xref: /optee_os/core/kernel/dt_driver.c (revision 193944aadbe838780b4c6b9c94c0a739526b5e79)
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 	case DT_DRIVER_REGULATOR:
114 		return;
115 	default:
116 		assert(0);
117 	}
118 }
119 
120 /*
121  * Driver provider registering API functions
122  */
123 
124 TEE_Result dt_driver_register_provider(const void *fdt, int nodeoffset,
125 				       get_of_device_func get_of_device,
126 				       void *priv, enum dt_driver_type type)
127 {
128 	struct dt_driver_provider *prv = NULL;
129 	int provider_cells = 0;
130 	uint32_t phandle = 0;
131 
132 	assert_type_is_valid(type);
133 
134 	provider_cells = fdt_get_dt_driver_cells(fdt, nodeoffset, type);
135 	if (provider_cells < 0) {
136 		DMSG("Failed to find provider cells: %d", provider_cells);
137 		return TEE_ERROR_GENERIC;
138 	}
139 
140 	phandle = fdt_get_phandle(fdt, nodeoffset);
141 	if (phandle == (uint32_t)-1) {
142 		DMSG("Failed to find provide phandle");
143 		return TEE_ERROR_GENERIC;
144 	}
145 
146 	prv = calloc(1, sizeof(*prv));
147 	if (!prv)
148 		return TEE_ERROR_OUT_OF_MEMORY;
149 
150 	prv->nodeoffset = nodeoffset;
151 	prv->type = type;
152 	prv->provider_cells = provider_cells;
153 	prv->phandle = phandle;
154 	prv->get_of_device = get_of_device;
155 	prv->priv_data = priv;
156 
157 	SLIST_INSERT_HEAD(&dt_driver_provider_list, prv, link);
158 
159 	return TEE_SUCCESS;
160 }
161 
162 static bool dt_driver_use_parent_controller(enum dt_driver_type type)
163 {
164 	switch (type) {
165 	case DT_DRIVER_PINCTRL:
166 		return true;
167 	default:
168 		return false;
169 	}
170 }
171 
172 /*
173  * Helper functions for dt_drivers querying driver provider information
174  */
175 
176 int fdt_get_dt_driver_cells(const void *fdt, int nodeoffset,
177 			    enum dt_driver_type type)
178 {
179 	const char *cells_name = NULL;
180 	const fdt32_t *c = NULL;
181 	int len = 0;
182 
183 	if (dt_driver_use_parent_controller(type))
184 		return 0;
185 
186 	switch (type) {
187 	case DT_DRIVER_CLK:
188 		cells_name = "#clock-cells";
189 		break;
190 	case DT_DRIVER_INTERRUPT:
191 		cells_name = "#interrupt-cells";
192 		break;
193 	case DT_DRIVER_RSTCTRL:
194 		cells_name = "#reset-cells";
195 		break;
196 	case DT_DRIVER_GPIO:
197 		cells_name = "#gpio-cells";
198 		break;
199 	case DT_DRIVER_I2C:
200 	case DT_DRIVER_REGULATOR:
201 		return 0;
202 	default:
203 		panic();
204 	}
205 
206 	c = fdt_getprop(fdt, nodeoffset, cells_name, &len);
207 	if (!c)
208 		return len;
209 
210 	if (len != sizeof(*c))
211 		return -FDT_ERR_BADNCELLS;
212 
213 	return fdt32_to_cpu(*c);
214 }
215 
216 unsigned int dt_driver_provider_cells(struct dt_driver_provider *prv)
217 {
218 	return prv->provider_cells;
219 }
220 
221 struct dt_driver_provider *
222 dt_driver_get_provider_by_node(int nodeoffset, enum dt_driver_type type)
223 {
224 	struct dt_driver_provider *prv = NULL;
225 
226 	SLIST_FOREACH(prv, &dt_driver_provider_list, link)
227 		if (prv->nodeoffset == nodeoffset && prv->type == type)
228 			return prv;
229 
230 	return NULL;
231 }
232 
233 struct dt_driver_provider *
234 dt_driver_get_provider_by_phandle(uint32_t phandle, enum dt_driver_type type)
235 {
236 	struct dt_driver_provider *prv = NULL;
237 
238 	SLIST_FOREACH(prv, &dt_driver_provider_list, link)
239 		if (prv->phandle == phandle && prv->type == type)
240 			return prv;
241 
242 	return NULL;
243 }
244 
