1/*
2 * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 *               2002-3 Open Source Development Lab
6 *
7 * This file is released under the GPLv2
8 *
9 * This exports a 'system' bus type.
10 * By default, a 'sys' bus gets added to the root of the system. There will
11 * always be core system devices. Devices can use sysdev_register() to
12 * add themselves as children of the system bus.
13 */
14
15#include <linux/sysdev.h>
16#include <linux/err.h>
17#include <linux/module.h>
18#include <linux/kernel.h>
19#include <linux/init.h>
20#include <linux/slab.h>
21#include <linux/string.h>
22#include <linux/pm.h>
23#include <linux/device.h>
24#include <asm/semaphore.h>
25
26#include "base.h"
27
28extern struct kset devices_subsys;
29
30#define to_sysdev(k) container_of(k, struct sys_device, kobj)
31#define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
32
33
34static ssize_t
35sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
36{
37	struct sys_device * sysdev = to_sysdev(kobj);
38	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
39
40	if (sysdev_attr->show)
41		return sysdev_attr->show(sysdev, buffer);
42	return -EIO;
43}
44
45
46static ssize_t
47sysdev_store(struct kobject * kobj, struct attribute * attr,
48	     const char * buffer, size_t count)
49{
50	struct sys_device * sysdev = to_sysdev(kobj);
51	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);
52
53	if (sysdev_attr->store)
54		return sysdev_attr->store(sysdev, buffer, count);
55	return -EIO;
56}
57
58static struct sysfs_ops sysfs_ops = {
59	.show	= sysdev_show,
60	.store	= sysdev_store,
61};
62
63static struct kobj_type ktype_sysdev = {
64	.sysfs_ops	= &sysfs_ops,
65};
66
67
68int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
69{
70	return sysfs_create_file(&s->kobj, &a->attr);
71}
72
73
74void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
75{
76	sysfs_remove_file(&s->kobj, &a->attr);
77}
78
79EXPORT_SYMBOL_GPL(sysdev_create_file);
80EXPORT_SYMBOL_GPL(sysdev_remove_file);
81
82#define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)
83#define to_sysdev_class_attr(a) container_of(a, \
84	struct sysdev_class_attribute, attr)
85
86static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,
87				 char *buffer)
88{
89	struct sysdev_class * class = to_sysdev_class(kobj);
90	struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);
91
92	if (class_attr->show)
93		return class_attr->show(class, buffer);
94	return -EIO;
95}
96
97static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,
98				  const char *buffer, size_t count)
99{
100	struct sysdev_class * class = to_sysdev_class(kobj);
101	struct sysdev_class_attribute * class_attr = to_sysdev_class_attr(attr);
102
103	if (class_attr->store)
104		return class_attr->store(class, buffer, count);
105	return -EIO;
106}
107
108static struct sysfs_ops sysfs_class_ops = {
109	.show	= sysdev_class_show,
110	.store	= sysdev_class_store,
111};
112
113static struct kobj_type ktype_sysdev_class = {
114	.sysfs_ops	= &sysfs_class_ops,
115};
116
117int sysdev_class_create_file(struct sysdev_class *c,
118			     struct sysdev_class_attribute *a)
119{
120	return sysfs_create_file(&c->kset.kobj, &a->attr);
121}
122EXPORT_SYMBOL_GPL(sysdev_class_create_file);
123
124void sysdev_class_remove_file(struct sysdev_class *c,
125			      struct sysdev_class_attribute *a)
126{
127	sysfs_remove_file(&c->kset.kobj, &a->attr);
128}
129EXPORT_SYMBOL_GPL(sysdev_class_remove_file);
130
131/*
132 * declare system_subsys
133 */
134static decl_subsys(system, &ktype_sysdev_class, NULL);
135
136int sysdev_class_register(struct sysdev_class * cls)
137{
138	pr_debug("Registering sysdev class '%s'\n",
139		 kobject_name(&cls->kset.kobj));
140	INIT_LIST_HEAD(&cls->drivers);
141	cls->kset.kobj.parent = &system_subsys.kobj;
142	kset_set_kset_s(cls, system_subsys);
143	return kset_register(&cls->kset);
144}
145
146void sysdev_class_unregister(struct sysdev_class * cls)
147{
148	pr_debug("Unregistering sysdev class '%s'\n",
149		 kobject_name(&cls->kset.kobj));
150	kset_unregister(&cls->kset);
151}
152
153EXPORT_SYMBOL_GPL(sysdev_class_register);
154EXPORT_SYMBOL_GPL(sysdev_class_unregister);
155
156
157static LIST_HEAD(sysdev_drivers);
158static DECLARE_MUTEX(sysdev_drivers_lock);
159
160/**
161 *	sysdev_driver_register - Register auxillary driver
162 * 	@cls:	Device class driver belongs to.
