summaryrefslogtreecommitdiff
path: root/drivers/base/firmware_class.c
blob: 1fef7df8c9d601417312c088a6c0b8b9351646c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
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
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
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
197
198
199
200
201
202
203
204
205
206
207
208
209
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
242
243
244
245
246
247
248
249
250
251
252
253
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
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
/*
 * firmware_class.c - Multi purpose firmware loading support
 *
 * Copyright (c) 2003 Manuel Estrada Sainz
 *
 * Please see Documentation/firmware_class/ for more information.
 *
 */

#include <linux/capability.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/kthread.h>

#include <linux/firmware.h>
#include "base.h"

#define to_dev(obj) container_of(obj, struct device, kobj)

MODULE_AUTHOR("Manuel Estrada Sainz");
MODULE_DESCRIPTION("Multi purpose firmware loading support");
MODULE_LICENSE("GPL");

enum {
	FW_STATUS_LOADING,
	FW_STATUS_DONE,
	FW_STATUS_ABORT,
};

static int loading_timeout = 60;	/* In seconds */

/* fw_lock could be moved to 'struct firmware_priv' but since it is just
 * guarding for corner cases a global lock should be OK */
static DEFINE_MUTEX(fw_lock);

struct firmware_priv {
	char fw_id[FIRMWARE_NAME_MAX];
	struct completion completion;
	struct bin_attribute attr_data;
	struct firmware *fw;
	unsigned long status;
	int alloc_size;
	struct timer_list timeout;
};

static void
fw_load_abort(struct firmware_priv *fw_priv)
{
	set_bit(FW_STATUS_ABORT, &fw_priv->status);
	wmb();
	complete(&fw_priv->completion);
}

static ssize_t
firmware_timeout_show(struct class *class, char *buf)
{
	return sprintf(buf, "%d\n", loading_timeout);
}

/**
 * firmware_timeout_store - set number of seconds to wait for firmware
 * @class: device class pointer
 * @buf: buffer to scan for timeout value
 * @count: number of bytes in @buf
 *
 *	Sets the number of seconds to wait for the firmware.  Once
 *	this expires an error will be returned to the driver and no
 *	firmware will be provided.
 *
 *	Note: zero means 'wait forever'.
 **/
static ssize_t
firmware_timeout_store(struct class *class, const char *buf, size_t count)
{
	loading_timeout = simple_strtol(buf, NULL, 10);
	if (loading_timeout < 0)
		loading_timeout = 0;
	return count;
}

static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);

static void fw_dev_release(struct device *dev);

static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct firmware_priv *fw_priv = dev_get_drvdata(dev);

	if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
		return -ENOMEM;
	if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
		return -ENOMEM;

	return 0;
}

static struct class firmware_class = {
	.name		= "firmware",
	.dev_uevent	= firmware_uevent,
	.dev_release	= fw_dev_release,
};

static ssize_t firmware_loading_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct firmware_priv *fw_priv = dev_get_drvdata(dev);
	int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
	return sprintf(buf, "%d\n", loading);
}

/**
 * firmware_loading_store - set value in the 'loading' control file
 * @dev: device pointer
 * @attr: device attribute pointer
 * @buf: buffer to scan for loading control value
 * @count: number of bytes in @buf
 *
 *	The relevant values are:
 *
 *	 1: Start a load, discarding any previous partial load.
 *	 0: Conclude the load and hand the data to the driver code.
 *	-1: Conclude the load with an error and discard any written data.
 **/
static ssize_t firmware_loading_store(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf, size_t count)
{
	struct firmware_priv *fw_priv = dev_get_drvdata(dev);
	int loading = simple_strtol(buf, NULL, 10);

	switch (loading) {
	case 1:
		mutex_lock(&fw_lock);
		if (!fw_priv->fw) {
			mutex_unlock(&fw_lock);
			break;
		}
		vfree(fw_priv->fw->data);
		fw_priv->fw->data = NULL;
		fw_priv->fw->size = 0;
		fw_priv->alloc_size = 0;
		set_bit(FW_STATUS_LOADING, &fw_priv->status);
		mutex_unlock(&fw_lock);
		break;
	case 0:
		if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
			complete(&fw_priv->completion);
			clear_bit(FW_STATUS_LOADING, &fw_priv->status);
			break;
		}
		/* fallthrough */
	default:
		printk(KERN_ERR "%s: unexpected value (%d)\n", __func__,
		       loading);
		/* fallthrough */
	case -1:
		fw_load_abort(fw_priv);
		break;
	}

	return count;
}

static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);

static ssize_t
firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
		   char *buffer, loff_t offset, size_t count)
{
	struct device *dev = to_dev(kobj);
	struct firmware_priv *fw_priv = dev_get_drvdata(dev);
	struct firmware *fw;
	ssize_t ret_count = count;

	mutex_lock(&fw_lock);
	fw = fw_priv->fw;
	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
		ret_count = -ENODEV;
		goto out;
	}
	if (offset > fw->size) {
		ret_count = 0;
		goto out;
	}
	if (offset + ret_count > fw->size)
		ret_count = fw->size - offset;

