device.c

linux 内核源代码

		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_call_sch_unregister);
		queue_work(slow_path_wq, &cdev->private->kick_work);
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
		break;
	case DEV_STATE_BOXED:
		/* Device did not respond in time. */
	case DEV_STATE_OFFLINE:
		/* 
		 * We can't register the device in interrupt context so
		 * we schedule a work item.
		 */
		if (!get_device(&cdev->dev))
			break;
		PREPARE_WORK(&cdev->private->kick_work,
			     io_subchannel_register);
		queue_work(slow_path_wq, &cdev->private->kick_work);
		break;
	}
}

static int
io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
{
	int rc;
	struct ccw_device_private *priv;

	sch->dev.driver_data = cdev;
	sch->driver = &io_subchannel_driver;
	cdev->ccwlock = sch->lock;

	/* Init private data. */
	priv = cdev->private;
	priv->dev_id.devno = sch->schib.pmcw.dev;
	priv->dev_id.ssid = sch->schid.ssid;
	priv->schid = sch->schid;
	priv->state = DEV_STATE_NOT_OPER;
	INIT_LIST_HEAD(&priv->cmb_list);
	init_waitqueue_head(&priv->wait_q);
	init_timer(&priv->timer);

	/* Set an initial name for the device. */
	snprintf (cdev->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x",
		  sch->schid.ssid, sch->schib.pmcw.dev);

	/* Increase counter of devices currently in recognition. */
	atomic_inc(&ccw_device_init_count);

	/* Start async. device sensing. */
	spin_lock_irq(sch->lock);
	rc = ccw_device_recognition(cdev);
	spin_unlock_irq(sch->lock);
	if (rc) {
		if (atomic_dec_and_test(&ccw_device_init_count))
			wake_up(&ccw_device_init_wq);
	}
	return rc;
}

static void ccw_device_move_to_sch(struct work_struct *work)
{
	struct ccw_device_private *priv;
	int rc;
	struct subchannel *sch;
	struct ccw_device *cdev;
	struct subchannel *former_parent;

	priv = container_of(work, struct ccw_device_private, kick_work);
	sch = priv->sch;
	cdev = priv->cdev;
	former_parent = ccw_device_is_orphan(cdev) ?
		NULL : to_subchannel(get_device(cdev->dev.parent));
	mutex_lock(&sch->reg_mutex);
	/* Try to move the ccw device to its new subchannel. */
	rc = device_move(&cdev->dev, &sch->dev);
	mutex_unlock(&sch->reg_mutex);
	if (rc) {
		CIO_MSG_EVENT(2, "Moving device 0.%x.%04x to subchannel "
			      "0.%x.%04x failed (ret=%d)!\n",
			      cdev->private->dev_id.ssid,
			      cdev->private->dev_id.devno, sch->schid.ssid,
			      sch->schid.sch_no, rc);
		css_sch_device_unregister(sch);
		goto out;
	}
	if (former_parent) {
		spin_lock_irq(former_parent->lock);
		former_parent->dev.driver_data = NULL;
		spin_unlock_irq(former_parent->lock);
		css_sch_device_unregister(former_parent);
		/* Reset intparm to zeroes. */
		former_parent->schib.pmcw.intparm = 0;
		cio_modify(former_parent);
	}
	sch_attach_device(sch, cdev);
out:
	if (former_parent)
		put_device(&former_parent->dev);
	put_device(&cdev->dev);
}

static int
io_subchannel_probe (struct subchannel *sch)
{
	struct ccw_device *cdev;
	int rc;
	unsigned long flags;
	struct ccw_dev_id dev_id;

	if (sch->dev.driver_data) {
		/*
		 * This subchannel already has an associated ccw_device.
		 * Register it and exit. This happens for all early
		 * device, e.g. the console.
		 */
		cdev = sch->dev.driver_data;
		cdev->dev.groups = ccwdev_attr_groups;
		device_initialize(&cdev->dev);
		ccw_device_register(cdev);
		/*
		 * Check if the device is already online. If it is
		 * the reference count needs to be corrected
		 * (see ccw_device_online and css_init_done for the
		 * ugly details).
		 */
		if (cdev->private->state != DEV_STATE_NOT_OPER &&
		    cdev->private->state != DEV_STATE_OFFLINE &&
		    cdev->private->state != DEV_STATE_BOXED)
			get_device(&cdev->dev);
		return 0;
	}
	/*
	 * First check if a fitting device may be found amongst the
	 * disconnected devices or in the orphanage.
	 */
	dev_id.devno = sch->schib.pmcw.dev;
	dev_id.ssid = sch->schid.ssid;
	cdev = get_disc_ccwdev_by_dev_id(&dev_id, NULL);
	if (!cdev)
		cdev = get_orphaned_ccwdev_by_dev_id(to_css(sch->dev.parent),
						     &dev_id);
	if (cdev) {
		/*
		 * Schedule moving the device until when we have a registered
		 * subchannel to move to and succeed the probe. We can
		 * unregister later again, when the probe is through.
		 */
		cdev->private->sch = sch;
		PREPARE_WORK(&cdev->private->kick_work,
			     ccw_device_move_to_sch);
		queue_work(slow_path_wq, &cdev->private->kick_work);
		return 0;
	}
	cdev = io_subchannel_create_ccwdev(sch);
	if (IS_ERR(cdev))
		return PTR_ERR(cdev);

