1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
4  *			 <benh@kernel.crashing.org>
5  *    and		 Arnd Bergmann, IBM Corp.
6  *    Merged from powerpc/kernel/of_platform.c and
7  *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
8  */
9 
10 #define pr_fmt(fmt)	"OF: " fmt
11 
12 #include <linux/errno.h>
13 #include <linux/module.h>
14 #include <linux/amba/bus.h>
15 #include <linux/device.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/slab.h>
18 #include <linux/of_address.h>
19 #include <linux/of_device.h>
20 #include <linux/of_iommu.h>
21 #include <linux/of_irq.h>
22 #include <linux/of_platform.h>
23 #include <linux/platform_device.h>
24 
25 const struct of_device_id of_default_bus_match_table[] = {
26 	{ .compatible = "simple-bus", },
27 	{ .compatible = "simple-mfd", },
28 	{ .compatible = "isa", },
29 #ifdef CONFIG_ARM_AMBA
30 	{ .compatible = "arm,amba-bus", },
31 #endif /* CONFIG_ARM_AMBA */
32 	{} /* Empty terminated list */
33 };
34 
35 static const struct of_device_id of_skipped_node_table[] = {
36 	{ .compatible = "operating-points-v2", },
37 	{} /* Empty terminated list */
38 };
39 
of_dev_node_match(struct device * dev,void * data)40 static int of_dev_node_match(struct device *dev, void *data)
41 {
42 	return dev->of_node == data;
43 }
44 
45 /**
46  * of_find_device_by_node - Find the platform_device associated with a node
47  * @np: Pointer to device tree node
48  *
49  * Takes a reference to the embedded struct device which needs to be dropped
50  * after use.
51  *
52  * Returns platform_device pointer, or NULL if not found
53  */
of_find_device_by_node(struct device_node * np)54 struct platform_device *of_find_device_by_node(struct device_node *np)
55 {
56 	struct device *dev;
57 
58 	dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
59 	return dev ? to_platform_device(dev) : NULL;
60 }
61 EXPORT_SYMBOL(of_find_device_by_node);
62 
63 #ifdef CONFIG_OF_ADDRESS
64 /*
65  * The following routines scan a subtree and registers a device for
66  * each applicable node.
67  *
68  * Note: sparc doesn't use these routines because it has a different
69  * mechanism for creating devices from device tree nodes.
70  */
71 
72 /**
73  * of_device_make_bus_id - Use the device node data to assign a unique name
74  * @dev: pointer to device structure that is linked to a device tree node
75  *
76  * This routine will first try using the translated bus address to
77  * derive a unique name. If it cannot, then it will prepend names from
78  * parent nodes until a unique name can be derived.
79  */
of_device_make_bus_id(struct device * dev)80 static void of_device_make_bus_id(struct device *dev)
81 {
82 	struct device_node *node = dev->of_node;
83 	const __be32 *reg;
84 	u64 addr;
85 
86 	/* Construct the name, using parent nodes if necessary to ensure uniqueness */
87 	while (node->parent) {
88 		/*
89 		 * If the address can be translated, then that is as much
90 		 * uniqueness as we need. Make it the first component and return
91 		 */
92 		reg = of_get_property(node, "reg", NULL);
93 		if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
94 			dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
95 				     (unsigned long long)addr, node,
96 				     dev_name(dev));
97 			return;
98 		}
99 
100 		/* format arguments only used if dev_name() resolves to NULL */
101 		dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
102 			     kbasename(node->full_name), dev_name(dev));
103 		node = node->parent;
104 	}
105 }
106 
107 /**
108  * of_device_alloc - Allocate and initialize an of_device
109  * @np: device node to assign to device
110  * @bus_id: Name to assign to the device.  May be null to use default name.
111  * @parent: Parent device.