245 static TEE_Result device_from_provider_prop(struct dt_driver_provider *prv,
246 					    const void *fdt, int phandle_node,
247 					    const uint32_t *prop, void **device)
248 {
249 	TEE_Result res = TEE_ERROR_GENERIC;
250 	struct dt_pargs *pargs = NULL;
251 	unsigned int n = 0;
252 
253 	pargs = calloc(1, prv->provider_cells * sizeof(uint32_t *) +
254 		       sizeof(*pargs));
255 	if (!pargs)
256 		return TEE_ERROR_OUT_OF_MEMORY;
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 	res = prv->get_of_device(pargs, prv->priv_data, device);
265 
266 	free(pargs);
267 
268 	return res;
269 }
270 
271 TEE_Result dt_driver_device_from_parent(const void *fdt, int nodeoffset,
272 					enum dt_driver_type type, void **device)
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 		return TEE_ERROR_GENERIC;
282 
283 	prv = dt_driver_get_provider_by_node(parent, type);
284 	if (!prv) {
285 		/* No provider registered yet */
286 		return TEE_ERROR_DEFER_DRIVER_INIT;
287 	}
288 
289 	return device_from_provider_prop(prv, fdt, nodeoffset, NULL, device);
290 }
291 
292 TEE_Result dt_driver_device_from_node_idx_prop_phandle(const char *prop_name,
293 						       const void *fdt,
294 						       int nodeoffs,
295 						       unsigned int prop_index,
296 						       enum dt_driver_type type,
297 						       uint32_t phandle,
298 						       void **device)
299 {
300 	int len = 0;
301 	const uint32_t *prop = NULL;
302 	int phandle_node_unused = -1;
303 	struct dt_driver_provider *prv = NULL;
304 
305 	prop = fdt_getprop(fdt, nodeoffs, prop_name, &len);
306 	if (!prop) {
307 		if (len != -FDT_ERR_NOTFOUND) {
308 			DMSG("Corrupted node %s", prop_name);
309 			return TEE_ERROR_GENERIC;
310 		} else {
311 			DMSG("Property %s missing in node %s", prop_name,
312 			     fdt_get_name(fdt, nodeoffs, NULL));
313 			return TEE_ERROR_ITEM_NOT_FOUND;
314 		}
315 	}
316 
317 	prv = dt_driver_get_provider_by_phandle(phandle, type);
318 	if (!prv)
319 		return TEE_ERROR_DEFER_DRIVER_INIT;
320 
321 	prop_index *= dt_driver_provider_cells(prv);
322 	if ((prop_index + 1) * sizeof(*prop) > (size_t)len)
323 		return TEE_ERROR_ITEM_NOT_FOUND;
324 
325 	return device_from_provider_prop(prv, fdt, phandle_node_unused,
326 					 prop + prop_index, device);
327 }
328 
329 TEE_Result dt_driver_device_from_node_idx_prop(const char *prop_name,
330 					       const void *fdt, int nodeoffset,
331 					       unsigned int prop_idx,
332 					       enum dt_driver_type type,
333 					       void **device)
334 {
335 	int len = 0;
336 	int idx = 0;
337 	int idx32 = 0;
338 	int prv_cells = 0;
339 	int phandle_node = -1;
340 	uint32_t phandle = 0;
341 	const uint32_t *prop = NULL;
342 	struct dt_driver_provider *prv = NULL;
343 
344 	prop = fdt_getprop(fdt, nodeoffset, prop_name, &len);
345 	if (!prop) {
346 		DMSG("Property %s missing in node %s", prop_name,
347 		     fdt_get_name(fdt, nodeoffset, NULL));
348 		return TEE_ERROR_ITEM_NOT_FOUND;
349 	}
350 
351 	while (idx < len) {
352 		idx32 = idx / sizeof(uint32_t);
353 		phandle = fdt32_to_cpu(prop[idx32]);
354 		if (!phandle) {
355 			if (!prop_idx)
356 				break;
357 			idx += sizeof(phandle);
358 			prop_idx--;
359 			continue;
360 		}
361 
362 		/*
363 		 * In some cases, pinctrl, i2c, nvmem, etc, the consumer phandle
364 		 * points directly to a subnode of the parent. In such cases,
365 		 * the provider does not have any "-cells" property and
366 		 * potentially no "phandle" property.
