attribute_container.c 11.9 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
/*
 * attribute_container.c - implementation of a simple container for classes
 *
 * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
 *
 * This file is licensed under GPLv2
 *
 * The basic idea here is to enable a device to be attached to an
 * aritrary numer of classes without having to allocate storage for them.
 * Instead, the contained classes select the devices they need to attach
 * to via a matching function.
 */

#include <linux/attribute_container.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/module.h>

/* This is a private structure used to tie the classdev and the
 * container .. it should never be visible outside this file */
struct internal_container {
25
	struct klist_node node;
Linus Torvalds's avatar
Linus Torvalds committed
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
	struct attribute_container *cont;
	struct class_device classdev;
};

/**
 * attribute_container_classdev_to_container - given a classdev, return the container
 *
 * @classdev: the class device created by attribute_container_add_device.
 *
 * Returns the container associated with this classdev.
 */
struct attribute_container *
attribute_container_classdev_to_container(struct class_device *classdev)
{
	struct internal_container *ic =
		container_of(classdev, struct internal_container, classdev);
	return ic->cont;
}
EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container);

static struct list_head attribute_container_list;

static DECLARE_MUTEX(attribute_container_mutex);

/**
 * attribute_container_register - register an attribute container
 *
 * @cont: The container to register.  This must be allocated by the
 *        callee and should also be zeroed by it.
 */
int
attribute_container_register(struct attribute_container *cont)
{
	INIT_LIST_HEAD(&cont->node);
60
	klist_init(&cont->containers);
Linus Torvalds's avatar
Linus Torvalds committed
61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
		
	down(&attribute_container_mutex);
	list_add_tail(&cont->node, &attribute_container_list);
	up(&attribute_container_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(attribute_container_register);

/**
 * attribute_container_unregister - remove a container registration
 *
 * @cont: previously registered container to remove
 */
int
attribute_container_unregister(struct attribute_container *cont)
{
	int retval = -EBUSY;
	down(&attribute_container_mutex);
80 81
	spin_lock(&cont->containers.k_lock);
	if (!list_empty(&cont->containers.k_list))
Linus Torvalds's avatar
Linus Torvalds committed
82 83 84 85
		goto out;
	retval = 0;
	list_del(&cont->node);
 out:
86
	spin_unlock(&cont->containers.k_lock);
Linus Torvalds's avatar
Linus Torvalds committed
87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
	up(&attribute_container_mutex);
	return retval;
		
}
EXPORT_SYMBOL_GPL(attribute_container_unregister);

/* private function used as class release */
static void attribute_container_release(struct class_device *classdev)
{
	struct internal_container *ic 
		= container_of(classdev, struct internal_container, classdev);
	struct device *dev = classdev->dev;

	kfree(ic);
	put_device(dev);
}

/**
 * attribute_container_add_device - see if any container is interested in dev
 *
 * @dev: device to add attributes to
 * @fn:	 function to trigger addition of class device.
 *
 * This function allocates storage for the class device(s) to be
 * attached to dev (one for each matching attribute_container).  If no
 * fn is provided, the code will simply register the class device via
 * class_device_add.  If a function is provided, it is expected to add
 * the class device at the appropriate time.  One of the things that
 * might be necessary is to allocate and initialise the classdev and
 * then add it a later time.  To do this, call this routine for
 * allocation and initialisation and then use
 * attribute_container_device_trigger() to call class_device_add() on
 * it.  Note: after this, the class device contains a reference to dev
 * which is not relinquished until the release of the classdev.
 */
void
attribute_container_add_device(struct device *dev,
			       int (*fn)(struct attribute_container *,
					 struct device *,
					 struct class_device *))
{
	struct attribute_container *cont;

	down(&attribute_container_mutex);
	list_for_each_entry(cont, &attribute_container_list, node) {
		struct internal_container *ic;

		if (attribute_container_no_classdevs(cont))
			continue;

		if (!cont->match(cont, dev))
			continue;
		ic = kmalloc(sizeof(struct internal_container), GFP_KERNEL);
		if (!ic) {
			dev_printk(KERN_ERR, dev, "failed to allocate class container\n");
			continue;
		}
		memset(ic, 0, sizeof(struct internal_container));
		ic->cont = cont;
		class_device_initialize(&ic->classdev);
		ic->classdev.dev = get_device(dev);
		ic->classdev.class = cont->class;
		cont->class->release = attribute_container_release;
		strcpy(ic->classdev.class_id, dev->bus_id);
		if (fn)
			fn(cont, dev, &ic->classdev);
		else
			attribute_container_add_class_device(&ic->classdev);
155
		klist_add_tail(&ic->node, &cont->containers);
Linus Torvalds's avatar
Linus Torvalds committed
156 157 158 159
	}
	up(&attribute_container_mutex);
}