	memcpy(buffer, fw->data + offset, ret_count);
out:
	mutex_unlock(&fw_lock);
	return ret_count;
}

static int
fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
{
	u8 *new_data;
	int new_size = fw_priv->alloc_size;

	if (min_size <= fw_priv->alloc_size)
		return 0;

	new_size = ALIGN(min_size, PAGE_SIZE);
	new_data = vmalloc(new_size);
	if (!new_data) {
		printk(KERN_ERR "%s: unable to alloc buffer\n", __func__);
		/* Make sure that we don't keep incomplete data */
		fw_load_abort(fw_priv);
		return -ENOMEM;
	}
	fw_priv->alloc_size = new_size;
	if (fw_priv->fw->data) {
		memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
		vfree(fw_priv->fw->data);
	}
	fw_priv->fw->data = new_data;
	BUG_ON(min_size > fw_priv->alloc_size);
	return 0;
}

/**
 * firmware_data_write - write method for firmware
 * @kobj: kobject for the device
 * @bin_attr: bin_attr structure
 * @buffer: buffer being written
 * @offset: buffer offset for write in total data store area
 * @count: buffer size
 *
 *	Data written to the 'data' attribute will be later handed to
 *	the driver as a firmware image.
 **/
static ssize_t
firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
		    char *buffer, loff_t offset, size_t count)
{
	struct device *dev = to_dev(kobj);
	struct firmware_priv *fw_priv = dev_get_drvdata(dev);
	struct firmware *fw;
	ssize_t retval;

	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

	mutex_lock(&fw_lock);
	fw = fw_priv->fw;
	if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
		retval = -ENODEV;
		goto out;
	}
	retval = fw_realloc_buffer(fw_priv, offset + count);
	if (retval)
		goto out;

	memcpy(fw->data + offset, buffer, count);

	fw->size = max_t(size_t, offset + count, fw->size);
	retval = count;
out:
	mutex_unlock(&fw_lock);
	return retval;
}

static struct bin_attribute firmware_attr_data_tmpl = {
	.attr = {.name = "data", .mode = 0644},
	.size = 0,
	.read = firmware_data_read,
	.write = firmware_data_write,
};

static void fw_dev_release(struct device *dev)
{
	struct firmware_priv *fw_priv = dev_get_drvdata(dev);

	kfree(fw_priv);
	kfree(dev);

	module_put(THIS_MODULE);
}

static void
firmware_class_timeout(u_long data)
{
	struct firmware_priv *fw_priv = (struct firmware_priv *) data;
	fw_load_abort(fw_priv);
}

static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
{
	/* XXX warning we should watch out for name collisions */
	strlcpy(f_dev->bus_id, dev->bus_id, BUS_ID_SIZE);
}

static int fw_register_device(struct device **dev_p, const char *fw_name,
			      struct device *device)
{
	int retval;
	struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
						GFP_KERNEL);
	struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);

	*dev_p = NULL;

	if (!fw_priv || !f_dev) {
		printk(KERN_ERR "%s: kmalloc failed\n", __func__);
		retval = -ENOMEM;
		goto error_kfree;
	}

	init_completion(&fw_priv->completion);
	fw_priv->attr_data = firmware_attr_data_tmpl;
	strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);

	fw_priv->timeout.function = firmware_class_timeout;
	fw_priv->timeout.data = (u_long) fw_priv;
	init_timer(&fw_priv->timeout);

	fw_setup_device_id(f_dev, device);
	f_dev->parent = device;
	f_dev->class = &firmware_class;
	dev_set_drvdata(f_dev, fw_priv);
	f_dev->uevent_suppress = 1;
	retval = device_register(f_dev);
	if (retval) {
		printk(KERN_ERR "%s: device_register failed\n",
		       __func__);
		goto error_kfree;
	}
	*dev_p = f_dev;
	return 0;

error_kfree:
	kfree(fw_priv);
	kfree(f_dev);
	return retval;
}

static int fw_setup_device(struct firmware *fw, struct device **dev_p,
			   const char *fw_name, struct device *device,
			   int uevent)
{
	struct device *f_dev;
	struct firmware_priv *fw_priv;
	int retval;

	*dev_p = NULL;
	retval = fw_register_device(&f_dev, fw_name, device);
	if (retval)
		goto out;

	/* Need to pin this module until class device is destroyed */
	__module_get(THIS_MODULE);

	fw_priv = dev_get_drvdata(f_dev);

	fw_priv->fw = fw;
	retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
	if (retval) {
		printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
		       __func__);
		goto error_unreg;
	}

	retval = device_create_file(f_dev, &dev_attr_loading);
	if (retval) {
		printk(KERN_ERR "%s: device_create_file failed\n",
		       __func__);
		goto error_unreg;
	}

	if (uevent)
		f_dev->uevent_suppress = 0;
	*dev_p = f_dev;
	goto out;

error_unreg:
	device_unregister(f_dev);
out:
	return retval;
}

static int
_request_firmware(const struct firmware **firmware_p, const char *name,
		 struct device *device, int uevent)
{
	struct device *f_dev;
	struct firmware_priv *fw_priv;
	struct firmware *firmware;
	int retval;

	if (!firmware_p)
		return -EINVAL;

