Function resource_list_alloc

freebsd/kern/subr_bus.c:3408–3462

* @brief Helper function for implementing BUS_ALLOC_RESOURCE() * * Implement BUS_ALLOC_RESOURCE() by looking up a resource from the list * and passing the allocation up to the parent of @p bus. This assumes * that the first entry of @c device_get_ivars(child) is a struct * resource_list. This also handles 'passthrough' allocations where a * child is a remote descendant of bus by passing the

 *			resource could be allocated
 */
struct resource *
resource_list_alloc(struct resource_list *rl, device_t bus, device_t child,
    int type, int *rid, rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
	struct resource_list_entry *rle = NULL;
	int passthrough = (device_get_parent(child) != bus);
	int isdefault = RMAN_IS_DEFAULT_RANGE(start, end);

	if (passthrough) {
		return (BUS_ALLOC_RESOURCE(device_get_parent(bus), child,
		    type, rid, start, end, count, flags));
	}

	rle = resource_list_find(rl, type, *rid);

	if (!rle)
		return (NULL);		/* no resource of that type/rid */

	if (rle->res) {
		if (rle->flags & RLE_RESERVED) {
			if (rle->flags & RLE_ALLOCATED)
				return (NULL);
			if ((flags & RF_ACTIVE) &&
			    bus_activate_resource(child, type, *rid,
			    rle->res) != 0)
				return (NULL);
			rle->flags |= RLE_ALLOCATED;
			return (rle->res);
		}
		device_printf(bus,
		    "resource entry %#x type %d for child %s is busy\n", *rid,
		    type, device_get_nameunit(child));
		return (NULL);
	}

	if (isdefault) {
		start = rle->start;
		count = ulmax(count, rle->count);
		end = ulmax(rle->end, start + count - 1);
	}

	rle->res = BUS_ALLOC_RESOURCE(device_get_parent(bus), child,
	    type, rid, start, end, count, flags);

	/*
	 * Record the new range.
	 */
	if (rle->res) {
		rle->start = rman_get_start(rle->res);
		rle->end = rman_get_end(rle->res);
		rle->count = count;
	}

	return (rle->res);
}

/**
 * @brief Helper function for implementing BUS_RELEASE_RESOURCE()