	rc = io_subchannel_recog(cdev, sch);
	if (rc) {
		spin_lock_irqsave(sch->lock, flags);
		sch->dev.driver_data = NULL;
		spin_unlock_irqrestore(sch->lock, flags);
		if (cdev->dev.release)
			cdev->dev.release(&cdev->dev);
	}

	return rc;
}

static int
io_subchannel_remove (struct subchannel *sch)
{
	struct ccw_device *cdev;
	unsigned long flags;

	if (!sch->dev.driver_data)
		return 0;
	cdev = sch->dev.driver_data;
	/* Set ccw device to not operational and drop reference. */
	spin_lock_irqsave(cdev->ccwlock, flags);
	sch->dev.driver_data = NULL;
	cdev->private->state = DEV_STATE_NOT_OPER;
	spin_unlock_irqrestore(cdev->ccwlock, flags);
	ccw_device_unregister(cdev);
	put_device(&cdev->dev);
	return 0;
}

static int
io_subchannel_notify(struct device *dev, int event)
{
	struct ccw_device *cdev;

	cdev = dev->driver_data;
	if (!cdev)
		return 0;
	if (!cdev->drv)
		return 0;
	if (!cdev->online)
		return 0;
	return cdev->drv->notify ? cdev->drv->notify(cdev, event) : 0;
}

static void
io_subchannel_verify(struct device *dev)
{
	struct ccw_device *cdev;

	cdev = dev->driver_data;
	if (cdev)
		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
}

static void
io_subchannel_ioterm(struct device *dev)
{
	struct ccw_device *cdev;

	cdev = dev->driver_data;
	if (!cdev)
		return;
	/* Internal I/O will be retried by the interrupt handler. */
	if (cdev->private->flags.intretry)
		return;
	cdev->private->state = DEV_STATE_CLEAR_VERIFY;
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
}

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

	cdev = sch->dev.driver_data;

	if (cio_is_console(sch->schid))
		return;
	if (!sch->schib.pmcw.ena)
		/* Nothing to do. */
		return;
	ret = cio_disable_subchannel(sch);
	if (ret != -EBUSY)
		/* Subchannel is disabled, we're done. */
		return;
	cdev->private->state = DEV_STATE_QUIESCE;
	if (cdev->handler)
		cdev->handler(cdev, cdev->private->intparm,
			      ERR_PTR(-EIO));
	ret = ccw_device_cancel_halt_clear(cdev);
	if (ret == -EBUSY) {
		ccw_device_set_timeout(cdev, HZ/10);
		wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
	}
	cio_disable_subchannel(sch);
}

#ifdef CONFIG_CCW_CONSOLE
static struct ccw_device console_cdev;
static struct ccw_device_private console_private;
static int console_cdev_in_use;

static DEFINE_SPINLOCK(ccw_console_lock);

spinlock_t * cio_get_console_lock(void)
{
	return &ccw_console_lock;
}

static int
ccw_device_console_enable (struct ccw_device *cdev, struct subchannel *sch)
{
	int rc;

	/* Initialize the ccw_device structure. */
	cdev->dev.parent= &sch->dev;
	rc = io_subchannel_recog(cdev, sch);
	if (rc)
		return rc;

	/* Now wait for the async. recognition to come to an end. */
	spin_lock_irq(cdev->ccwlock);
	while (!dev_fsm_final_state(cdev))
		wait_cons_dev();
	rc = -EIO;
	if (cdev->private->state != DEV_STATE_OFFLINE)
		goto out_unlock;
	ccw_device_online(cdev);
	while (!dev_fsm_final_state(cdev))
		wait_cons_dev();
	if (cdev->private->state != DEV_STATE_ONLINE)
		goto out_unlock;
	rc = 0;
out_unlock:
	spin_unlock_irq(cdev->ccwlock);
	return 0;
}

struct ccw_device *
ccw_device_probe_console(void)
{
	struct subchannel *sch;
	int ret;

	if (xchg(&console_cdev_in_use, 1) != 0)
		return ERR_PTR(-EBUSY);
	sch = cio_probe_console();
	if (IS_ERR(sch)) {
		console_cdev_in_use = 0;
		return (void *) sch;
	}
	memset(&console_cdev, 0, sizeof(struct ccw_device));
	memset(&console_private, 0, sizeof(struct ccw_device_private));
	console_cdev.private = &console_private;
	console_private.cdev = &console_cdev;
	ret = ccw_device_console_enable(&console_cdev, sch);
	if (ret) {
		cio_release_console();
		console_cdev_in_use = 0;
		return ERR_PTR(ret);
	}
	console_cdev.online = 1;
	return &console_cdev;
}
#endif

