[PATCH] firmware: fix all kernel-doc warnings
[linux-2.6.git] / drivers / base / firmware_class.c
1 /*
2  * firmware_class.c - Multi purpose firmware loading support
3  *
4  * Copyright (c) 2003 Manuel Estrada Sainz <ranty@debian.org>
5  *
6  * Please see Documentation/firmware_class/ for more information.
7  *
8  */
9
10 #include <linux/device.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/timer.h>
14 #include <linux/vmalloc.h>
15 #include <linux/interrupt.h>
16 #include <linux/bitops.h>
17 #include <asm/semaphore.h>
18
19 #include <linux/firmware.h>
20 #include "base.h"
21
22 MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>");
23 MODULE_DESCRIPTION("Multi purpose firmware loading support");
24 MODULE_LICENSE("GPL");
25
26 enum {
27         FW_STATUS_LOADING,
28         FW_STATUS_DONE,
29         FW_STATUS_ABORT,
30         FW_STATUS_READY,
31         FW_STATUS_READY_NOHOTPLUG,
32 };
33
34 static int loading_timeout = 10;        /* In seconds */
35
36 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
37  * guarding for corner cases a global lock should be OK */
38 static DECLARE_MUTEX(fw_lock);
39
40 struct firmware_priv {
41         char fw_id[FIRMWARE_NAME_MAX];
42         struct completion completion;
43         struct bin_attribute attr_data;
44         struct firmware *fw;
45         unsigned long status;
46         int alloc_size;
47         struct timer_list timeout;
48 };
49
50 static inline void
51 fw_load_abort(struct firmware_priv *fw_priv)
52 {
53         set_bit(FW_STATUS_ABORT, &fw_priv->status);
54         wmb();
55         complete(&fw_priv->completion);
56 }
57
58 static ssize_t
59 firmware_timeout_show(struct class *class, char *buf)
60 {
61         return sprintf(buf, "%d\n", loading_timeout);
62 }
63
64 /**
65  * firmware_timeout_store - set number of seconds to wait for firmware
66  * @class: device class pointer
67  * @buf: buffer to scan for timeout value
68  * @count: number of bytes in @buf
69  *
70  *      Sets the number of seconds to wait for the firmware.  Once
71  *      this expires an error will be returned to the driver and no
72  *      firmware will be provided.
73  *
74  *      Note: zero means 'wait forever'.
75  **/
76 static ssize_t
77 firmware_timeout_store(struct class *class, const char *buf, size_t count)
78 {
79         loading_timeout = simple_strtol(buf, NULL, 10);
80         if (loading_timeout < 0)
81                 loading_timeout = 0;
82         return count;
83 }
84
85 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
86
87 static void  fw_class_dev_release(struct class_device *class_dev);
88 int firmware_class_hotplug(struct class_device *dev, char **envp,
89                            int num_envp, char *buffer, int buffer_size);
90
91 static struct class firmware_class = {
92         .name           = "firmware",
93         .hotplug        = firmware_class_hotplug,
94         .release        = fw_class_dev_release,
95 };
96
97 int
98 firmware_class_hotplug(struct class_device *class_dev, char **envp,
99                        int num_envp, char *buffer, int buffer_size)
100 {
101         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
102         int i = 0, len = 0;
103
104         if (!test_bit(FW_STATUS_READY, &fw_priv->status))
105                 return -ENODEV;
106
107         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
108                         "FIRMWARE=%s", fw_priv->fw_id))
109                 return -ENOMEM;
110         if (add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &len,
111                         "TIMEOUT=%i", loading_timeout))
112                 return -ENOMEM;
113
114         envp[i] = NULL;
115
116         return 0;
117 }
118
119 static ssize_t
120 firmware_loading_show(struct class_device *class_dev, char *buf)
121 {
122         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
123         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
124         return sprintf(buf, "%d\n", loading);
125 }
126
127 /**
128  * firmware_loading_store - set value in the 'loading' control file
129  * @class_dev: class_device pointer
130  * @buf: buffer to scan for loading control value
131  * @count: number of bytes in @buf
132  *
133  *      The relevant values are:
134  *
135  *       1: Start a load, discarding any previous partial load.
136  *       0: Conclude the load and hand the data to the driver code.
137  *      -1: Conclude the load with an error and discard any written data.
