xref: /optee_os/core/drivers/stm32_rng.c (revision 209c34dc03563af70f1e406f304008495dae7a5e)
1 // SPDX-License-Identifier: BSD-3-Clause
2 /*
3  * Copyright (c) 2018-2023, STMicroelectronics
4  */
5 
6 #include <assert.h>
7 #include <drivers/clk.h>
8 #include <drivers/clk_dt.h>
9 #include <drivers/rstctrl.h>
10 #include <io.h>
11 #include <kernel/boot.h>
12 #include <kernel/delay.h>
13 #include <kernel/dt.h>
14 #include <kernel/dt_driver.h>
15 #include <kernel/panic.h>
16 #include <kernel/pm.h>
17 #include <kernel/thread.h>
18 #include <libfdt.h>
19 #include <mm/core_memprot.h>
20 #include <rng_support.h>
21 #include <stdbool.h>
22 #include <stm32_util.h>
23 #include <string.h>
24 #include <tee/tee_cryp_utl.h>
25 #include <util.h>
26 
27 #define RNG_CR			U(0x00)
28 #define RNG_SR			U(0x04)
29 #define RNG_DR			U(0x08)
30 #define RNG_NSCR		U(0x0C)
31 #define RNG_HTCR		U(0x10)
32 #define RNG_VERR		U(0x3F4)
33 
34 #define RNG_CR_RNGEN		BIT(2)
35 #define RNG_CR_IE		BIT(3)
36 #define RNG_CR_CED		BIT(5)
37 #define RNG_CR_CONFIG1		GENMASK_32(11, 8)
38 #define RNG_CR_NISTC		BIT(12)
39 #define RNG_CR_POWER_OPTIM	BIT(13)
40 #define RNG_CR_CONFIG2		GENMASK_32(15, 13)
41 #define RNG_CR_CLKDIV		GENMASK_32(19, 16)
42 #define RNG_CR_CLKDIV_SHIFT	U(16)
43 #define RNG_CR_CONFIG3		GENMASK_32(25, 20)
44 #define RNG_CR_CONDRST		BIT(30)
45 #define RNG_CR_ENTROPY_SRC_MASK	(RNG_CR_CONFIG1 | RNG_CR_NISTC | \
46 				 RNG_CR_CONFIG2 | RNG_CR_CONFIG3)
47 
48 #define RNG_SR_DRDY		BIT(0)
49 #define RNG_SR_CECS		BIT(1)
50 #define RNG_SR_SECS		BIT(2)
51 #define RNG_SR_CEIS		BIT(5)
52 #define RNG_SR_SEIS		BIT(6)
53 
54 #define RNG_NSCR_MASK		GENMASK_32(17, 0)
55 
56 #define RNG_VERR_MINOR_MASK	GENMASK_32(3, 0)
57 #define RNG_VERR_MAJOR_MASK	GENMASK_32(7, 4)
58 #define RNG_VERR_MAJOR_SHIFT	U(4)
59 
60 #if TRACE_LEVEL > TRACE_DEBUG
61 #define RNG_READY_TIMEOUT_US	U(100000)
62 #else
63 #define RNG_READY_TIMEOUT_US	U(10000)
64 #endif
65 #define RNG_RESET_TIMEOUT_US	U(1000)
66 
67 #define RNG_FIFO_BYTE_DEPTH	U(16)
68 
69 #define RNG_CONFIG_MASK		(RNG_CR_ENTROPY_SRC_MASK | RNG_CR_CED | \
70 				 RNG_CR_CLKDIV)
71 
72 struct stm32_rng_driver_data {
73 	unsigned long max_noise_clk_freq;
74 	unsigned long nb_clock;
75 	uint32_t cr;
76 	uint32_t nscr;
77 	uint32_t htcr;
78 	bool has_power_optim;
79 	bool has_cond_reset;
80 };
81 
82 struct stm32_rng_instance {
83 	struct io_pa_va base;
84 	struct clk *clock;
85 	struct clk *bus_clock;
86 	struct rstctrl *rstctrl;
87 	const struct stm32_rng_driver_data *ddata;
88 	unsigned int lock;
89 	uint64_t error_to_ref;
90 	uint32_t pm_cr;
91 	uint32_t pm_health;
92 	uint32_t pm_noise_ctrl;
93 	uint32_t health_test_conf;
94 	uint32_t noise_ctrl_conf;
95 	uint32_t rng_config;
96 	bool release_post_boot;
97 	bool clock_error;
98 	bool error_conceal;
99 };
100 
101 /* Expect at most a single RNG instance */
102 static struct stm32_rng_instance *stm32_rng;
103 
104 static vaddr_t get_base(void)
105 {
106 	assert(stm32_rng);
107 
108 	return io_pa_or_va(&stm32_rng->base, 1);
109 }
110 
111 /*
112  * Extracts from the STM32 RNG specification when RNG supports CONDRST.
