34 /* the current rng has been explicitly chosen by user via sysfs */
41 /* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */
56 static int hwrng_init(struct hwrng *rng);
59 static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
67 static void add_early_randomness(struct hwrng *rng)  in add_early_randomness()  argument
72 	bytes_read = rng_get_data(rng, rng_fillbuf, 32, 0);  in add_early_randomness()
75 		size_t entropy = bytes_read * 8 * rng->quality / 1024;  in add_early_randomness()
82 	struct hwrng *rng = container_of(kref, struct hwrng, ref);  in cleanup_rng()  local
84 	if (rng->cleanup)  in cleanup_rng()
85 		rng->cleanup(rng);  in cleanup_rng()
87 	complete(&rng->cleanup_done);  in cleanup_rng()
90 static int set_current_rng(struct hwrng *rng)  in set_current_rng()  argument
96 	err = hwrng_init(rng);  in set_current_rng()
101 	current_rng = rng;  in set_current_rng()
137 	struct hwrng *rng;  in get_current_rng()  local
142 	rng = get_current_rng_nolock();  in get_current_rng()
145 	return rng;  in get_current_rng()
148 static void put_rng(struct hwrng *rng)  in put_rng()  argument
152 	 * on rng again immediately.  in put_rng()
155 	if (rng)  in put_rng()
156 		kref_put(&rng->ref, cleanup_rng);  in put_rng()
160 static int hwrng_init(struct hwrng *rng)  in hwrng_init()  argument
162 	if (kref_get_unless_zero(&rng->ref))  in hwrng_init()
165 	if (rng->init) {  in hwrng_init()
168 		ret =  rng->init(rng);  in hwrng_init()
173 	kref_init(&rng->ref);  in hwrng_init()
174 	reinit_completion(&rng->cleanup_done);  in hwrng_init()
177 	current_quality = rng->quality; /* obsolete */  in hwrng_init()
192 static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,  in rng_get_data()  argument
197 	if (rng->read)  in rng_get_data()
198 		return rng->read(rng, (void *)buffer, size, wait);  in rng_get_data()
200 	if (rng->data_present)  in rng_get_data()
201 		present = rng->data_present(rng, wait);  in rng_get_data()
206 		return rng->data_read(rng, (u32 *)buffer);  in rng_get_data()
218 	struct hwrng *rng;  in rng_dev_read()  local
221 		rng = get_current_rng();  in rng_dev_read()
222 		if (IS_ERR(rng)) {  in rng_dev_read()
223 			err = PTR_ERR(rng);  in rng_dev_read()
226 		if (!rng) {  in rng_dev_read()
236 			bytes_read = rng_get_data(rng, rng_buffer,  in rng_dev_read()
261 		put_rng(rng);  in rng_dev_read()
289 	put_rng(rng);  in rng_dev_read()
312 	struct hwrng *rng, *new_rng = NULL;  in enable_best_rng()  local
317 	/* no rng to use? */  in enable_best_rng()
324 	/* use the rng which offers the best quality */  in enable_best_rng()
325 	list_for_each_entry(rng, &rng_list, list) {  in enable_best_rng()
326 		if (!new_rng || rng->quality > new_rng->quality)  in enable_best_rng()
327 			new_rng = rng;  in enable_best_rng()
342 	struct hwrng *rng, *old_rng, *new_rng;  in rng_current_store()  local
352 		list_for_each_entry(rng, &rng_list, list) {  in rng_current_store()
353 			if (sysfs_streq(rng->name, buf)) {  in rng_current_store()
354 				err = set_current_rng(rng);  in rng_current_store()
378 	struct hwrng *rng;  in rng_current_show()  local
380 	rng = get_current_rng();  in rng_current_show()
381 	if (IS_ERR(rng))  in rng_current_show()
382 		return PTR_ERR(rng);  in rng_current_show()
384 	ret = snprintf(buf, PAGE_SIZE, "%s\n", rng ? rng->name : "none");  in rng_current_show()
