+enum {
+ REREAD_BIB_ERROR,
+ REREAD_BIB_GONE,
+ REREAD_BIB_UNCHANGED,
+ REREAD_BIB_CHANGED,
+};
+
+/* Reread and compare bus info block and header of root directory */
+static int reread_bus_info_block(struct fw_device *device, int generation)
+{
+ u32 q;
+ int i;
+
+ for (i = 0; i < 6; i++) {
+ if (read_rom(device, generation, i, &q) != RCODE_COMPLETE)
+ return REREAD_BIB_ERROR;
+
+ if (i == 0 && q == 0)
+ return REREAD_BIB_GONE;
+
+ if (i > device->config_rom_length || q != device->config_rom[i])
+ return REREAD_BIB_CHANGED;
+ }
+
+ return REREAD_BIB_UNCHANGED;
+}
+
+static void fw_device_refresh(struct work_struct *work)
+{
+ struct fw_device *device =
+ container_of(work, struct fw_device, work.work);
+ struct fw_card *card = device->card;
+ int node_id = device->node_id;
+
+ switch (reread_bus_info_block(device, device->generation)) {
+ case REREAD_BIB_ERROR:
+ if (device->config_rom_retries < MAX_RETRIES / 2 &&
+ atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
+ device->config_rom_retries++;
+ schedule_delayed_work(&device->work, RETRY_DELAY / 2);
+
+ return;
+ }
+ goto give_up;
+
+ case REREAD_BIB_GONE:
+ goto gone;
+
+ case REREAD_BIB_UNCHANGED:
+ if (atomic_cmpxchg(&device->state,
+ FW_DEVICE_INITIALIZING,
+ FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
+ goto gone;
+
+ fw_device_update(work);
+ device->config_rom_retries = 0;
+ goto out;
+
+ case REREAD_BIB_CHANGED:
+ break;
+ }
+
+ /*
+ * Something changed. We keep things simple and don't investigate
+ * further. We just destroy all previous units and create new ones.
+ */
+ device_for_each_child(&device->device, NULL, shutdown_unit);
+
+ if (read_bus_info_block(device, device->generation) < 0) {
+ if (device->config_rom_retries < MAX_RETRIES &&
+ atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
+ device->config_rom_retries++;
+ schedule_delayed_work(&device->work, RETRY_DELAY);
+
+ return;
+ }
+ goto give_up;
+ }
+
+ create_units(device);
+
+ if (atomic_cmpxchg(&device->state,
+ FW_DEVICE_INITIALIZING,
+ FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
+ goto gone;
+
+ fw_notify("refreshed device %s\n", device->device.bus_id);
+ device->config_rom_retries = 0;
+ goto out;
+
+ give_up:
+ fw_notify("giving up on refresh of device %s\n", device->device.bus_id);
+ gone:
+ atomic_set(&device->state, FW_DEVICE_SHUTDOWN);
+ fw_device_shutdown(work);
+ out:
+ if (node_id == card->root_node->node_id)
+ schedule_delayed_work(&card->work, 0);
+}
+