113  *
114  * When a noise source (or seed) error occurs, the RNG stops generating
115  * random numbers and sets to “1” both SEIS and SECS bits to indicate
116  * that a seed error occurred. (...)
117  *
118  * 1. Software reset by writing CONDRST at 1 and at 0 (see bitfield
119  * description for details). This step is needed only if SECS is set.
120  * Indeed, when SEIS is set and SECS is cleared it means RNG performed
121  * the reset automatically (auto-reset).
122  * 2. If SECS was set in step 1 (no auto-reset) wait for CONDRST
123  * to be cleared in the RNG_CR register, then confirm that SEIS is
124  * cleared in the RNG_SR register. Otherwise just clear SEIS bit in
125  * the RNG_SR register.
126  * 3. If SECS was set in step 1 (no auto-reset) wait for SECS to be
127  * cleared by RNG. The random number generation is now back to normal.
128  */
129 static void conceal_seed_error_cond_reset(void)
130 {
131 	struct stm32_rng_instance *dev = stm32_rng;
132 	vaddr_t rng_base = get_base();
133 
134 	if (!dev->error_conceal) {
135 		uint32_t sr = io_read32(rng_base + RNG_SR);
136 
137 		if (sr & RNG_SR_SECS) {
138 			/* Conceal by resetting the subsystem (step 1.) */
139 			io_setbits32(rng_base + RNG_CR, RNG_CR_CONDRST);
140 			io_clrbits32(rng_base + RNG_CR, RNG_CR_CONDRST);
141 
142 			/* Arm timeout for error_conceal sequence */
143 			dev->error_to_ref =
144 				timeout_init_us(RNG_READY_TIMEOUT_US);
145 			dev->error_conceal = true;
146 		} else {
147 			/* RNG auto-reset (step 2.) */
148 			io_clrbits32(rng_base + RNG_SR, RNG_SR_SEIS);
149 		}
150 	} else {
151 		/* Measure time before possible reschedule */
152 		bool timed_out = timeout_elapsed(dev->error_to_ref);
153 
154 		/* Wait CONDRST is cleared (step 2.) */
155 		if (io_read32(rng_base + RNG_CR) & RNG_CR_CONDRST) {
156 			if (timed_out)
157 				panic();
158 
159 			/* Wait subsystem reset cycle completes */
160 			return;
161 		}
162 
163 		/* Check SEIS is cleared (step 2.) */
164 		if (io_read32(rng_base + RNG_SR) & RNG_SR_SEIS)
165 			panic();
166 
167 		/* Wait SECS is cleared (step 3.) */
168 		if (io_read32(rng_base + RNG_SR) & RNG_SR_SECS) {
169 			if (timed_out)
170 				panic();
171 
172 			/* Wait subsystem reset cycle completes */
173 			return;
174 		}
175 
176 		dev->error_conceal = false;
177 	}
178 }
179 
180 /*
181  * Extracts from the STM32 RNG specification, when CONDRST is not supported
182  *
183  * When a noise source (or seed) error occurs, the RNG stops generating
184  * random numbers and sets to “1” both SEIS and SECS bits to indicate
185  * that a seed error occurred. (...)
186  *
187  * The following sequence shall be used to fully recover from a seed
188  * error after the RNG initialization:
189  * 1. Clear the SEIS bit by writing it to “0”.
190  * 2. Read out 12 words from the RNG_DR register, and discard each of
191  * them in order to clean the pipeline.
192  * 3. Confirm that SEIS is still cleared. Random number generation is
193  * back to normal.
