Root/drivers/base/firmware_class.c

1/*
2 * firmware_class.c - Multi purpose firmware loading support
3 *
4 * Copyright (c) 2003 Manuel Estrada Sainz
5 *
6 * Please see Documentation/firmware_class/ for more information.
7 *
8 */
9
10#include <linux/capability.h>
11#include <linux/device.h>
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/timer.h>
15#include <linux/vmalloc.h>
16#include <linux/interrupt.h>
17#include <linux/bitops.h>
18#include <linux/mutex.h>
19#include <linux/workqueue.h>
20#include <linux/highmem.h>
21#include <linux/firmware.h>
22#include <linux/slab.h>
23#include <linux/sched.h>
24
25MODULE_AUTHOR("Manuel Estrada Sainz");
26MODULE_DESCRIPTION("Multi purpose firmware loading support");
27MODULE_LICENSE("GPL");
28
29/* Builtin firmware support */
30
31#ifdef CONFIG_FW_LOADER
32
33extern struct builtin_fw __start_builtin_fw[];
34extern struct builtin_fw __end_builtin_fw[];
35
36static bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
37{
38    struct builtin_fw *b_fw;
39
40    for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++) {
41        if (strcmp(name, b_fw->name) == 0) {
42            fw->size = b_fw->size;
43            fw->data = b_fw->data;
44            return true;
45        }
46    }
47
48    return false;
49}
50
51static bool fw_is_builtin_firmware(const struct firmware *fw)
52{
53    struct builtin_fw *b_fw;
54
55    for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw; b_fw++)
56        if (fw->data == b_fw->data)
57            return true;
58
59    return false;
60}
61
62#else /* Module case - no builtin firmware support */
63
64static inline bool fw_get_builtin_firmware(struct firmware *fw, const char *name)
65{
66    return false;
67}
68
69static inline bool fw_is_builtin_firmware(const struct firmware *fw)
70{
71    return false;
72}
73#endif
74
75enum {
76    FW_STATUS_LOADING,
77    FW_STATUS_DONE,
78    FW_STATUS_ABORT,
79};
80
81static int loading_timeout = 60; /* In seconds */
82
83static inline long firmware_loading_timeout(void)
84{
85    return loading_timeout > 0 ? loading_timeout * HZ : MAX_SCHEDULE_TIMEOUT;
86}
87
88/* fw_lock could be moved to 'struct firmware_priv' but since it is just
89 * guarding for corner cases a global lock should be OK */
90static DEFINE_MUTEX(fw_lock);
91
92struct firmware_priv {
93    struct completion completion;
94    struct firmware *fw;
95    unsigned long status;
96    struct page **pages;
97    int nr_pages;
98    int page_array_size;
99    struct timer_list timeout;
100    struct device dev;
101    bool nowait;
102    char fw_id[];
103};
104
105static struct firmware_priv *to_firmware_priv(struct device *dev)
106{
107    return container_of(dev, struct firmware_priv, dev);
108}
109
110static void fw_load_abort(struct firmware_priv *fw_priv)
111{
112    set_bit(FW_STATUS_ABORT, &fw_priv->status);
113    wmb();
114    complete(&fw_priv->completion);
115}
116
117static ssize_t firmware_timeout_show(struct class *class,
118                     struct class_attribute *attr,
119                     char *buf)
120{
121    return sprintf(buf, "%d\n", loading_timeout);
122}
123
124/**
125 * firmware_timeout_store - set number of seconds to wait for firmware
126 * @class: device class pointer
127 * @attr: device attribute pointer
128 * @buf: buffer to scan for timeout value
129 * @count: number of bytes in @buf
130 *
131 * Sets the number of seconds to wait for the firmware. Once
132 * this expires an error will be returned to the driver and no
133 * firmware will be provided.
134 *
135 * Note: zero means 'wait forever'.
