HAL_FIQClear

Hardware Abstraction Layer

HAL entry points from RISC OS

» HAL_FIQClear

HAL_FIQClear

(HAL entry #9)

void HAL_FIQClear(int device)

Use

This call has a dual purpose:

1. To clear the interrupt state of certain integrated devices
   1. Timers (as reported by HAL_TimerDevice)
   2. VSync (as reported by HAL_VideoFlybackDevice)
2. To trigger the interrupt controller to start looking for new interrupt sources (required for interrupt controllers that latch the device number of the interrupt source, and thus could claim that the device is still interrupting even if it’s been successfully serviced).

Note that the kernel currently doesn’t use FIQ interrupts for HAL timers or the video flyback device, so point 1 could be ignored.

Because of point 2, this means that all interrupt service routines must call this routine after servicing the device. Current versions of the kernel will not call HAL_FIQClear for you – it is your responsibility to do so yourself. This is new functionality added for the Cortex/OMAP3 port, to account for the behaviour of the OMAP3 interrupt controller.

See also

• HAL interrupt handling API
• HAL timer API
• HAL Video API

Information sources: Kernel.Docs.HAL.MoreEnts, HAL.Tungsten.s.Interrupts, HAL.OMAP3.s.Interrupts in CVS