+static int io_subchannel_get_status(struct subchannel *sch)
+{
+ struct schib schib;
+
+ if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
+ return CIO_GONE;
+ if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
+ return CIO_REVALIDATE;
+ if (!sch->lpm)
+ return CIO_NO_PATH;
+ return CIO_OPER;
+}
+
+static int device_is_disconnected(struct ccw_device *cdev)
+{
+ if (!cdev)
+ return 0;
+ return (cdev->private->state == DEV_STATE_DISCONNECTED ||
+ cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
+}
+
+static int recovery_check(struct device *dev, void *data)
+{
+ struct ccw_device *cdev = to_ccwdev(dev);
+ int *redo = data;
+
+ spin_lock_irq(cdev->ccwlock);
+ switch (cdev->private->state) {
+ case DEV_STATE_DISCONNECTED:
+ CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n",
+ cdev->private->dev_id.ssid,
+ cdev->private->dev_id.devno);
+ dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+ *redo = 1;
+ break;
+ case DEV_STATE_DISCONNECTED_SENSE_ID:
+ *redo = 1;
+ break;
+ }
+ spin_unlock_irq(cdev->ccwlock);
+
+ return 0;
+}
+
+static void recovery_work_func(struct work_struct *unused)
+{
+ int redo = 0;
+
+ bus_for_each_dev(&ccw_bus_type, NULL, &redo, recovery_check);
+ if (redo) {
+ spin_lock_irq(&recovery_lock);
+ if (!timer_pending(&recovery_timer)) {
+ if (recovery_phase < ARRAY_SIZE(recovery_delay) - 1)
+ recovery_phase++;
+ mod_timer(&recovery_timer, jiffies +
+ recovery_delay[recovery_phase] * HZ);
+ }
+ spin_unlock_irq(&recovery_lock);
+ } else
+ CIO_MSG_EVENT(4, "recovery: end\n");
+}
+
+static DECLARE_WORK(recovery_work, recovery_work_func);
+
+static void recovery_func(unsigned long data)
+{
+ /*
+ * We can't do our recovery in softirq context and it's not
+ * performance critical, so we schedule it.
+ */
+ schedule_work(&recovery_work);
+}
+
+static void ccw_device_schedule_recovery(void)
+{
+ unsigned long flags;
+
+ CIO_MSG_EVENT(4, "recovery: schedule\n");
+ spin_lock_irqsave(&recovery_lock, flags);
+ if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) {
+ recovery_phase = 0;
+ mod_timer(&recovery_timer, jiffies + recovery_delay[0] * HZ);
+ }
+ spin_unlock_irqrestore(&recovery_lock, flags);
+}
+
+static void device_set_disconnected(struct ccw_device *cdev)
+{
+ if (!cdev)
+ return;
+ ccw_device_set_timeout(cdev, 0);
+ cdev->private->flags.fake_irb = 0;
+ cdev->private->state = DEV_STATE_DISCONNECTED;
+ if (cdev->online)
+ ccw_device_schedule_recovery();
+}
+
+static int io_subchannel_sch_event(struct subchannel *sch, int slow)
+{
+ int event, ret, disc;
+ unsigned long flags;
+ enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
+ struct ccw_device *cdev;
+
+ spin_lock_irqsave(sch->lock, flags);
+ cdev = sch_get_cdev(sch);
+ disc = device_is_disconnected(cdev);
+ if (disc && slow) {
+ /* Disconnected devices are evaluated directly only.*/
+ spin_unlock_irqrestore(sch->lock, flags);
+ return 0;
+ }
+ /* No interrupt after machine check - kill pending timers. */
+ if (cdev)
+ ccw_device_set_timeout(cdev, 0);
+ if (!disc && !slow) {
+ /* Non-disconnected devices are evaluated on the slow path. */
+ spin_unlock_irqrestore(sch->lock, flags);
+ return -EAGAIN;
+ }
+ event = io_subchannel_get_status(sch);
+ CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
+ sch->schid.ssid, sch->schid.sch_no, event,
+ disc ? "disconnected" : "normal",
+ slow ? "slow" : "fast");
+ /* Analyze subchannel status. */
+ action = NONE;
+ switch (event) {
+ case CIO_NO_PATH:
+ if (disc) {
+ /* Check if paths have become available. */
+ action = REPROBE;
+ break;
+ }
+ /* fall through */
+ case CIO_GONE:
+ /* Prevent unwanted effects when opening lock. */
+ cio_disable_subchannel(sch);
+ device_set_disconnected(cdev);
+ /* Ask driver what to do with device. */
+ action = UNREGISTER;
+ spin_unlock_irqrestore(sch->lock, flags);
+ ret = io_subchannel_notify(sch, event);
+ spin_lock_irqsave(sch->lock, flags);
+ if (ret)
+ action = NONE;
+ break;
+ case CIO_REVALIDATE:
+ /* Device will be removed, so no notify necessary. */
+ if (disc)
+ /* Reprobe because immediate unregister might block. */
+ action = REPROBE;
+ else
+ action = UNREGISTER_PROBE;
+ break;
+ case CIO_OPER:
+ if (disc)
+ /* Get device operational again. */
+ action = REPROBE;
+ break;
+ }
+ /* Perform action. */
+ ret = 0;
+ switch (action) {
+ case UNREGISTER:
+ case UNREGISTER_PROBE:
+ /* Unregister device (will use subchannel lock). */
+ spin_unlock_irqrestore(sch->lock, flags);
+ css_sch_device_unregister(sch);
+ spin_lock_irqsave(sch->lock, flags);
+
+ /* Reset intparm to zeroes. */
+ sch->schib.pmcw.intparm = 0;
+ cio_modify(sch);
+ break;
+ case REPROBE:
+ ccw_device_trigger_reprobe(cdev);
+ break;
+ default:
+ break;
+ }
+ spin_unlock_irqrestore(sch->lock, flags);
+ /* Probe if necessary. */
+ if (action == UNREGISTER_PROBE)
+ ret = css_probe_device(sch->schid);
+
+ return ret;
+}
+