194  */
195 static void conceal_seed_error_sw_reset(void)
196 {
197 	vaddr_t rng_base = get_base();
198 	size_t i = 0;
199 
200 	io_clrbits32(rng_base + RNG_SR, RNG_SR_SEIS);
201 
202 	for (i = 12; i != 0; i--)
203 		(void)io_read32(rng_base + RNG_DR);
204 
205 	if (io_read32(rng_base + RNG_SR) & RNG_SR_SEIS)
206 		panic("RNG noise");
207 }
208 
209 static void conceal_seed_error(void)
210 {
211 	if (stm32_rng->ddata->has_cond_reset)
212 		conceal_seed_error_cond_reset();
213 	else
214 		conceal_seed_error_sw_reset();
215 }
216 
217 static TEE_Result read_available(vaddr_t rng_base, uint8_t *out, size_t *size)
218 {
219 	struct stm32_rng_instance *dev = stm32_rng;
220 	uint8_t *buf = NULL;
221 	size_t req_size = 0;
222 	size_t len = 0;
223 
224 	if (dev->error_conceal || io_read32(rng_base + RNG_SR) & RNG_SR_SEIS)
225 		conceal_seed_error();
226 
227 	if (!(io_read32(rng_base + RNG_SR) & RNG_SR_DRDY)) {
228 		FMSG("RNG not ready");
229 		return TEE_ERROR_NO_DATA;
230 	}
231 
232 	if (io_read32(rng_base + RNG_SR) & RNG_SR_SEIS) {
233 		FMSG("RNG noise error");
234 		return TEE_ERROR_NO_DATA;
235 	}
236 
237 	buf = out;
238 	req_size = MIN(RNG_FIFO_BYTE_DEPTH, *size);
239 	len = req_size;
240 
241 	/* RNG is ready: read up to 4 32bit words */
242 	while (len) {
243 		uint32_t data32 = 0;
244 		size_t sz = MIN(len, sizeof(uint32_t));
245 
246 		if (!(io_read32(rng_base + RNG_SR) & RNG_SR_DRDY))
247 			break;
248 		data32 = io_read32(rng_base + RNG_DR);
249 
250 		/* Late seed error case: DR being 0 is an error status */
251 		if (!data32) {
252 			conceal_seed_error();
253 			return TEE_ERROR_NO_DATA;
254 		}
255 
256 		memcpy(buf, &data32, sz);
257 		buf += sz;
258 		len -= sz;
259 	}
260 
261 	*size = req_size - len;
262 
263 	return TEE_SUCCESS;
264 }
265 
266 static uint32_t stm32_rng_clock_freq_restrain(void)
267 {
268 	struct stm32_rng_instance *dev = stm32_rng;
269 	unsigned long clock_rate = 0;
270 	uint32_t clock_div = 0;
271 
272 	clock_rate = clk_get_rate(dev->clock);
273 
274 	/*
275 	 * Get the exponent to apply on the CLKDIV field in RNG_CR register
276 	 * No need to handle the case when clock-div > 0xF as it is physically
277 	 * impossible
278 	 */
279 	while ((clock_rate >> clock_div) > dev->ddata->max_noise_clk_freq)
280 		clock_div++;
281 
282 	DMSG("RNG clk rate : %lu", clk_get_rate(dev->clock) >> clock_div);
283 
284 	return clock_div;
285 }
286 
287 static TEE_Result init_rng(void)
288 {
289 	vaddr_t rng_base = get_base();
290 	uint32_t cr_ced_mask = 0;
291 	uint32_t value = 0;
292 
293 	if (!stm32_rng->clock_error)
294 		cr_ced_mask = RNG_CR_CED;
295 
296 	/* Clean error indications */
297 	io_write32(rng_base + RNG_SR, 0);
298 
299 	if (stm32_rng->ddata->has_cond_reset) {
300 		uint32_t clock_div = stm32_rng_clock_freq_restrain();
301 
302 		/*
303 		 * Keep default RNG configuration if none was specified.
304 		 * 0 is an invalid value as it disables all entropy sources.
305 		 */
306 		if (!stm32_rng->rng_config)
307 			stm32_rng->rng_config = io_read32(rng_base + RNG_CR) &
308 						RNG_CR_ENTROPY_SRC_MASK;
309 
310 		/*
311 		 * Configuration must be set in the same access that sets
312 		 * RNG_CR_CONDRST bit. Otherwise, the configuration setting is
313 		 * not taken into account. CONFIGLOCK bit is always cleared at
314 		 * this stage.
