Function isa_alloc_resource

freebsd/x86/isa/isa.c:88–132

* This implementation simply passes the request up to the parent * bus, which in our case is the special i386 nexus, substituting any * configured values if the caller defaulted. We can get away with * this because there is no special mapping for ISA resources on an Intel * platform. When porting this code to another architecture, it may be * necessary to interpose a mapping layer here. */

 * necessary to interpose a mapping layer here.
 */
struct resource *
isa_alloc_resource(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)
{
	/*
	 * Consider adding a resource definition.
	 */
	int passthrough = (device_get_parent(child) != bus);
	int isdefault = RMAN_IS_DEFAULT_RANGE(start, end);
	struct isa_device* idev = DEVTOISA(child);
	struct resource_list *rl = &idev->id_resources;
	struct resource_list_entry *rle;

	if (!passthrough && !isdefault) {
		rle = resource_list_find(rl, type, *rid);
		if (!rle) {
			if (*rid < 0)
				return 0;
			switch (type) {
			case SYS_RES_IRQ:
				if (*rid >= ISA_NIRQ)
					return 0;
				break;
			case SYS_RES_DRQ:
				if (*rid >= ISA_NDRQ)
					return 0;
				break;
			case SYS_RES_MEMORY:
				if (*rid >= ISA_NMEM)
					return 0;
				break;
			case SYS_RES_IOPORT:
				if (*rid >= ISA_NPORT)
					return 0;
				break;
			default:
				return 0;
			}
			resource_list_add(rl, type, *rid, start, end, count);
		}
	}

	return resource_list_alloc(rl, bus, child, type, rid,
				   start, end, count, flags);
}

int
isa_release_resource(device_t bus, device_t child, int type, int rid,