136 **/
137static ssize_t firmware_timeout_store(struct class *class,
138                      struct class_attribute *attr,
139                      const char *buf, size_t count)
140{
141    loading_timeout = simple_strtol(buf, NULL, 10);
142    if (loading_timeout < 0)
143        loading_timeout = 0;
144
145    return count;
146}
147
148static struct class_attribute firmware_class_attrs[] = {
149    __ATTR(timeout, S_IWUSR | S_IRUGO,
150        firmware_timeout_show, firmware_timeout_store),
151    __ATTR_NULL
152};
153
154static void fw_dev_release(struct device *dev)
155{
156    struct firmware_priv *fw_priv = to_firmware_priv(dev);
157    int i;
158
159    for (i = 0; i < fw_priv->nr_pages; i++)
160        __free_page(fw_priv->pages[i]);
161    kfree(fw_priv->pages);
162    kfree(fw_priv);
163
164    module_put(THIS_MODULE);
165}
166
167static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
168{
169    struct firmware_priv *fw_priv = to_firmware_priv(dev);
170
171    if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
172        return -ENOMEM;
173    if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
174        return -ENOMEM;
175    if (add_uevent_var(env, "ASYNC=%d", fw_priv->nowait))
176        return -ENOMEM;
177
178    return 0;
179}
180
181static struct class firmware_class = {
182    .name = "firmware",
183    .class_attrs = firmware_class_attrs,
184    .dev_uevent = firmware_uevent,
185    .dev_release = fw_dev_release,
186};
187
188static ssize_t firmware_loading_show(struct device *dev,
189                     struct device_attribute *attr, char *buf)
190{
191    struct firmware_priv *fw_priv = to_firmware_priv(dev);
192    int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
193
194    return sprintf(buf, "%d\n", loading);
195}
196
197static void firmware_free_data(const struct firmware *fw)
198{
199    int i;
200    vunmap(fw->data);
201    if (fw->pages) {
202        for (i = 0; i < PFN_UP(fw->size); i++)
203            __free_page(fw->pages[i]);
204        kfree(fw->pages);
205    }
206}
207
208/* Some architectures don't have PAGE_KERNEL_RO */
209#ifndef PAGE_KERNEL_RO
210#define PAGE_KERNEL_RO PAGE_KERNEL
211#endif
212/**
213 * firmware_loading_store - set value in the 'loading' control file
214 * @dev: device pointer
215 * @attr: device attribute pointer
216 * @buf: buffer to scan for loading control value
217 * @count: number of bytes in @buf
218 *
219 * The relevant values are:
220 *
221 * 1: Start a load, discarding any previous partial load.
222 * 0: Conclude the load and hand the data to the driver code.
223 * -1: Conclude the load with an error and discard any written data.
224 **/
225static ssize_t firmware_loading_store(struct device *dev,
226                      struct device_attribute *attr,
227                      const char *buf, size_t count)
228{
229    struct firmware_priv *fw_priv = to_firmware_priv(dev);
230    int loading = simple_strtol(buf, NULL, 10);
231    int i;
232
233    mutex_lock(&fw_lock);
234
235    if (!fw_priv->fw)
236        goto out;
237
238    switch (loading) {
239    case 1:
240        firmware_free_data(fw_priv->fw);
241        memset(fw_priv->fw, 0, sizeof(struct firmware));
242        /* If the pages are not owned by 'struct firmware' */
243        for (i = 0; i < fw_priv->nr_pages; i++)
244            __free_page(fw_priv->pages[i]);
245        kfree(fw_priv->pages);
246        fw_priv->pages = NULL;
247        fw_priv->page_array_size = 0;
248        fw_priv->nr_pages = 0;
249        set_bit(FW_STATUS_LOADING, &fw_priv->status);
250        break;
251    case 0:
252        if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
253            vunmap(fw_priv->fw->data);
254            fw_priv->fw->data = vmap(fw_priv->pages,
255                         fw_priv->nr_pages,
256                         0, PAGE_KERNEL_RO);
257            if (!fw_priv->fw->data) {
258                dev_err(dev, "%s: vmap() failed\n", __func__);
259                goto err;
260            }
261            /* Pages are now owned by 'struct firmware' */
262            fw_priv->fw->pages = fw_priv->pages;
263            fw_priv->pages = NULL;
264
265            fw_priv->page_array_size = 0;
266            fw_priv->nr_pages = 0;
267            complete(&fw_priv->completion);
268            clear_bit(FW_STATUS_LOADING, &fw_priv->status);
269            break;
270        }
271        /* fallthrough */
272    default:
273        dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
274        /* fallthrough */
275    case -1:
276    err:
277        fw_load_abort(fw_priv);
278        break;
279    }
280out:
281    mutex_unlock(&fw_lock);
282    return count;
283}
284
285static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
286
287static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
288                  struct bin_attribute *bin_attr,
289                  char *buffer, loff_t offset, size_t count)
290{
291    struct device *dev = kobj_to_dev(kobj);
292    struct firmware_priv *fw_priv = to_firmware_priv(dev);
293    struct firmware *fw;
294    ssize_t ret_count;
295
296    mutex_lock(&fw_lock);
297    fw = fw_priv->fw;
298    if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
299        ret_count = -ENODEV;
300        goto out;
301    }
302    if (offset > fw->size) {
303        ret_count = 0;
304        goto out;
305    }
306    if (count > fw->size - offset)
307        count = fw->size - offset;
308
309    ret_count = count;
310
311    while (count) {
312        void *page_data;
313        int page_nr = offset >> PAGE_SHIFT;
314        int page_ofs = offset & (PAGE_SIZE-1);
315        int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
316
317        page_data = kmap(fw_priv->pages[page_nr]);
318
319        memcpy(buffer, page_data + page_ofs, page_cnt);
320
321        kunmap(fw_priv->pages[page_nr]);
322        buffer += page_cnt;
323        offset += page_cnt;
324        count -= page_cnt;
325    }
326out:
327    mutex_unlock(&fw_lock);
328    return ret_count;
329}
330
331static int fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
332{
333    int pages_needed = ALIGN(min_size, PAGE_SIZE) >> PAGE_SHIFT;
334
335    /* If the array of pages is too small, grow it... */
336    if (fw_priv->page_array_size < pages_needed) {
337        int new_array_size = max(pages_needed,
338                     fw_priv->page_array_size * 2);
339        struct page **new_pages;
340
341        new_pages = kmalloc(new_array_size * sizeof(void *),
342                    GFP_KERNEL);
343        if (!new_pages) {
344            fw_load_abort(fw_priv);
345            return -ENOMEM;
346        }
347        memcpy(new_pages, fw_priv->pages,
348               fw_priv->page_array_size * sizeof(void *));
349        memset(&new_pages[fw_priv->page_array_size], 0, sizeof(void *) *
350               (new_array_size - fw_priv->page_array_size));
351        kfree(fw_priv->pages);
352        fw_priv->pages = new_pages;
353        fw_priv->page_array_size = new_array_size;
354    }
355
356    while (fw_priv->nr_pages < pages_needed) {
357        fw_priv->pages[fw_priv->nr_pages] =
358            alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
359
360        if (!fw_priv->pages[fw_priv->nr_pages]) {
361            fw_load_abort(fw_priv);
362            return -ENOMEM;
363        }
364        fw_priv->nr_pages++;
365    }
366    return 0;
367}
368
369/**
370 * firmware_data_write - write method for firmware
371 * @filp: open sysfs file
372 * @kobj: kobject for the device
373 * @bin_attr: bin_attr structure
374 * @buffer: buffer being written
375 * @offset: buffer offset for write in total data store area
376 * @count: buffer size
377 *
378 * Data written to the 'data' attribute will be later handed to
379 * the driver as a firmware image.
380 **/
381static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
382                   struct bin_attribute *bin_attr,
383                   char *buffer, loff_t offset, size_t count)
384{
385    struct device *dev = kobj_to_dev(kobj);
386    struct firmware_priv *fw_priv = to_firmware_priv(dev);
387    struct firmware *fw;
388    ssize_t retval;
389
390    if (!capable(CAP_SYS_RAWIO))
391        return -EPERM;
392
393    mutex_lock(&fw_lock);
394    fw = fw_priv->fw;
395    if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
396        retval = -ENODEV;
397        goto out;
398    }
399    retval = fw_realloc_buffer(fw_priv, offset + count);
400    if (retval)
401        goto out;
402
403    retval = count;
404
405    while (count) {
406        void *page_data;
407        int page_nr = offset >> PAGE_SHIFT;
408        int page_ofs = offset & (PAGE_SIZE - 1);
409        int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
410
411        page_data = kmap(fw_priv->pages[page_nr]);
412
413        memcpy(page_data + page_ofs, buffer, page_cnt);
414
415        kunmap(fw_priv->pages[page_nr]);
416        buffer += page_cnt;
417        offset += page_cnt;
418        count -= page_cnt;
419    }
420
421    fw->size = max_t(size_t, offset, fw->size);
422out:
423    mutex_unlock(&fw_lock);
424    return retval;
425}
426
427static struct bin_attribute firmware_attr_data = {
428    .attr = { .name = "data", .mode = 0644 },
429    .size = 0,
430    .read = firmware_data_read,
