1 // SPDX-License-Identifier: GPL-2.0
3 * bus driver for ccwgroup
5 * Copyright IBM Corp. 2002, 2012
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Cornelia Huck (cornelia.huck@de.ibm.com)
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>
20 #include <asm/ccwdev.h>
21 #include <asm/ccwgroup.h>
25 #define CCW_BUS_ID_SIZE 10
27 /* In Linux 2.4, we had a channel device layer called "chandev"
28 * that did all sorts of obscure stuff for networking devices.
29 * This is another driver that serves as a replacement for just
30 * one of its functions, namely the translation of single subchannels
31 * to devices that use multiple subchannels.
34 static struct bus_type ccwgroup_bus_type;
36 static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
41 for (i = 0; i < gdev->count; i++) {
42 sprintf(str, "cdev%d", i);
43 sysfs_remove_link(&gdev->dev.kobj, str);
44 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
49 * Remove references from ccw devices to ccw group device and from
50 * ccw group device to ccw devices.
52 static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
54 struct ccw_device *cdev;
57 for (i = 0; i < gdev->count; i++) {
61 spin_lock_irq(cdev->ccwlock);
62 dev_set_drvdata(&cdev->dev, NULL);
63 spin_unlock_irq(cdev->ccwlock);
65 put_device(&cdev->dev);
70 * ccwgroup_set_online() - enable a ccwgroup device
71 * @gdev: target ccwgroup device
73 * This function attempts to put the ccwgroup device into the online state.
75 * %0 on success and a negative error value on failure.
77 int ccwgroup_set_online(struct ccwgroup_device *gdev)
79 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
82 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
84 if (gdev->state == CCWGROUP_ONLINE)
87 ret = gdrv->set_online(gdev);
91 gdev->state = CCWGROUP_ONLINE;
93 atomic_set(&gdev->onoff, 0);
96 EXPORT_SYMBOL(ccwgroup_set_online);
99 * ccwgroup_set_offline() - disable a ccwgroup device
100 * @gdev: target ccwgroup device
102 * This function attempts to put the ccwgroup device into the offline state.
104 * %0 on success and a negative error value on failure.
106 int ccwgroup_set_offline(struct ccwgroup_device *gdev)
108 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
111 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
113 if (gdev->state == CCWGROUP_OFFLINE)
115 if (gdrv->set_offline)
116 ret = gdrv->set_offline(gdev);
120 gdev->state = CCWGROUP_OFFLINE;
122 atomic_set(&gdev->onoff, 0);
125 EXPORT_SYMBOL(ccwgroup_set_offline);
127 static ssize_t ccwgroup_online_store(struct device *dev,
128 struct device_attribute *attr,
129 const char *buf, size_t count)
131 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
141 ret = kstrtoul(buf, 0, &value);
146 ret = ccwgroup_set_online(gdev);
148 ret = ccwgroup_set_offline(gdev);
153 return (ret == 0) ? count : ret;
156 static ssize_t ccwgroup_online_show(struct device *dev,
157 struct device_attribute *attr,
160 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
163 online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
165 return scnprintf(buf, PAGE_SIZE, "%d\n", online);
169 * Provide an 'ungroup' attribute so the user can remove group devices no
170 * longer needed or accidentially created. Saves memory :)
172 static void ccwgroup_ungroup(struct ccwgroup_device *gdev)
174 mutex_lock(&gdev->reg_mutex);
175 if (device_is_registered(&gdev->dev)) {
176 __ccwgroup_remove_symlinks(gdev);
177 device_unregister(&gdev->dev);
178 __ccwgroup_remove_cdev_refs(gdev);
180 mutex_unlock(&gdev->reg_mutex);
183 static ssize_t ccwgroup_ungroup_store(struct device *dev,
184 struct device_attribute *attr,
185 const char *buf, size_t count)
187 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
190 /* Prevent concurrent online/offline processing and ungrouping. */
191 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
193 if (gdev->state != CCWGROUP_OFFLINE) {
198 if (device_remove_file_self(dev, attr))
199 ccwgroup_ungroup(gdev);
204 /* Release onoff "lock" when ungrouping failed. */
205 atomic_set(&gdev->onoff, 0);
210 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
211 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
213 static struct attribute *ccwgroup_attrs[] = {
214 &dev_attr_online.attr,
215 &dev_attr_ungroup.attr,
218 static struct attribute_group ccwgroup_attr_group = {
