[S390] cio: Rework css driver.

Rework the css driver methods to provide sane callbacks for
subchannels of all types.

As a bonus, this cleans up and simplyfies the machine check
handling for I/O subchannels a lot.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 279 insertions, 86 deletions

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 23b129fd4d8d..9281b25087a6 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -2,8 +2,7 @@
  *  drivers/s390/cio/device.c
  *  bus driver for ccw devices
  *
- *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
- *                       IBM Corporation
+ *    Copyright IBM Corp. 2002,2008
  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
  *               Cornelia Huck (cornelia.huck@de.ibm.com)
  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
@@ -126,19 +125,17 @@ struct bus_type ccw_bus_type;
 static void io_subchannel_irq(struct subchannel *);
 static int io_subchannel_probe(struct subchannel *);
 static int io_subchannel_remove(struct subchannel *);
-static int io_subchannel_notify(struct subchannel *, int);
-static void io_subchannel_verify(struct subchannel *);
-static void io_subchannel_ioterm(struct subchannel *);
 static void io_subchannel_shutdown(struct subchannel *);
+static int io_subchannel_sch_event(struct subchannel *, int);
+static int io_subchannel_chp_event(struct subchannel *, void *, int);
 
 static struct css_driver io_subchannel_driver = {
         .owner = THIS_MODULE,
         .subchannel_type = SUBCHANNEL_TYPE_IO,
         .name = "io_subchannel",
         .irq = io_subchannel_irq,
-        .notify = io_subchannel_notify,
-        .verify = io_subchannel_verify,
-        .termination = io_subchannel_ioterm,
+        .sch_event = io_subchannel_sch_event,
+        .chp_event = io_subchannel_chp_event,
         .probe = io_subchannel_probe,
         .remove = io_subchannel_remove,
         .shutdown = io_subchannel_shutdown,
@@ -786,7 +783,7 @@ static void sch_attach_device(struct subchannel *sch,
         sch_set_cdev(sch, cdev);
         cdev->private->schid = sch->schid;
         cdev->ccwlock = sch->lock;
-        device_trigger_reprobe(sch);
+        ccw_device_trigger_reprobe(cdev);
         spin_unlock_irq(sch->lock);
 }
 
@@ -1265,11 +1262,7 @@ static int io_subchannel_notify(struct subchannel *sch, int event)
         cdev = sch_get_cdev(sch);
         if (!cdev)
                 return 0;
-        if (!cdev->drv)
-                return 0;
-        if (!cdev->online)
-                return 0;
-        return cdev->drv->notify ? cdev->drv->notify(cdev, event) : 0;
+        return ccw_device_notify(cdev, event);
 }
 
 static void io_subchannel_verify(struct subchannel *sch)
@@ -1281,22 +1274,98 @@ static void io_subchannel_verify(struct subchannel *sch)
                 dev_fsm_event(cdev, DEV_EVENT_VERIFY);
 }
 
-static void io_subchannel_ioterm(struct subchannel *sch)
+static int check_for_io_on_path(struct subchannel *sch, int mask)
 {
-        struct ccw_device *cdev;
+        int cc;
 
-        cdev = sch_get_cdev(sch);
-        if (!cdev)
-                return;
-        /* Internal I/O will be retried by the interrupt handler. */
-        if (cdev->private->flags.intretry)
+        cc = stsch(sch->schid, &sch->schib);
+        if (cc)
+                return 0;
+        if (sch->schib.scsw.actl && sch->schib.pmcw.lpum == mask)
+                return 1;
+        return 0;
+}
+
+static void terminate_internal_io(struct subchannel *sch,
+                                  struct ccw_device *cdev)
+{
+        if (cio_clear(sch)) {
+                /* Recheck device in case clear failed. */
+                sch->lpm = 0;
+                if (cdev->online)
+                        dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+                else
+                        css_schedule_eval(sch->schid);
                 return;
+        }
         cdev->private->state = DEV_STATE_CLEAR_VERIFY;
+        /* Request retry of internal operation. */
+        cdev->private->flags.intretry = 1;
+        /* Call handler. */
         if (cdev->handler)
                 cdev->handler(cdev, cdev->private->intparm,
                               ERR_PTR(-EIO));
 }
 
+static void io_subchannel_terminate_path(struct subchannel *sch, u8 mask)
+{
+        struct ccw_device *cdev;
+
+        cdev = sch_get_cdev(sch);
+        if (!cdev)
+                return;
+        if (check_for_io_on_path(sch, mask)) {
+                if (cdev->private->state == DEV_STATE_ONLINE)
+                        ccw_device_kill_io(cdev);
+                else {
+                        terminate_internal_io(sch, cdev);
+                        /* Re-start path verification. */
+                        dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+                }
+        } else
+                /* trigger path verification. */
+                dev_fsm_event(cdev, DEV_EVENT_VERIFY);
+
+}
+
+static int io_subchannel_chp_event(struct subchannel *sch, void *data,
+                                   int event)
+{
+        int mask;
+        struct res_acc_data *res_data;
+
+        res_data = data;
+        mask = chp_ssd_get_mask(&sch->ssd_info, res_data);
+        if (!mask)
+                return 0;
+        switch (event) {
+        case CHP_VARY_OFF:
+                sch->opm &= ~mask;
+                sch->lpm &= ~mask;
+                io_subchannel_terminate_path(sch, mask);
+                break;
+        case CHP_VARY_ON:
+                sch->opm |= mask;
+                sch->lpm |= mask;
+                io_subchannel_verify(sch);
+                break;
+        case CHP_OFFLINE:
+                if (stsch(sch->schid, &sch->schib))
+                        return -ENXIO;
+                if (!css_sch_is_valid(&sch->schib))
+                        return -ENODEV;
+                io_subchannel_terminate_path(sch, mask);
+                break;
+        case CHP_ONLINE:
+                if (stsch(sch->schid, &sch->schib))
+                        return -ENXIO;
+                sch->lpm |= mask & sch->opm;
+                io_subchannel_verify(sch);
+                break;
+        }
+        return 0;
+}
+
 static void
 io_subchannel_shutdown(struct subchannel *sch)
 {
@@ -1326,6 +1395,195 @@ io_subchannel_shutdown(struct subchannel *sch)
         cio_disable_subchannel(sch);
 }
 
+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;
+}
+
 #ifdef CONFIG_CCW_CONSOLE
 static struct ccw_device console_cdev;
 static struct ccw_device_private console_private;
@@ -1558,71 +1816,6 @@ ccw_device_get_subchannel_id(struct ccw_device *cdev)
         return sch->schid;
 }
 
-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(4, "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);
-}
-
-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);
-}
-
 MODULE_LICENSE("GPL");
 EXPORT_SYMBOL(ccw_device_set_online);
 EXPORT_SYMBOL(ccw_device_set_offline);