device.c

优龙2410linux2.6.8内核源代码

void
ccw_device_do_unreg_rereg(void *data)
{
	struct ccw_device *cdev;
	struct subchannel *sch;
	int need_rename;

	cdev = (struct ccw_device *)data;
	sch = to_subchannel(cdev->dev.parent);
	if (cdev->private->devno != sch->schib.pmcw.dev) {
		/*
		 * The device number has changed. This is usually only when
		 * a device has been detached under VM and then re-appeared
		 * on another subchannel because of a different attachment
		 * order than before. Ideally, we should should just switch
		 * subchannels, but unfortunately, this is not possible with
		 * the current implementation.
		 * Instead, we search for the old subchannel for this device
		 * number and deregister so there are no collisions with the
		 * newly registered ccw_device.
		 * FIXME: Find another solution so the block layer doesn't
		 *        get possibly sick...
		 */
		struct ccw_device *other_cdev;

		need_rename = 1;
		other_cdev = get_disc_ccwdev_by_devno(sch->schib.pmcw.dev,
						      cdev);
		if (other_cdev) {
			struct subchannel *other_sch;

			other_sch = to_subchannel(other_cdev->dev.parent);
			if (get_device(&other_sch->dev)) {
				stsch(other_sch->irq, &other_sch->schib);
				if (other_sch->schib.pmcw.dnv) {
					other_sch->schib.pmcw.intparm = 0;
					cio_modify(other_sch);
				}
				device_unregister(&other_sch->dev);
			}
		}
		cdev->private->devno = sch->schib.pmcw.dev;
	} else
		need_rename = 0;
	device_remove_files(&cdev->dev);
	device_del(&cdev->dev);
	if (need_rename)
		snprintf (cdev->dev.bus_id, BUS_ID_SIZE, "0.0.%04x",
			  sch->schib.pmcw.dev);
	if (device_add(&cdev->dev)) {
		put_device(&cdev->dev);
		return;
	}
	if (device_add_files(&cdev->dev))
		device_unregister(&cdev->dev);
}

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

	cdev = to_ccwdev(dev);
	kfree(cdev->private);
	kfree(cdev);
}

/*
 * Register recognized device.
 */
static void
io_subchannel_register(void *data)
{
	struct ccw_device *cdev;
	struct subchannel *sch;
	int ret;

	cdev = (struct ccw_device *) data;
	sch = to_subchannel(cdev->dev.parent);

	if (!list_empty(&sch->dev.children)) {
		bus_rescan_devices(&ccw_bus_type);
		goto out;
	}
	/* make it known to the system */
	ret = ccw_device_register(cdev);
	if (ret) {
		printk (KERN_WARNING "%s: could not register %s\n",
			__func__, cdev->dev.bus_id);
		put_device(&cdev->dev);
		sch->dev.driver_data = 0;
		kfree (cdev->private);
		kfree (cdev);
		goto out;
	}

	ret = subchannel_add_files(cdev->dev.parent);
	if (ret)
		printk(KERN_WARNING "%s: could not add attributes to %s\n",
		       __func__, sch->dev.bus_id);
	put_device(&cdev->dev);
out:
	cdev->private->flags.recog_done = 1;
	put_device(&sch->dev);
	wake_up(&cdev->private->wait_q);
}

void
ccw_device_call_sch_unregister(void *data)
{
	struct ccw_device *cdev = data;
	struct subchannel *sch;

	sch = to_subchannel(cdev->dev.parent);
	device_unregister(&sch->dev);
	/* Reset intparm to zeroes. */
	sch->schib.pmcw.intparm = 0;
	cio_modify(sch);
	put_device(&cdev->dev);
	put_device(&sch->dev);
}

/*
 * subchannel recognition done. Called from the state machine.
 */
void
io_subchannel_recog_done(struct ccw_device *cdev)
{
	struct subchannel *sch;

	if (css_init_done == 0) {
		cdev->private->flags.recog_done = 1;
		return;
	}
	switch (cdev->private->state) {
	case DEV_STATE_NOT_OPER:
		cdev->private->flags.recog_done = 1;
		/* Remove device found not operational. */
		if (!get_device(&cdev->dev))
			break;
		sch = to_subchannel(cdev->dev.parent);
		INIT_WORK(&cdev->private->kick_work,
			  ccw_device_call_sch_unregister, (void *) cdev);
		queue_work(slow_path_wq, &cdev->private->kick_work);
		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;
		INIT_WORK(&cdev->private->kick_work,
			  io_subchannel_register, (void *) cdev);
		queue_work(ccw_device_work, &cdev->private->kick_work);
		break;
	}
	if (atomic_dec_and_test(&ccw_device_init_count))
		wake_up(&ccw_device_init_wq);
}

