xref: /optee_os/core/kernel/dt_driver.c (revision 74bd878e0765e11f55580667e985bd408aed6167)
1 // SPDX-License-Identifier: BSD-2-Clause
2 /*
3  * Copyright (c) 2021, Linaro Limited
4  * Copyright (c) 2021, Bootlin
5  * Copyright (c) 2021, Linaro Limited
6  * Copyright (c) 2021, STMicroelectronics
7  */
8 
9 #include <assert.h>
10 #include <config.h>
11 #include <initcall.h>
12 #include <kernel/boot.h>
13 #include <kernel/dt.h>
14 #include <kernel/dt_driver.h>
15 #include <libfdt.h>
16 #include <malloc.h>
17 #include <sys/queue.h>
18 #include <tee_api_defines_extensions.h>
19 #include <tee_api_types.h>
20 
21 /*
22  * struct dt_driver_probe - Node instance in secure FDT to probe a driver for
23  *
24  * @link: List hook
25  * @nodeoffset: Node offset of device referenced in the FDT
26  * @type: One of DT_DRIVER_* or DT_DRIVER_NOTYPE.
27  * @deferrals: Driver probe deferrals count
28  * @dt_drv: Matching driver to probe if found or NULL
29  * @dm: Matching reference if applicable or NULL
30  */
31 struct dt_driver_probe {
32 	int nodeoffset;
33 	enum dt_driver_type type;
34 	unsigned int deferrals;
35 	const struct dt_driver *dt_drv;
36 	const struct dt_device_match *dm;
37 	TAILQ_ENTRY(dt_driver_probe) link;
38 };
39 
40 /*
41  * struct dt_driver_provider - DT related info on probed device
42  *
43  * Saves information on the probed device so that device
44  * drivers can get resources from DT phandle and related arguments.
45  *
46  * @nodeoffset: Node offset of device referenced in the FDT
47  * @type: One of DT_DRIVER_* or DT_DRIVER_NOTYPE.
48  * @provider_cells: Cells count in the FDT used by the driver's references
49  * @get_of_device: Function to get driver's device ref from phandle data
50  * @priv_data: Driver private data passed as @get_of_device argument
51  * @link: Reference in DT driver providers list
52  */
53 struct dt_driver_provider {
54 	int nodeoffset;
55 	enum dt_driver_type type;
56 	unsigned int provider_cells;
57 	uint32_t phandle;
58 	get_of_device_func get_of_device;
59 	void *priv_data;
60 	SLIST_ENTRY(dt_driver_provider) link;
61 };
62 
63 /*
64  * Device driver providers are able to provide a driver specific instance
65  * related to device phandle arguments found in the secure embedded FDT.
66  */
67 static SLIST_HEAD(, dt_driver_provider) dt_driver_provider_list =
68 	SLIST_HEAD_INITIALIZER(dt_driver_provider_list);
69 
70 /* FDT nodes for which a matching driver is to be probed */
71 static TAILQ_HEAD(dt_driver_probe_head, dt_driver_probe) dt_driver_probe_list =
72 	TAILQ_HEAD_INITIALIZER(dt_driver_probe_list);
73 
74 /* FDT nodes for which a matching driver has been successfully probed */
75 static TAILQ_HEAD(, dt_driver_probe) dt_driver_ready_list =
76 	TAILQ_HEAD_INITIALIZER(dt_driver_ready_list);
77 
78 /* List of the nodes for which a compatible driver but reported a failure */
79 static TAILQ_HEAD(, dt_driver_probe) dt_driver_failed_list =
80 	TAILQ_HEAD_INITIALIZER(dt_driver_failed_list);
81 
82 /* Flag enabled when a new node (possibly typed) is added in the probe list */
83 static bool added_node;
84 
85 /* Resolve drivers dependencies on core crypto layer */
86 static bool tee_crypt_is_ready;
87 
88 void dt_driver_crypt_init_complete(void)
89 {
90 	assert(!tee_crypt_is_ready);
91 	tee_crypt_is_ready = true;
92 }
93 
94 TEE_Result dt_driver_get_crypto(void)
95 {
96 	if (tee_crypt_is_ready)
97 		return TEE_SUCCESS;
98 	else
99 		return TEE_ERROR_DEFER_DRIVER_INIT;
100 }
101 
102 static void assert_type_is_valid(enum dt_driver_type type)
103 {
104 	switch (type) {
105 	case DT_DRIVER_NOTYPE:
106 	case DT_DRIVER_CLK:
107 	case DT_DRIVER_RSTCTRL:
108 	case DT_DRIVER_UART:
109 		return;
110 	default:
111 		assert(0);
112 	}
113 }
114 
115 /*
116  * Driver provider registering API functions
117  */
118 
119 TEE_Result dt_driver_register_provider(const void *fdt, int nodeoffset,
120 				       get_of_device_func get_of_device,
121 				       void *priv, enum dt_driver_type type)
122 {
123 	struct dt_driver_provider *prv = NULL;
124 	int provider_cells = 0;
125 	uint32_t phandle = 0;
126 
127 	assert_type_is_valid(type);
128 
129 	provider_cells = fdt_get_dt_driver_cells(fdt, nodeoffset, type);
130 	if (provider_cells < 0) {
131 		DMSG("Failed to find provider cells: %d", provider_cells);
132 		return TEE_ERROR_GENERIC;
133 	}
134 
135 	phandle = fdt_get_phandle(fdt, nodeoffset);
136 	if (!phandle || phandle == (uint32_t)-1) {
137 		DMSG("Failed to find provide phandle");
138 		return TEE_ERROR_GENERIC;
139 	}
140 
141 	prv = calloc(1, sizeof(*prv));
142 	if (!prv)
143 		return TEE_ERROR_OUT_OF_MEMORY;
144 
145 	prv->nodeoffset = nodeoffset;
146 	prv->type = type;
147 	prv->provider_cells = provider_cells;
148 	prv->phandle = phandle;
149 	prv->get_of_device = get_of_device;
150 	prv->priv_data = priv;
151 
152 	SLIST_INSERT_HEAD(&dt_driver_provider_list, prv, link);
153 
154 	return TEE_SUCCESS;
155 }
156 
157 /*
158  * Helper functions for dt_drivers querying driver provider information
159  */
160 
161 int fdt_get_dt_driver_cells(const void *fdt, int nodeoffset,
162 			    enum dt_driver_type type)
163 {
164 	const char *cells_name = NULL;
165 	const fdt32_t *c = NULL;
166 	int len = 0;
167 
168 	switch (type) {
169 	case DT_DRIVER_CLK:
170 		cells_name = "#clock-cells";
171 		break;
172 	case DT_DRIVER_RSTCTRL:
173 		cells_name = "#reset-cells";
174 		break;
175 	default:
176 		panic();
177 	}
178 
179 	c = fdt_getprop(fdt, nodeoffset, cells_name, &len);
180 	if (!c)
181 		return len;
182 
183 	if (len != sizeof(*c))
184 		return -FDT_ERR_BADNCELLS;
185 
186 	return fdt32_to_cpu(*c);
187 }
188 
189 unsigned int dt_driver_provider_cells(struct dt_driver_provider *prv)
190 {
191 	return prv->provider_cells;
192 }
193 
194 struct dt_driver_provider *
195 dt_driver_get_provider_by_node(int nodeoffset, enum dt_driver_type type)
196 {
197 	struct dt_driver_provider *prv = NULL;
198 
199 	SLIST_FOREACH(prv, &dt_driver_provider_list, link)
200 		if (prv->nodeoffset == nodeoffset && prv->type == type)
201 			return prv;
202 
203 	return NULL;
204 }
205 
206 struct dt_driver_provider *
207 dt_driver_get_provider_by_phandle(uint32_t phandle, enum dt_driver_type type)
208 {
209 	struct dt_driver_provider *prv = NULL;
210 
211 	SLIST_FOREACH(prv, &dt_driver_provider_list, link)
212 		if (prv->phandle == phandle && prv->type == type)
213 			return prv;
214 
215 	return NULL;
216 }
217 
218 static void *device_from_provider_prop(struct dt_driver_provider *prv,
219 					  const uint32_t *prop,
220 					  TEE_Result *res)
221 {
222 	struct dt_driver_phandle_args *pargs = NULL;
223 	unsigned int n = 0;
224 	void *device = NULL;
225 
226 	pargs = calloc(1, prv->provider_cells * sizeof(uint32_t *) +
227 		       sizeof(*pargs));
228 	if (!pargs) {
229 		*res = TEE_ERROR_OUT_OF_MEMORY;
230 		return NULL;
231 	}
232 
233 	pargs->args_count = prv->provider_cells;
234 	for (n = 0; n < prv->provider_cells; n++)
235 		pargs->args[n] = fdt32_to_cpu(prop[n + 1]);
236 
237 	device = prv->get_of_device(pargs, prv->priv_data, res);
238 
239 	free(pargs);
240 
241 	return device;
242 }
243 
244 void *dt_driver_device_from_node_idx_prop(const char *prop_name,
245 					  const void *fdt, int nodeoffset,
246 					  unsigned int prop_idx,
247 					  enum dt_driver_type type,
248 					  TEE_Result *res)
249 {
250 	int len = 0;
251 	int idx = 0;
252 	int idx32 = 0;
253 	int prv_cells = 0;
254 	uint32_t phandle = 0;
255 	const uint32_t *prop = NULL;
256 	struct dt_driver_provider *prv = NULL;
257 
258 	prop = fdt_getprop(fdt, nodeoffset, prop_name, &len);
259 	if (!prop) {
260 		DMSG("Property %s missing in node %s", prop_name,
261 		     fdt_get_name(fdt, nodeoffset, NULL));
262 		*res = TEE_ERROR_GENERIC;
263 		return NULL;
264 	}
265 
266 	while (idx < len) {
267 		idx32 = idx / sizeof(uint32_t);
268 		phandle = fdt32_to_cpu(prop[idx32]);
269 		if (!phandle) {
270 			if (!prop_idx)
271 				break;
272 			idx += sizeof(phandle);
273 			prop_idx--;
274 			continue;
275 		}
276 
277 		prv = dt_driver_get_provider_by_phandle(phandle, type);
278 		if (!prv) {
279 			/* No provider registered yet */
280 			*res = TEE_ERROR_DEFER_DRIVER_INIT;
281 			return NULL;
282 		}
283 
284 		prv_cells = dt_driver_provider_cells(prv);
285 		if (prop_idx) {
286 			prop_idx--;
287 			idx += sizeof(phandle) + prv_cells * sizeof(uint32_t);
288 			continue;
289 		}
290 
291 		return device_from_provider_prop(prv, prop + idx32, res);
292 	}
293 
294 	*res = TEE_ERROR_GENERIC;
295 	return NULL;
296 }
297 
298 static void __maybe_unused print_probe_list(const void *fdt __maybe_unused)
299 {
300 	struct dt_driver_probe *elt = NULL;
301 	unsigned int count = 0;
302 
303 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
304 		count++;
305 
306 	DMSG("Probe list: %u elements", count);
307 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
308 		DMSG("|- Driver %s probes on node %s",
309 		     elt->dt_drv->name,
310 		     fdt_get_name(fdt, elt->nodeoffset, NULL));
311 
312 	DMSG("`- Probe list end");
313 
314 	count = 0;
315 	TAILQ_FOREACH(elt, &dt_driver_failed_list, link)
316 		count++;
317 
318 	DMSG("Failed list: %u elements", count);
319 	TAILQ_FOREACH(elt, &dt_driver_failed_list, link)
320 		EMSG("|- Driver %s on node %s failed", elt->dt_drv->name,
321 		     fdt_get_name(fdt, elt->nodeoffset, NULL));
322 
323 	DMSG("`- Failed list end");
324 }
325 
326 /*
327  * Probe element: push to ready list if succeeds, push to probe list if probe
328  * if deferred, panic with an error trace otherwise.
329  */
330 static TEE_Result probe_driver_node(const void *fdt,
331 				    struct dt_driver_probe *elt)
332 {
333 	TEE_Result res = TEE_ERROR_GENERIC;
334 	const char __maybe_unused *drv_name = NULL;
335 	const char __maybe_unused *node_name = NULL;
336 
337 	node_name = fdt_get_name(fdt, elt->nodeoffset, NULL);
338 	drv_name = elt->dt_drv->name;
339 
340 	if (!elt->dt_drv->probe) {
341 		DMSG("No probe operator for driver %s, skipped", drv_name);
342 		return TEE_SUCCESS;
343 	}
344 
345 	FMSG("Probing %s on node %s", drv_name, node_name);
346 
347 	res = elt->dt_drv->probe(fdt, elt->nodeoffset, elt->dm->compat_data);
348 	switch (res) {
349 	case TEE_SUCCESS:
350 		TAILQ_INSERT_HEAD(&dt_driver_ready_list, elt, link);
351 
352 		DMSG("element: %s on node %s initialized", drv_name, node_name);
353 		break;
354 	case TEE_ERROR_DEFER_DRIVER_INIT:
355 		elt->deferrals++;
356 		TAILQ_INSERT_TAIL(&dt_driver_probe_list, elt, link);
357 
358 		DMSG("element: %s on node %s deferred %u time(s)", drv_name,
359 		     node_name, elt->deferrals);
360 		break;
361 	default:
362 		TAILQ_INSERT_HEAD(&dt_driver_failed_list, elt, link);
363 
364 		EMSG("Failed to probe %s on node %s: %#"PRIx32,
365 		     drv_name, node_name, res);
366 		break;
367 	}
368 
369 	return res;
370 }
371 
372 static TEE_Result alloc_elt_and_probe(const void *fdt, int node,
373 				      const struct dt_driver *dt_drv,
374 				      const struct dt_device_match *dm)
375 {
376 	struct dt_driver_probe *elt = NULL;
377 
378 	/* Will be freed when lists are released */
379 	elt = calloc(1, sizeof(*elt));
380 	if (!elt)
381 		return TEE_ERROR_OUT_OF_MEMORY;
382 
383 	elt->nodeoffset = node;
384 	elt->dt_drv = dt_drv;
385 	elt->dm = dm;
386 	elt->type = dt_drv->type;
387 
388 	return probe_driver_node(fdt, elt);
389 }
390 
391 /* Lookup a compatible driver, possibly of a specific @type, for the FDT node */
392 static TEE_Result probe_device_by_compat(const void *fdt, int node,
393 					 const char *compat,
394 					 enum dt_driver_type type)
395 {
396 	const struct dt_driver *drv = NULL;
397 	const struct dt_device_match *dm = NULL;
398 
399 	for_each_dt_driver(drv) {
400 		if (drv->type != type)
401 			continue;
402 
403 		for (dm = drv->match_table; dm && dm->compatible; dm++)
404 			if (strcmp(dm->compatible, compat) == 0)
405 				return alloc_elt_and_probe(fdt, node, drv, dm);
406 	}
407 
408 	return TEE_ERROR_ITEM_NOT_FOUND;
409 }
410 
411 /*
412  * Lookup the best matching compatible driver, possibly of a specific @type,
413  * for the FDT node.
414  */
415 TEE_Result dt_driver_probe_device_by_node(const void *fdt, int nodeoffset,
416 					  enum dt_driver_type type)
417 {
418 	int idx = 0;
419 	int len = 0;
420 	int count = 0;
421 	const char *compat = NULL;
422 	TEE_Result res = TEE_ERROR_GENERIC;
423 
424 	assert_type_is_valid(type);
425 
426 	count = fdt_stringlist_count(fdt, nodeoffset, "compatible");
427 	if (count < 0)
428 		return TEE_ERROR_ITEM_NOT_FOUND;
429 
430 	for (idx = 0; idx < count; idx++) {
431 		compat = fdt_stringlist_get(fdt, nodeoffset, "compatible",
432 					    idx, &len);
433 		if (!compat)
434 			return TEE_ERROR_GENERIC;
435 
436 		res = probe_device_by_compat(fdt, nodeoffset, compat, type);
437 
438 		if (res != TEE_ERROR_ITEM_NOT_FOUND)
439 			return res;
440 	}
441 
442 	return TEE_ERROR_ITEM_NOT_FOUND;
443 }
444 
445 static TEE_Result process_probe_list(const void *fdt)
446 {
447 	struct dt_driver_probe *elt = NULL;
448 	struct dt_driver_probe *prev = NULL;
449 	static unsigned int __maybe_unused loop_count;
450 	static unsigned int __maybe_unused deferral_loop_count;
451 	bool __maybe_unused one_deferred = false;
452 	bool one_probed_ok = false;
453 
454 	do {
455 		loop_count++;
456 		FMSG("Probe loop %u after %u for deferral(s)", loop_count,
457 		     deferral_loop_count);
458 
459 		/* Hack here for TRACE_DEBUG messages on probe list elements */
460 		if (TRACE_LEVEL >= TRACE_FLOW)
461 			print_probe_list(fdt);
462 
463 		if (TAILQ_EMPTY(&dt_driver_probe_list))
464 			return TEE_SUCCESS;
465 
466 		/*
467 		 * Probe from current end to top. Deferred probed node are
468 		 * pushed back after current tail for the next probe round.
469 		 * Reset probe result flags and see status after probe round.
470 		 */
471 		one_deferred = false;
472 		one_probed_ok = false;
473 		added_node = false;
474 
475 		TAILQ_FOREACH_REVERSE_SAFE(elt, &dt_driver_probe_list,
476 					   dt_driver_probe_head, link, prev) {
477 			TAILQ_REMOVE(&dt_driver_probe_list, elt, link);
478 
479 			switch (probe_driver_node(fdt, elt)) {
480 			case TEE_SUCCESS:
481 				one_probed_ok = true;
482 				break;
483 			case TEE_ERROR_DEFER_DRIVER_INIT:
484 				one_deferred = true;
485 				break;
486 			default:
487 				break;
488 			}
489 		}
490 
491 		if (one_deferred)
492 			deferral_loop_count++;
493 
494 	} while (added_node || one_probed_ok);
495 
496 	DMSG("Unresolved dependencies after %u rounds, %u deferred",
497 	     loop_count, deferral_loop_count);
498 
499 	if (one_deferred)
500 		return TEE_ERROR_DEFER_DRIVER_INIT;
501 	else
502 		return TEE_ERROR_GENERIC;
503 }
504 
505 static int driver_probe_compare(struct dt_driver_probe *candidate,
506 				struct dt_driver_probe *elt)
507 {
508 	if (candidate->nodeoffset != elt->nodeoffset ||
509 	    candidate->type != elt->type)
510 		return 1;
511 
512 	assert(elt->dt_drv == candidate->dt_drv);
513 	return 0;
514 }
515 
516 /*
517  * Return TEE_SUCCESS if compatible found
518  *	  TEE_ERROR_OUT_OF_MEMORY if heap is exhausted
519  */
520 static TEE_Result add_node_to_probe(const void *fdt, int node,
521 				    const struct dt_driver *dt_drv,
522 				    const struct dt_device_match *dm)
523 {
524 	const char __maybe_unused *node_name = fdt_get_name(fdt, node, NULL);
525 	const char __maybe_unused *drv_name = dt_drv->name;
526 	struct dt_driver_probe *elt = NULL;
527 	struct dt_driver_probe elt_new = {
528 		.dm = dm,
529 		.dt_drv = dt_drv,
530 		.nodeoffset = node,
531 		.type = dt_drv->type,
532 	};
533 
534 	/* If node/type found in probe list or ready list, nothing to do */
535 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
536 		if (!driver_probe_compare(&elt_new, elt))
537 			return TEE_SUCCESS;
538 
539 	TAILQ_FOREACH(elt, &dt_driver_ready_list, link)
540 		if (!driver_probe_compare(&elt_new, elt))
541 			return TEE_SUCCESS;
542 
543 	elt = malloc(sizeof(*elt));
544 	if (!elt)
545 		return TEE_ERROR_OUT_OF_MEMORY;
546 
547 	DMSG("element: %s on node %s", node_name, drv_name);
548 
549 	memcpy(elt, &elt_new, sizeof(*elt));
550 
551 	added_node = true;
552 
553 	TAILQ_INSERT_TAIL(&dt_driver_probe_list, elt, link);
554 
555 	/* Hack here for TRACE_DEBUG messages on current probe list elements */
556 	if (TRACE_LEVEL >= TRACE_FLOW)
557 		print_probe_list(fdt);
558 
559 	return TEE_SUCCESS;
560 }
561 
562 /*
563  * Add a node to the probe list if a dt_driver matches target compatible.
564  *
565  * If @type is DT_DRIVER_ANY, probe list can hold only 1 driver to probe for
566  * the node. A node may probe several drivers if have a unique driver type.
567  *
568  * Return TEE_SUCCESS if compatible found
569  *	  TEE_ERROR_ITEM_NOT_FOUND if no matching driver
570  *	  TEE_ERROR_OUT_OF_MEMORY if heap is exhausted
571  */
572 static TEE_Result add_probe_node_by_compat(const void *fdt, int node,
573 					   const char *compat)
574 {
575 	TEE_Result res = TEE_ERROR_ITEM_NOT_FOUND;
576 	const struct dt_driver *dt_drv = NULL;
577 	const struct dt_device_match *dm = NULL;
578 	uint32_t found_types = 0;
579 
580 	for_each_dt_driver(dt_drv) {
581 		for (dm = dt_drv->match_table; dm && dm->compatible; dm++) {
582 			if (strcmp(dm->compatible, compat) == 0) {
583 				assert(dt_drv->type < 32);
584 
585 				res = add_node_to_probe(fdt, node, dt_drv, dm);
586 				if (res)
587 					return res;
588 
589 				if (found_types & BIT(dt_drv->type)) {
590 					EMSG("Driver %s multi hit on type %u",
591 					     dt_drv->name, dt_drv->type);
592 					panic();
593 				}
594 				found_types |= BIT(dt_drv->type);
595 
596 				/* Matching found for this driver, try next */
597 				break;
598 			}
599 		}
600 	}
601 
602 	return res;
603 }
604 
605 /*
606  * Add the node to the probe list if matching compatible drivers are found.
607  * Follow node's compatible property list ordering to find matching driver.
608  */
609 TEE_Result dt_driver_maybe_add_probe_node(const void *fdt, int node)
610 {
611 	int idx = 0;
612 	int len = 0;
613 	int count = 0;
614 	const char *compat = NULL;
615 	TEE_Result res = TEE_ERROR_GENERIC;
616 
617 	if (_fdt_get_status(fdt, node) == DT_STATUS_DISABLED)
618 		return TEE_SUCCESS;
619 
620 	count = fdt_stringlist_count(fdt, node, "compatible");
621 	if (count < 0)
622 		return TEE_SUCCESS;
623 
624 	for (idx = 0; idx < count; idx++) {
625 		compat = fdt_stringlist_get(fdt, node, "compatible", idx, &len);
626 		assert(compat && len > 0);
627 
628 		res = add_probe_node_by_compat(fdt, node, compat);
629 
630 		/* Stop lookup if something was found */
631 		if (res != TEE_ERROR_ITEM_NOT_FOUND)
632 			return res;
633 	}
634 
635 	return TEE_SUCCESS;
636 }
637 
638 static void parse_node(const void *fdt, int node)
639 {
640 	TEE_Result __maybe_unused res = TEE_ERROR_GENERIC;
641 	int subnode = 0;
642 
643 	fdt_for_each_subnode(subnode, fdt, node) {
644 		res = dt_driver_maybe_add_probe_node(fdt, subnode);
645 		if (res) {
646 			EMSG("Failed on node %s with %#"PRIx32,
647 			     fdt_get_name(fdt, subnode, NULL), res);
648 			panic();
649 		}
650 
651 		/*
652 		 * Rescursively parse the FDT, skipping disabled nodes.
653 		 * FDT is expected reliable and core shall have sufficient
654 		 * stack depth to possibly parse all DT nodes.
