device_fsm.c

linux-2.6.15.6

	if (ret != 0)
		/* Couldn't enable the subchannel for i/o. Sick device. */
		return ret;

	/* After 60s the device recognition is considered to have failed. */
	ccw_device_set_timeout(cdev, 60*HZ);

	/*
	 * We used to start here with a sense pgid to find out whether a device
	 * is locked by someone else. Unfortunately, the sense pgid command
	 * code has other meanings on devices predating the path grouping
	 * algorithm, so we start with sense id and box the device after an
	 * timeout (or if sense pgid during path verification detects the device
	 * is locked, as may happen on newer devices).
	 */
	cdev->private->flags.recog_done = 0;
	cdev->private->state = DEV_STATE_SENSE_ID;
	ccw_device_sense_id_start(cdev);
	return 0;
}

/*
 * Handle timeout in device recognition.
 */
static void
ccw_device_recog_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
	int ret;

	ret = ccw_device_cancel_halt_clear(cdev);
	switch (ret) {
	case 0:
		ccw_device_recog_done(cdev, DEV_STATE_BOXED);
		break;
	case -ENODEV:
		ccw_device_recog_done(cdev, DEV_STATE_NOT_OPER);
		break;
	default:
		ccw_device_set_timeout(cdev, 3*HZ);
	}
}


static void
ccw_device_nopath_notify(void *data)
{
	struct ccw_device *cdev;
	struct subchannel *sch;
	int ret;

	cdev = (struct ccw_device *)data;
	sch = to_subchannel(cdev->dev.parent);
	/* Extra sanity. */
	if (sch->lpm)
		return;
	ret = (sch->driver && sch->driver->notify) ?
		sch->driver->notify(&sch->dev, CIO_NO_PATH) : 0;
	if (!ret) {
		if (get_device(&sch->dev)) {
			/* Driver doesn't want to keep device. */
			cio_disable_subchannel(sch);
			if (get_device(&cdev->dev)) {
				PREPARE_WORK(&cdev->private->kick_work,
					     ccw_device_call_sch_unregister,
					     (void *)cdev);
				queue_work(ccw_device_work,
					   &cdev->private->kick_work);
			} else
				put_device(&sch->dev);
		}
	} else {
		cio_disable_subchannel(sch);
		ccw_device_set_timeout(cdev, 0);
		cdev->private->flags.fake_irb = 0;
		cdev->private->state = DEV_STATE_DISCONNECTED;
		wake_up(&cdev->private->wait_q);
	}
}

void
ccw_device_verify_done(struct ccw_device *cdev, int err)
{
	cdev->private->flags.doverify = 0;
	switch (err) {
	case -EOPNOTSUPP: /* path grouping not supported, just set online. */
		cdev->private->options.pgroup = 0;
	case 0:
		ccw_device_done(cdev, DEV_STATE_ONLINE);
		/* Deliver fake irb to device driver, if needed. */
		if (cdev->private->flags.fake_irb) {
			memset(&cdev->private->irb, 0, sizeof(struct irb));
			cdev->private->irb.scsw = (struct scsw) {
				.cc = 1,
				.fctl = SCSW_FCTL_START_FUNC,
				.actl = SCSW_ACTL_START_PEND,
				.stctl = SCSW_STCTL_STATUS_PEND,
			};
			cdev->private->flags.fake_irb = 0;
			if (cdev->handler)
				cdev->handler(cdev, cdev->private->intparm,
					      &cdev->private->irb);
			memset(&cdev->private->irb, 0, sizeof(struct irb));
		}
		break;
	case -ETIME:
		ccw_device_done(cdev, DEV_STATE_BOXED);
		break;
	default:
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_nopath_notify, (void *)cdev);
		queue_work(ccw_device_notify_work, &cdev->private->kick_work);
		ccw_device_done(cdev, DEV_STATE_NOT_OPER);
		break;
	}
}