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

	sch->dev.driver_data = cdev;
	sch->driver = &io_subchannel_driver;
	cdev->ccwlock = &sch->lock;
	*cdev->private = (struct ccw_device_private) {
		.devno	= sch->schib.pmcw.dev,
		.irq	= sch->irq,
		.state	= DEV_STATE_NOT_OPER,
		.cmb_list = LIST_HEAD_INIT(cdev->private->cmb_list),
	};
	init_waitqueue_head(&cdev->private->wait_q);
	init_timer(&cdev->private->timer);

	/* Set an initial name for the device. */
	snprintf (cdev->dev.bus_id, BUS_ID_SIZE, "0.0.%04x",
		  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 int
io_subchannel_probe (struct device *pdev)
{
	struct subchannel *sch;
	struct ccw_device *cdev;
	int rc;

	sch = to_subchannel(pdev);
	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;
		device_initialize(&cdev->dev);
		ccw_device_register(cdev);
		subchannel_add_files(&sch->dev);
		/*
		 * 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;
	}
	cdev  = kmalloc (sizeof(*cdev), GFP_KERNEL);
	if (!cdev)
		return -ENOMEM;
	memset(cdev, 0, sizeof(struct ccw_device));
	cdev->private = kmalloc(sizeof(struct ccw_device_private), 
				GFP_KERNEL | GFP_DMA);
	if (!cdev->private) {
		kfree(cdev);
		return -ENOMEM;
	}
	memset(cdev->private, 0, sizeof(struct ccw_device_private));
	atomic_set(&cdev->private->onoff, 0);
	cdev->dev = (struct device) {
		.parent = pdev,
		.release = ccw_device_release,
	};
	/* Do first half of device_register. */
	device_initialize(&cdev->dev);

	if (!get_device(&sch->dev)) {
		if (cdev->dev.release)
			cdev->dev.release(&cdev->dev);
		return -ENODEV;
	}

	rc = io_subchannel_recog(cdev, to_subchannel(pdev));
	if (rc) {
		sch->dev.driver_data = 0;
		if (cdev->dev.release)
			cdev->dev.release(&cdev->dev);
	}

	return rc;
}

static int
io_subchannel_remove (struct device *dev)
{
	struct ccw_device *cdev;

	if (!dev->driver_data)
		return 0;
	cdev = dev->driver_data;
	/* Set ccw device to not operational and drop reference. */
	cdev->private->state = DEV_STATE_NOT_OPER;
	/*
	 * Careful here. Our ccw device might be yet unregistered when
	 * de-registering its subchannel (machine check during device
	 * recognition). Better look if the subchannel has children.
	 */
	if (!list_empty(&dev->children))
		device_unregister(&cdev->dev);
	dev->driver_data = NULL;
	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;
	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 device *dev)
{
	struct subchannel *sch;
	struct ccw_device *cdev;
	int ret;

	sch = to_subchannel(dev);
	cdev = dev->driver_data;

	if (cio_is_console(sch->irq))
		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 int
ccw_device_console_enable (struct ccw_device *cdev, struct subchannel *sch)
{
	int rc;

	/* Initialize the ccw_device structure. */
	cdev->dev = (struct device) {
		.parent = &sch->dev,
	};
	/* Initialize the subchannel structure */
	sch->dev.parent = &css_bus_device;
	sch->dev.bus = &css_bus_type;

	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 NULL;
	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;
	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
 */
struct ccw_device *
get_ccwdev_by_busid(struct ccw_driver *cdrv, const char *bus_id)
{
	struct device *d, *dev;
	struct device_driver *drv;

	drv = get_driver(&cdrv->driver);
	if (!drv)
		return 0;

	down_read(&drv->bus->subsys.rwsem);

	dev = NULL;
	list_for_each_entry(d, &drv->devices, driver_list) {
		dev = get_device(d);

		if (dev && !strncmp(bus_id, dev->bus_id, BUS_ID_SIZE))
			break;
		else if (dev) {
			put_device(dev);
			dev = NULL;
		}
	}
	up_read(&drv->bus->subsys.rwsem);
	put_driver(drv);

	return dev ? to_ccwdev(dev) : 0;
}

/************************** 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 = 0;
		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;

	pr_debug("removing device %s\n", cdev->dev.bus_id);
	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!
			pr_debug("ccw_device_offline returned %d, device %s\n",
				 ret, cdev->dev.bus_id);
	}
	ccw_device_set_timeout(cdev, 0);
	cdev->drv = 0;
	return 0;
}

int
ccw_driver_register (struct ccw_driver *cdriver)
{
	struct device_driver *drv = &cdriver->driver;

	drv->bus = &ccw_bus_type;
	drv->name = cdriver->name;
	drv->probe = ccw_device_probe;
	drv->remove = ccw_device_remove;

	return driver_register(drv);
}

void
ccw_driver_unregister (struct ccw_driver *cdriver)
{
	driver_unregister(&cdriver->driver);
}

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);