[deliverable/linux.git] / drivers / s390 / cio / ccwgroup.c

/*
 *  drivers/s390/cio/ccwgroup.c
 *  bus driver for ccwgroup
 *
 *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
 *                       IBM Corporation
 *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *               Cornelia Huck (cornelia.huck@de.ibm.com)
 */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/ctype.h>
#include <linux/dcache.h>

#include <asm/semaphore.h>
#include <asm/ccwdev.h>
#include <asm/ccwgroup.h>

/* In Linux 2.4, we had a channel device layer called "chandev"
 * that did all sorts of obscure stuff for networking devices.
 * This is another driver that serves as a replacement for just
 * one of its functions, namely the translation of single subchannels
 * to devices that use multiple subchannels.
 */

/* a device matches a driver if all its slave devices match the same
 * entry of the driver */
static int
ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	gdev = container_of(dev, struct ccwgroup_device, dev);
	gdrv = container_of(drv, struct ccwgroup_driver, driver);

	if (gdev->creator_id == gdrv->driver_id)
		return 1;

	return 0;
}
static int
ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
{
	/* TODO */
	return 0;
}

static struct bus_type ccwgroup_bus_type;

static void
__ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
{
	int i;
	char str[8];

	for (i = 0; i < gdev->count; i++) {
		sprintf(str, "cdev%d", i);
		sysfs_remove_link(&gdev->dev.kobj, str);
		sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
	}
	
}

/*
 * Provide an 'ungroup' attribute so the user can remove group devices no
 * longer needed or accidentially created. Saves memory :)
 */
static void ccwgroup_ungroup_callback(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);

	mutex_lock(&gdev->reg_mutex);
	__ccwgroup_remove_symlinks(gdev);
	device_unregister(dev);
	mutex_unlock(&gdev->reg_mutex);
}

static ssize_t
ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct ccwgroup_device *gdev;
	int rc;

	gdev = to_ccwgroupdev(dev);

	if (gdev->state != CCWGROUP_OFFLINE)
		return -EINVAL;

	/* Note that we cannot unregister the device from one of its
	 * attribute methods, so we have to use this roundabout approach.
	 */
	rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
	if (rc)
		count = rc;
	return count;
}

static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);

static void
ccwgroup_release (struct device *dev)
{
	struct ccwgroup_device *gdev;
	int i;

	gdev = to_ccwgroupdev(dev);

	for (i = 0; i < gdev->count; i++) {
		gdev->cdev[i]->dev.driver_data = NULL;
		put_device(&gdev->cdev[i]->dev);
	}
	kfree(gdev);
}

static int
__ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
{
	char str[8];
	int i, rc;

	for (i = 0; i < gdev->count; i++) {
		rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
				       "group_device");
		if (rc) {
			for (--i; i >= 0; i--)
				sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
						  "group_device");
			return rc;
		}
	}
	for (i = 0; i < gdev->count; i++) {
		sprintf(str, "cdev%d", i);
		rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
				       str);
		if (rc) {
			for (--i; i >= 0; i--) {
				sprintf(str, "cdev%d", i);
				sysfs_remove_link(&gdev->dev.kobj, str);
			}
			for (i = 0; i < gdev->count; i++)
				sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
						  "group_device");
			return rc;
		}
	}
	return 0;
}

/*
 * try to add a new ccwgroup device for one driver
 * argc and argv[] are a list of bus_id's of devices
 * belonging to the driver.
 */
int
ccwgroup_create(struct device *root,
		unsigned int creator_id,
		struct ccw_driver *cdrv,
		int argc, char *argv[])
{
	struct ccwgroup_device *gdev;
	int i;
	int rc;

	if (argc > 256) /* disallow dumb users */
		return -EINVAL;

	gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
	if (!gdev)
		return -ENOMEM;

	atomic_set(&gdev->onoff, 0);
	mutex_init(&gdev->reg_mutex);
	mutex_lock(&gdev->reg_mutex);
	for (i = 0; i < argc; i++) {
		gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);