163 *	@drv:	Driver.
164 *
165 *	If @cls is valid, then @drv is inserted into @cls->drivers to be
166 *	called on each operation on devices of that class. The refcount
167 *	of @cls is incremented.
168 *	Otherwise, @drv is inserted into sysdev_drivers, and called for
169 *	each device.
170 */
171
172int sysdev_driver_register(struct sysdev_class * cls,
173			   struct sysdev_driver * drv)
174{
175	down(&sysdev_drivers_lock);
176	if (cls && kset_get(&cls->kset)) {
177		list_add_tail(&drv->entry, &cls->drivers);
178
179		/* If devices of this class already exist, tell the driver */
180		if (drv->add) {
181			struct sys_device *dev;
182			list_for_each_entry(dev, &cls->kset.list, kobj.entry)
183				drv->add(dev);
184		}
185	} else
186		list_add_tail(&drv->entry, &sysdev_drivers);
187	up(&sysdev_drivers_lock);
188	return 0;
189}
190
191
192/**
193 *	sysdev_driver_unregister - Remove an auxillary driver.
194 *	@cls:	Class driver belongs to.
195 *	@drv:	Driver.
196 */
197void sysdev_driver_unregister(struct sysdev_class * cls,
198			      struct sysdev_driver * drv)
199{
200	down(&sysdev_drivers_lock);
201	list_del_init(&drv->entry);
202	if (cls) {
203		if (drv->remove) {
204			struct sys_device *dev;
205			list_for_each_entry(dev, &cls->kset.list, kobj.entry)
206				drv->remove(dev);
207		}
208		kset_put(&cls->kset);
209	}
210	up(&sysdev_drivers_lock);
211}
212
213EXPORT_SYMBOL_GPL(sysdev_driver_register);
214EXPORT_SYMBOL_GPL(sysdev_driver_unregister);
215
216
217
218/**
219 *	sysdev_register - add a system device to the tree
220 *	@sysdev:	device in question
221 *
222 */
223int sysdev_register(struct sys_device * sysdev)
224{
225	int error;
226	struct sysdev_class * cls = sysdev->cls;
227
228	if (!cls)
229		return -EINVAL;
230
231	/* Make sure the kset is set */
232	sysdev->kobj.kset = &cls->kset;
233
234	/* But make sure we point to the right type for sysfs translation */
235	sysdev->kobj.ktype = &ktype_sysdev;
236	error = kobject_set_name(&sysdev->kobj, "%s%d",
237			 kobject_name(&cls->kset.kobj), sysdev->id);
238	if (error)
239		return error;
240
241	pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));
242
243	/* Register the object */
244	error = kobject_register(&sysdev->kobj);
245
246	if (!error) {
247		struct sysdev_driver * drv;
248
249		down(&sysdev_drivers_lock);
250		/* Generic notification is implicit, because it's that
251		 * code that should have called us.