112  */
of_device_alloc(struct device_node * np,const char * bus_id,struct device * parent)113 struct platform_device *of_device_alloc(struct device_node *np,
114 				  const char *bus_id,
115 				  struct device *parent)
116 {
117 	struct platform_device *dev;
118 	int rc, i, num_reg = 0, num_irq;
119 	struct resource *res, temp_res;
120 
121 	dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
122 	if (!dev)
123 		return NULL;
124 
125 	/* count the io and irq resources */
126 	while (of_address_to_resource(np, num_reg, &temp_res) == 0)
127 		num_reg++;
128 	num_irq = of_irq_count(np);
129 
130 	/* Populate the resource table */
131 	if (num_irq || num_reg) {
132 		res = kcalloc(num_irq + num_reg, sizeof(*res), GFP_KERNEL);
133 		if (!res) {
134 			platform_device_put(dev);
135 			return NULL;
136 		}
137 
138 		dev->num_resources = num_reg + num_irq;
139 		dev->resource = res;
140 		for (i = 0; i < num_reg; i++, res++) {
141 			rc = of_address_to_resource(np, i, res);
142 			WARN_ON(rc);
143 		}
144 		if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
145 			pr_debug("not all legacy IRQ resources mapped for %pOFn\n",
146 				 np);
147 	}
148 
149 	dev->dev.of_node = of_node_get(np);
150 	dev->dev.fwnode = &np->fwnode;
151 	dev->dev.parent = parent ? : &platform_bus;
152 
153 	if (bus_id)
154 		dev_set_name(&dev->dev, "%s", bus_id);
155 	else
156 		of_device_make_bus_id(&dev->dev);
157 
158 	return dev;
159 }
160 EXPORT_SYMBOL(of_device_alloc);
161 
162 /**
163  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
164  * @np: pointer to node to create device for
165  * @bus_id: name to assign device
166  * @platform_data: pointer to populate platform_data pointer with
167  * @parent: Linux device model parent device.
168  *
169  * Returns pointer to created platform device, or NULL if a device was not
170  * registered.  Unavailable devices will not get registered.
171  */
of_platform_device_create_pdata(struct device_node * np,const char * bus_id,void * platform_data,struct device * parent)172 static struct platform_device *of_platform_device_create_pdata(
173 					struct device_node *np,
174 					const char *bus_id,
175 					void *platform_data,
176 					struct device *parent)
177 {
178 	struct platform_device *dev;
179 
180 	if (!of_device_is_available(np) ||
181 	    of_node_test_and_set_flag(np, OF_POPULATED))
182 		return NULL;
183 
184 	dev = of_device_alloc(np, bus_id, parent);
185 	if (!dev)
186 		goto err_clear_flag;
187 
188 	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
189 	if (!dev->dev.dma_mask)
190 		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
191 	dev->dev.bus = &platform_bus_type;
192 	dev->dev.platform_data = platform_data;
193 	of_msi_configure(&dev->dev, dev->dev.of_node);
194 
195 	if (of_device_add(dev) != 0) {
196 		platform_device_put(dev);
197 		goto err_clear_flag;
198 	}
199 
200 	return dev;
201 
202 err_clear_flag:
203 	of_node_clear_flag(np, OF_POPULATED);
204 	return NULL;
205 }
206 
207 /**
208  * of_platform_device_create - Alloc, initialize and register an of_device
209  * @np: pointer to node to create device for
210  * @bus_id: name to assign device
211  * @parent: Linux device model parent device.
212  *
213  * Returns pointer to created platform device, or NULL if a device was not
214  * registered.  Unavailable devices will not get registered.
215  */
of_platform_device_create(struct device_node * np,const char * bus_id,struct device * parent)216 struct platform_device *of_platform_device_create(struct device_node *np,
217 					    const char *bus_id,
218 					    struct device *parent)
219 {
220 	return of_platform_device_create_pdata(np, bus_id, NULL, parent);
221 }
222 EXPORT_SYMBOL(of_platform_device_create);
223 
224 #ifdef CONFIG_ARM_AMBA
of_amba_device_create(struct device_node * node,const char * bus_id,void * platform_data,struct device * parent)225 static struct amba_device *of_amba_device_create(struct device_node *node,
226 						 const char *bus_id,
227 						 void *platform_data,
228 						 struct device *parent)
229 {
230 	struct amba_device *dev;
231 	const void *prop;
232 	int i, ret;
233 
234 	pr_debug("Creating amba device %pOF\n", node);
235 
236 	if (!of_device_is_available(node) ||
237 	    of_node_test_and_set_flag(node, OF_POPULATED))
238 		return NULL;
239 
240 	dev = amba_device_alloc(NULL, 0, 0);
241 	if (!dev)
242 		goto err_clear_flag;
243 
244 	/* AMBA devices only support a single DMA mask */
245 	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
246 	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
247 
248 	/* setup generic device info */
249 	dev->dev.of_node = of_node_get(node);
250 	dev->dev.fwnode = &node->fwnode;
