xref: /optee_os/core/kernel/dt_driver.c (revision 50dd2af06ae420fe19ee027d21d8282a2578509f)
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 	case DT_DRIVER_GPIO:
110 	case DT_DRIVER_I2C:
111 	case DT_DRIVER_PINCTRL:
112 	case DT_DRIVER_INTERRUPT:
113 		return;
114 	default:
115 		assert(0);
116 	}
117 }
118 
119 /*
120  * Driver provider registering API functions
121  */
122 
123 TEE_Result dt_driver_register_provider(const void *fdt, int nodeoffset,
124 				       get_of_device_func get_of_device,
125 				       void *priv, enum dt_driver_type type)
126 {
127 	struct dt_driver_provider *prv = NULL;
128 	int provider_cells = 0;
129 	uint32_t phandle = 0;
130 
131 	assert_type_is_valid(type);
132 
133 	provider_cells = fdt_get_dt_driver_cells(fdt, nodeoffset, type);
134 	if (provider_cells < 0) {
135 		DMSG("Failed to find provider cells: %d", provider_cells);
136 		return TEE_ERROR_GENERIC;
137 	}
138 
139 	phandle = fdt_get_phandle(fdt, nodeoffset);
140 	if (phandle == (uint32_t)-1) {
141 		DMSG("Failed to find provide phandle");
142 		return TEE_ERROR_GENERIC;
143 	}
144 
145 	prv = calloc(1, sizeof(*prv));
146 	if (!prv)
147 		return TEE_ERROR_OUT_OF_MEMORY;
148 
149 	prv->nodeoffset = nodeoffset;
150 	prv->type = type;
151 	prv->provider_cells = provider_cells;
152 	prv->phandle = phandle;
153 	prv->get_of_device = get_of_device;
154 	prv->priv_data = priv;
155 
156 	SLIST_INSERT_HEAD(&dt_driver_provider_list, prv, link);
157 
158 	return TEE_SUCCESS;
159 }
160 
161 static bool dt_driver_use_parent_controller(enum dt_driver_type type)
162 {
163 	switch (type) {
164 	case DT_DRIVER_PINCTRL:
165 		return true;
166 	default:
167 		return false;
168 	}
169 }
170 
171 /*
172  * Helper functions for dt_drivers querying driver provider information
173  */
174 
175 int fdt_get_dt_driver_cells(const void *fdt, int nodeoffset,
176 			    enum dt_driver_type type)
177 {
178 	const char *cells_name = NULL;
179 	const fdt32_t *c = NULL;
180 	int len = 0;
181 
182 	if (dt_driver_use_parent_controller(type))
183 		return 0;
184 
185 	switch (type) {
186 	case DT_DRIVER_CLK:
187 		cells_name = "#clock-cells";
188 		break;
189 	case DT_DRIVER_INTERRUPT:
190 		cells_name = "#interrupt-cells";
191 		break;
192 	case DT_DRIVER_RSTCTRL:
193 		cells_name = "#reset-cells";
194 		break;
195 	case DT_DRIVER_GPIO:
196 		cells_name = "#gpio-cells";
197 		break;
198 	case DT_DRIVER_I2C:
199 		return 0;
200 	default:
201 		panic();
202 	}
203 
204 	c = fdt_getprop(fdt, nodeoffset, cells_name, &len);
205 	if (!c)
206 		return len;
207 
208 	if (len != sizeof(*c))
209 		return -FDT_ERR_BADNCELLS;
210 
211 	return fdt32_to_cpu(*c);
212 }
213 
214 unsigned int dt_driver_provider_cells(struct dt_driver_provider *prv)
215 {
216 	return prv->provider_cells;
217 }
218 
219 struct dt_driver_provider *
220 dt_driver_get_provider_by_node(int nodeoffset, enum dt_driver_type type)
221 {
222 	struct dt_driver_provider *prv = NULL;
223 
224 	SLIST_FOREACH(prv, &dt_driver_provider_list, link)
225 		if (prv->nodeoffset == nodeoffset && prv->type == type)
226 			return prv;
227 
228 	return NULL;
229 }
230 
231 struct dt_driver_provider *