160 161 162 163 164 165
/* FIXME: can't break out of this unless klist_iter_exit is also
 * called before doing the break
 */
#define klist_for_each_entry(pos, head, member, iter) \
	for (klist_iter_init(head, iter); (pos = ({ \
		struct klist_node *n = klist_next(iter); \
166 167
		n ? ({ klist_iter_exit(iter) ; NULL; }) : \
			container_of(n, typeof(*pos), member);\
168 169 170
	}) ) != NULL; )
			

Linus Torvalds's avatar
Linus Torvalds committed
171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196
/**
 * attribute_container_remove_device - make device eligible for removal.
 *
 * @dev:  The generic device
 * @fn:	  A function to call to remove the device
 *
 * This routine triggers device removal.  If fn is NULL, then it is
 * simply done via class_device_unregister (note that if something
 * still has a reference to the classdev, then the memory occupied
 * will not be freed until the classdev is released).  If you want a
 * two phase release: remove from visibility and then delete the
 * device, then you should use this routine with a fn that calls
 * class_device_del() and then use
 * attribute_container_device_trigger() to do the final put on the
 * classdev.
 */
void
attribute_container_remove_device(struct device *dev,
				  void (*fn)(struct attribute_container *,
					     struct device *,
					     struct class_device *))
{
	struct attribute_container *cont;

	down(&attribute_container_mutex);
	list_for_each_entry(cont, &attribute_container_list, node) {
197 198
		struct internal_container *ic;
		struct klist_iter iter;
Linus Torvalds's avatar
Linus Torvalds committed
199 200 201 202 203 204

		if (attribute_container_no_classdevs(cont))
			continue;

		if (!cont->match(cont, dev))
			continue;
205 206

		klist_for_each_entry(ic, &cont->containers, node, &iter) {
Linus Torvalds's avatar
Linus Torvalds committed
207 208
			if (dev != ic->classdev.dev)
				continue;
209
			klist_remove(&ic->node);
Linus Torvalds's avatar
Linus Torvalds committed
210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241
			if (fn)
				fn(cont, dev, &ic->classdev);
			else {
				attribute_container_remove_attrs(&ic->classdev);
				class_device_unregister(&ic->classdev);
			}
		}
	}
	up(&attribute_container_mutex);
}
EXPORT_SYMBOL_GPL(attribute_container_remove_device);

/**
 * attribute_container_device_trigger - execute a trigger for each matching classdev
 *
 * @dev:  The generic device to run the trigger for
 * @fn	  the function to execute for each classdev.
 *
 * This funcion is for executing a trigger when you need to know both
 * the container and the classdev.  If you only care about the
 * container, then use attribute_container_trigger() instead.
 */
void
attribute_container_device_trigger(struct device *dev, 
				   int (*fn)(struct attribute_container *,
					     struct device *,
					     struct class_device *))
{
	struct attribute_container *cont;

	down(&attribute_container_mutex);
	list_for_each_entry(cont, &attribute_container_list, node) {
242 243
		struct internal_container *ic;
		struct klist_iter iter;
Linus Torvalds's avatar
Linus Torvalds committed
244 245 246 247

		if (!cont->match(cont, dev))
			continue;

248 249 250 251 252
		if (attribute_container_no_classdevs(cont)) {
			fn(cont, dev, NULL);
			continue;
		}

253
		klist_for_each_entry(ic, &cont->containers, node, &iter) {
Linus Torvalds's avatar
Linus Torvalds committed
254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390
			if (dev == ic->classdev.dev)
				fn(cont, dev, &ic->classdev);
		}
	}
	up(&attribute_container_mutex);
}
EXPORT_SYMBOL_GPL(attribute_container_device_trigger);