219 .attrs = ccwgroup_attrs,
221 static const struct attribute_group *ccwgroup_attr_groups[] = {
222 &ccwgroup_attr_group,
226 static void ccwgroup_ungroup_workfn(struct work_struct *work)
228 struct ccwgroup_device *gdev =
229 container_of(work, struct ccwgroup_device, ungroup_work);
231 ccwgroup_ungroup(gdev);
232 put_device(&gdev->dev);
235 static void ccwgroup_release(struct device *dev)
237 kfree(to_ccwgroupdev(dev));
240 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
245 for (i = 0; i < gdev->count; i++) {
246 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
247 &gdev->dev.kobj, "group_device");
249 for (--i; i >= 0; i--)
250 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
255 for (i = 0; i < gdev->count; i++) {
256 sprintf(str, "cdev%d", i);
257 rc = sysfs_create_link(&gdev->dev.kobj,
258 &gdev->cdev[i]->dev.kobj, str);
260 for (--i; i >= 0; i--) {
261 sprintf(str, "cdev%d", i);
262 sysfs_remove_link(&gdev->dev.kobj, str);
264 for (i = 0; i < gdev->count; i++)
265 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
273 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
275 unsigned int cssid, ssid, devno;
279 start = (char *)*buf;
280 end = strchr(start, ',');
282 /* Last entry. Strip trailing newline, if applicable. */
283 end = strchr(start, '\n');
286 len = strlen(start) + 1;
288 len = end - start + 1;
291 if (len <= CCW_BUS_ID_SIZE) {
292 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
306 * ccwgroup_create_dev() - create and register a ccw group device
307 * @parent: parent device for the new device
308 * @gdrv: driver for the new group device
309 * @num_devices: number of slave devices
310 * @buf: buffer containing comma separated bus ids of slave devices
312 * Create and register a new ccw group device as a child of @parent. Slave
313 * devices are obtained from the list of bus ids given in @buf.
315 * %0 on success and an error code on failure.
319 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
320 int num_devices, const char *buf)
322 struct ccwgroup_device *gdev;
323 struct ccw_dev_id dev_id;
329 gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL);
333 atomic_set(&gdev->onoff, 0);
334 mutex_init(&gdev->reg_mutex);
335 mutex_lock(&gdev->reg_mutex);
336 INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
337 gdev->count = num_devices;
338 gdev->dev.bus = &ccwgroup_bus_type;
339 gdev->dev.parent = parent;
340 gdev->dev.release = ccwgroup_release;
341 device_initialize(&gdev->dev);
343 for (i = 0; i < num_devices && buf; i++) {
344 rc = __get_next_id(&buf, &dev_id);
347 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
349 * All devices have to be of the same type in
350 * order to be grouped.
352 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
353 gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
354 gdev->cdev[i]->id.driver_info !=
355 gdev->cdev[0]->id.driver_info) {
359 /* Don't allow a device to belong to more than one group. */
360 spin_lock_irq(gdev->cdev[i]->ccwlock);
361 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
362 spin_unlock_irq(gdev->cdev[i]->ccwlock);
366 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
367 spin_unlock_irq(gdev->cdev[i]->ccwlock);
369 /* Check for sufficient number of bus ids. */
370 if (i < num_devices) {
374 /* Check for trailing stuff. */
375 if (i == num_devices && buf && strlen(buf) > 0) {
379 /* Check if the devices are bound to the required ccw driver. */
380 if (gdrv && gdrv->ccw_driver &&
381 gdev->cdev[0]->drv != gdrv->ccw_driver) {
386 dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
387 gdev->dev.groups = ccwgroup_attr_groups;
390 gdev->dev.driver = &gdrv->driver;
391 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
395 rc = device_add(&gdev->dev);
398 rc = __ccwgroup_create_symlinks(gdev);
400 device_del(&gdev->dev);
403 mutex_unlock(&gdev->reg_mutex);
406 for (i = 0; i < num_devices; i++)
408 spin_lock_irq(gdev->cdev[i]->ccwlock);
409 if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
410 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
411 spin_unlock_irq(gdev->cdev[i]->ccwlock);
412 put_device(&gdev->cdev[i]->dev);
413 gdev->cdev[i] = NULL;
415 mutex_unlock(&gdev->reg_mutex);
416 put_device(&gdev->dev);
419 EXPORT_SYMBOL(ccwgroup_create_dev);