431    .write = firmware_data_write,
432};
433
434static void firmware_class_timeout(u_long data)
435{
436    struct firmware_priv *fw_priv = (struct firmware_priv *) data;
437
438    fw_load_abort(fw_priv);
439}
440
441static struct firmware_priv *
442fw_create_instance(struct firmware *firmware, const char *fw_name,
443           struct device *device, bool uevent, bool nowait)
444{
445    struct firmware_priv *fw_priv;
446    struct device *f_dev;
447
448    fw_priv = kzalloc(sizeof(*fw_priv) + strlen(fw_name) + 1 , GFP_KERNEL);
449    if (!fw_priv) {
450        dev_err(device, "%s: kmalloc failed\n", __func__);
451        return ERR_PTR(-ENOMEM);
452    }
453
454    fw_priv->fw = firmware;
455    fw_priv->nowait = nowait;
456    strcpy(fw_priv->fw_id, fw_name);
457    init_completion(&fw_priv->completion);
458    setup_timer(&fw_priv->timeout,
459            firmware_class_timeout, (u_long) fw_priv);
460
461    f_dev = &fw_priv->dev;
462
463    device_initialize(f_dev);
464    dev_set_name(f_dev, "%s", dev_name(device));
465    f_dev->parent = device;
466    f_dev->class = &firmware_class;
467
468    return fw_priv;
469}
470
471static struct firmware_priv *
472_request_firmware_prepare(const struct firmware **firmware_p, const char *name,
473              struct device *device, bool uevent, bool nowait)
474{
475    struct firmware *firmware;
476    struct firmware_priv *fw_priv;
477
478    if (!firmware_p)
479        return ERR_PTR(-EINVAL);
480
481    *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
482    if (!firmware) {
483        dev_err(device, "%s: kmalloc(struct firmware) failed\n",
484            __func__);
485        return ERR_PTR(-ENOMEM);
486    }
487
488    if (fw_get_builtin_firmware(firmware, name)) {
489        dev_dbg(device, "firmware: using built-in firmware %s\n", name);
490        return NULL;
491    }
492
493    fw_priv = fw_create_instance(firmware, name, device, uevent, nowait);
494    if (IS_ERR(fw_priv)) {
495        release_firmware(firmware);
496        *firmware_p = NULL;
497    }
498    return fw_priv;
499}
500
501static void _request_firmware_cleanup(const struct firmware **firmware_p)
502{
503    release_firmware(*firmware_p);
504    *firmware_p = NULL;
505}
506
507static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
508                  long timeout)
509{
510    int retval = 0;
511    struct device *f_dev = &fw_priv->dev;
512
513    dev_set_uevent_suppress(f_dev, true);
514
515    /* Need to pin this module until class device is destroyed */
516    __module_get(THIS_MODULE);
517
518    retval = device_add(f_dev);
519    if (retval) {
520        dev_err(f_dev, "%s: device_register failed\n", __func__);
521        goto err_put_dev;
522    }
523
524    retval = device_create_bin_file(f_dev, &firmware_attr_data);
525    if (retval) {
526        dev_err(f_dev, "%s: sysfs_create_bin_file failed\n", __func__);
527        goto err_del_dev;
528    }
529
530    retval = device_create_file(f_dev, &dev_attr_loading);
531    if (retval) {
532        dev_err(f_dev, "%s: device_create_file failed\n", __func__);
533        goto err_del_bin_attr;
534    }
535
536    if (uevent) {
537        dev_set_uevent_suppress(f_dev, false);
538        dev_dbg(f_dev, "firmware: requesting %s\n", fw_priv->fw_id);
539        if (timeout != MAX_SCHEDULE_TIMEOUT)
540            mod_timer(&fw_priv->timeout,
541                  round_jiffies_up(jiffies + timeout));
542
543        kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
544    }
545
546    wait_for_completion(&fw_priv->completion);
547
548    set_bit(FW_STATUS_DONE, &fw_priv->status);
549    del_timer_sync(&fw_priv->timeout);
550
551    mutex_lock(&fw_lock);
552    if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))
553        retval = -ENOENT;
554    fw_priv->fw = NULL;
555    mutex_unlock(&fw_lock);
556
557    device_remove_file(f_dev, &dev_attr_loading);
558err_del_bin_attr:
559    device_remove_bin_file(f_dev, &firmware_attr_data);
560err_del_dev:
561    device_del(f_dev);
562err_put_dev:
563    put_device(f_dev);
564    return retval;
565}
566
567/**
568 * request_firmware: - send firmware request and wait for it
569 * @firmware_p: pointer to firmware image
570 * @name: name of firmware file
571 * @device: device for which firmware is being loaded
572 *
573 * @firmware_p will be used to return a firmware image by the name
574 * of @name for device @device.
575 *
576 * Should be called from user context where sleeping is allowed.
577 *
578 * @name will be used as $FIRMWARE in the uevent environment and
579 * should be distinctive enough not to be confused with any other
580 * firmware image for this or any other device.