	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
	if (!firmware) {
		printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
		       __func__);
		retval = -ENOMEM;
		goto out;
	}

	retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
	if (retval)
		goto error_kfree_fw;

	fw_priv = dev_get_drvdata(f_dev);

	if (uevent) {
		if (loading_timeout > 0) {
			fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
			add_timer(&fw_priv->timeout);
		}

		kobject_uevent(&f_dev->kobj, KOBJ_ADD);
		wait_for_completion(&fw_priv->completion);
		set_bit(FW_STATUS_DONE, &fw_priv->status);
		del_timer_sync(&fw_priv->timeout);
	} else
		wait_for_completion(&fw_priv->completion);

	mutex_lock(&fw_lock);
	if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
		retval = -ENOENT;
		release_firmware(fw_priv->fw);
		*firmware_p = NULL;
	}
	fw_priv->fw = NULL;
	mutex_unlock(&fw_lock);
	device_unregister(f_dev);
	goto out;

error_kfree_fw:
	kfree(firmware);
	*firmware_p = NULL;
out:
	return retval;
}

/**
 * request_firmware: - send firmware request and wait for it
 * @firmware_p: pointer to firmware image
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 *
 *      @firmware_p will be used to return a firmware image by the name
 *      of @name for device @device.
 *
 *      Should be called from user context where sleeping is allowed.
 *
 *      @name will be used as $FIRMWARE in the uevent environment and
 *      should be distinctive enough not to be confused with any other
 *      firmware image for this or any other device.
 **/
int
request_firmware(const struct firmware **firmware_p, const char *name,
                 struct device *device)
{
        int uevent = 1;
        return _request_firmware(firmware_p, name, device, uevent);
}

/**
 * release_firmware: - release the resource associated with a firmware image
 * @fw: firmware resource to release
 **/
void
release_firmware(const struct firmware *fw)
{
	if (fw) {
		vfree(fw->data);
		kfree(fw);
	}
}

/* Async support */
struct firmware_work {
	struct work_struct work;
	struct module *module;
	const char *name;
	struct device *device;
	void *context;
	void (*cont)(const struct firmware *fw, void *context);
	int uevent;
};

static int
request_firmware_work_func(void *arg)
{
	struct firmware_work *fw_work = arg;
	const struct firmware *fw;
	int ret;
	if (!arg) {
		WARN_ON(1);
		return 0;
	}
	ret = _request_firmware(&fw, fw_work->name, fw_work->device,
		fw_work->uevent);
	if (ret < 0)
		fw_work->cont(NULL, fw_work->context);
	else {
		fw_work->cont(fw, fw_work->context);
		release_firmware(fw);
	}
	module_put(fw_work->module);
	kfree(fw_work);
	return ret;
}

/**
 * request_firmware_nowait: asynchronous version of request_firmware
 * @module: module requesting the firmware
 * @uevent: sends uevent to copy the firmware image if this flag
 *	is non-zero else the firmware copy must be done manually.
 * @name: name of firmware file
 * @device: device for which firmware is being loaded
 * @context: will be passed over to @cont, and
 *	@fw may be %NULL if firmware request fails.
 * @cont: function will be called asynchronously when the firmware
 *	request is over.
 *
 *	Asynchronous variant of request_firmware() for contexts where
 *	it is not possible to sleep.
 **/
int
request_firmware_nowait(
	struct module *module, int uevent,
	const char *name, struct device *device, void *context,
	void (*cont)(const struct firmware *fw, void *context))
{
	struct task_struct *task;
	struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
						GFP_ATOMIC);

	if (!fw_work)
		return -ENOMEM;
	if (!try_module_get(module)) {
		kfree(fw_work);
		return -EFAULT;
	}

	*fw_work = (struct firmware_work) {
		.module = module,
		.name = name,
		.device = device,
		.context = context,
		.cont = cont,
		.uevent = uevent,
	};

	task = kthread_run(request_firmware_work_func, fw_work,
			    "firmware/%s", name);

	if (IS_ERR(task)) {
		fw_work->cont(NULL, fw_work->context);
		module_put(fw_work->module);
		kfree(fw_work);
		return PTR_ERR(task);
	}
	return 0;
}

static int __init
firmware_class_init(void)
{
	int error;
	error = class_register(&firmware_class);
	if (error) {
		printk(KERN_ERR "%s: class_register failed\n", __func__);
		return error;
	}
	error = class_create_file(&firmware_class, &class_attr_timeout);
	if (error) {
		printk(KERN_ERR "%s: class_create_file failed\n",
		       __func__);
		class_unregister(&firmware_class);
	}
	return error;

}
static void __exit
firmware_class_exit(void)
{
	class_unregister(&firmware_class);
}

fs_initcall(firmware_class_init);
module_exit(firmware_class_exit);

EXPORT_SYMBOL(release_firmware);
EXPORT_SYMBOL(request_firmware);
EXPORT_SYMBOL(request_firmware_nowait);