Function fiq_release

freebsd/arm/arm/fiq.c:132–166

* fiq_release: * * Release the FIQ vector. */

 *	Release the FIQ vector.
 */
void
fiq_release(struct fiqhandler *fh)
{
	u_int oldirqstate;
	struct fiqhandler *ofh;

	oldirqstate = disable_interrupts(PSR_F);

	/*
	 * If we are the currently active FIQ handler, then we
	 * need to save our registers and pop the next one back
	 * into the vector.
	 */
	if (fh == TAILQ_FIRST(&fiqhandler_stack)) {
		if (fh->fh_regs != NULL)
			fiq_getregs(fh->fh_regs);
		TAILQ_REMOVE(&fiqhandler_stack, fh, fh_list);
		if ((ofh = TAILQ_FIRST(&fiqhandler_stack)) != NULL) {
			if (ofh->fh_regs != NULL)
				fiq_setregs(ofh->fh_regs);
			fiq_installhandler(ofh->fh_func, ofh->fh_size);
		}
	} else
		TAILQ_REMOVE(&fiqhandler_stack, fh, fh_list);

	if (TAILQ_FIRST(&fiqhandler_stack) == NULL) {
		/* Copy the NULL handler back down into the vector. */
		fiq_installhandler(fiq_nullhandler_code, fiq_nullhandler_size);

		/* Make sure FIQs are disabled when we return. */
		oldirqstate |= PSR_F;
	}

	restore_interrupts(oldirqstate);
}