367 		 */
368 		if (dt_driver_use_parent_controller(type)) {
369 			phandle_node = fdt_node_offset_by_phandle(fdt, phandle);
370 			if (phandle_node < 0)
371 				return TEE_ERROR_GENERIC;
372 
373 			nodeoffset = fdt_parent_offset(fdt, phandle_node);
374 			if (nodeoffset < 0)
375 				return TEE_ERROR_GENERIC;
376 
377 			prv = dt_driver_get_provider_by_node(nodeoffset, type);
378 			if (!prv)
379 				return TEE_ERROR_DEFER_DRIVER_INIT;
380 		} else {
381 			prv = dt_driver_get_provider_by_phandle(phandle, type);
382 			if (!prv)
383 				return TEE_ERROR_DEFER_DRIVER_INIT;
384 		}
385 
386 		prv_cells = dt_driver_provider_cells(prv);
387 		if (prop_idx) {
388 			prop_idx--;
389 			idx += sizeof(phandle) + prv_cells * sizeof(uint32_t);
390 			continue;
391 		}
392 
393 		return device_from_provider_prop(prv, fdt, phandle_node,
394 						 prop + idx32, device);
395 	}
396 
397 	return TEE_ERROR_ITEM_NOT_FOUND;
398 }
399 
400 static void __maybe_unused print_probe_list(const void *fdt __maybe_unused)
401 {
402 	struct dt_driver_probe *elt = NULL;
403 	unsigned int count = 0;
404 
405 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
406 		count++;
407 
408 	DMSG("Probe list: %u elements", count);
409 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
410 		DMSG("|- Driver %s probes on node %s",
411 		     elt->dt_drv->name,
412 		     fdt_get_name(fdt, elt->nodeoffset, NULL));
413 
414 	DMSG("`- Probe list end");
415 
416 	count = 0;
417 	TAILQ_FOREACH(elt, &dt_driver_failed_list, link)
418 		count++;
419 
420 	DMSG("Failed list: %u elements", count);
421 	TAILQ_FOREACH(elt, &dt_driver_failed_list, link)
422 		EMSG("|- Driver %s on node %s failed", elt->dt_drv->name,
423 		     fdt_get_name(fdt, elt->nodeoffset, NULL));
424 
425 	DMSG("`- Failed list end");
426 }
427 
428 /*
429  * Probe element: push to ready list if succeeds, push to probe list if probe
430  * if deferred, panic with an error trace otherwise.