232 dt_driver_get_provider_by_phandle(uint32_t phandle, enum dt_driver_type type)
233 {
234 	struct dt_driver_provider *prv = NULL;
235 
236 	SLIST_FOREACH(prv, &dt_driver_provider_list, link)
237 		if (prv->phandle == phandle && prv->type == type)
238 			return prv;
239 
240 	return NULL;
241 }
242 
243 static void *device_from_provider_prop(struct dt_driver_provider *prv,
244 				       const void *fdt, int phandle_node,
245 				       const uint32_t *prop, TEE_Result *res)
246 {
247 	struct dt_pargs *pargs = NULL;
248 	unsigned int n = 0;
249 	void *device = NULL;
250 
251 	pargs = calloc(1, prv->provider_cells * sizeof(uint32_t *) +
252 		       sizeof(*pargs));
253 	if (!pargs) {
254 		*res = TEE_ERROR_OUT_OF_MEMORY;
255 		return NULL;
256 	}
257 
258 	pargs->fdt = fdt;
259 	pargs->phandle_node = phandle_node;
260 	pargs->args_count = prv->provider_cells;
261 	for (n = 0; n < prv->provider_cells; n++)
262 		pargs->args[n] = fdt32_to_cpu(prop[n + 1]);
263 
264 	device = prv->get_of_device(pargs, prv->priv_data, res);
265 
266 	free(pargs);
267 
268 	return device;
269 }
270 
271 void *dt_driver_device_from_parent(const void *fdt, int nodeoffset,
272 				   enum dt_driver_type type, TEE_Result *res)
273 {
274 	int parent = -1;
275 	struct dt_driver_provider *prv = NULL;
276 
277 	assert(fdt == get_secure_dt());
278 
279 	parent = fdt_parent_offset(fdt, nodeoffset);
280 	if (parent < 0) {
281 		*res =  TEE_ERROR_GENERIC;
282 		return NULL;
283 	}
284 
285 	prv = dt_driver_get_provider_by_node(parent, type);
286 	if (!prv) {
287 		/* No provider registered yet */
288 		*res = TEE_ERROR_DEFER_DRIVER_INIT;
289 		return NULL;
290 	}
291 
292 	return device_from_provider_prop(prv, fdt, nodeoffset, NULL, res);
293 }
294 
295 void *dt_driver_device_from_node_idx_prop_phandle(const char *prop_name,
296 						  const void *fdt, int nodeoffs,
297 						  unsigned int prop_index,
298 						  enum dt_driver_type type,
299 						  uint32_t phandle,
300 						  TEE_Result *res)
301 {
302 	int len = 0;
303 	const uint32_t *prop = NULL;
304 	int phandle_node_unused = -1;
305 	struct dt_driver_provider *prv = NULL;
306 
307 	prop = fdt_getprop(fdt, nodeoffs, prop_name, &len);
308 	if (!prop) {
309 		if (len != -FDT_ERR_NOTFOUND) {
310 			DMSG("Corrupted node %s", prop_name);
311 			*res = TEE_ERROR_GENERIC;
312 		} else {
313 			DMSG("Property %s missing in node %s", prop_name,
314 			     fdt_get_name(fdt, nodeoffs, NULL));
315 			*res = TEE_ERROR_ITEM_NOT_FOUND;
316 		}
317 		return NULL;
318 	}
319 
320 	prv = dt_driver_get_provider_by_phandle(phandle, type);
321 	if (!prv) {
322 		*res = TEE_ERROR_DEFER_DRIVER_INIT;
323 		return NULL;
324 	}
325 
326 	prop_index *= dt_driver_provider_cells(prv);
327 	if ((prop_index + 1) * sizeof(*prop) > (size_t)len) {
328 		*res = TEE_ERROR_ITEM_NOT_FOUND;
329 		return NULL;
330 	}
331 
332 	return device_from_provider_prop(prv, fdt, phandle_node_unused,
333 					 prop + prop_index, res);
334 }
335 
336 void *dt_driver_device_from_node_idx_prop(const char *prop_name,
337 					  const void *fdt, int nodeoffset,
338 					  unsigned int prop_idx,
339 					  enum dt_driver_type type,
340 					  TEE_Result *res)
341 {
342 	int len = 0;
343 	int idx = 0;
344 	int idx32 = 0;
345 	int prv_cells = 0;
346 	int phandle_node = -1;
347 	uint32_t phandle = 0;
348 	const uint32_t *prop = NULL;
349 	struct dt_driver_provider *prv = NULL;
350 
351 	prop = fdt_getprop(fdt, nodeoffset, prop_name, &len);
352 	if (!prop) {
353 		DMSG("Property %s missing in node %s", prop_name,
354 		     fdt_get_name(fdt, nodeoffset, NULL));
355 		*res = TEE_ERROR_ITEM_NOT_FOUND;
356 		return NULL;
357 	}
358 
359 	while (idx < len) {
360 		idx32 = idx / sizeof(uint32_t);
361 		phandle = fdt32_to_cpu(prop[idx32]);
362 		if (!phandle) {
363 			if (!prop_idx)
364 				break;
365 			idx += sizeof(phandle);
366 			prop_idx--;
367 			continue;
368 		}
369 
370 		/*
371 		 * In some cases, pinctrl, i2c, nvmem, etc, the consumer phandle
372 		 * points directly to a subnode of the parent. In such cases,
373 		 * the provider does not have any "-cells" property and
374 		 * potentially no "phandle" property.
375 		 */
376 		if (dt_driver_use_parent_controller(type)) {
377 			phandle_node = fdt_node_offset_by_phandle(fdt, phandle);
378 			if (phandle_node < 0) {
379 				*res = TEE_ERROR_GENERIC;
380 				return NULL;
381 			}
382 
383 			nodeoffset = fdt_parent_offset(fdt, phandle_node);
384 			if (nodeoffset < 0) {
385 				*res = TEE_ERROR_GENERIC;
386 				return NULL;
387 			}
388 
389 			prv = dt_driver_get_provider_by_node(nodeoffset, type);
390 			if (!prv) {
391 				*res = TEE_ERROR_DEFER_DRIVER_INIT;
392 				return NULL;
393 			}
394 		} else {
395 			prv = dt_driver_get_provider_by_phandle(phandle, type);
396 			if (!prv) {
397 				/* No provider registered yet */
398 				*res = TEE_ERROR_DEFER_DRIVER_INIT;
399 				return NULL;
400 			}
401 		}
402 
403 		prv_cells = dt_driver_provider_cells(prv);
404 		if (prop_idx) {
405 			prop_idx--;
406 			idx += sizeof(phandle) + prv_cells * sizeof(uint32_t);
407 			continue;
408 		}
409 
410 		return device_from_provider_prop(prv, fdt, phandle_node,
411 						 prop + idx32, res);
412 	}
413 
414 	*res = TEE_ERROR_ITEM_NOT_FOUND;
415 	return NULL;
416 }
417 
418 static void __maybe_unused print_probe_list(const void *fdt __maybe_unused)
419 {
420 	struct dt_driver_probe *elt = NULL;
421 	unsigned int count = 0;
422 
423 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
424 		count++;
425 
426 	DMSG("Probe list: %u elements", count);
427 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
428 		DMSG("|- Driver %s probes on node %s",
429 		     elt->dt_drv->name,
430 		     fdt_get_name(fdt, elt->nodeoffset, NULL));
431 
432 	DMSG("`- Probe list end");
433 
434 	count = 0;
435 	TAILQ_FOREACH(elt, &dt_driver_failed_list, link)
436 		count++;
437 
438 	DMSG("Failed list: %u elements", count);
439 	TAILQ_FOREACH(elt, &dt_driver_failed_list, link)
440 		EMSG("|- Driver %s on node %s failed", elt->dt_drv->name,
441 		     fdt_get_name(fdt, elt->nodeoffset, NULL));
442 
443 	DMSG("`- Failed list end");
444 }
445 
446 /*
447  * Probe element: push to ready list if succeeds, push to probe list if probe
448  * if deferred, panic with an error trace otherwise.
449  */
450 static TEE_Result probe_driver_node(const void *fdt,
451 				    struct dt_driver_probe *elt)
452 {
453 	TEE_Result res = TEE_ERROR_GENERIC;
454 	const char __maybe_unused *drv_name = NULL;
455 	const char __maybe_unused *node_name = NULL;
456 
457 	node_name = fdt_get_name(fdt, elt->nodeoffset, NULL);
458 	drv_name = elt->dt_drv->name;
459 
460 	if (!elt->dt_drv->probe) {
461 		DMSG("No probe operator for driver %s, skipped", drv_name);
462 		return TEE_SUCCESS;
463 	}
464 
465 	FMSG("Probing %s on node %s", drv_name, node_name);
466 
467 	res = elt->dt_drv->probe(fdt, elt->nodeoffset, elt->dm->compat_data);
468 	switch (res) {
469 	case TEE_SUCCESS:
470 		TAILQ_INSERT_HEAD(&dt_driver_ready_list, elt, link);
471 
472 		DMSG("element: %s on node %s initialized", drv_name, node_name);
473 		break;
474 	case TEE_ERROR_DEFER_DRIVER_INIT:
475 		elt->deferrals++;
476 		TAILQ_INSERT_TAIL(&dt_driver_probe_list, elt, link);
477 
478 		DMSG("element: %s on node %s deferred %u time(s)", drv_name,
479 		     node_name, elt->deferrals);
480 		break;
481 	case TEE_ERROR_NODE_DISABLED:
482 		DMSG("element: %s on node %s is disabled", drv_name, node_name);
483 		break;
484 	default:
485 		TAILQ_INSERT_HEAD(&dt_driver_failed_list, elt, link);
486 
487 		EMSG("Failed to probe %s on node %s: %#"PRIx32,
488 		     drv_name, node_name, res);
489 		break;
490 	}
491 
492 	return res;
493 }
494 
495 static TEE_Result alloc_elt_and_probe(const void *fdt, int node,
496 				      const struct dt_driver *dt_drv,
497 				      const struct dt_device_match *dm)
498 {
499 	struct dt_driver_probe *elt = NULL;
500 
501 	/* Will be freed when lists are released */
502 	elt = calloc(1, sizeof(*elt));
503 	if (!elt)
504 		return TEE_ERROR_OUT_OF_MEMORY;
505 
506 	elt->nodeoffset = node;
507 	elt->dt_drv = dt_drv;
508 	elt->dm = dm;
509 	elt->type = dt_drv->type;
510 
511 	return probe_driver_node(fdt, elt);
512 }
513 
514 /* Lookup a compatible driver, possibly of a specific @type, for the FDT node */
515 static TEE_Result probe_device_by_compat(const void *fdt, int node,
516 					 const char *compat,
517 					 enum dt_driver_type type)
518 {
519 	const struct dt_driver *drv = NULL;
520 	const struct dt_device_match *dm = NULL;
521 
522 	for_each_dt_driver(drv) {
523 		if (drv->type != type)
524 			continue;
525 
526 		for (dm = drv->match_table; dm && dm->compatible; dm++)
527 			if (strcmp(dm->compatible, compat) == 0)
528 				return alloc_elt_and_probe(fdt, node, drv, dm);
529 	}
530 
531 	return TEE_ERROR_ITEM_NOT_FOUND;
532 }
533 
534 /*
535  * Lookup the best matching compatible driver, possibly of a specific @type,
536  * for the FDT node.
537  */
538 TEE_Result dt_driver_probe_device_by_node(const void *fdt, int nodeoffset,
539 					  enum dt_driver_type type)
540 {
541 	int idx = 0;
542 	int len = 0;
543 	int count = 0;
544 	const char *compat = NULL;
545 	TEE_Result res = TEE_ERROR_GENERIC;
546 
547 	assert_type_is_valid(type);
548 
549 	count = fdt_stringlist_count(fdt, nodeoffset, "compatible");
550 	if (count < 0)
551 		return TEE_ERROR_ITEM_NOT_FOUND;
552 
553 	for (idx = 0; idx < count; idx++) {
554 		compat = fdt_stringlist_get(fdt, nodeoffset, "compatible",
555 					    idx, &len);
556 		if (!compat)
557 			return TEE_ERROR_GENERIC;
558 
559 		res = probe_device_by_compat(fdt, nodeoffset, compat, type);
560 
561 		if (res != TEE_ERROR_ITEM_NOT_FOUND)
562 			return res;
563 	}
564 
565 	return TEE_ERROR_ITEM_NOT_FOUND;
566 }
567 
568 static TEE_Result process_probe_list(const void *fdt)
569 {
570 	struct dt_driver_probe *elt = NULL;
571 	struct dt_driver_probe *prev = NULL;
572 	static unsigned int __maybe_unused loop_count;
573 	static unsigned int __maybe_unused deferral_loop_count;
574 	bool __maybe_unused one_deferred = false;
575 	bool one_probed_ok = false;
576 
577 	do {
578 		loop_count++;
579 		FMSG("Probe loop %u after %u for deferral(s)", loop_count,
580 		     deferral_loop_count);
581 
582 		/* Hack here for TRACE_DEBUG messages on probe list elements */
583 		if (TRACE_LEVEL >= TRACE_FLOW)
584 			print_probe_list(fdt);
585 
586 		if (TAILQ_EMPTY(&dt_driver_probe_list))
587 			return TEE_SUCCESS;
588 
589 		/*
590 		 * Probe from current end to top. Deferred probed node are
591 		 * pushed back after current tail for the next probe round.
592 		 * Reset probe result flags and see status after probe round.
593 		 */
594 		one_deferred = false;
595 		one_probed_ok = false;
596 		added_node = false;
597 
598 		TAILQ_FOREACH_REVERSE_SAFE(elt, &dt_driver_probe_list,
599 					   dt_driver_probe_head, link, prev) {
600 			TAILQ_REMOVE(&dt_driver_probe_list, elt, link);
601 
602 			switch (probe_driver_node(fdt, elt)) {
603 			case TEE_SUCCESS:
604 				one_probed_ok = true;
605 				break;
606 			case TEE_ERROR_DEFER_DRIVER_INIT:
607 				one_deferred = true;
608 				break;
609 			default:
610 				break;
611 			}
612 		}
613 
614 		if (one_deferred)
615 			deferral_loop_count++;
616 
617 	} while (added_node || one_probed_ok);
618 
619 	DMSG("Unresolved dependencies after %u rounds, %u deferred",
620 	     loop_count, deferral_loop_count);
621 
622 	if (one_deferred)
623 		return TEE_ERROR_DEFER_DRIVER_INIT;
624 	else
625 		return TEE_ERROR_GENERIC;
626 }
627 
628 static int driver_probe_compare(struct dt_driver_probe *candidate,
629 				struct dt_driver_probe *elt)
630 {
631 	if (candidate->nodeoffset != elt->nodeoffset ||
632 	    candidate->type != elt->type)
633 		return 1;
634 
635 	assert(elt->dt_drv == candidate->dt_drv);
636 	return 0;
637 }
638 
639 /*
640  * Return TEE_SUCCESS if compatible found
641  *	  TEE_ERROR_OUT_OF_MEMORY if heap is exhausted
642  */
643 static TEE_Result add_node_to_probe(const void *fdt, int node,
644 				    const struct dt_driver *dt_drv,
645 				    const struct dt_device_match *dm)
646 {
647 	const char __maybe_unused *node_name = fdt_get_name(fdt, node, NULL);
648 	const char __maybe_unused *drv_name = dt_drv->name;
649 	struct dt_driver_probe *elt = NULL;
650 	struct dt_driver_probe elt_new = {
651 		.dm = dm,
652 		.dt_drv = dt_drv,
653 		.nodeoffset = node,
654 		.type = dt_drv->type,
655 	};
656 
657 	/* If node/type found in probe list or ready list, nothing to do */
658 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
659 		if (!driver_probe_compare(&elt_new, elt))
660 			return TEE_SUCCESS;
661 
662 	TAILQ_FOREACH(elt, &dt_driver_ready_list, link)
663 		if (!driver_probe_compare(&elt_new, elt))
664 			return TEE_SUCCESS;
665 
666 	elt = malloc(sizeof(*elt));
667 	if (!elt)
668 		return TEE_ERROR_OUT_OF_MEMORY;
669 
670 	DMSG("element: %s on node %s", node_name, drv_name);
671 
672 	memcpy(elt, &elt_new, sizeof(*elt));
673 
674 	added_node = true;
675 
676 	TAILQ_INSERT_TAIL(&dt_driver_probe_list, elt, link);
677 
678 	/* Hack here for TRACE_DEBUG messages on current probe list elements */
679 	if (TRACE_LEVEL >= TRACE_FLOW)
680 		print_probe_list(fdt);
681 
682 	return TEE_SUCCESS;
683 }
684 
685 /*
686  * Add a node to the probe list if a dt_driver matches target compatible.