315 		 */
316 		io_clrsetbits32(rng_base + RNG_CR, RNG_CONFIG_MASK,
317 				stm32_rng->rng_config | RNG_CR_CONDRST |
318 				cr_ced_mask |
319 				SHIFT_U32(clock_div, RNG_CR_CLKDIV_SHIFT));
320 
321 		/*
322 		 * Write health test and noise source control configuration
323 		 * according to current RNG entropy source configuration
324 		 */
325 		if (stm32_rng->noise_ctrl_conf)
326 			io_write32(rng_base + RNG_NSCR,
327 				   stm32_rng->noise_ctrl_conf);
328 
329 		if (stm32_rng->health_test_conf)
330 			io_write32(rng_base + RNG_HTCR,
331 				   stm32_rng->health_test_conf);
332 
333 		io_clrsetbits32(rng_base + RNG_CR, RNG_CR_CONDRST,
334 				RNG_CR_RNGEN);
335 
336 		if (IO_READ32_POLL_TIMEOUT(rng_base + RNG_CR, value,
337 					   !(value & RNG_CR_CONDRST), 0,
338 					   RNG_READY_TIMEOUT_US))
339 			panic();
340 
341 		DMSG("RNG control register %#"PRIx32,
342 		     io_read32(rng_base + RNG_CR));
343 		DMSG("RNG noise source control register %#"PRIx32,
344 		     io_read32(rng_base + RNG_NSCR));
345 		DMSG("RNG health test register %#"PRIx32,
346 		     io_read32(rng_base + RNG_HTCR));
347 	} else {
348 		io_setbits32(rng_base + RNG_CR, RNG_CR_RNGEN | cr_ced_mask);
349 	}
350 
351 	if (IO_READ32_POLL_TIMEOUT(rng_base + RNG_SR, value,
352 				   value & RNG_SR_DRDY, 0,
353 				   RNG_READY_TIMEOUT_US))
354 		return TEE_ERROR_GENERIC;
355 
356 	return TEE_SUCCESS;
357 }
358 
359 static TEE_Result stm32_rng_read(uint8_t *out, size_t size)
360 {
361 	TEE_Result rc = TEE_ERROR_GENERIC;
362 	bool burst_timeout = false;
363 	uint64_t timeout_ref = 0;
364 	uint32_t exceptions = 0;
365 	uint8_t *out_ptr = out;
366 	vaddr_t rng_base = 0;
367 	size_t out_size = 0;
368 
369 	if (!stm32_rng) {
370 		DMSG("No RNG");
371 		return TEE_ERROR_NOT_SUPPORTED;
372 	}
373 
374 	rc = clk_enable(stm32_rng->clock);
375 	if (rc)
376 		return rc;
377 
378 	if (stm32_rng->bus_clock) {
379 		rc = clk_enable(stm32_rng->bus_clock);
380 		if (rc) {
381 			clk_disable(stm32_rng->clock);
382 			return rc;
383 		}
384 	}
385 
386 	rng_base = get_base();
387 
388 	/* Arm timeout */
389 	timeout_ref = timeout_init_us(RNG_READY_TIMEOUT_US);
390 	burst_timeout = false;
391 
392 	while (out_size < size) {
393 		/* Read by chunks of the size the RNG FIFO depth */
394 		size_t sz = size - out_size;
395 
396 		exceptions = may_spin_lock(&stm32_rng->lock);
397 
398 		rc = read_available(rng_base, out_ptr, &sz);
399 
400 		/* Raise timeout only if we failed to get some samples */
401 		assert(!rc || rc == TEE_ERROR_NO_DATA);
402 		if (rc)
403 			burst_timeout = timeout_elapsed(timeout_ref);
404 
405 		may_spin_unlock(&stm32_rng->lock, exceptions);
406 
407 		if (burst_timeout) {
408 			rc = TEE_ERROR_GENERIC;