421 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
424 struct ccwgroup_device *gdev = to_ccwgroupdev(data);
426 if (action == BUS_NOTIFY_UNBIND_DRIVER) {
427 get_device(&gdev->dev);
428 schedule_work(&gdev->ungroup_work);
434 static struct notifier_block ccwgroup_nb = {
435 .notifier_call = ccwgroup_notifier
438 static int __init init_ccwgroup(void)
442 ret = bus_register(&ccwgroup_bus_type);
446 ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
448 bus_unregister(&ccwgroup_bus_type);
453 static void __exit cleanup_ccwgroup(void)
455 bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
456 bus_unregister(&ccwgroup_bus_type);
459 module_init(init_ccwgroup);
460 module_exit(cleanup_ccwgroup);
462 /************************** driver stuff ******************************/
464 static int ccwgroup_remove(struct device *dev)
466 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
467 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
477 static void ccwgroup_shutdown(struct device *dev)
479 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
480 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
485 gdrv->shutdown(gdev);
488 static struct bus_type ccwgroup_bus_type = {
490 .remove = ccwgroup_remove,
491 .shutdown = ccwgroup_shutdown,
494 bool dev_is_ccwgroup(struct device *dev)
496 return dev->bus == &ccwgroup_bus_type;
498 EXPORT_SYMBOL(dev_is_ccwgroup);
501 * ccwgroup_driver_register() - register a ccw group driver
502 * @cdriver: driver to be registered
504 * This function is mainly a wrapper around driver_register().
506 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
508 /* register our new driver with the core */
509 cdriver->driver.bus = &ccwgroup_bus_type;
511 return driver_register(&cdriver->driver);
513 EXPORT_SYMBOL(ccwgroup_driver_register);
516 * ccwgroup_driver_unregister() - deregister a ccw group driver
517 * @cdriver: driver to be deregistered
519 * This function is mainly a wrapper around driver_unregister().
521 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
525 /* We don't want ccwgroup devices to live longer than their driver. */
526 while ((dev = driver_find_next_device(&cdriver->driver, NULL))) {
527 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
529 ccwgroup_ungroup(gdev);
532 driver_unregister(&cdriver->driver);
534 EXPORT_SYMBOL(ccwgroup_driver_unregister);
537 * get_ccwgroupdev_by_busid() - obtain device from a bus id
538 * @gdrv: driver the device is owned by
539 * @bus_id: bus id of the device to be searched
541 * This function searches all devices owned by @gdrv for a device with a bus
542 * id matching @bus_id.
544 * If a match is found, its reference count of the found device is increased
545 * and it is returned; else %NULL is returned.
547 struct ccwgroup_device *get_ccwgroupdev_by_busid(struct ccwgroup_driver *gdrv,
552 dev = driver_find_device_by_name(&gdrv->driver, bus_id);
554 return dev ? to_ccwgroupdev(dev) : NULL;
556 EXPORT_SYMBOL_GPL(get_ccwgroupdev_by_busid);
559 * ccwgroup_probe_ccwdev() - probe function for slave devices
560 * @cdev: ccw device to be probed
562 * This is a dummy probe function for ccw devices that are slave devices in
563 * a ccw group device.
567 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
571 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
574 * ccwgroup_remove_ccwdev() - remove function for slave devices
575 * @cdev: ccw device to be removed
577 * This is a remove function for ccw devices that are slave devices in a ccw
578 * group device. It sets the ccw device offline and also deregisters the
579 * embedding ccw group device.
581 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
583 struct ccwgroup_device *gdev;
585 /* Ignore offlining errors, device is gone anyway. */
586 ccw_device_set_offline(cdev);
587 /* If one of its devices is gone, the whole group is done for. */
588 spin_lock_irq(cdev->ccwlock);
589 gdev = dev_get_drvdata(&cdev->dev);
591 spin_unlock_irq(cdev->ccwlock);
594 /* Get ccwgroup device reference for local processing. */
595 get_device(&gdev->dev);
596 spin_unlock_irq(cdev->ccwlock);
597 /* Unregister group device. */
598 ccwgroup_ungroup(gdev);
599 /* Release ccwgroup device reference for local processing. */
600 put_device(&gdev->dev);
602 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
603 MODULE_LICENSE("GPL");