2 * bus driver for ccwgroup
4 * Copyright IBM Corp. 2002, 2012
6 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
7 * Cornelia Huck (cornelia.huck@de.ibm.com)
9 #include <linux/module.h>
10 #include <linux/errno.h>
11 #include <linux/slab.h>
12 #include <linux/list.h>
13 #include <linux/device.h>
14 #include <linux/init.h>
15 #include <linux/ctype.h>
16 #include <linux/dcache.h>
19 #include <asm/ccwdev.h>
20 #include <asm/ccwgroup.h>
24 #define CCW_BUS_ID_SIZE 10
26 /* In Linux 2.4, we had a channel device layer called "chandev"
27 * that did all sorts of obscure stuff for networking devices.
28 * This is another driver that serves as a replacement for just
29 * one of its functions, namely the translation of single subchannels
30 * to devices that use multiple subchannels.
33 static struct bus_type ccwgroup_bus_type;
35 static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
40 for (i = 0; i < gdev->count; i++) {
41 sprintf(str, "cdev%d", i);
42 sysfs_remove_link(&gdev->dev.kobj, str);
43 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
48 * Remove references from ccw devices to ccw group device and from
49 * ccw group device to ccw devices.
51 static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
53 struct ccw_device *cdev;
56 for (i = 0; i < gdev->count; i++) {
60 spin_lock_irq(cdev->ccwlock);
61 dev_set_drvdata(&cdev->dev, NULL);
62 spin_unlock_irq(cdev->ccwlock);
64 put_device(&cdev->dev);
69 * ccwgroup_set_online() - enable a ccwgroup device
70 * @gdev: target ccwgroup device
72 * This function attempts to put the ccwgroup device into the online state.
74 * %0 on success and a negative error value on failure.
76 int ccwgroup_set_online(struct ccwgroup_device *gdev)
78 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
81 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
83 if (gdev->state == CCWGROUP_ONLINE)
86 ret = gdrv->set_online(gdev);
90 gdev->state = CCWGROUP_ONLINE;
92 atomic_set(&gdev->onoff, 0);
95 EXPORT_SYMBOL(ccwgroup_set_online);
98 * ccwgroup_set_offline() - disable a ccwgroup device
99 * @gdev: target ccwgroup device
101 * This function attempts to put the ccwgroup device into the offline state.
103 * %0 on success and a negative error value on failure.
105 int ccwgroup_set_offline(struct ccwgroup_device *gdev)
107 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
110 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
112 if (gdev->state == CCWGROUP_OFFLINE)
114 if (gdrv->set_offline)
115 ret = gdrv->set_offline(gdev);
119 gdev->state = CCWGROUP_OFFLINE;
121 atomic_set(&gdev->onoff, 0);
124 EXPORT_SYMBOL(ccwgroup_set_offline);
126 static ssize_t ccwgroup_online_store(struct device *dev,
127 struct device_attribute *attr,
128 const char *buf, size_t count)
130 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
140 ret = kstrtoul(buf, 0, &value);
145 ret = ccwgroup_set_online(gdev);
147 ret = ccwgroup_set_offline(gdev);
152 return (ret == 0) ? count : ret;
155 static ssize_t ccwgroup_online_show(struct device *dev,
156 struct device_attribute *attr,
159 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
162 online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
164 return scnprintf(buf, PAGE_SIZE, "%d\n", online);
168 * Provide an 'ungroup' attribute so the user can remove group devices no
169 * longer needed or accidentially created. Saves memory :)
171 static void ccwgroup_ungroup(struct ccwgroup_device *gdev)
173 mutex_lock(&gdev->reg_mutex);
174 if (device_is_registered(&gdev->dev)) {
175 __ccwgroup_remove_symlinks(gdev);
176 device_unregister(&gdev->dev);
177 __ccwgroup_remove_cdev_refs(gdev);
179 mutex_unlock(&gdev->reg_mutex);
182 static ssize_t ccwgroup_ungroup_store(struct device *dev,
183 struct device_attribute *attr,
184 const char *buf, size_t count)
186 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
189 /* Prevent concurrent online/offline processing and ungrouping. */
190 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
192 if (gdev->state != CCWGROUP_OFFLINE) {
197 if (device_remove_file_self(dev, attr))
198 ccwgroup_ungroup(gdev);
202 /* Release onoff "lock" when ungrouping failed. */
203 atomic_set(&gdev->onoff, 0);
208 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
209 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
211 static struct attribute *ccwgroup_attrs[] = {
212 &dev_attr_online.attr,
213 &dev_attr_ungroup.attr,
216 static struct attribute_group ccwgroup_attr_group = {
217 .attrs = ccwgroup_attrs,
219 static const struct attribute_group *ccwgroup_attr_groups[] = {
220 &ccwgroup_attr_group,
224 static void ccwgroup_ungroup_workfn(struct work_struct *work)
226 struct ccwgroup_device *gdev =
227 container_of(work, struct ccwgroup_device, ungroup_work);
