31 /* the current rng has been explicitly chosen by user via sysfs */
38 /* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */
53 static int hwrng_init(struct hwrng *rng);
56 static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
64 static void add_early_randomness(struct hwrng *rng)  in add_early_randomness()  argument
70 	bytes_read = rng_get_data(rng, rng_buffer, size, 0);  in add_early_randomness()
78 	struct hwrng *rng = container_of(kref, struct hwrng, ref);  in cleanup_rng()  local
80 	if (rng->cleanup)  in cleanup_rng()
81 		rng->cleanup(rng);  in cleanup_rng()
83 	complete(&rng->cleanup_done);  in cleanup_rng()
86 static int set_current_rng(struct hwrng *rng)  in set_current_rng()  argument
92 	err = hwrng_init(rng);  in set_current_rng()
97 	current_rng = rng;  in set_current_rng()
124 	struct hwrng *rng;  in get_current_rng()  local
129 	rng = get_current_rng_nolock();  in get_current_rng()
132 	return rng;  in get_current_rng()
135 static void put_rng(struct hwrng *rng)  in put_rng()  argument
139 	 * on rng again immediately.  in put_rng()
142 	if (rng)  in put_rng()
143 		kref_put(&rng->ref, cleanup_rng);  in put_rng()
147 static int hwrng_init(struct hwrng *rng)  in hwrng_init()  argument
149 	if (kref_get_unless_zero(&rng->ref))  in hwrng_init()
152 	if (rng->init) {  in hwrng_init()
155 		ret =  rng->init(rng);  in hwrng_init()
160 	kref_init(&rng->ref);  in hwrng_init()
161 	reinit_completion(&rng->cleanup_done);  in hwrng_init()
164 	current_quality = rng->quality ? : default_quality;  in hwrng_init()
186 static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,  in rng_get_data()  argument
191 	if (rng->read)  in rng_get_data()
192 		return rng->read(rng, (void *)buffer, size, wait);  in rng_get_data()
194 	if (rng->data_present)  in rng_get_data()
195 		present = rng->data_present(rng, wait);  in rng_get_data()
200 		return rng->data_read(rng, (u32 *)buffer);  in rng_get_data()
211 	struct hwrng *rng;  in rng_dev_read()  local
214 		rng = get_current_rng();  in rng_dev_read()
215 		if (IS_ERR(rng)) {  in rng_dev_read()
216 			err = PTR_ERR(rng);  in rng_dev_read()
219 		if (!rng) {  in rng_dev_read()
229 			bytes_read = rng_get_data(rng, rng_buffer,  in rng_dev_read()
262 		put_rng(rng);  in rng_dev_read()
278 	put_rng(rng);  in rng_dev_read()
327 	struct hwrng *rng, *old_rng, *new_rng;  in hwrng_attr_current_store()  local
337 		list_for_each_entry(rng, &rng_list, list) {  in hwrng_attr_current_store()
338 			if (sysfs_streq(rng->name, buf)) {  in hwrng_attr_current_store()
340 				err = set_current_rng(rng);  in hwrng_attr_current_store()
362 	struct hwrng *rng;  in hwrng_attr_current_show()  local
364 	rng = get_current_rng();  in hwrng_attr_current_show()
365 	if (IS_ERR(rng))  in hwrng_attr_current_show()
366 		return PTR_ERR(rng);  in hwrng_attr_current_show()
368 	ret = snprintf(buf, PAGE_SIZE, "%s\n", rng ? rng->name : "none");  in hwrng_attr_current_show()
369 	put_rng(rng);  in hwrng_attr_current_show()
379 	struct hwrng *rng;  in hwrng_attr_available_show()  local
385 	list_for_each_entry(rng, &rng_list, list) {  in hwrng_attr_available_show()
386 		strlcat(buf, rng->name, PAGE_SIZE);  in hwrng_attr_available_show()
436 		struct hwrng *rng;  in hwrng_fillfn()  local
438 		rng = get_current_rng();  in hwrng_fillfn()
439 		if (IS_ERR(rng) || !rng)  in hwrng_fillfn()
442 		rc = rng_get_data(rng, rng_fillbuf,  in hwrng_fillfn()
445 		put_rng(rng);  in hwrng_fillfn()
468 int hwrng_register(struct hwrng *rng)  in hwrng_register()  argument
475 	if (!rng->name || (!rng->data_read && !rng->read))  in hwrng_register()
483 		if (strcmp(tmp->name, rng->name) == 0)  in hwrng_register()
487 	init_completion(&rng->cleanup_done);  in hwrng_register()
488 	complete(&rng->cleanup_done);  in hwrng_register()
493 		if (tmp->quality < rng->quality)  in hwrng_register()
496 	list_add_tail(&rng->list, rng_list_ptr);  in hwrng_register()
499 	    (!cur_rng_set_by_user && rng->quality > current_rng->quality)) {  in hwrng_register()
501 		 * Set new rng as current as the new rng source  in hwrng_register()
505 		err = set_current_rng(rng);  in hwrng_register()
512 		kref_get(&rng->ref);  in hwrng_register()
515 	if (is_new_current || !rng->init) {  in hwrng_register()
518 		 * the system.  If this rng device isn't going to be  in hwrng_register()
523 		add_early_randomness(rng);  in hwrng_register()
526 		put_rng(rng);  in hwrng_register()
535 void hwrng_unregister(struct hwrng *rng)  in hwrng_unregister()  argument
543 	list_del(&rng->list);  in hwrng_unregister()
544 	if (current_rng == rng) {  in hwrng_unregister()
566 	wait_for_completion(&rng->cleanup_done);  in hwrng_unregister()
585 int devm_hwrng_register(struct device *dev, struct hwrng *rng)  in devm_hwrng_register()  argument
594 	error = hwrng_register(rng);  in devm_hwrng_register()
600 	*ptr = rng;  in devm_hwrng_register()
606 void devm_hwrng_unregister(struct device *dev, struct hwrng *rng)  in devm_hwrng_unregister()  argument
608 	devres_release(dev, devm_hwrng_release, devm_hwrng_match, rng);  in devm_hwrng_unregister()
650 MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver");