_frs_install(
      my_edt.e_adap, /* edt struct from example_edtinit */
      ((vme_intrs_t *)my_edt.e_bus_info)->v_brl,
      intrgroup);
   /*
   ** Step 2: any hardware initialization required.
   */
   /*
   ** Step 3: note that we are now in use.
   */
   FRS_is_active = 1;
}

Only VME device drivers need to call vme_frs_install(). As suggested by the code in Example 7-9, the arguments to vme_frs_install() can be taken from data supplied at boot time to the device driver's pfxedtinit() function:

the adapter number is in the edt.e_adap field
the configured interrupt priority level is in the vme_intrs.v_brl addressed by the edt.e_bus_info field

The pfxedtinit() entry point is documented in the IRIX Device Driver Programming Guide.

Tip: The vme_frs_install() function is a dynamic version of the VECTOR configuration statement. You are not required to use the IPL value from the configuration file.