		/* all devices have to be of the same type in
		 * order to be grouped */
		if (!gdev->cdev[i]
		    || gdev->cdev[i]->id.driver_info !=
		    gdev->cdev[0]->id.driver_info) {
			rc = -EINVAL;
			goto error;
		}
		/* Don't allow a device to belong to more than one group. */
		if (gdev->cdev[i]->dev.driver_data) {
			rc = -EINVAL;
			goto error;
		}
		gdev->cdev[i]->dev.driver_data = gdev;
	}

	gdev->creator_id = creator_id;
	gdev->count = argc;
	gdev->dev.bus = &ccwgroup_bus_type;
	gdev->dev.parent = root;
	gdev->dev.release = ccwgroup_release;

	snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
			gdev->cdev[0]->dev.bus_id);

	rc = device_register(&gdev->dev);
	if (rc)
		goto error;
	get_device(&gdev->dev);
	rc = device_create_file(&gdev->dev, &dev_attr_ungroup);

	if (rc) {
		device_unregister(&gdev->dev);
		goto error;
	}

	rc = __ccwgroup_create_symlinks(gdev);
	if (!rc) {
		mutex_unlock(&gdev->reg_mutex);
		put_device(&gdev->dev);
		return 0;
	}
	device_remove_file(&gdev->dev, &dev_attr_ungroup);
	device_unregister(&gdev->dev);
error:
	for (i = 0; i < argc; i++)
		if (gdev->cdev[i]) {
			if (gdev->cdev[i]->dev.driver_data == gdev)
				gdev->cdev[i]->dev.driver_data = NULL;
			put_device(&gdev->cdev[i]->dev);
		}
	mutex_unlock(&gdev->reg_mutex);
	put_device(&gdev->dev);
	return rc;
}

static int __init
init_ccwgroup (void)
{
	return bus_register (&ccwgroup_bus_type);
}

static void __exit
cleanup_ccwgroup (void)
{
	bus_unregister (&ccwgroup_bus_type);
}

module_init(init_ccwgroup);
module_exit(cleanup_ccwgroup);

/************************** driver stuff ******************************/

static int
ccwgroup_set_online(struct ccwgroup_device *gdev)
{
	struct ccwgroup_driver *gdrv;
	int ret;

	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state == CCWGROUP_ONLINE) {
		ret = 0;
		goto out;
	}
	if (!gdev->dev.driver) {
		ret = -EINVAL;
		goto out;
	}
	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
		goto out;

	gdev->state = CCWGROUP_ONLINE;
 out:
	atomic_set(&gdev->onoff, 0);
	return ret;
}

static int
ccwgroup_set_offline(struct ccwgroup_device *gdev)
{
	struct ccwgroup_driver *gdrv;
	int ret;

	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state == CCWGROUP_OFFLINE) {
		ret = 0;
		goto out;
	}
	if (!gdev->dev.driver) {
		ret = -EINVAL;
		goto out;
	}
	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
		goto out;

	gdev->state = CCWGROUP_OFFLINE;
 out:
	atomic_set(&gdev->onoff, 0);
	return ret;
}

static ssize_t
ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;
	unsigned int value;
	int ret;

	gdev = to_ccwgroupdev(dev);
	if (!dev->driver)
		return count;

	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	if (!try_module_get(gdrv->owner))
		return -EINVAL;

	value = simple_strtoul(buf, NULL, 0);
	ret = count;
	if (value == 1)
		ccwgroup_set_online(gdev);
	else if (value == 0)
		ccwgroup_set_offline(gdev);
	else
		ret = -EINVAL;
	module_put(gdrv->owner);
	return ret;
}

static ssize_t
ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
{
	int online;

	online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);

	return sprintf(buf, online ? "1\n" : "0\n");
}

static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);

static int
ccwgroup_probe (struct device *dev)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	int ret;

	gdev = to_ccwgroupdev(dev);
	gdrv = to_ccwgroupdrv(dev->driver);

	if ((ret = device_create_file(dev, &dev_attr_online)))
		return ret;

	ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
	if (ret)
		device_remove_file(dev, &dev_attr_online);

	return ret;
}

static int
ccwgroup_remove (struct device *dev)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	gdev = to_ccwgroupdev(dev);
	gdrv = to_ccwgroupdrv(dev->driver);

	device_remove_file(dev, &dev_attr_online);

	if (gdrv && gdrv->remove)
		gdrv->remove(gdev);
	return 0;
}

static struct bus_type ccwgroup_bus_type = {
	.name   = "ccwgroup",
	.match  = ccwgroup_bus_match,
	.uevent = ccwgroup_uevent,
	.probe  = ccwgroup_probe,
	.remove = ccwgroup_remove,
};

int
ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
{
	/* register our new driver with the core */
	cdriver->driver.bus = &ccwgroup_bus_type;
	cdriver->driver.name = cdriver->name;

	return driver_register(&cdriver->driver);
}

static int
__ccwgroup_match_all(struct device *dev, void *data)
{
	return 1;
}

void
ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
{
	struct device *dev;

	/* We don't want ccwgroup devices to live longer than their driver. */
	get_driver(&cdriver->driver);
	while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
					 __ccwgroup_match_all))) {
		struct ccwgroup_device *gdev = to_ccwgroupdev(dev);

		mutex_lock(&gdev->reg_mutex);
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(dev);
		mutex_unlock(&gdev->reg_mutex);
		put_device(dev);
	}
	put_driver(&cdriver->driver);
	driver_unregister(&cdriver->driver);
}

int
ccwgroup_probe_ccwdev(struct ccw_device *cdev)
{
	return 0;
}

static struct ccwgroup_device *
__ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
{
	struct ccwgroup_device *gdev;

	if (cdev->dev.driver_data) {
		gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
		if (get_device(&gdev->dev)) {
			mutex_lock(&gdev->reg_mutex);
			if (device_is_registered(&gdev->dev))
				return gdev;
			mutex_unlock(&gdev->reg_mutex);
			put_device(&gdev->dev);
		}
		return NULL;
	}
	return NULL;
}

void
ccwgroup_remove_ccwdev(struct ccw_device *cdev)
{
	struct ccwgroup_device *gdev;

	/* Ignore offlining errors, device is gone anyway. */
	ccw_device_set_offline(cdev);
	/* If one of its devices is gone, the whole group is done for. */
	gdev = __ccwgroup_get_gdev_by_cdev(cdev);
	if (gdev) {
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(&gdev->dev);
		mutex_unlock(&gdev->reg_mutex);
		put_device(&gdev->dev);
	}
}