581 **/
582int
583request_firmware(const struct firmware **firmware_p, const char *name,
584                 struct device *device)
585{
586    struct firmware_priv *fw_priv;
587    int ret;
588
589    fw_priv = _request_firmware_prepare(firmware_p, name, device, true,
590                        false);
591    if (IS_ERR_OR_NULL(fw_priv))
592        return PTR_RET(fw_priv);
593
594    ret = usermodehelper_read_trylock();
595    if (WARN_ON(ret)) {
596        dev_err(device, "firmware: %s will not be loaded\n", name);
597    } else {
598        ret = _request_firmware_load(fw_priv, true,
599                    firmware_loading_timeout());
600        usermodehelper_read_unlock();
601    }
602    if (ret)
603        _request_firmware_cleanup(firmware_p);
604
605    return ret;
606}
607
608/**
609 * release_firmware: - release the resource associated with a firmware image
610 * @fw: firmware resource to release
611 **/
612void release_firmware(const struct firmware *fw)
613{
614    if (fw) {
615        if (!fw_is_builtin_firmware(fw))
616            firmware_free_data(fw);
617        kfree(fw);
618    }
619}
620
621/* Async support */
622struct firmware_work {
623    struct work_struct work;
624    struct module *module;
625    const char *name;
626    struct device *device;
627    void *context;
628    void (*cont)(const struct firmware *fw, void *context);
629    bool uevent;
630};
631
632static void request_firmware_work_func(struct work_struct *work)
633{
634    struct firmware_work *fw_work;
635    const struct firmware *fw;
636    struct firmware_priv *fw_priv;
637    long timeout;
638    int ret;
639
640    fw_work = container_of(work, struct firmware_work, work);
641    fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
642            fw_work->uevent, true);
643    if (IS_ERR_OR_NULL(fw_priv)) {
644        ret = PTR_RET(fw_priv);
645        goto out;
646    }
647
648    timeout = usermodehelper_read_lock_wait(firmware_loading_timeout());
649    if (timeout) {
650        ret = _request_firmware_load(fw_priv, fw_work->uevent, timeout);
651        usermodehelper_read_unlock();
652    } else {
653        dev_dbg(fw_work->device, "firmware: %s loading timed out\n",
654            fw_work->name);
655        ret = -EAGAIN;
656    }
657    if (ret)
658        _request_firmware_cleanup(&fw);
659
660 out:
661    fw_work->cont(fw, fw_work->context);
662
663    module_put(fw_work->module);
664    kfree(fw_work);
665}
666
667/**
668 * request_firmware_nowait - asynchronous version of request_firmware
669 * @module: module requesting the firmware
670 * @uevent: sends uevent to copy the firmware image if this flag
671 * is non-zero else the firmware copy must be done manually.
672 * @name: name of firmware file
673 * @device: device for which firmware is being loaded
674 * @gfp: allocation flags
675 * @context: will be passed over to @cont, and
676 * @fw may be %NULL if firmware request fails.
677 * @cont: function will be called asynchronously when the firmware
678 * request is over.
679 *
680 * Asynchronous variant of request_firmware() for user contexts where
681 * it is not possible to sleep for long time. It can't be called
682 * in atomic contexts.
683 **/
684int
685request_firmware_nowait(
686    struct module *module, bool uevent,
687    const char *name, struct device *device, gfp_t gfp, void *context,
688    void (*cont)(const struct firmware *fw, void *context))
689{
690    struct firmware_work *fw_work;
691
692    fw_work = kzalloc(sizeof (struct firmware_work), gfp);
693    if (!fw_work)
694        return -ENOMEM;
695
696    fw_work->module = module;
697    fw_work->name = name;
698    fw_work->device = device;
699    fw_work->context = context;
700    fw_work->cont = cont;
701    fw_work->uevent = uevent;
702
703    if (!try_module_get(module)) {
704        kfree(fw_work);
705        return -EFAULT;
706    }
707
708    INIT_WORK(&fw_work->work, request_firmware_work_func);
709    schedule_work(&fw_work->work);
710    return 0;
711}
712
713static int __init firmware_class_init(void)
714{
715    return class_register(&firmware_class);
716}
717
718static void __exit firmware_class_exit(void)
719{
720    class_unregister(&firmware_class);
721}
722
723fs_initcall(firmware_class_init);
724module_exit(firmware_class_exit);
725
726EXPORT_SYMBOL(release_firmware);
727EXPORT_SYMBOL(request_firmware);
728EXPORT_SYMBOL(request_firmware_nowait);
729

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