138  **/
139 static ssize_t
140 firmware_loading_store(struct class_device *class_dev,
141                        const char *buf, size_t count)
142 {
143         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
144         int loading = simple_strtol(buf, NULL, 10);
145
146         switch (loading) {
147         case 1:
148                 down(&fw_lock);
149                 if (!fw_priv->fw) {
150                         up(&fw_lock);
151                         break;
152                 }
153                 vfree(fw_priv->fw->data);
154                 fw_priv->fw->data = NULL;
155                 fw_priv->fw->size = 0;
156                 fw_priv->alloc_size = 0;
157                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
158                 up(&fw_lock);
159                 break;
160         case 0:
161                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
162                         complete(&fw_priv->completion);
163                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
164                         break;
165                 }
166                 /* fallthrough */
167         default:
168                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
169                        loading);
170                 /* fallthrough */
171         case -1:
172                 fw_load_abort(fw_priv);
173                 break;
174         }
175
176         return count;
177 }
178
179 static CLASS_DEVICE_ATTR(loading, 0644,
180                         firmware_loading_show, firmware_loading_store);
181
182 static ssize_t
183 firmware_data_read(struct kobject *kobj,
184                    char *buffer, loff_t offset, size_t count)
185 {
186         struct class_device *class_dev = to_class_dev(kobj);
187         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
188         struct firmware *fw;
189         ssize_t ret_count = count;
190
191         down(&fw_lock);
192         fw = fw_priv->fw;
193         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
194                 ret_count = -ENODEV;
195                 goto out;
196         }
197         if (offset > fw->size) {
198                 ret_count = 0;
199                 goto out;
200         }
201         if (offset + ret_count > fw->size)
202                 ret_count = fw->size - offset;
203
204         memcpy(buffer, fw->data + offset, ret_count);
205 out:
206         up(&fw_lock);
207         return ret_count;
208 }
209
210 static int
211 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
212 {
213         u8 *new_data;
214
215         if (min_size <= fw_priv->alloc_size)
216                 return 0;
217
218         new_data = vmalloc(fw_priv->alloc_size + PAGE_SIZE);
219         if (!new_data) {
220                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
221                 /* Make sure that we don't keep incomplete data */
222                 fw_load_abort(fw_priv);
223                 return -ENOMEM;
224         }
225         fw_priv->alloc_size += PAGE_SIZE;
226         if (fw_priv->fw->data) {
227                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
228                 vfree(fw_priv->fw->data);
229         }
230         fw_priv->fw->data = new_data;
231         BUG_ON(min_size > fw_priv->alloc_size);
232         return 0;
233 }
234
235 /**
236  * firmware_data_write - write method for firmware
237  * @kobj: kobject for the class_device
238  * @buffer: buffer being written
239  * @offset: buffer offset for write in total data store area
240  * @count: buffer size
241  *
242  *      Data written to the 'data' attribute will be later handed to
243  *      the driver as a firmware image.
244  **/
245 static ssize_t
246 firmware_data_write(struct kobject *kobj,
247                     char *buffer, loff_t offset, size_t count)
248 {
249         struct class_device *class_dev = to_class_dev(kobj);
250         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
251         struct firmware *fw;
252         ssize_t retval;
253
254         if (!capable(CAP_SYS_RAWIO))
255                 return -EPERM;
256
257         down(&fw_lock);
258         fw = fw_priv->fw;
259         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
260                 retval = -ENODEV;
261                 goto out;
262         }
263         retval = fw_realloc_buffer(fw_priv, offset + count);
264         if (retval)
265                 goto out;
266
267         memcpy(fw->data + offset, buffer, count);
268
269         fw->size = max_t(size_t, offset + count, fw->size);
270         retval = count;
271 out:
272         up(&fw_lock);
273         return retval;
274 }
275
276 static struct bin_attribute firmware_attr_data_tmpl = {
277         .attr = {.name = "data", .mode = 0644, .owner = THIS_MODULE},
278         .size = 0,
279         .read = firmware_data_read,
280         .write = firmware_data_write,
281 };
282
283 static void
284 fw_class_dev_release(struct class_device *class_dev)
285 {
286         struct firmware_priv *fw_priv = class_get_devdata(class_dev);
287
288         kfree(fw_priv);
289         kfree(class_dev);
290
291         module_put(THIS_MODULE);
292 }
293
294 static void
295 firmware_class_timeout(u_long data)
296 {
297         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
298         fw_load_abort(fw_priv);
299 }
300
301 static inline void
302 fw_setup_class_device_id(struct class_device *class_dev, struct device *dev)
303 {
304         /* XXX warning we should watch out for name collisions */
305         strlcpy(class_dev->class_id, dev->bus_id, BUS_ID_SIZE);
306 }
307
308 static int