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ccwgroup_driver_register);
EXPORT_SYMBOL(ccwgroup_driver_unregister);
EXPORT_SYMBOL(ccwgroup_create);
EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* drivers/s390/cio/ccwgroup.c
	3	* bus driver for ccwgroup
1da177e4 LT	4	*
	5	* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
	6	* IBM Corporation
	7	* Author(s): Arnd Bergmann (arndb@de.ibm.com)
4ce3b30c	8	* Cornelia Huck (cornelia.huck@de.ibm.com)
1da177e4 LT	9	*/
	10	#include <linux/module.h>
	11	#include <linux/errno.h>
	12	#include <linux/slab.h>
	13	#include <linux/list.h>
	14	#include <linux/device.h>
	15	#include <linux/init.h>
	16	#include <linux/ctype.h>
	17	#include <linux/dcache.h>
	18
	19	#include <asm/semaphore.h>
	20	#include <asm/ccwdev.h>
	21	#include <asm/ccwgroup.h>
	22
	23	/* In Linux 2.4, we had a channel device layer called "chandev"
	24	* that did all sorts of obscure stuff for networking devices.
	25	* This is another driver that serves as a replacement for just
	26	* one of its functions, namely the translation of single subchannels
	27	* to devices that use multiple subchannels.
	28	*/
	29
	30	/* a device matches a driver if all its slave devices match the same
	31	* entry of the driver */
	32	static int
	33	ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
	34	{
	35	struct ccwgroup_device *gdev;
	36	struct ccwgroup_driver *gdrv;
	37
	38	gdev = container_of(dev, struct ccwgroup_device, dev);
	39	gdrv = container_of(drv, struct ccwgroup_driver, driver);
	40
	41	if (gdev->creator_id == gdrv->driver_id)
	42	return 1;
	43
	44	return 0;
	45	}
	46	static int
7eff2e7a	47	ccwgroup_uevent (struct device dev, struct kobj_uevent_env env)
1da177e4 LT	48	{
	49	/* TODO */
	50	return 0;
	51	}
	52
f9ccf456	53	static struct bus_type ccwgroup_bus_type;
1da177e4	54
4d284cac	55	static void
1da177e4 LT	56	__ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
	57	{
	58	int i;
	59	char str[8];
	60
	61	for (i = 0; i < gdev->count; i++) {
	62	sprintf(str, "cdev%d", i);
	63	sysfs_remove_link(&gdev->dev.kobj, str);
	64	sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
	65	}
	66
	67	}
	68
	69	/*
	70	* Provide an 'ungroup' attribute so the user can remove group devices no
	71	* longer needed or accidentially created. Saves memory :)
	72	*/
d9a9cdfb AS	73	static void ccwgroup_ungroup_callback(struct device *dev)
	74	{
	75	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	76
d76123eb	77	mutex_lock(&gdev->reg_mutex);
d9a9cdfb AS	78	__ccwgroup_remove_symlinks(gdev);
d9a9cdfb AS	79	device_unregister(dev);
d76123eb	80	mutex_unlock(&gdev->reg_mutex);
d9a9cdfb AS	81	}
d9a9cdfb AS	82
1da177e4	83	static ssize_t
3fd3c0a5	84	ccwgroup_ungroup_store(struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	85	{
1da177e4 LT	86	struct ccwgroup_device *gdev;
d9a9cdfb	87	int rc;
1da177e4 LT	88
	89	gdev = to_ccwgroupdev(dev);
	90
	91	if (gdev->state != CCWGROUP_OFFLINE)
	92	return -EINVAL;
	93
d9a9cdfb AS	94	/* Note that we cannot unregister the device from one of its
	95	* attribute methods, so we have to use this roundabout approach.
	96	*/
	97	rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
	98	if (rc)
	99	count = rc;
1da177e4 LT	100	return count;
	101	}
	102
	103	static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
	104
	105	static void
	106	ccwgroup_release (struct device *dev)
	107	{
	108	struct ccwgroup_device *gdev;
	109	int i;
	110
	111	gdev = to_ccwgroupdev(dev);
	112
	113	for (i = 0; i < gdev->count; i++) {
	114	gdev->cdev[i]->dev.driver_data = NULL;
	115	put_device(&gdev->cdev[i]->dev);
	116	}
	117	kfree(gdev);
	118	}
	119
4d284cac	120	static int
1da177e4 LT	121	__ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
	122	{
	123	char str[8];
	124	int i, rc;
	125
	126	for (i = 0; i < gdev->count; i++) {
	127	rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
	128	"group_device");
	129	if (rc) {
	130	for (--i; i >= 0; i--)
	131	sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
	132	"group_device");
	133	return rc;
	134	}
	135	}
	136	for (i = 0; i < gdev->count; i++) {
	137	sprintf(str, "cdev%d", i);
	138	rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
	139	str);
	140	if (rc) {
	141	for (--i; i >= 0; i--) {
	142	sprintf(str, "cdev%d", i);
	143	sysfs_remove_link(&gdev->dev.kobj, str);
	144	}
	145	for (i = 0; i < gdev->count; i++)
	146	sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
	147	"group_device");
	148	return rc;
	149	}
	150	}
	151	return 0;
	152	}
	153
	154	/*
	155	* try to add a new ccwgroup device for one driver
	156	* argc and argv[] are a list of bus_id's of devices
	157	* belonging to the driver.
	158	*/
	159	int
	160	ccwgroup_create(struct device *root,
	161	unsigned int creator_id,
	162	struct ccw_driver *cdrv,
	163	int argc, char *argv[])
	164	{
	165	struct ccwgroup_device *gdev;
	166	int i;
	167	int rc;
1da177e4 LT	168
	169	if (argc > 256) /* disallow dumb users */
	170	return -EINVAL;
	171
88abaab4	172	gdev = kzalloc(sizeof(gdev) + argcsizeof(gdev->cdev[0]), GFP_KERNEL);
1da177e4 LT	173	if (!gdev)
	174	return -ENOMEM;
	175
1da177e4	176	atomic_set(&gdev->onoff, 0);
d76123eb CH	177	mutex_init(&gdev->reg_mutex);
d76123eb CH	178	mutex_lock(&gdev->reg_mutex);
1da177e4 LT	179	for (i = 0; i < argc; i++) {
	180	gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
	181
	182	/* all devices have to be of the same type in
	183	* order to be grouped */
	184	if (!gdev->cdev[i]
	185	\|\| gdev->cdev[i]->id.driver_info !=
	186	gdev->cdev[0]->id.driver_info) {
	187	rc = -EINVAL;
d76123eb	188	goto error;
1da177e4 LT	189	}
	190	/* Don't allow a device to belong to more than one group. */
	191	if (gdev->cdev[i]->dev.driver_data) {
	192	rc = -EINVAL;
d76123eb	193	goto error;
1da177e4	194	}
1da177e4	195	gdev->cdev[i]->dev.driver_data = gdev;
17088229	196	}
1da177e4 LT	197
	198	gdev->creator_id = creator_id;
	199	gdev->count = argc;
292888c8 HC	200	gdev->dev.bus = &ccwgroup_bus_type;
	201	gdev->dev.parent = root;
	202	gdev->dev.release = ccwgroup_release;
1da177e4 LT	203
	204	snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
	205	gdev->cdev[0]->dev.bus_id);
	206
	207	rc = device_register(&gdev->dev);
1da177e4	208	if (rc)
d76123eb	209	goto error;
1da177e4 LT	210	get_device(&gdev->dev);
	211	rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
	212
	213	if (rc) {
	214	device_unregister(&gdev->dev);
	215	goto error;
	216	}
	217
	218	rc = __ccwgroup_create_symlinks(gdev);
	219	if (!rc) {
d76123eb	220	mutex_unlock(&gdev->reg_mutex);
1da177e4 LT	221	put_device(&gdev->dev);
	222	return 0;
	223	}
	224	device_remove_file(&gdev->dev, &dev_attr_ungroup);
	225	device_unregister(&gdev->dev);
	226	error:
1da177e4 LT	227	for (i = 0; i < argc; i++)
1da177e4 LT	228	if (gdev->cdev[i]) {
17088229	229	if (gdev->cdev[i]->dev.driver_data == gdev)