229 ccwgroup_ungroup(gdev);
232 static void ccwgroup_release(struct device *dev)
234 kfree(to_ccwgroupdev(dev));
237 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
242 for (i = 0; i < gdev->count; i++) {
243 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
244 &gdev->dev.kobj, "group_device");
246 for (--i; i >= 0; i--)
247 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
252 for (i = 0; i < gdev->count; i++) {
253 sprintf(str, "cdev%d", i);
254 rc = sysfs_create_link(&gdev->dev.kobj,
255 &gdev->cdev[i]->dev.kobj, str);
257 for (--i; i >= 0; i--) {
258 sprintf(str, "cdev%d", i);
259 sysfs_remove_link(&gdev->dev.kobj, str);
261 for (i = 0; i < gdev->count; i++)
262 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
270 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
272 unsigned int cssid, ssid, devno;
276 start = (char *)*buf;
277 end = strchr(start, ',');
279 /* Last entry. Strip trailing newline, if applicable. */
280 end = strchr(start, '\n');
283 len = strlen(start) + 1;
285 len = end - start + 1;
288 if (len <= CCW_BUS_ID_SIZE) {
289 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
303 * ccwgroup_create_dev() - create and register a ccw group device
304 * @parent: parent device for the new device
305 * @gdrv: driver for the new group device
306 * @num_devices: number of slave devices
307 * @buf: buffer containing comma separated bus ids of slave devices
309 * Create and register a new ccw group device as a child of @parent. Slave
310 * devices are obtained from the list of bus ids given in @buf.
312 * %0 on success and an error code on failure.
316 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
317 int num_devices, const char *buf)
319 struct ccwgroup_device *gdev;
320 struct ccw_dev_id dev_id;
323 gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
328 atomic_set(&gdev->onoff, 0);
329 mutex_init(&gdev->reg_mutex);
330 mutex_lock(&gdev->reg_mutex);
331 INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
332 gdev->count = num_devices;
333 gdev->dev.bus = &ccwgroup_bus_type;
334 gdev->dev.parent = parent;
335 gdev->dev.release = ccwgroup_release;
336 device_initialize(&gdev->dev);
338 for (i = 0; i < num_devices && buf; i++) {
339 rc = __get_next_id(&buf, &dev_id);
342 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
344 * All devices have to be of the same type in
345 * order to be grouped.
347 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
348 gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
349 gdev->cdev[i]->id.driver_info !=
350 gdev->cdev[0]->id.driver_info) {
354 /* Don't allow a device to belong to more than one group. */
355 spin_lock_irq(gdev->cdev[i]->ccwlock);
356 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
357 spin_unlock_irq(gdev->cdev[i]->ccwlock);
361 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
362 spin_unlock_irq(gdev->cdev[i]->ccwlock);
364 /* Check for sufficient number of bus ids. */
365 if (i < num_devices) {
369 /* Check for trailing stuff. */
370 if (i == num_devices && strlen(buf) > 0) {
375 dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
376 gdev->dev.groups = ccwgroup_attr_groups;
379 gdev->dev.driver = &gdrv->driver;
380 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
384 rc = device_add(&gdev->dev);
387 rc = __ccwgroup_create_symlinks(gdev);
389 device_del(&gdev->dev);
392 mutex_unlock(&gdev->reg_mutex);
395 for (i = 0; i < num_devices; i++)
397 spin_lock_irq(gdev->cdev[i]->ccwlock);
398 if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
399 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
400 spin_unlock_irq(gdev->cdev[i]->ccwlock);
401 put_device(&gdev->cdev[i]->dev);
402 gdev->cdev[i] = NULL;
404 mutex_unlock(&gdev->reg_mutex);
405 put_device(&gdev->dev);
408 EXPORT_SYMBOL(ccwgroup_create_dev);
410 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
413 struct ccwgroup_device *gdev = to_ccwgroupdev(data);
415 if (action == BUS_NOTIFY_UNBIND_DRIVER)
416 schedule_work(&gdev->ungroup_work);
421 static struct notifier_block ccwgroup_nb = {
422 .notifier_call = ccwgroup_notifier
425 static int __init init_ccwgroup(void)
429 ret = bus_register(&ccwgroup_bus_type);
433 ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
435 bus_unregister(&ccwgroup_bus_type);
440 static void __exit cleanup_ccwgroup(void)
442 bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
443 bus_unregister(&ccwgroup_bus_type);
446 module_init(init_ccwgroup);
447 module_exit(cleanup_ccwgroup);
449 /************************** driver stuff ******************************/
451 static int ccwgroup_remove(struct device *dev)
453 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
454 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
