Function orm_identify

freebsd/x86/isa/orm.c:83–159

}

static void
orm_identify(driver_t* driver, device_t parent)
{
	bus_space_handle_t	bh;
	bus_space_tag_t		bt;
	device_t		child;
	u_int32_t		chunk = IOMEM_START;
	struct resource		*res;
	int			rid;
	u_int32_t		rom_size;
	struct orm_softc	*sc;
	u_int8_t		buf[3];

	if (resource_disabled("orm", 0))
		return;

	child = BUS_ADD_CHILD(parent, ISA_ORDER_SENSITIVE, "orm", -1);
	device_set_driver(child, driver);
	isa_set_logicalid(child, ORM_ID);
	isa_set_vendorid(child, ORM_ID);
	sc = device_get_softc(child);
	sc->rnum = 0;
	while (sc->rnum < MAX_ROMS && chunk < IOMEM_END) {
		bus_set_resource(child, SYS_RES_MEMORY, sc->rnum, chunk,
		    IOMEM_STEP);
		rid = sc->rnum;
		res = bus_alloc_resource_any(child, SYS_RES_MEMORY, &rid,
		    RF_ACTIVE);
		if (res == NULL) {
			bus_delete_resource(child, SYS_RES_MEMORY, sc->rnum);
			chunk += IOMEM_STEP;
			continue;
		}
		bt = rman_get_bustag(res);
		bh = rman_get_bushandle(res);
		bus_space_read_region_1(bt, bh, 0, buf, sizeof(buf));

		/*
		 * We need to release and delete the resource since we're
		 * changing its size, or the rom isn't there.  There
		 * is a checksum field in the ROM to prevent false
		 * positives.  However, some common hardware (IBM thinkpads)
		 * neglects to put a valid checksum in the ROM, so we do
		 * not double check the checksum here.  On the ISA bus
		 * areas that have no hardware read back as 0xff, so the
		 * tests to see if we have 0x55 followed by 0xaa are
		 * generally sufficient.
		 */
		bus_release_resource(child, SYS_RES_MEMORY, rid, res);
		bus_delete_resource(child, SYS_RES_MEMORY, sc->rnum);
		if (buf[0] != 0x55 || buf[1] != 0xAA || (buf[2] & 0x03) != 0) {
			chunk += IOMEM_STEP;
			continue;
		}
		rom_size = buf[2] << 9;
		bus_set_resource(child, SYS_RES_MEMORY, sc->rnum, chunk,
		    rom_size);
		rid = sc->rnum;