/**
 * attribute_container_trigger - trigger a function for each matching container
 *
 * @dev:  The generic device to activate the trigger for
 * @fn:	  the function to trigger
 *
 * This routine triggers a function that only needs to know the
 * matching containers (not the classdev) associated with a device.
 * It is more lightweight than attribute_container_device_trigger, so
 * should be used in preference unless the triggering function
 * actually needs to know the classdev.
 */
void
attribute_container_trigger(struct device *dev,
			    int (*fn)(struct attribute_container *,
				      struct device *))
{
	struct attribute_container *cont;

	down(&attribute_container_mutex);
	list_for_each_entry(cont, &attribute_container_list, node) {
		if (cont->match(cont, dev))
			fn(cont, dev);
	}
	up(&attribute_container_mutex);
}
EXPORT_SYMBOL_GPL(attribute_container_trigger);

/**
 * attribute_container_add_attrs - add attributes
 *
 * @classdev: The class device
 *
 * This simply creates all the class device sysfs files from the
 * attributes listed in the container
 */
int
attribute_container_add_attrs(struct class_device *classdev)
{
	struct attribute_container *cont =
		attribute_container_classdev_to_container(classdev);
	struct class_device_attribute **attrs =	cont->attrs;
	int i, error;

	if (!attrs)
		return 0;

	for (i = 0; attrs[i]; i++) {
		error = class_device_create_file(classdev, attrs[i]);
		if (error)
			return error;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(attribute_container_add_attrs);

/**
 * attribute_container_add_class_device - same function as class_device_add
 *
 * @classdev:	the class device to add
 *
 * This performs essentially the same function as class_device_add except for
 * attribute containers, namely add the classdev to the system and then
 * create the attribute files
 */
int
attribute_container_add_class_device(struct class_device *classdev)
{
	int error = class_device_add(classdev);
	if (error)
		return error;
	return attribute_container_add_attrs(classdev);
}
EXPORT_SYMBOL_GPL(attribute_container_add_class_device);

/**
 * attribute_container_add_class_device_adapter - simple adapter for triggers
 *
 * This function is identical to attribute_container_add_class_device except
 * that it is designed to be called from the triggers
 */
int
attribute_container_add_class_device_adapter(struct attribute_container *cont,
					     struct device *dev,
					     struct class_device *classdev)
{
	return attribute_container_add_class_device(classdev);
}
EXPORT_SYMBOL_GPL(attribute_container_add_class_device_adapter);

/**
 * attribute_container_remove_attrs - remove any attribute files
 *
 * @classdev: The class device to remove the files from
 *
 */
void
attribute_container_remove_attrs(struct class_device *classdev)
{
	struct attribute_container *cont =
		attribute_container_classdev_to_container(classdev);
	struct class_device_attribute **attrs =	cont->attrs;
	int i;

	if (!attrs)
		return;

	for (i = 0; attrs[i]; i++)
		class_device_remove_file(classdev, attrs[i]);
}
EXPORT_SYMBOL_GPL(attribute_container_remove_attrs);

/**
 * attribute_container_class_device_del - equivalent of class_device_del
 *
 * @classdev: the class device
 *
 * This function simply removes all the attribute files and then calls
 * class_device_del.
 */
void
attribute_container_class_device_del(struct class_device *classdev)
{
	attribute_container_remove_attrs(classdev);
	class_device_del(classdev);
}
EXPORT_SYMBOL_GPL(attribute_container_class_device_del);

391 392 393 394 395 396 397 398 399 400 401 402 403 404 405
/**
 * attribute_container_find_class_device - find the corresponding class_device
 *
 * @cont:	the container
 * @dev:	the generic device
 *
 * Looks up the device in the container's list of class devices and returns
 * the corresponding class_device.
 */
struct class_device *
attribute_container_find_class_device(struct attribute_container *cont,
				      struct device *dev)
{
	struct class_device *cdev = NULL;
	struct internal_container *ic;
406
	struct klist_iter iter;
407

408
	klist_for_each_entry(ic, &cont->containers, node, &iter) {
409 410
		if (ic->classdev.dev == dev) {
			cdev = &ic->classdev;
411 412
			/* FIXME: must exit iterator then break */
			klist_iter_exit(&iter);
413 414 415 416 417 418 419 420
			break;
		}
	}

	return cdev;
}
EXPORT_SYMBOL_GPL(attribute_container_find_class_device);

Linus Torvalds's avatar
Linus Torvalds committed
421 422 423 424 425 426
int __init
attribute_container_init(void)
{
	INIT_LIST_HEAD(&attribute_container_list);
	return 0;
}