409 			goto out;
410 		}
411 
412 		if (!rc) {
413 			out_size += sz;
414 			out_ptr += sz;
415 			/* Re-arm timeout */
416 			timeout_ref = timeout_init_us(RNG_READY_TIMEOUT_US);
417 			burst_timeout = false;
418 		}
419 	}
420 
421 out:
422 	assert(!rc || rc == TEE_ERROR_GENERIC);
423 	clk_disable(stm32_rng->clock);
424 	if (stm32_rng->bus_clock)
425 		clk_disable(stm32_rng->bus_clock);
426 
427 	return rc;
428 }
429 
430 #ifdef CFG_WITH_SOFTWARE_PRNG
431 /* Override weak plat_rng_init with platform handler to seed PRNG */
432 void plat_rng_init(void)
433 {
434 	uint8_t seed[RNG_FIFO_BYTE_DEPTH] = { };
435 
436 	if (stm32_rng_read(seed, sizeof(seed)))
437 		panic();
438 
439 	if (crypto_rng_init(seed, sizeof(seed)))
440 		panic();
441 
442 	DMSG("PRNG seeded with RNG");
443 }
444 #else
445 TEE_Result hw_get_random_bytes(void *out, size_t size)
446 {
447 	return stm32_rng_read(out, size);
448 }
449 
450 void plat_rng_init(void)
451 {
452 }
453 #endif
454 
455 static TEE_Result stm32_rng_pm_resume(void)
456 {
457 	vaddr_t base = get_base();
458 
459 	/* Clean error indications */
460 	io_write32(base + RNG_SR, 0);
461 
462 	if (stm32_rng->ddata->has_cond_reset) {
463 		uint64_t timeout_ref = 0;
464 
465 		/*
466 		 * Configuration must be set in the same access that sets
467 		 * RNG_CR_CONDRST bit. Otherwise, the configuration setting is
468 		 * not taken into account. CONFIGLOCK bit is always cleared in
469 		 * this configuration.
470 		 */
471 		io_write32(base + RNG_CR, stm32_rng->pm_cr | RNG_CR_CONDRST);
472 
473 		/* Restore health test and noise control configuration */
474 		io_write32(base + RNG_NSCR, stm32_rng->pm_noise_ctrl);
475 		io_write32(base + RNG_HTCR, stm32_rng->pm_health);
476 
477 		io_clrsetbits32(base + RNG_CR, RNG_CR_CONDRST, RNG_CR_RNGEN);
478 
479 		timeout_ref = timeout_init_us(RNG_READY_TIMEOUT_US);
480 		while (io_read32(base + RNG_CR) & RNG_CR_CONDRST)
481 			if (timeout_elapsed(timeout_ref))
482 				break;
483 		if (io_read32(base + RNG_CR) & RNG_CR_CONDRST)
484 			panic();
485 	} else {
486 		io_write32(base + RNG_CR, RNG_CR_RNGEN | stm32_rng->pm_cr);
487 	}
488 
489 	return TEE_SUCCESS;
490 }
491 
492 static TEE_Result stm32_rng_pm_suspend(void)
493 {
494 	vaddr_t rng_base = get_base();
495 
496 	stm32_rng->pm_cr = io_read32(rng_base + RNG_CR);
497 
498 	if (stm32_rng->ddata->has_cond_reset) {
499 		stm32_rng->pm_health = io_read32(rng_base + RNG_HTCR);
500 		stm32_rng->pm_noise_ctrl = io_read32(rng_base + RNG_NSCR);
501 	}
502 
503 	if (stm32_rng->ddata->has_power_optim) {
504 		uint64_t timeout_ref = 0;
505 
506 		/*
507 		 * As per reference manual, it is recommended to set
508 		 * RNG_CONFIG2[bit0] when RNG power consumption is critical.