1da177e4	230	gdev->cdev[i]->dev.driver_data = NULL;
17088229	231	put_device(&gdev->cdev[i]->dev);
1da177e4	232	}
d76123eb CH	233	mutex_unlock(&gdev->reg_mutex);
d76123eb CH	234	put_device(&gdev->dev);
1da177e4 LT	235	return rc;
	236	}
	237
	238	static int __init
	239	init_ccwgroup (void)
	240	{
	241	return bus_register (&ccwgroup_bus_type);
	242	}
	243
	244	static void __exit
	245	cleanup_ccwgroup (void)
	246	{
	247	bus_unregister (&ccwgroup_bus_type);
	248	}
	249
	250	module_init(init_ccwgroup);
	251	module_exit(cleanup_ccwgroup);
	252
	253	/************************ driver stuff ****************************/
	254
	255	static int
	256	ccwgroup_set_online(struct ccwgroup_device *gdev)
	257	{
	258	struct ccwgroup_driver *gdrv;
	259	int ret;
	260
973bd993	261	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
1da177e4 LT	262	return -EAGAIN;
	263	if (gdev->state == CCWGROUP_ONLINE) {
	264	ret = 0;
	265	goto out;
	266	}
	267	if (!gdev->dev.driver) {
	268	ret = -EINVAL;
	269	goto out;
	270	}
	271	gdrv = to_ccwgroupdrv (gdev->dev.driver);
a0016408	272	if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
1da177e4 LT	273	goto out;
	274
	275	gdev->state = CCWGROUP_ONLINE;
	276	out:
	277	atomic_set(&gdev->onoff, 0);
	278	return ret;
	279	}
	280
	281	static int
	282	ccwgroup_set_offline(struct ccwgroup_device *gdev)
	283	{
	284	struct ccwgroup_driver *gdrv;
	285	int ret;
	286
973bd993	287	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
1da177e4 LT	288	return -EAGAIN;
	289	if (gdev->state == CCWGROUP_OFFLINE) {
	290	ret = 0;
	291	goto out;
	292	}
	293	if (!gdev->dev.driver) {
	294	ret = -EINVAL;
	295	goto out;
	296	}
	297	gdrv = to_ccwgroupdrv (gdev->dev.driver);
a0016408	298	if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
1da177e4 LT	299	goto out;
	300
	301	gdev->state = CCWGROUP_OFFLINE;
	302	out:
	303	atomic_set(&gdev->onoff, 0);
	304	return ret;
	305	}
	306
	307	static ssize_t
3fd3c0a5	308	ccwgroup_online_store (struct device dev, struct device_attribute attr, const char *buf, size_t count)
1da177e4 LT	309	{
	310	struct ccwgroup_device *gdev;
	311	struct ccwgroup_driver *gdrv;
	312	unsigned int value;
	313	int ret;
	314
	315	gdev = to_ccwgroupdev(dev);
	316	if (!dev->driver)
	317	return count;
	318
	319	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	320	if (!try_module_get(gdrv->owner))
	321	return -EINVAL;
	322
d2c993d8	323	value = simple_strtoul(buf, NULL, 0);
1da177e4 LT	324	ret = count;
	325	if (value == 1)
	326	ccwgroup_set_online(gdev);
	327	else if (value == 0)
	328	ccwgroup_set_offline(gdev);
	329	else
	330	ret = -EINVAL;
	331	module_put(gdrv->owner);
	332	return ret;
	333	}
	334
	335	static ssize_t
3fd3c0a5	336	ccwgroup_online_show (struct device dev, struct device_attribute attr, char *buf)
1da177e4 LT	337	{
	338	int online;
	339
	340	online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
	341
	342	return sprintf(buf, online ? "1\n" : "0\n");
	343	}
	344
	345	static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
	346
	347	static int
	348	ccwgroup_probe (struct device *dev)
	349	{
	350	struct ccwgroup_device *gdev;
	351	struct ccwgroup_driver *gdrv;
	352
	353	int ret;
	354
	355	gdev = to_ccwgroupdev(dev);
	356	gdrv = to_ccwgroupdrv(dev->driver);
	357
	358	if ((ret = device_create_file(dev, &dev_attr_online)))
	359	return ret;
	360