/*
 * Get device online.
 */
int
ccw_device_online(struct ccw_device *cdev)
{
	struct subchannel *sch;
	int ret;

	if ((cdev->private->state != DEV_STATE_OFFLINE) &&
	    (cdev->private->state != DEV_STATE_BOXED))
		return -EINVAL;
	sch = to_subchannel(cdev->dev.parent);
	if (css_init_done && !get_device(&cdev->dev))
		return -ENODEV;
	ret = cio_enable_subchannel(sch, sch->schib.pmcw.isc);
	if (ret != 0) {
		/* Couldn't enable the subchannel for i/o. Sick device. */
		if (ret == -ENODEV)
			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
		return ret;
	}
	/* Do we want to do path grouping? */
	if (!cdev->private->options.pgroup) {
		/* No, set state online immediately. */
		ccw_device_done(cdev, DEV_STATE_ONLINE);
		return 0;
	}
	/* Do a SensePGID first. */
	cdev->private->state = DEV_STATE_SENSE_PGID;
	ccw_device_sense_pgid_start(cdev);
	return 0;
}

void
ccw_device_disband_done(struct ccw_device *cdev, int err)
{
	switch (err) {
	case 0:
		ccw_device_done(cdev, DEV_STATE_OFFLINE);
		break;
	case -ETIME:
		ccw_device_done(cdev, DEV_STATE_BOXED);
		break;
	default:
		ccw_device_done(cdev, DEV_STATE_NOT_OPER);
		break;
	}
}

/*
 * Shutdown device.
 */
int
ccw_device_offline(struct ccw_device *cdev)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	if (stsch(sch->irq, &sch->schib) || !sch->schib.pmcw.dnv)
		return -ENODEV;
	if (cdev->private->state != DEV_STATE_ONLINE) {
		if (sch->schib.scsw.actl != 0)
			return -EBUSY;
		return -EINVAL;
	}
	if (sch->schib.scsw.actl != 0)
		return -EBUSY;
	/* Are we doing path grouping? */
	if (!cdev->private->options.pgroup) {
		/* No, set state offline immediately. */
		ccw_device_done(cdev, DEV_STATE_OFFLINE);
		return 0;
	}
	/* Start Set Path Group commands. */
	cdev->private->state = DEV_STATE_DISBAND_PGID;
	ccw_device_disband_start(cdev);
	return 0;
}

/*
 * Handle timeout in device online/offline process.
 */
static void
ccw_device_onoff_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
	int ret;

	ret = ccw_device_cancel_halt_clear(cdev);
	switch (ret) {
	case 0:
		ccw_device_done(cdev, DEV_STATE_BOXED);
		break;
	case -ENODEV:
		ccw_device_done(cdev, DEV_STATE_NOT_OPER);
		break;
	default:
		ccw_device_set_timeout(cdev, 3*HZ);
	}
}

/*
 * Handle not oper event in device recognition.
 */
static void
ccw_device_recog_notoper(struct ccw_device *cdev, enum dev_event dev_event)
{
	ccw_device_recog_done(cdev, DEV_STATE_NOT_OPER);
}

/*
 * Handle not operational event while offline.
 */
static void
ccw_device_offline_notoper(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct subchannel *sch;

	cdev->private->state = DEV_STATE_NOT_OPER;
	sch = to_subchannel(cdev->dev.parent);
	if (get_device(&cdev->dev)) {
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_call_sch_unregister, (void *)cdev);
		queue_work(ccw_device_work, &cdev->private->kick_work);
	}
	wake_up(&cdev->private->wait_q);
}

/*
 * Handle not operational event while online.
 */
static void
ccw_device_online_notoper(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	if (sch->driver->notify &&
	    sch->driver->notify(&sch->dev, sch->lpm ? CIO_GONE : CIO_NO_PATH)) {
			ccw_device_set_timeout(cdev, 0);
			cdev->private->flags.fake_irb = 0;
			cdev->private->state = DEV_STATE_DISCONNECTED;
			wake_up(&cdev->private->wait_q);
			return;
	}
	cdev->private->state = DEV_STATE_NOT_OPER;
	cio_disable_subchannel(sch);
	if (sch->schib.scsw.actl != 0) {
		// FIXME: not-oper indication to device driver ?
		ccw_device_call_handler(cdev);
	}
	if (get_device(&cdev->dev)) {
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_call_sch_unregister, (void *)cdev);
		queue_work(ccw_device_work, &cdev->private->kick_work);
	}
	wake_up(&cdev->private->wait_q);
}