509 		 */
510 		io_setbits32(rng_base + RNG_CR, RNG_CR_POWER_OPTIM |
511 				RNG_CR_CONDRST);
512 		io_clrbits32(rng_base + RNG_CR, RNG_CR_CONDRST);
513 
514 		timeout_ref = timeout_init_us(RNG_READY_TIMEOUT_US);
515 		while (io_read32(rng_base + RNG_CR) & RNG_CR_CONDRST)
516 			if (timeout_elapsed(timeout_ref))
517 				break;
518 		if (io_read32(rng_base + RNG_CR) & RNG_CR_CONDRST)
519 			panic();
520 	} else {
521 		io_clrbits32(rng_base + RNG_CR, RNG_CR_RNGEN);
522 	}
523 
524 	return TEE_SUCCESS;
525 }
526 
527 static TEE_Result
528 stm32_rng_pm(enum pm_op op, unsigned int pm_hint __unused,
529 	     const struct pm_callback_handle *pm_handle __unused)
530 {
531 	TEE_Result res = TEE_ERROR_GENERIC;
532 
533 	assert(stm32_rng && (op == PM_OP_SUSPEND || op == PM_OP_RESUME));
534 
535 	res = clk_enable(stm32_rng->clock);
536 	if (res)
537 		return res;
538 
539 	if (stm32_rng->bus_clock) {
540 		res = clk_enable(stm32_rng->bus_clock);
541 		if (res) {
542 			clk_disable(stm32_rng->clock);
543 			return res;
544 		}
545 	}
546 
547 	if (op == PM_OP_RESUME)
548 		res = stm32_rng_pm_resume();
549 	else
550 		res = stm32_rng_pm_suspend();
551 
552 	clk_disable(stm32_rng->clock);
553 	if (stm32_rng->bus_clock)
554 		clk_disable(stm32_rng->bus_clock);
555 
556 	return res;
557 }
558 DECLARE_KEEP_PAGER(stm32_rng_pm);
559 
560 static TEE_Result stm32_rng_parse_fdt(const void *fdt, int node)
561 {
562 	TEE_Result res = TEE_ERROR_GENERIC;
563 	struct dt_node_info dt_rng = { };
564 
565 	fdt_fill_device_info(fdt, &dt_rng, node);
566 	if (dt_rng.reg == DT_INFO_INVALID_REG)
567 		return TEE_ERROR_BAD_PARAMETERS;
568 
569 	stm32_rng->base.pa = dt_rng.reg;
570 	stm32_rng->base.va = io_pa_or_va_secure(&stm32_rng->base,
571 						dt_rng.reg_size);
572 	assert(stm32_rng->base.va);
573 
574 	res = rstctrl_dt_get_by_index(fdt, node, 0, &stm32_rng->rstctrl);
575 	if (res != TEE_SUCCESS && res != TEE_ERROR_ITEM_NOT_FOUND)
576 		return res;
577 
578 	if (stm32_rng->ddata->nb_clock > 1) {
579 		res = clk_dt_get_by_name(fdt, node, "rng_clk",
580 					 &stm32_rng->clock);
581 		if (res)
582 			return res;
583 
584 		res = clk_dt_get_by_name(fdt, node, "rng_hclk",
585 					 &stm32_rng->bus_clock);
586 		if (res)
587 			return res;
588 	} else {
589 		res = clk_dt_get_by_index(fdt, node, 0, &stm32_rng->clock);
590 		if (res)
591 			return res;
592 	}
593 
594 	if (fdt_getprop(fdt, node, "clock-error-detect", NULL))
595 		stm32_rng->clock_error = true;
596 
597 	/* Release device if not used at runtime or for pm transitions */
598 	stm32_rng->release_post_boot = IS_ENABLED(CFG_WITH_SOFTWARE_PRNG) &&
599 				       !IS_ENABLED(CFG_PM);
600 
601 	stm32_rng->rng_config = stm32_rng->ddata->cr;
602 	if (stm32_rng->rng_config & ~RNG_CR_ENTROPY_SRC_MASK)
603 		panic("Incorrect entropy source configuration");
604 	stm32_rng->health_test_conf = stm32_rng->ddata->htcr;
605 	stm32_rng->noise_ctrl_conf = stm32_rng->ddata->nscr;
606 	if (stm32_rng->noise_ctrl_conf & ~RNG_NSCR_MASK)
607 		panic("Incorrect noise source control configuration");
608 
609 	return TEE_SUCCESS;
610 }
611 
612 static TEE_Result stm32_rng_probe(const void *fdt, int offs,
613 				  const void *compat_data)
614 {
615 	TEE_Result res = TEE_ERROR_GENERIC;
616 	unsigned int __maybe_unused version = 0;
617 
618 	/* Expect a single RNG instance */
619 	assert(!stm32_rng);
620 
621 	stm32_rng = calloc(1, sizeof(*stm32_rng));