464 static void ccwgroup_shutdown(struct device *dev)
466 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
467 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
472 gdrv->shutdown(gdev);
475 static int ccwgroup_pm_prepare(struct device *dev)
477 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
478 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
480 /* Fail while device is being set online/offline. */
481 if (atomic_read(&gdev->onoff))
484 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
487 return gdrv->prepare ? gdrv->prepare(gdev) : 0;
490 static void ccwgroup_pm_complete(struct device *dev)
492 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
493 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
495 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
499 gdrv->complete(gdev);
502 static int ccwgroup_pm_freeze(struct device *dev)
504 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
505 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
507 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
510 return gdrv->freeze ? gdrv->freeze(gdev) : 0;
513 static int ccwgroup_pm_thaw(struct device *dev)
515 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
516 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
518 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
521 return gdrv->thaw ? gdrv->thaw(gdev) : 0;
524 static int ccwgroup_pm_restore(struct device *dev)
526 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
527 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
529 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
532 return gdrv->restore ? gdrv->restore(gdev) : 0;
535 static const struct dev_pm_ops ccwgroup_pm_ops = {
536 .prepare = ccwgroup_pm_prepare,
537 .complete = ccwgroup_pm_complete,
538 .freeze = ccwgroup_pm_freeze,
539 .thaw = ccwgroup_pm_thaw,
540 .restore = ccwgroup_pm_restore,
543 static struct bus_type ccwgroup_bus_type = {
545 .remove = ccwgroup_remove,
546 .shutdown = ccwgroup_shutdown,
547 .pm = &ccwgroup_pm_ops,
551 * ccwgroup_driver_register() - register a ccw group driver
552 * @cdriver: driver to be registered
554 * This function is mainly a wrapper around driver_register().
556 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
558 /* register our new driver with the core */
559 cdriver->driver.bus = &ccwgroup_bus_type;
561 return driver_register(&cdriver->driver);
563 EXPORT_SYMBOL(ccwgroup_driver_register);
565 static int __ccwgroup_match_all(struct device *dev, void *data)
571 * ccwgroup_driver_unregister() - deregister a ccw group driver
572 * @cdriver: driver to be deregistered
574 * This function is mainly a wrapper around driver_unregister().
576 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
580 /* We don't want ccwgroup devices to live longer than their driver. */
581 while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
582 __ccwgroup_match_all))) {
583 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
585 mutex_lock(&gdev->reg_mutex);
586 __ccwgroup_remove_symlinks(gdev);
587 device_unregister(dev);
588 __ccwgroup_remove_cdev_refs(gdev);
589 mutex_unlock(&gdev->reg_mutex);
592 driver_unregister(&cdriver->driver);
594 EXPORT_SYMBOL(ccwgroup_driver_unregister);
597 * ccwgroup_probe_ccwdev() - probe function for slave devices
598 * @cdev: ccw device to be probed
600 * This is a dummy probe function for ccw devices that are slave devices in
601 * a ccw group device.
605 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
609 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
612 * ccwgroup_remove_ccwdev() - remove function for slave devices
613 * @cdev: ccw device to be removed
615 * This is a remove function for ccw devices that are slave devices in a ccw
616 * group device. It sets the ccw device offline and also deregisters the
617 * embedding ccw group device.
619 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
621 struct ccwgroup_device *gdev;
623 /* Ignore offlining errors, device is gone anyway. */
624 ccw_device_set_offline(cdev);
625 /* If one of its devices is gone, the whole group is done for. */
626 spin_lock_irq(cdev->ccwlock);
627 gdev = dev_get_drvdata(&cdev->dev);
629 spin_unlock_irq(cdev->ccwlock);
632 /* Get ccwgroup device reference for local processing. */
633 get_device(&gdev->dev);
634 spin_unlock_irq(cdev->ccwlock);
635 /* Unregister group device. */
636 mutex_lock(&gdev->reg_mutex);
637 if (device_is_registered(&gdev->dev)) {
638 __ccwgroup_remove_symlinks(gdev);
639 device_unregister(&gdev->dev);
640 __ccwgroup_remove_cdev_refs(gdev);
642 mutex_unlock(&gdev->reg_mutex);
643 /* Release ccwgroup device reference for local processing. */
644 put_device(&gdev->dev);
646 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
647 MODULE_LICENSE("GPL");