309 fw_register_class_device(struct class_device **class_dev_p,
310                          const char *fw_name, struct device *device)
311 {
312         int retval;
313         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
314                                                 GFP_KERNEL);
315         struct class_device *class_dev = kzalloc(sizeof(*class_dev),
316                                                  GFP_KERNEL);
317
318         *class_dev_p = NULL;
319
320         if (!fw_priv || !class_dev) {
321                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
322                 retval = -ENOMEM;
323                 goto error_kfree;
324         }
325
326         init_completion(&fw_priv->completion);
327         fw_priv->attr_data = firmware_attr_data_tmpl;
328         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
329
330         fw_priv->timeout.function = firmware_class_timeout;
331         fw_priv->timeout.data = (u_long) fw_priv;
332         init_timer(&fw_priv->timeout);
333
334         fw_setup_class_device_id(class_dev, device);
335         class_dev->dev = device;
336         class_dev->class = &firmware_class;
337         class_set_devdata(class_dev, fw_priv);
338         retval = class_device_register(class_dev);
339         if (retval) {
340                 printk(KERN_ERR "%s: class_device_register failed\n",
341                        __FUNCTION__);
342                 goto error_kfree;
343         }
344         *class_dev_p = class_dev;
345         return 0;
346
347 error_kfree:
348         kfree(fw_priv);
349         kfree(class_dev);
350         return retval;
351 }
352
353 static int
354 fw_setup_class_device(struct firmware *fw, struct class_device **class_dev_p,
355                       const char *fw_name, struct device *device, int hotplug)
356 {
357         struct class_device *class_dev;
358         struct firmware_priv *fw_priv;
359         int retval;
360
361         *class_dev_p = NULL;
362         retval = fw_register_class_device(&class_dev, fw_name, device);
363         if (retval)
364                 goto out;
365
366         /* Need to pin this module until class device is destroyed */
367         __module_get(THIS_MODULE);
368
369         fw_priv = class_get_devdata(class_dev);
370
371         fw_priv->fw = fw;
372         retval = sysfs_create_bin_file(&class_dev->kobj, &fw_priv->attr_data);
373         if (retval) {
374                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
375                        __FUNCTION__);
376                 goto error_unreg;
377         }
378
379         retval = class_device_create_file(class_dev,
380                                           &class_device_attr_loading);
381         if (retval) {
382                 printk(KERN_ERR "%s: class_device_create_file failed\n",
383                        __FUNCTION__);
384                 goto error_unreg;
385         }
386
387         if (hotplug)
388                 set_bit(FW_STATUS_READY, &fw_priv->status);
389         else
390                 set_bit(FW_STATUS_READY_NOHOTPLUG, &fw_priv->status);
391         *class_dev_p = class_dev;
392         goto out;
393
394 error_unreg:
395         class_device_unregister(class_dev);
396 out:
397         return retval;
398 }
399
400 static int
401 _request_firmware(const struct firmware **firmware_p, const char *name,
402                  struct device *device, int hotplug)
403 {
404         struct class_device *class_dev;
405         struct firmware_priv *fw_priv;
406         struct firmware *firmware;
407         int retval;
408
409         if (!firmware_p)
410                 return -EINVAL;
411
412         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
413         if (!firmware) {
414                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
415                        __FUNCTION__);
416                 retval = -ENOMEM;
417                 goto out;
418         }
419
420         retval = fw_setup_class_device(firmware, &class_dev, name, device,
421                 hotplug);
422         if (retval)
423                 goto error_kfree_fw;
424
425         fw_priv = class_get_devdata(class_dev);
426
427         if (hotplug) {
428                 if (loading_timeout > 0) {
429                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
430                         add_timer(&fw_priv->timeout);
431                 }
432
433                 kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
434                 wait_for_completion(&fw_priv->completion);
435                 set_bit(FW_STATUS_DONE, &fw_priv->status);
436                 del_timer_sync(&fw_priv->timeout);
437         } else
438                 wait_for_completion(&fw_priv->completion);
439
440         down(&fw_lock);
441         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
442                 retval = -ENOENT;
443                 release_firmware(fw_priv->fw);
444                 *firmware_p = NULL;
445         }
446         fw_priv->fw = NULL;
447         up(&fw_lock);
448         class_device_unregister(class_dev);
449         goto out;
450
451 error_kfree_fw:
452         kfree(firmware);
453         *firmware_p = NULL;
454 out:
455         return retval;
456 }
457
458 /**
459  * request_firmware: - request firmware to hotplug and wait for it
460  * @firmware_p: pointer to firmware image
461  * @name: name of firmware file
462  * @device: device for which firmware is being loaded
463  *
464  *      @firmware_p will be used to return a firmware image by the name
465  *      of @name for device @device.
466  *
467  *      Should be called from user context where sleeping is allowed.