622 	if (!stm32_rng)
623 		panic();
624 
625 	stm32_rng->ddata = compat_data;
626 	assert(stm32_rng->ddata);
627 
628 	res = stm32_rng_parse_fdt(fdt, offs);
629 	if (res)
630 		goto err;
631 
632 	res = clk_enable(stm32_rng->clock);
633 	if (res)
634 		goto err;
635 
636 	if (stm32_rng->bus_clock) {
637 		res = clk_enable(stm32_rng->bus_clock);
638 		if (res) {
639 			clk_disable(stm32_rng->clock);
640 			goto err;
641 		}
642 	}
643 
644 	version = io_read32(get_base() + RNG_VERR);
645 	DMSG("RNG version Major %u, Minor %u",
646 	     (version & RNG_VERR_MAJOR_MASK) >> RNG_VERR_MAJOR_SHIFT,
647 	     version & RNG_VERR_MINOR_MASK);
648 
649 	if (stm32_rng->rstctrl &&
650 	    rstctrl_assert_to(stm32_rng->rstctrl, RNG_RESET_TIMEOUT_US)) {
651 		res = TEE_ERROR_GENERIC;
652 		goto err_clk;
653 	}
654 
655 	if (stm32_rng->rstctrl &&
656 	    rstctrl_deassert_to(stm32_rng->rstctrl, RNG_RESET_TIMEOUT_US)) {
657 		res = TEE_ERROR_GENERIC;
658 		goto err_clk;
659 	}
660 
661 	res = init_rng();
662 	if (res)
663 		goto err_clk;
664 
665 	clk_disable(stm32_rng->clock);
666 	if (stm32_rng->bus_clock)
667 		clk_disable(stm32_rng->bus_clock);
668 
669 	if (stm32_rng->release_post_boot)
670 		stm32mp_register_non_secure_periph_iomem(stm32_rng->base.pa);
671 	else
672 		stm32mp_register_secure_periph_iomem(stm32_rng->base.pa);
673 
674 	/* Power management implementation expects both or none are set */
675 	assert(stm32_rng->ddata->has_power_optim ==
676 	       stm32_rng->ddata->has_cond_reset);
677 
678 	register_pm_core_service_cb(stm32_rng_pm, &stm32_rng, "rng-service");
679 
680 	return TEE_SUCCESS;
681 
682 err_clk:
683 	clk_disable(stm32_rng->clock);
684 	if (stm32_rng->bus_clock)
685 		clk_disable(stm32_rng->bus_clock);
686 err:
687 	free(stm32_rng);
688 	stm32_rng = NULL;
689 
690 	return res;
691 }
692 
693 static const struct stm32_rng_driver_data mp13_data[] = {
694 	{
695 		.max_noise_clk_freq = U(48000000),
696 		.nb_clock = 1,
697 		.has_cond_reset = true,
698 		.has_power_optim = true,
699 		.cr = 0x00F00D00,
700 		.nscr = 0x2B5BB,
701 		.htcr = 0x969D,
702 	},
703 };
704 
705 static const struct stm32_rng_driver_data mp15_data[] = {
706 	{
707 		.max_noise_clk_freq = U(48000000),
708 		.nb_clock = 1,
709 		.has_cond_reset = false,
710 		.has_power_optim = false,
711 	},
712 };
713 DECLARE_KEEP_PAGER(mp15_data);
714 
715 static const struct stm32_rng_driver_data mp25_data[] = {
716 	{
717 		.max_noise_clk_freq = U(48000000),
718 		.nb_clock = 2,
719 		.has_cond_reset = true,
720 		.has_power_optim = true,
721 		.cr = 0x00F00D00,
722 		.nscr = 0x2B5BB,
723 		.htcr = 0x969D,
724 	},
725 };
726 
727 static const struct dt_device_match rng_match_table[] = {
728 	{ .compatible = "st,stm32-rng", .compat_data = &mp15_data },
729 	{ .compatible = "st,stm32mp13-rng", .compat_data = &mp13_data },
730 	{ .compatible = "st,stm32mp25-rng", .compat_data = &mp25_data },
731 	{ }
732 };
733 
734 DEFINE_DT_DRIVER(stm32_rng_dt_driver) = {
735 	.name = "stm32_rng",
736 	.match_table = rng_match_table,
737 	.probe = stm32_rng_probe,
738 };
739 
740 static TEE_Result stm32_rng_release(void)
741 {
742 	if (stm32_rng && stm32_rng->release_post_boot) {
743 		DMSG("Release RNG driver");
744 		free(stm32_rng);
745 		stm32_rng = NULL;
746 	}
747 
748 	return TEE_SUCCESS;
749 }
750 
751 release_init_resource(stm32_rng_release);
752