252		 */
253
254		/* Notify global drivers */
255		list_for_each_entry(drv, &sysdev_drivers, entry) {
256			if (drv->add)
257				drv->add(sysdev);
258		}
259
260		/* Notify class auxillary drivers */
261		list_for_each_entry(drv, &cls->drivers, entry) {
262			if (drv->add)
263				drv->add(sysdev);
264		}
265		up(&sysdev_drivers_lock);
266	}
267	return error;
268}
269
270void sysdev_unregister(struct sys_device * sysdev)
271{
272	struct sysdev_driver * drv;
273
274	down(&sysdev_drivers_lock);
275	list_for_each_entry(drv, &sysdev_drivers, entry) {
276		if (drv->remove)
277			drv->remove(sysdev);
278	}
279
280	list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
281		if (drv->remove)
282			drv->remove(sysdev);
283	}
284	up(&sysdev_drivers_lock);
285
286	kobject_unregister(&sysdev->kobj);
287}
288
289
290
291/**
292 *	sysdev_shutdown - Shut down all system devices.
293 *
294 *	Loop over each class of system devices, and the devices in each
295 *	of those classes. For each device, we call the shutdown method for
296 *	each driver registered for the device - the globals, the auxillaries,
297 *	and the class driver.
298 *
299 *	Note: The list is iterated in reverse order, so that we shut down
300 *	child devices before we shut down thier parents. The list ordering
301 *	is guaranteed by virtue of the fact that child devices are registered
302 *	after their parents.
303 */
304
305void sysdev_shutdown(void)
306{
307	struct sysdev_class * cls;
308
309	pr_debug("Shutting Down System Devices\n");
310
311	down(&sysdev_drivers_lock);
312	list_for_each_entry_reverse(cls, &system_subsys.list,
313				    kset.kobj.entry) {
314		struct sys_device * sysdev;
315
316		pr_debug("Shutting down type '%s':\n",
317			 kobject_name(&cls->kset.kobj));
318
319		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
320			struct sysdev_driver * drv;
321			pr_debug(" %s\n", kobject_name(&sysdev->kobj));
322
323			/* Call global drivers first. */
324			list_for_each_entry(drv, &sysdev_drivers, entry) {
325				if (drv->shutdown)
326					drv->shutdown(sysdev);
327			}
328
329			/* Call auxillary drivers next. */
330			list_for_each_entry(drv, &cls->drivers, entry) {
331				if (drv->shutdown)
332					drv->shutdown(sysdev);
333			}
334
335			/* Now call the generic one */
336			if (cls->shutdown)
337				cls->shutdown(sysdev);
338		}
339	}
340	up(&sysdev_drivers_lock);
341}
342
343static void __sysdev_resume(struct sys_device *dev)
344{
345	struct sysdev_class *cls = dev->cls;
346	struct sysdev_driver *drv;
347
348	/* First, call the class-specific one */
349	if (cls->resume)
350		cls->resume(dev);
351
352	/* Call auxillary drivers next. */
353	list_for_each_entry(drv, &cls->drivers, entry) {
354		if (drv->resume)
355			drv->resume(dev);
356	}
357
358	/* Call global drivers. */
359	list_for_each_entry(drv, &sysdev_drivers, entry) {
360		if (drv->resume)
361			drv->resume(dev);
362	}
363}
364
365/**
366 *	sysdev_suspend - Suspend all system devices.
367 *	@state:		Power state to enter.
368 *
369 *	We perform an almost identical operation as sys_device_shutdown()
370 *	above, though calling ->suspend() instead. Interrupts are disabled
371 *	when this called. Devices are responsible for both saving state and
372 *	quiescing or powering down the device.
373 *
374 *	This is only called by the device PM core, so we let them handle
375 *	all synchronization.