431  */
432 static TEE_Result probe_driver_node(const void *fdt,
433 				    struct dt_driver_probe *elt)
434 {
435 	TEE_Result res = TEE_ERROR_GENERIC;
436 	const char __maybe_unused *drv_name = NULL;
437 	const char __maybe_unused *node_name = NULL;
438 
439 	node_name = fdt_get_name(fdt, elt->nodeoffset, NULL);
440 	drv_name = elt->dt_drv->name;
441 
442 	if (!elt->dt_drv->probe) {
443 		DMSG("No probe operator for driver %s, skipped", drv_name);
444 		return TEE_SUCCESS;
445 	}
446 
447 	FMSG("Probing %s on node %s", drv_name, node_name);
448 
449 	res = elt->dt_drv->probe(fdt, elt->nodeoffset, elt->dm->compat_data);
450 	switch (res) {
451 	case TEE_SUCCESS:
452 		TAILQ_INSERT_HEAD(&dt_driver_ready_list, elt, link);
453 
454 		DMSG("element: %s on node %s initialized", drv_name, node_name);
455 		break;
456 	case TEE_ERROR_DEFER_DRIVER_INIT:
457 		elt->deferrals++;
458 		TAILQ_INSERT_TAIL(&dt_driver_probe_list, elt, link);
459 
460 		DMSG("element: %s on node %s deferred %u time(s)", drv_name,
461 		     node_name, elt->deferrals);
462 		break;
463 	case TEE_ERROR_NODE_DISABLED:
464 		DMSG("element: %s on node %s is disabled", drv_name, node_name);
465 		break;
466 	default:
467 		TAILQ_INSERT_HEAD(&dt_driver_failed_list, elt, link);
468 
469 		EMSG("Failed to probe %s on node %s: %#"PRIx32,
470 		     drv_name, node_name, res);
471 		break;
472 	}
473 
474 	return res;
475 }
476 
477 static TEE_Result alloc_elt_and_probe(const void *fdt, int node,
478 				      const struct dt_driver *dt_drv,
479 				      const struct dt_device_match *dm)
480 {
481 	struct dt_driver_probe *elt = NULL;
482 
483 	/* Will be freed when lists are released */
484 	elt = calloc(1, sizeof(*elt));
485 	if (!elt)
486 		return TEE_ERROR_OUT_OF_MEMORY;
487 
488 	elt->nodeoffset = node;
489 	elt->dt_drv = dt_drv;
490 	elt->dm = dm;
491 	elt->type = dt_drv->type;
492 
493 	return probe_driver_node(fdt, elt);
494 }
495 
496 /* Lookup a compatible driver, possibly of a specific @type, for the FDT node */
497 static TEE_Result probe_device_by_compat(const void *fdt, int node,
498 					 const char *compat,
499 					 enum dt_driver_type type)
500 {
501 	const struct dt_driver *drv = NULL;
502 	const struct dt_device_match *dm = NULL;
503 
504 	for_each_dt_driver(drv) {
505 		if (drv->type != type)
506 			continue;
507 
508 		for (dm = drv->match_table; dm && dm->compatible; dm++)
509 			if (strcmp(dm->compatible, compat) == 0)
510 				return alloc_elt_and_probe(fdt, node, drv, dm);
511 	}
512 
513 	return TEE_ERROR_ITEM_NOT_FOUND;
514 }
515 
516 /*
517  * Lookup the best matching compatible driver, possibly of a specific @type,
518  * for the FDT node.
519  */
520 TEE_Result dt_driver_probe_device_by_node(const void *fdt, int nodeoffset,
521 					  enum dt_driver_type type)
522 {
523 	int idx = 0;
524 	int len = 0;
525 	int count = 0;
526 	const char *compat = NULL;
527 	TEE_Result res = TEE_ERROR_GENERIC;
528 
529 	assert_type_is_valid(type);
530 
531 	count = fdt_stringlist_count(fdt, nodeoffset, "compatible");
532 	if (count < 0)
533 		return TEE_ERROR_ITEM_NOT_FOUND;
534 
535 	for (idx = 0; idx < count; idx++) {
536 		compat = fdt_stringlist_get(fdt, nodeoffset, "compatible",
537 					    idx, &len);
538 		if (!compat)
539 			return TEE_ERROR_GENERIC;
540 
541 		res = probe_device_by_compat(fdt, nodeoffset, compat, type);
542 
543 		if (res != TEE_ERROR_ITEM_NOT_FOUND)
544 			return res;
545 	}
546 
547 	return TEE_ERROR_ITEM_NOT_FOUND;
548 }
549 
550 static TEE_Result process_probe_list(const void *fdt)
551 {
552 	struct dt_driver_probe *elt = NULL;
553 	struct dt_driver_probe *prev = NULL;
554 	static unsigned int __maybe_unused loop_count;
555 	static unsigned int __maybe_unused deferral_loop_count;
556 	bool __maybe_unused one_deferred = false;
557 	bool one_probed_ok = false;
558 
559 	do {
560 		loop_count++;
561 		FMSG("Probe loop %u after %u for deferral(s)", loop_count,
562 		     deferral_loop_count);
563 
564 		/* Hack here for TRACE_DEBUG messages on probe list elements */
565 		if (TRACE_LEVEL >= TRACE_FLOW)
566 			print_probe_list(fdt);
567 
568 		if (TAILQ_EMPTY(&dt_driver_probe_list))
569 			return TEE_SUCCESS;
570 
571 		/*
572 		 * Probe from current end to top. Deferred probed node are
573 		 * pushed back after current tail for the next probe round.
574 		 * Reset probe result flags and see status after probe round.
575 		 */
576 		one_deferred = false;
577 		one_probed_ok = false;
578 		added_node = false;
579 
580 		TAILQ_FOREACH_REVERSE_SAFE(elt, &dt_driver_probe_list,
581 					   dt_driver_probe_head, link, prev) {
582 			TAILQ_REMOVE(&dt_driver_probe_list, elt, link);
583 
584 			switch (probe_driver_node(fdt, elt)) {
585 			case TEE_SUCCESS:
586 				one_probed_ok = true;
587 				break;
588 			case TEE_ERROR_DEFER_DRIVER_INIT:
589 				one_deferred = true;
590 				break;
591 			default:
592 				break;
593 			}
594 		}
595 
596 		if (one_deferred)
597 			deferral_loop_count++;
598 
599 	} while (added_node || one_probed_ok);
600 
601 	DMSG("Unresolved dependencies after %u rounds, %u deferred",
602 	     loop_count, deferral_loop_count);
603 
604 	if (one_deferred)
605 		return TEE_ERROR_DEFER_DRIVER_INIT;
606 	else
607 		return TEE_ERROR_GENERIC;
608 }
609 
610 static int driver_probe_compare(struct dt_driver_probe *candidate,
611 				struct dt_driver_probe *elt)
612 {
613 	if (candidate->nodeoffset != elt->nodeoffset ||
614 	    candidate->type != elt->type)
615 		return 1;
616 
617 	assert(elt->dt_drv == candidate->dt_drv);
618 	return 0;
619 }
620 
621 /*
622  * Return TEE_SUCCESS if compatible found
623  *	  TEE_ERROR_OUT_OF_MEMORY if heap is exhausted
624  */
625 static TEE_Result add_node_to_probe(const void *fdt, int node,
626 				    const struct dt_driver *dt_drv,
627 				    const struct dt_device_match *dm)
628 {
629 	const char __maybe_unused *node_name = fdt_get_name(fdt, node, NULL);
630 	const char __maybe_unused *drv_name = dt_drv->name;
631 	struct dt_driver_probe *elt = NULL;
632 	struct dt_driver_probe elt_new = {
633 		.dm = dm,
634 		.dt_drv = dt_drv,
635 		.nodeoffset = node,
636 		.type = dt_drv->type,
637 	};
638 
639 	/* If node/type found in probe list or ready list, nothing to do */
640 	TAILQ_FOREACH(elt, &dt_driver_probe_list, link)
641 		if (!driver_probe_compare(&elt_new, elt))
642 			return TEE_SUCCESS;
643 
644 	TAILQ_FOREACH(elt, &dt_driver_ready_list, link)
645 		if (!driver_probe_compare(&elt_new, elt))
646 			return TEE_SUCCESS;
647 
648 	elt = malloc(sizeof(*elt));
649 	if (!elt)
650 		return TEE_ERROR_OUT_OF_MEMORY;
651 
652 	DMSG("element: %s on node %s", node_name, drv_name);
653 
654 	memcpy(elt, &elt_new, sizeof(*elt));
655 
656 	added_node = true;
657 
658 	TAILQ_INSERT_TAIL(&dt_driver_probe_list, elt, link);
659 
660 	/* Hack here for TRACE_DEBUG messages on current probe list elements */
661 	if (TRACE_LEVEL >= TRACE_FLOW)
662 		print_probe_list(fdt);
663 
664 	return TEE_SUCCESS;
665 }
666 
667 /*
668  * Add a node to the probe list if a dt_driver matches target compatible.
669  *
670  * If @type is DT_DRIVER_ANY, probe list can hold only 1 driver to probe for
671  * the node. A node may probe several drivers if have a unique driver type.
672  *
673  * Return TEE_SUCCESS if compatible found
674  *	  TEE_ERROR_ITEM_NOT_FOUND if no matching driver
675  *	  TEE_ERROR_OUT_OF_MEMORY if heap is exhausted
676  */
677 static TEE_Result add_probe_node_by_compat(const void *fdt, int node,
678 					   const char *compat)
679 {
680 	TEE_Result res = TEE_ERROR_ITEM_NOT_FOUND;
681 	const struct dt_driver *dt_drv = NULL;
682 	const struct dt_device_match *dm = NULL;
683 	uint32_t found_types = 0;
684 
685 	for_each_dt_driver(dt_drv) {
686 		for (dm = dt_drv->match_table; dm && dm->compatible; dm++) {
687 			if (strcmp(dm->compatible, compat) == 0) {
688 				assert(dt_drv->type < 32);
689 
690 				res = add_node_to_probe(fdt, node, dt_drv, dm);
691 				if (res)
692 					return res;
693 
694 				if (found_types & BIT(dt_drv->type)) {
695 					EMSG("Driver %s multi hit on type %u",
696 					     dt_drv->name, dt_drv->type);
697 					panic();
698 				}
699 				found_types |= BIT(dt_drv->type);
700 
701 				/* Matching found for this driver, try next */
702 				break;
703 			}
704 		}
705 	}
706 
707 	return res;
708 }
709 
710 /*
711  * Add the node to the probe list if matching compatible drivers are found.
712  * Follow node's compatible property list ordering to find matching driver.
713  */
714 TEE_Result dt_driver_maybe_add_probe_node(const void *fdt, int node)
715 {
716 	int idx = 0;
717 	int len = 0;
718 	int count = 0;
719 	const char *compat = NULL;
720 	TEE_Result res = TEE_ERROR_GENERIC;
721 
722 	if (fdt_get_status(fdt, node) == DT_STATUS_DISABLED)
723 		return TEE_SUCCESS;
724 
725 	count = fdt_stringlist_count(fdt, node, "compatible");
726 	if (count < 0)
727 		return TEE_SUCCESS;
728 
729 	for (idx = 0; idx < count; idx++) {
730 		compat = fdt_stringlist_get(fdt, node, "compatible", idx, &len);
731 		assert(compat && len > 0);
732 
733 		res = add_probe_node_by_compat(fdt, node, compat);
734 
735 		/* Stop lookup if something was found */
736 		if (res != TEE_ERROR_ITEM_NOT_FOUND)
737 			return res;
738 	}
739 
740 	return TEE_SUCCESS;
741 }
742 
743 static void parse_node(const void *fdt, int node)
744 {
745 	TEE_Result __maybe_unused res = TEE_ERROR_GENERIC;
746 	int subnode = 0;
747 
748 	fdt_for_each_subnode(subnode, fdt, node) {
749 		res = dt_driver_maybe_add_probe_node(fdt, subnode);
750 		if (res) {
751 			EMSG("Failed on node %s with %#"PRIx32,
752 			     fdt_get_name(fdt, subnode, NULL), res);
753 			panic();
754 		}
755 
756 		/*
757 		 * Rescursively parse the FDT, skipping disabled nodes.
758 		 * FDT is expected reliable and core shall have sufficient
759 		 * stack depth to possibly parse all DT nodes.