/*
 * get ccw_device matching the busid, but only if owned by cdrv
 */
static int
__ccwdev_check_busid(struct device *dev, void *id)
{
	char *bus_id;

	bus_id = id;

	return (strncmp(bus_id, dev->bus_id, BUS_ID_SIZE) == 0);
}


/**
 * get_ccwdev_by_busid() - obtain device from a bus id
 * @cdrv: driver the device is owned by
 * @bus_id: bus id of the device to be searched
 *
 * This function searches all devices owned by @cdrv for a device with a bus
 * id matching @bus_id.
 * Returns:
 *  If a match is found, its reference count of the found device is increased
 *  and it is returned; else %NULL is returned.
 */
struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
				       const char *bus_id)
{
	struct device *dev;
	struct device_driver *drv;

	drv = get_driver(&cdrv->driver);
	if (!drv)
		return NULL;

	dev = driver_find_device(drv, NULL, (void *)bus_id,
				 __ccwdev_check_busid);
	put_driver(drv);

	return dev ? to_ccwdev(dev) : NULL;
}

/************************** device driver handling ************************/

/* This is the implementation of the ccw_driver class. The probe, remove
 * and release methods are initially very similar to the device_driver
 * implementations, with the difference that they have ccw_device
 * arguments.
 *
 * A ccw driver also contains the information that is needed for
 * device matching.
 */
static int
ccw_device_probe (struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_driver *cdrv = to_ccwdrv(dev->driver);
	int ret;

	cdev->drv = cdrv; /* to let the driver call _set_online */

	ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;

	if (ret) {
		cdev->drv = NULL;
		return ret;
	}

	return 0;
}

static int
ccw_device_remove (struct device *dev)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct ccw_driver *cdrv = cdev->drv;
	int ret;

	if (cdrv->remove)
		cdrv->remove(cdev);
	if (cdev->online) {
		cdev->online = 0;
		spin_lock_irq(cdev->ccwlock);
		ret = ccw_device_offline(cdev);
		spin_unlock_irq(cdev->ccwlock);
		if (ret == 0)
			wait_event(cdev->private->wait_q,
				   dev_fsm_final_state(cdev));
		else
			//FIXME: we can't fail!
			CIO_MSG_EVENT(2, "ccw_device_offline returned %d, "
				      "device 0.%x.%04x\n",
				      ret, cdev->private->dev_id.ssid,
				      cdev->private->dev_id.devno);
	}
	ccw_device_set_timeout(cdev, 0);
	cdev->drv = NULL;
	return 0;
}

static void ccw_device_shutdown(struct device *dev)
{
	struct ccw_device *cdev;

	cdev = to_ccwdev(dev);
	if (cdev->drv && cdev->drv->shutdown)
		cdev->drv->shutdown(cdev);
	disable_cmf(cdev);
}

struct bus_type ccw_bus_type = {
	.name   = "ccw",
	.match  = ccw_bus_match,
	.uevent = ccw_uevent,
	.probe  = ccw_device_probe,
	.remove = ccw_device_remove,
	.shutdown = ccw_device_shutdown,
};

/**
 * ccw_driver_register() - register a ccw driver
 * @cdriver: driver to be registered
 *
 * This function is mainly a wrapper around driver_register().
 * Returns:
 *   %0 on success and a negative error value on failure.
 */
int ccw_driver_register(struct ccw_driver *cdriver)
{
	struct device_driver *drv = &cdriver->driver;

	drv->bus = &ccw_bus_type;
	drv->name = cdriver->name;

	return driver_register(drv);
}

/**
 * ccw_driver_unregister() - deregister a ccw driver
 * @cdriver: driver to be deregistered
 *
 * This function is mainly a wrapper around driver_unregister().
 */
void ccw_driver_unregister(struct ccw_driver *cdriver)
{
	driver_unregister(&cdriver->driver);
}

/* Helper func for qdio. */
struct subchannel_id
ccw_device_get_subchannel_id(struct ccw_device *cdev)
{
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	return sch->schid;
}

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ccw_device_set_online);
EXPORT_SYMBOL(ccw_device_set_offline);
EXPORT_SYMBOL(ccw_driver_register);
EXPORT_SYMBOL(ccw_driver_unregister);
EXPORT_SYMBOL(get_ccwdev_by_busid);
EXPORT_SYMBOL(ccw_bus_type);
EXPORT_SYMBOL(ccw_device_work);
EXPORT_SYMBOL(ccw_device_notify_work);
EXPORT_SYMBOL_GPL(ccw_device_get_subchannel_id);