655 		 */
656 		if (IS_ENABLED(CFG_DRIVERS_DT_RECURSIVE_PROBE)) {
657 			if (_fdt_get_status(fdt, subnode) == DT_STATUS_DISABLED)
658 				continue;
659 
660 			parse_node(fdt, subnode);
661 		}
662 	}
663 }
664 
665 /*
666  * Parse FDT for nodes and save in probe list the node for which a dt_driver
667  * matches node's compatible property.
668  */
669 static TEE_Result probe_dt_drivers_early(void)
670 {
671 	TEE_Result res = TEE_ERROR_GENERIC;
672 	const void *fdt = NULL;
673 
674 	if (!IS_ENABLED(CFG_EMBED_DTB))
675 		return TEE_SUCCESS;
676 
677 	fdt = get_embedded_dt();
678 	assert(fdt);
679 
680 	parse_node(fdt, fdt_path_offset(fdt, "/"));
681 
682 	res = process_probe_list(fdt);
683 	if (res == TEE_ERROR_DEFER_DRIVER_INIT) {
684 		DMSG("Deferred drivers probing");
685 		print_probe_list(fdt);
686 		res = TEE_SUCCESS;
687 	}
688 
689 	return res;
690 }
691 
692 static TEE_Result probe_dt_drivers(void)
693 {
694 	TEE_Result res = TEE_ERROR_GENERIC;
695 	const void *fdt = NULL;
696 
697 	if (!IS_ENABLED(CFG_EMBED_DTB))
698 		return TEE_SUCCESS;
699 
700 	fdt = get_embedded_dt();
701 	assert(fdt);
702 
703 	res = process_probe_list(fdt);
704 	if (res || !TAILQ_EMPTY(&dt_driver_failed_list)) {
705 		EMSG("Probe sequence result: %#"PRIx32, res);
706 		print_probe_list(fdt);
707 	}
708 	if (res)
709 		panic();
710 
711 	return TEE_SUCCESS;
712 }
713 
714 early_init_late(probe_dt_drivers_early);
715 driver_init(probe_dt_drivers);
716 
717 static TEE_Result release_probe_lists(void)
718 {
719 	struct dt_driver_probe *elt = NULL;
720 	struct dt_driver_probe *next = NULL;
721 	struct dt_driver_provider *prov = NULL;
722 	struct dt_driver_provider *next_prov = NULL;
723 	const void * __maybe_unused fdt = NULL;
724 
725 	if (!IS_ENABLED(CFG_EMBED_DTB))
726 		return TEE_SUCCESS;
727 
728 	fdt = get_embedded_dt();
729 
730 	assert(fdt && TAILQ_EMPTY(&dt_driver_probe_list));
731 
732 	TAILQ_FOREACH_SAFE(elt, &dt_driver_ready_list, link, next)
733 		free(elt);
734 
735 	TAILQ_FOREACH_SAFE(elt, &dt_driver_failed_list, link, next)
736 	       free(elt);
737 
738 	SLIST_FOREACH_SAFE(prov, &dt_driver_provider_list, link, next_prov)
739 	       free(prov);
740 
741 	return TEE_SUCCESS;
742 }
743 
744 release_init_resource(release_probe_lists);
745 
746 /*
747  * Simple bus support: handy to parse subnodes
748  */
749 static TEE_Result simple_bus_probe(const void *fdt, int node,
750 				   const void *compat_data __unused)
751 {
752 	TEE_Result res = TEE_ERROR_GENERIC;
753 	int subnode = 0;
754 
755 	fdt_for_each_subnode(subnode, fdt, node) {
756 		res = dt_driver_maybe_add_probe_node(fdt, subnode);
757 		if (res) {
758 			EMSG("Failed on node %s with %#"PRIx32,
759 			     fdt_get_name(fdt, subnode, NULL), res);
760 			panic();
761 		}
762 	}
763 
764 	return TEE_SUCCESS;
765 }
766 
767 static const struct dt_device_match simple_bus_match_table[] = {
768 	{ .compatible = "simple-bus" },
769 	{ }
770 };
771 
772 DEFINE_DT_DRIVER(simple_bus_dt_driver) = {
773 	.name = "simple-bus",
774 	.match_table = simple_bus_match_table,
775 	.probe = simple_bus_probe,
776 };
777