/*
 * Handle path verification event.
 */
static void
ccw_device_online_verify(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct subchannel *sch;

	if (!cdev->private->options.pgroup)
		return;
	if (cdev->private->state == DEV_STATE_W4SENSE) {
		cdev->private->flags.doverify = 1;
		return;
	}
	sch = to_subchannel(cdev->dev.parent);
	/*
	 * Since we might not just be coming from an interrupt from the
	 * subchannel we have to update the schib.
	 */
	stsch(sch->irq, &sch->schib);

	if (sch->schib.scsw.actl != 0 ||
	    (cdev->private->irb.scsw.stctl & SCSW_STCTL_STATUS_PEND)) {
		/*
		 * No final status yet or final status not yet delivered
		 * to the device driver. Can't do path verfication now,
		 * delay until final status was delivered.
		 */
		cdev->private->flags.doverify = 1;
		return;
	}
	/* Device is idle, we can do the path verification. */
	cdev->private->state = DEV_STATE_VERIFY;
	ccw_device_verify_start(cdev);
}

/*
 * Got an interrupt for a normal io (state online).
 */
static void
ccw_device_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct irb *irb;

	irb = (struct irb *) __LC_IRB;
	/* Check for unsolicited interrupt. */
	if ((irb->scsw.stctl ==
	    		(SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS))
	    && (!irb->scsw.cc)) {
		if ((irb->scsw.dstat & DEV_STAT_UNIT_CHECK) &&
		    !irb->esw.esw0.erw.cons) {
			/* Unit check but no sense data. Need basic sense. */
			if (ccw_device_do_sense(cdev, irb) != 0)
				goto call_handler_unsol;
			memcpy(irb, &cdev->private->irb, sizeof(struct irb));
			cdev->private->state = DEV_STATE_W4SENSE;
			cdev->private->intparm = 0;
			return;
		}
call_handler_unsol:
		if (cdev->handler)
			cdev->handler (cdev, 0, irb);
		return;
	}
	/* Accumulate status and find out if a basic sense is needed. */
	ccw_device_accumulate_irb(cdev, irb);
	if (cdev->private->flags.dosense) {
		if (ccw_device_do_sense(cdev, irb) == 0) {
			cdev->private->state = DEV_STATE_W4SENSE;
		}
		return;
	}
	/* Call the handler. */
	if (ccw_device_call_handler(cdev) && cdev->private->flags.doverify)
		/* Start delayed path verification. */
		ccw_device_online_verify(cdev, 0);
}

/*
 * Got an timeout in online state.
 */
static void
ccw_device_online_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
	int ret;

	ccw_device_set_timeout(cdev, 0);
	ret = ccw_device_cancel_halt_clear(cdev);
	if (ret == -EBUSY) {
		ccw_device_set_timeout(cdev, 3*HZ);
		cdev->private->state = DEV_STATE_TIMEOUT_KILL;
		return;
	}
	if (ret == -ENODEV) {
		struct subchannel *sch;

		sch = to_subchannel(cdev->dev.parent);
		if (!sch->lpm) {
			PREPARE_WORK(&cdev->private->kick_work,
				     ccw_device_nopath_notify, (void *)cdev);
			queue_work(ccw_device_notify_work,
				   &cdev->private->kick_work);
		} else
			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
	} else if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-ETIMEDOUT));
}

/*
 * Got an interrupt for a basic sense.
 */
void
ccw_device_w4sense(struct ccw_device *cdev, enum dev_event dev_event)
{
	struct irb *irb;

	irb = (struct irb *) __LC_IRB;
	/* Check for unsolicited interrupt. */
	if (irb->scsw.stctl ==
	    		(SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
		if (irb->scsw.cc == 1)
			/* Basic sense hasn't started. Try again. */
			ccw_device_do_sense(cdev, irb);
		else {
			printk("Huh? %s(%s): unsolicited interrupt...\n",
			       __FUNCTION__, cdev->dev.bus_id);
			if (cdev->handler)
				cdev->handler (cdev, 0, irb);
		}
		return;
	}
	/* Add basic sense info to irb. */
	ccw_device_accumulate_basic_sense(cdev, irb);
	if (cdev->private->flags.dosense) {
		/* Another basic sense is needed. */
		ccw_device_do_sense(cdev, irb);
		return;
	}
	cdev->private->state = DEV_STATE_ONLINE;
	/* Call the handler. */
	if (ccw_device_call_handler(cdev) && cdev->private->flags.doverify)
		/* Start delayed path verification. */
		ccw_device_online_verify(cdev, 0);