385 	put_rng(rng);  in rng_current_show()
395 	struct hwrng *rng;  in rng_available_show()  local
401 	list_for_each_entry(rng, &rng_list, list) {  in rng_available_show()
402 		strlcat(buf, rng->name, PAGE_SIZE);  in rng_available_show()
423 	struct hwrng *rng;  in rng_quality_show()  local
425 	rng = get_current_rng();  in rng_quality_show()
426 	if (IS_ERR(rng))  in rng_quality_show()
427 		return PTR_ERR(rng);  in rng_quality_show()
429 	if (!rng) /* no need to put_rng */  in rng_quality_show()
432 	ret = sysfs_emit(buf, "%hu\n", rng->quality);  in rng_quality_show()
433 	put_rng(rng);  in rng_quality_show()
466 	/* the best available RNG may have changed */  in rng_quality_store()
506 		struct hwrng *rng;  in hwrng_fillfn()  local
508 		rng = get_current_rng();  in hwrng_fillfn()
509 		if (IS_ERR(rng) || !rng)  in hwrng_fillfn()
512 		rc = rng_get_data(rng, rng_fillbuf,  in hwrng_fillfn()
514 		if (current_quality != rng->quality)  in hwrng_fillfn()
515 			rng->quality = current_quality; /* obsolete */  in hwrng_fillfn()
516 		quality = rng->quality;  in hwrng_fillfn()
520 			hwrng_msleep(rng, 10000);  in hwrng_fillfn()
522 		put_rng(rng);  in hwrng_fillfn()
542 int hwrng_register(struct hwrng *rng)  in hwrng_register()  argument
548 	if (!rng->name || (!rng->data_read && !rng->read))  in hwrng_register()
556 		if (strcmp(tmp->name, rng->name) == 0)  in hwrng_register()
559 	list_add_tail(&rng->list, &rng_list);  in hwrng_register()
561 	init_completion(&rng->cleanup_done);  in hwrng_register()
562 	complete(&rng->cleanup_done);  in hwrng_register()
563 	init_completion(&rng->dying);  in hwrng_register()
566 	rng->quality = min_t(u16, min_t(u16, default_quality, 1024), rng->quality ?: 1024);  in hwrng_register()
569 	    (!cur_rng_set_by_user && rng->quality > current_rng->quality)) {  in hwrng_register()
571 		 * Set new rng as current as the new rng source  in hwrng_register()
575 		err = set_current_rng(rng);  in hwrng_register()
582 		kref_get(&rng->ref);  in hwrng_register()
585 	if (is_new_current || !rng->init) {  in hwrng_register()
588 		 * the system.  If this rng device isn't going to be  in hwrng_register()
593 		add_early_randomness(rng);  in hwrng_register()
596 		put_rng(rng);  in hwrng_register()
605 void hwrng_unregister(struct hwrng *rng)  in hwrng_unregister()  argument
613 	list_del(&rng->list);  in hwrng_unregister()
614 	complete_all(&rng->dying);  in hwrng_unregister()
615 	if (current_rng == rng) {  in hwrng_unregister()
637 	wait_for_completion(&rng->cleanup_done);  in hwrng_unregister()
656 int devm_hwrng_register(struct device *dev, struct hwrng *rng)  in devm_hwrng_register()  argument
665 	error = hwrng_register(rng);  in devm_hwrng_register()
671 	*ptr = rng;  in devm_hwrng_register()
677 void devm_hwrng_unregister(struct device *dev, struct hwrng *rng)  in devm_hwrng_unregister()  argument
679 	devres_release(dev, devm_hwrng_release, devm_hwrng_match, rng);  in devm_hwrng_unregister()
683 long hwrng_msleep(struct hwrng *rng, unsigned int msecs)  in hwrng_msleep()  argument
687 	return wait_for_completion_interruptible_timeout(&rng->dying, timeout);  in hwrng_msleep()
691 long hwrng_yield(struct hwrng *rng)  in hwrng_yield()  argument
693 	return wait_for_completion_interruptible_timeout(&rng->dying, 1);  in hwrng_yield()
735 MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");