SCO OpenServer

get_intr_arg(D3oddi)

get_intr_arg -- get value of argument passed to the interrupt routine

Synopsis

int get_intr_arg(bus, dev_func);

Description

The get_intr_arg( ) function returns the value of the argument that will be passed to the driver's interrupt handling routine.

Arguments

bus

PCI bus number

dev_func

PCI device and function number This is formed as follows:

If the driver registers itself with the idistributed(D3oddi) function, use the IDIST_PCI_IRQ( ) macro.
If the driver registers itself with the Sharegister(D3osdi) with the SHAREG_EX structure, use the SHAREG_PCI_INTVEC( ) macro.

Both macros take two arguments indicating the PCI device and function numbers.

Return values

The value returned is the argument that will be passed to the driver's interrupt handler upon receipt of an interrupt from the PCI device specified.

Usage

get_intr_arg( ) is used with drivers that use idistributed(D3oddi) or Sharegister(D3osdi) with the SHAREG_EX structure to register themselves. In these circumstances, the argument passed to the interrupt handler is not necessarily the same as the IRQ line on which the device interrupted. If the driver uses the argument passed to the interrupt handler, the get_intr_arg( ) function must be called to determine the interrupt handler argument that is passed when a particular PCI device interrupts.

get_intr_arg( ) function should only be called once for each device controlled by the driver. The value it returns should be stored internally to be accessed when needed.

get_intr_arg( ) must not be called at driver init time.
If the driver registers itself with the idistributed(D3oddi) function, call get_intr_arg( ) on the first entry into the driver's open(D2oddi) routine.
If the driver registers itself with the Sharegister(D3osdi) function, call get_intr_arg( ) on the first entry into the driver's _entry(D2osdi) routine.
get_intr_arg( ) can be called on the first entry into the driver's interrupt handler routine although this is not generally the preferred practice.

All PCI devices that share the same interrupt line will have the same number passed as the argument to the interrupt routine.

Context and synchronization

Blockable context

Also the context of the _entry(D2osdi) entry point routine.

Hardware applicability

All

Version applicability

oddi: 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp

Differences between versions

Beginning with SCO OpenServer Release 5.0.5, the return value of get_intr_arg( ) is internally implemented differently than it was in earlier SCO OpenServer releases. As long as drivers treat this value as a ``cookie'', they will not be affected by this change.

SVR5 DDI compatibility

There is no equivalent DDI function.

References

idistributed(D3oddi), Sharegister(D3osdi)

Examples

The following code snippet illustrates the calling sequence for get_intr_arg( ):

   int arg;
   arg = get_intr_arg(bus, SHAREG_PCI_INTVEC(device, function));

After this code executes, arg contains the value of the argument that will be passed to the interrupt handler when an interrupt is received from that particular PCI device.

See the idistributed(D3oddi) and the Sharegister(D3osdi) manual pages for full examples of get_intr_art( ).