687  *
688  * If @type is DT_DRIVER_ANY, probe list can hold only 1 driver to probe for
689  * the node. A node may probe several drivers if have a unique driver type.
690  *
691  * Return TEE_SUCCESS if compatible found
692  *	  TEE_ERROR_ITEM_NOT_FOUND if no matching driver
693  *	  TEE_ERROR_OUT_OF_MEMORY if heap is exhausted
694  */
695 static TEE_Result add_probe_node_by_compat(const void *fdt, int node,
696 					   const char *compat)
697 {
698 	TEE_Result res = TEE_ERROR_ITEM_NOT_FOUND;
699 	const struct dt_driver *dt_drv = NULL;
700 	const struct dt_device_match *dm = NULL;
701 	uint32_t found_types = 0;
702 
703 	for_each_dt_driver(dt_drv) {
704 		for (dm = dt_drv->match_table; dm && dm->compatible; dm++) {
705 			if (strcmp(dm->compatible, compat) == 0) {
706 				assert(dt_drv->type < 32);
707 
708 				res = add_node_to_probe(fdt, node, dt_drv, dm);
709 				if (res)
710 					return res;
711 
712 				if (found_types & BIT(dt_drv->type)) {
713 					EMSG("Driver %s multi hit on type %u",
714 					     dt_drv->name, dt_drv->type);
715 					panic();
716 				}
717 				found_types |= BIT(dt_drv->type);
718 
719 				/* Matching found for this driver, try next */
720 				break;
721 			}
722 		}
723 	}
724 
725 	return res;
726 }
727 
728 /*
729  * Add the node to the probe list if matching compatible drivers are found.
730  * Follow node's compatible property list ordering to find matching driver.
731  */
732 TEE_Result dt_driver_maybe_add_probe_node(const void *fdt, int node)
733 {
734 	int idx = 0;
735 	int len = 0;
736 	int count = 0;
737 	const char *compat = NULL;
738 	TEE_Result res = TEE_ERROR_GENERIC;
739 
740 	if (fdt_get_status(fdt, node) == DT_STATUS_DISABLED)
741 		return TEE_SUCCESS;
742 
743 	count = fdt_stringlist_count(fdt, node, "compatible");
744 	if (count < 0)
745 		return TEE_SUCCESS;
746 
747 	for (idx = 0; idx < count; idx++) {
748 		compat = fdt_stringlist_get(fdt, node, "compatible", idx, &len);
749 		assert(compat && len > 0);
750 
751 		res = add_probe_node_by_compat(fdt, node, compat);
752 
753 		/* Stop lookup if something was found */
754 		if (res != TEE_ERROR_ITEM_NOT_FOUND)
755 			return res;
756 	}
757 
758 	return TEE_SUCCESS;
759 }
760 
761 static void parse_node(const void *fdt, int node)
762 {
763 	TEE_Result __maybe_unused res = TEE_ERROR_GENERIC;
764 	int subnode = 0;
765 
766 	fdt_for_each_subnode(subnode, fdt, node) {
767 		res = dt_driver_maybe_add_probe_node(fdt, subnode);
768 		if (res) {
769 			EMSG("Failed on node %s with %#"PRIx32,
770 			     fdt_get_name(fdt, subnode, NULL), res);
771 			panic();
772 		}
773 
774 		/*
775 		 * Rescursively parse the FDT, skipping disabled nodes.
