int pnp_check_port()

in resource.c [166:227]

• 49 lines of code
• 16 McCabe index (conditional complexity)

int pnp_check_port(struct pnp_dev *dev, struct resource *res)
{
	int i;
	struct pnp_dev *tdev;
	struct resource *tres;
	resource_size_t *port, *end, *tport, *tend;

	port = &res->start;
	end = &res->end;

	/* if the resource doesn't exist, don't complain about it */
	if (cannot_compare(res->flags))
		return 1;

	/* check if the resource is already in use, skip if the
	 * device is active because it itself may be in use */
	if (!dev->active) {
		if (!request_region(*port, length(port, end), "pnp"))
			return 0;
		release_region(*port, length(port, end));
	}

	/* check if the resource is reserved */
	for (i = 0; i < 8; i++) {
		int rport = pnp_reserve_io[i << 1];
		int rend = pnp_reserve_io[(i << 1) + 1] + rport - 1;
		if (ranged_conflict(port, end, &rport, &rend))
			return 0;
	}

	/* check for internal conflicts */
	for (i = 0; (tres = pnp_get_resource(dev, IORESOURCE_IO, i)); i++) {
		if (tres != res && tres->flags & IORESOURCE_IO) {
			tport = &tres->start;
			tend = &tres->end;
			if (ranged_conflict(port, end, tport, tend))
				return 0;
		}
	}

	/* check for conflicts with other pnp devices */
	pnp_for_each_dev(tdev) {
		if (tdev == dev)
			continue;
		for (i = 0;
		     (tres = pnp_get_resource(tdev, IORESOURCE_IO, i));
		     i++) {
			if (tres->flags & IORESOURCE_IO) {
				if (cannot_compare(tres->flags))
					continue;
				if (tres->flags & IORESOURCE_WINDOW)
					continue;
				tport = &tres->start;
				tend = &tres->end;
				if (ranged_conflict(port, end, tport, tend))
					return 0;
			}
		}
	}

	return 1;
}