1da177e4 LT	361	ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
	362	if (ret)
	363	device_remove_file(dev, &dev_attr_online);
	364
	365	return ret;
	366	}
	367
	368	static int
	369	ccwgroup_remove (struct device *dev)
	370	{
	371	struct ccwgroup_device *gdev;
	372	struct ccwgroup_driver *gdrv;
	373
	374	gdev = to_ccwgroupdev(dev);
	375	gdrv = to_ccwgroupdrv(dev->driver);
	376
1da177e4 LT	377	device_remove_file(dev, &dev_attr_online);
	378
	379	if (gdrv && gdrv->remove)
	380	gdrv->remove(gdev);
	381	return 0;
	382	}
	383
f9ccf456 RK	384	static struct bus_type ccwgroup_bus_type = {
	385	.name = "ccwgroup",
	386	.match = ccwgroup_bus_match,
	387	.uevent = ccwgroup_uevent,
	388	.probe = ccwgroup_probe,
	389	.remove = ccwgroup_remove,
	390	};
	391
1da177e4 LT	392	int
	393	ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
	394	{
	395	/* register our new driver with the core */
292888c8 HC	396	cdriver->driver.bus = &ccwgroup_bus_type;
292888c8 HC	397	cdriver->driver.name = cdriver->name;
1da177e4 LT	398
	399	return driver_register(&cdriver->driver);
	400	}
	401
b0744bd2	402	static int
887ab599	403	__ccwgroup_match_all(struct device dev, void data)
1da177e4	404	{
887ab599	405	return 1;
1da177e4 LT	406	}
	407
	408	void
	409	ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
	410	{
887ab599 CH	411	struct device *dev;
887ab599 CH	412
1da177e4 LT	413	/* We don't want ccwgroup devices to live longer than their driver. */
1da177e4 LT	414	get_driver(&cdriver->driver);
887ab599 CH	415	while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
887ab599 CH	416	__ccwgroup_match_all))) {
d76123eb CH	417	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	418
	419	mutex_lock(&gdev->reg_mutex);
	420	__ccwgroup_remove_symlinks(gdev);
887ab599	421	device_unregister(dev);
d76123eb	422	mutex_unlock(&gdev->reg_mutex);
887ab599 CH	423	put_device(dev);
887ab599 CH	424	}
1da177e4 LT	425	put_driver(&cdriver->driver);
	426	driver_unregister(&cdriver->driver);
	427	}
	428
	429	int
	430	ccwgroup_probe_ccwdev(struct ccw_device *cdev)
	431	{
	432	return 0;
	433	}
	434
4d284cac	435	static struct ccwgroup_device *
1da177e4 LT	436	__ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
	437	{
	438	struct ccwgroup_device *gdev;
	439
	440	if (cdev->dev.driver_data) {
	441	gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
	442	if (get_device(&gdev->dev)) {
d76123eb	443	mutex_lock(&gdev->reg_mutex);
d305ef5d	444	if (device_is_registered(&gdev->dev))
1da177e4	445	return gdev;
d76123eb	446	mutex_unlock(&gdev->reg_mutex);
1da177e4 LT	447	put_device(&gdev->dev);
	448	}
	449	return NULL;
	450	}
	451	return NULL;
	452	}
	453
	454	void
	455	ccwgroup_remove_ccwdev(struct ccw_device *cdev)
	456	{
	457	struct ccwgroup_device *gdev;
	458
	459	/* Ignore offlining errors, device is gone anyway. */
	460	ccw_device_set_offline(cdev);
	461	/* If one of its devices is gone, the whole group is done for. */
	462	gdev = __ccwgroup_get_gdev_by_cdev(cdev);
	463	if (gdev) {
	464	__ccwgroup_remove_symlinks(gdev);
	465	device_unregister(&gdev->dev);
d76123eb	466	mutex_unlock(&gdev->reg_mutex);
1da177e4 LT	467	put_device(&gdev->dev);
	468	}
	469	}
	470
	471	MODULE_LICENSE("GPL");
	472	EXPORT_SYMBOL(ccwgroup_driver_register);
	473	EXPORT_SYMBOL(ccwgroup_driver_unregister);
	474	EXPORT_SYMBOL(ccwgroup_create);
	475	EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
	476	EXPORT_SYMBOL(ccwgroup_remove_ccwdev);