376 */
377
378int sysdev_suspend(pm_message_t state)
379{
380	struct sysdev_class * cls;
381	struct sys_device *sysdev, *err_dev;
382	struct sysdev_driver *drv, *err_drv;
383	int ret;
384
385	pr_debug("Suspending System Devices\n");
386
387	list_for_each_entry_reverse(cls, &system_subsys.list,
388				    kset.kobj.entry) {
389
390		pr_debug("Suspending type '%s':\n",
391			 kobject_name(&cls->kset.kobj));
392
393		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
394			pr_debug(" %s\n", kobject_name(&sysdev->kobj));
395
396			/* Call global drivers first. */
397			list_for_each_entry(drv, &sysdev_drivers, entry) {
398				if (drv->suspend) {
399					ret = drv->suspend(sysdev, state);
400					if (ret)
401						goto gbl_driver;
402				}
403			}
404
405			/* Call auxillary drivers next. */
406			list_for_each_entry(drv, &cls->drivers, entry) {
407				if (drv->suspend) {
408					ret = drv->suspend(sysdev, state);
409					if (ret)
410						goto aux_driver;
411				}
412			}
413
414			/* Now call the generic one */
415			if (cls->suspend) {
416				ret = cls->suspend(sysdev, state);
417				if (ret)
418					goto cls_driver;
419			}
420		}
421	}
422	return 0;
423	/* resume current sysdev */
424cls_driver:
425	drv = NULL;
426	printk(KERN_ERR "Class suspend failed for %s\n",
427		kobject_name(&sysdev->kobj));
428
429aux_driver:
430	if (drv)
431		printk(KERN_ERR "Class driver suspend failed for %s\n",
432				kobject_name(&sysdev->kobj));
433	list_for_each_entry(err_drv, &cls->drivers, entry) {
434		if (err_drv == drv)
435			break;
436		if (err_drv->resume)
437			err_drv->resume(sysdev);
438	}
439	drv = NULL;
440
441gbl_driver:
442	if (drv)
443		printk(KERN_ERR "sysdev driver suspend failed for %s\n",
444				kobject_name(&sysdev->kobj));
445	list_for_each_entry(err_drv, &sysdev_drivers, entry) {
446		if (err_drv == drv)
447			break;
448		if (err_drv->resume)
449			err_drv->resume(sysdev);
450	}
451	/* resume other sysdevs in current class */
452	list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
453		if (err_dev == sysdev)
454			break;
455		pr_debug(" %s\n", kobject_name(&err_dev->kobj));
456		__sysdev_resume(err_dev);
457	}
458
459	/* resume other classes */
460	list_for_each_entry_continue(cls, &system_subsys.list,
461					kset.kobj.entry) {
462		list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
463			pr_debug(" %s\n", kobject_name(&err_dev->kobj));
464			__sysdev_resume(err_dev);
465		}
466	}
467	return ret;
468}
469
470
471/**
472 *	sysdev_resume - Bring system devices back to life.
473 *
474 *	Similar to sys_device_suspend(), but we iterate the list forwards
475 *	to guarantee that parent devices are resumed before their children.
476 *
477 *	Note: Interrupts are disabled when called.
478 */
479
480int sysdev_resume(void)
481{
482	struct sysdev_class * cls;
483
484	pr_debug("Resuming System Devices\n");
485
486	list_for_each_entry(cls, &system_subsys.list, kset.kobj.entry) {
487		struct sys_device * sysdev;
488
489		pr_debug("Resuming type '%s':\n",
490			 kobject_name(&cls->kset.kobj));
491
492		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
493			pr_debug(" %s\n", kobject_name(&sysdev->kobj));
494
495			__sysdev_resume(sysdev);
496		}
497	}
498	return 0;
499}
500
501
502int __init system_bus_init(void)
503{
504	system_subsys.kobj.parent = &devices_subsys.kobj;
505	return subsystem_register(&system_subsys);
506}
507
508EXPORT_SYMBOL_GPL(sysdev_register);
509EXPORT_SYMBOL_GPL(sysdev_unregister);
510