776 		 * FDT is expected reliable and core shall have sufficient
777 		 * stack depth to possibly parse all DT nodes.
778 		 */
779 		if (IS_ENABLED(CFG_DRIVERS_DT_RECURSIVE_PROBE)) {
780 			if (fdt_get_status(fdt, subnode) == DT_STATUS_DISABLED)
781 				continue;
782 
783 			parse_node(fdt, subnode);
784 		}
785 	}
786 }
787 
788 /*
789  * Parse FDT for nodes and save in probe list the node for which a dt_driver
790  * matches node's compatible property.
791  */
792 static TEE_Result probe_dt_drivers_early(void)
793 {
794 	TEE_Result res = TEE_ERROR_GENERIC;
795 	const void *fdt = NULL;
796 
797 	fdt = get_secure_dt();
798 	if (!fdt)
799 		return TEE_SUCCESS;
800 
801 	parse_node(fdt, fdt_path_offset(fdt, "/"));
802 
803 	res = process_probe_list(fdt);
804 	if (res == TEE_ERROR_DEFER_DRIVER_INIT) {
805 		DMSG("Deferred drivers probing");
806 		print_probe_list(fdt);
807 		res = TEE_SUCCESS;
808 	}
809 
810 	return res;
811 }
812 
813 static TEE_Result probe_dt_drivers(void)
814 {
815 	TEE_Result res = TEE_ERROR_GENERIC;
816 	const void *fdt = NULL;
817 
818 	fdt = get_secure_dt();
819 	if (!fdt)
820 		return TEE_SUCCESS;
821 
822 	res = process_probe_list(fdt);
823 	if (res || !TAILQ_EMPTY(&dt_driver_failed_list)) {
824 		EMSG("Probe sequence result: %#"PRIx32, res);
825 		print_probe_list(fdt);
826 	}
827 	if (res)
828 		panic();
829 
830 	return TEE_SUCCESS;
831 }
832 
833 early_init_late(probe_dt_drivers_early);
834 driver_init(probe_dt_drivers);
835 
836 static TEE_Result release_probe_lists(void)
837 {
838 	struct dt_driver_probe *elt = NULL;
839 	struct dt_driver_probe *next = NULL;
840 	struct dt_driver_provider *prov = NULL;
841 	struct dt_driver_provider *next_prov = NULL;
842 	const void *fdt = NULL;
843 
844 	fdt = get_secure_dt();
845 	if (!fdt)
846 		return TEE_SUCCESS;
847 
848 	assert(fdt && TAILQ_EMPTY(&dt_driver_probe_list));
849 
850 	TAILQ_FOREACH_SAFE(elt, &dt_driver_ready_list, link, next)
851 		free(elt);
852 
853 	TAILQ_FOREACH_SAFE(elt, &dt_driver_failed_list, link, next)
854 	       free(elt);
855 
856 	SLIST_FOREACH_SAFE(prov, &dt_driver_provider_list, link, next_prov)
857 	       free(prov);
858 
859 	return TEE_SUCCESS;
860 }
861 
862 release_init_resource(release_probe_lists);
863 
864 /*
865  * Simple bus support: handy to parse subnodes
866  */
867 static TEE_Result simple_bus_probe(const void *fdt, int node,
868 				   const void *compat_data __unused)
869 {
870 	TEE_Result res = TEE_ERROR_GENERIC;
871 	int subnode = 0;
872 
873 	fdt_for_each_subnode(subnode, fdt, node) {
874 		res = dt_driver_maybe_add_probe_node(fdt, subnode);
875 		if (res) {
876 			EMSG("Failed on node %s with %#"PRIx32,
877 			     fdt_get_name(fdt, subnode, NULL), res);
878 			panic();
879 		}
880 	}
881 
882 	return TEE_SUCCESS;
883 }
884 
885 static const struct dt_device_match simple_bus_match_table[] = {
886 	{ .compatible = "simple-bus" },
887 	{ }
888 };
889 
890 DEFINE_DT_DRIVER(simple_bus_dt_driver) = {
891 	.name = "simple-bus",
892 	.match_table = simple_bus_match_table,
893 	.probe = simple_bus_probe,
894 };
895