468  *
469  *      @name will be used as $FIRMWARE in the hotplug environment and
470  *      should be distinctive enough not to be confused with any other
471  *      firmware image for this or any other device.
472  **/
473 int
474 request_firmware(const struct firmware **firmware_p, const char *name,
475                  struct device *device)
476 {
477         int hotplug = 1;
478         return _request_firmware(firmware_p, name, device, hotplug);
479 }
480
481 /**
482  * release_firmware: - release the resource associated with a firmware image
483  * @fw: firmware resource to release
484  **/
485 void
486 release_firmware(const struct firmware *fw)
487 {
488         if (fw) {
489                 vfree(fw->data);
490                 kfree(fw);
491         }
492 }
493
494 /**
495  * register_firmware: - provide a firmware image for later usage
496  * @name: name of firmware image file
497  * @data: buffer pointer for the firmware image
498  * @size: size of the data buffer area
499  *
500  *      Make sure that @data will be available by requesting firmware @name.
501  *
502  *      Note: This will not be possible until some kind of persistence
503  *      is available.
504  **/
505 void
506 register_firmware(const char *name, const u8 *data, size_t size)
507 {
508         /* This is meaningless without firmware caching, so until we
509          * decide if firmware caching is reasonable just leave it as a
510          * noop */
511 }
512
513 /* Async support */
514 struct firmware_work {
515         struct work_struct work;
516         struct module *module;
517         const char *name;
518         struct device *device;
519         void *context;
520         void (*cont)(const struct firmware *fw, void *context);
521         int hotplug;
522 };
523
524 static int
525 request_firmware_work_func(void *arg)
526 {
527         struct firmware_work *fw_work = arg;
528         const struct firmware *fw;
529         if (!arg) {
530                 WARN_ON(1);
531                 return 0;
532         }
533         daemonize("%s/%s", "firmware", fw_work->name);
534         _request_firmware(&fw, fw_work->name, fw_work->device,
535                 fw_work->hotplug);
536         fw_work->cont(fw, fw_work->context);
537         release_firmware(fw);
538         module_put(fw_work->module);
539         kfree(fw_work);
540         return 0;
541 }
542
543 /**
544  * request_firmware_nowait: asynchronous version of request_firmware
545  * @module: module requesting the firmware
546  * @hotplug: invokes hotplug event to copy the firmware image if this flag
547  *      is non-zero else the firmware copy must be done manually.
548  * @name: name of firmware file
549  * @device: device for which firmware is being loaded
550  * @context: will be passed over to @cont, and
551  *      @fw may be %NULL if firmware request fails.
552  * @cont: function will be called asynchronously when the firmware
553  *      request is over.
554  *
555  *      Asynchronous variant of request_firmware() for contexts where
556  *      it is not possible to sleep.
557  **/
558 int
559 request_firmware_nowait(
560         struct module *module, int hotplug,
561         const char *name, struct device *device, void *context,
562         void (*cont)(const struct firmware *fw, void *context))
563 {
564         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
565                                                 GFP_ATOMIC);
566         int ret;
567
568         if (!fw_work)
569                 return -ENOMEM;
570         if (!try_module_get(module)) {
571                 kfree(fw_work);
572                 return -EFAULT;
573         }
574
575         *fw_work = (struct firmware_work) {
576                 .module = module,
577                 .name = name,
578                 .device = device,
579                 .context = context,
580                 .cont = cont,
581                 .hotplug = hotplug,
582         };
583
584         ret = kernel_thread(request_firmware_work_func, fw_work,
585                             CLONE_FS | CLONE_FILES);
586
587         if (ret < 0) {
588                 fw_work->cont(NULL, fw_work->context);
589                 return ret;
590         }
591         return 0;
592 }
593
594 static int __init
595 firmware_class_init(void)
596 {
597         int error;
598         error = class_register(&firmware_class);
599         if (error) {
600                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
601                 return error;
602         }
603         error = class_create_file(&firmware_class, &class_attr_timeout);
604         if (error) {
605                 printk(KERN_ERR "%s: class_create_file failed\n",
606                        __FUNCTION__);
607                 class_unregister(&firmware_class);
608         }
609         return error;
610
611 }
612 static void __exit
613 firmware_class_exit(void)
614 {
615         class_unregister(&firmware_class);
616 }
617
618 module_init(firmware_class_init);
619 module_exit(firmware_class_exit);
620
621 EXPORT_SYMBOL(release_firmware);
622 EXPORT_SYMBOL(request_firmware);
623 EXPORT_SYMBOL(request_firmware_nowait);
624 EXPORT_SYMBOL(register_firmware);