760 		 */
761 		if (IS_ENABLED(CFG_DRIVERS_DT_RECURSIVE_PROBE)) {
762 			if (fdt_get_status(fdt, subnode) == DT_STATUS_DISABLED)
763 				continue;
764 
765 			parse_node(fdt, subnode);
766 		}
767 	}
768 }
769 
770 /*
771  * Parse FDT for nodes and save in probe list the node for which a dt_driver
772  * matches node's compatible property.
773  */
774 static TEE_Result probe_dt_drivers_early(void)
775 {
776 	TEE_Result res = TEE_ERROR_GENERIC;
777 	const void *fdt = NULL;
778 
779 	fdt = get_secure_dt();
780 	if (!fdt)
781 		return TEE_SUCCESS;
782 
783 	parse_node(fdt, fdt_path_offset(fdt, "/"));
784 
785 	res = process_probe_list(fdt);
786 	if (res == TEE_ERROR_DEFER_DRIVER_INIT) {
787 		DMSG("Deferred drivers probing");
788 		print_probe_list(fdt);
789 		res = TEE_SUCCESS;
790 	}
791 
792 	return res;
793 }
794 
795 static TEE_Result probe_dt_drivers(void)
796 {
797 	TEE_Result res = TEE_ERROR_GENERIC;
798 	const void *fdt = NULL;
799 
800 	fdt = get_secure_dt();
801 	if (!fdt)
802 		return TEE_SUCCESS;
803 
804 	res = process_probe_list(fdt);
805 	if (res || !TAILQ_EMPTY(&dt_driver_failed_list)) {
806 		EMSG("Probe sequence result: %#"PRIx32, res);
807 		print_probe_list(fdt);
808 		panic();
809 	}
810 
811 	return TEE_SUCCESS;
812 }
813 
814 early_init_late(probe_dt_drivers_early);
815 driver_init(probe_dt_drivers);
816 
817 static TEE_Result release_probe_lists(void)
818 {
819 	struct dt_driver_probe *elt = NULL;
820 	struct dt_driver_probe *next = NULL;
821 	struct dt_driver_provider *prov = NULL;
822 	struct dt_driver_provider *next_prov = NULL;
823 	const void *fdt = NULL;
824 
825 	fdt = get_secure_dt();
826 	if (!fdt)
827 		return TEE_SUCCESS;
828 
829 	assert(fdt && TAILQ_EMPTY(&dt_driver_probe_list));
830 
831 	TAILQ_FOREACH_SAFE(elt, &dt_driver_ready_list, link, next)
832 		free(elt);
833 
834 	TAILQ_FOREACH_SAFE(elt, &dt_driver_failed_list, link, next)
835 	       free(elt);
836 
837 	SLIST_FOREACH_SAFE(prov, &dt_driver_provider_list, link, next_prov)
838 	       free(prov);
839 
840 	return TEE_SUCCESS;
841 }
842 
843 release_init_resource(release_probe_lists);
844 
845 /*
846  * Simple bus support: handy to parse subnodes
847  */
848 static TEE_Result simple_bus_probe(const void *fdt, int node,
849 				   const void *compat_data __unused)
850 {
851 	TEE_Result res = TEE_ERROR_GENERIC;
852 	int subnode = 0;
853 
854 	fdt_for_each_subnode(subnode, fdt, node) {
855 		res = dt_driver_maybe_add_probe_node(fdt, subnode);
856 		if (res) {
857 			EMSG("Failed on node %s with %#"PRIx32,
858 			     fdt_get_name(fdt, subnode, NULL), res);
859 			panic();
860 		}
861 	}
862 
863 	return TEE_SUCCESS;
864 }
865 
866 static const struct dt_device_match simple_bus_match_table[] = {
867 	{ .compatible = "simple-bus" },
868 	{ }
869 };
870 
871 DEFINE_DT_DRIVER(simple_bus_dt_driver) = {
872 	.name = "simple-bus",
873 	.match_table = simple_bus_match_table,
874 	.probe = simple_bus_probe,
875 };
876