251 	dev->dev.parent = parent ? : &platform_bus;
252 	dev->dev.platform_data = platform_data;
253 	if (bus_id)
254 		dev_set_name(&dev->dev, "%s", bus_id);
255 	else
256 		of_device_make_bus_id(&dev->dev);
257 
258 	/* Allow the HW Peripheral ID to be overridden */
259 	prop = of_get_property(node, "arm,primecell-periphid", NULL);
260 	if (prop)
261 		dev->periphid = of_read_ulong(prop, 1);
262 
263 	/* Decode the IRQs and address ranges */
264 	for (i = 0; i < AMBA_NR_IRQS; i++)
265 		dev->irq[i] = irq_of_parse_and_map(node, i);
266 
267 	ret = of_address_to_resource(node, 0, &dev->res);
268 	if (ret) {
269 		pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
270 		       ret, node);
271 		goto err_free;
272 	}
273 
274 	ret = amba_device_add(dev, &iomem_resource);
275 	if (ret) {
276 		pr_err("amba_device_add() failed (%d) for %pOF\n",
277 		       ret, node);
278 		goto err_free;
279 	}
280 
281 	return dev;
282 
283 err_free:
284 	amba_device_put(dev);
285 err_clear_flag:
286 	of_node_clear_flag(node, OF_POPULATED);
287 	return NULL;
288 }
289 #else /* CONFIG_ARM_AMBA */
of_amba_device_create(struct device_node * node,const char * bus_id,void * platform_data,struct device * parent)290 static struct amba_device *of_amba_device_create(struct device_node *node,
291 						 const char *bus_id,
292 						 void *platform_data,
293 						 struct device *parent)
294 {
295 	return NULL;
296 }
297 #endif /* CONFIG_ARM_AMBA */
298 
299 /**
300  * of_devname_lookup() - Given a device node, lookup the preferred Linux name
301  */
of_dev_lookup(const struct of_dev_auxdata * lookup,struct device_node * np)302 static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
303 				 struct device_node *np)
304 {
305 	const struct of_dev_auxdata *auxdata;
306 	struct resource res;
307 	int compatible = 0;
308 
309 	if (!lookup)
310 		return NULL;
311 
312 	auxdata = lookup;
313 	for (; auxdata->compatible; auxdata++) {
314 		if (!of_device_is_compatible(np, auxdata->compatible))
315 			continue;
316 		compatible++;
317 		if (!of_address_to_resource(np, 0, &res))
318 			if (res.start != auxdata->phys_addr)
319 				continue;
320 		pr_debug("%pOF: devname=%s\n", np, auxdata->name);
321 		return auxdata;
322 	}
323 
324 	if (!compatible)
325 		return NULL;
326 
327 	/* Try compatible match if no phys_addr and name are specified */
328 	auxdata = lookup;
329 	for (; auxdata->compatible; auxdata++) {
330 		if (!of_device_is_compatible(np, auxdata->compatible))
331 			continue;
332 		if (!auxdata->phys_addr && !auxdata->name) {
333 			pr_debug("%pOF: compatible match\n", np);
334 			return auxdata;
335 		}
336 	}
337 
338 	return NULL;
339 }
340 
341 /**
342  * of_platform_bus_create() - Create a device for a node and its children.
343  * @bus: device node of the bus to instantiate
344  * @matches: match table for bus nodes
345  * @lookup: auxdata table for matching id and platform_data with device nodes
346  * @parent: parent for new device, or NULL for top level.
347  * @strict: require compatible property
348  *
349  * Creates a platform_device for the provided device_node, and optionally
350  * recursively create devices for all the child nodes.
351  */
of_platform_bus_create(struct device_node * bus,const struct of_device_id * matches,const struct of_dev_auxdata * lookup,struct device * parent,bool strict)352 static int of_platform_bus_create(struct device_node *bus,
353 				  const struct of_device_id *matches,
354 				  const struct of_dev_auxdata *lookup,
355 				  struct device *parent, bool strict)
356 {
357 	const struct of_dev_auxdata *auxdata;
358 	struct device_node *child;
359 	struct platform_device *dev;
360 	const char *bus_id = NULL;
361 	void *platform_data = NULL;
362 	int rc = 0;
363 
364 	/* Make sure it has a compatible property */
365 	if (strict && (!of_get_property(bus, "compatible", NULL))) {
366 		pr_debug("%s() - skipping %pOF, no compatible prop\n",
367 			 __func__, bus);
368 		return 0;
369 	}
370 
371 	/* Skip nodes for which we don't want to create devices */
372 	if (unlikely(of_match_node(of_skipped_node_table, bus))) {
373 		pr_debug("%s() - skipping %pOF node\n", __func__, bus);
374 		return 0;
375 	}
376 
377 	if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
378 		pr_debug("%s() - skipping %pOF, already populated\n",
379 			__func__, bus);
380 		return 0;
381 	}
382 
383 	auxdata = of_dev_lookup(lookup, bus);
384 	if (auxdata) {
385 		bus_id = auxdata->name;
386 		platform_data = auxdata->platform_data;
387 	}
388 
389 	if (of_device_is_compatible(bus, "arm,primecell")) {
390 		/*
391 		 * Don't return an error here to keep compatibility with older
392 		 * device tree files.
393 		 */
394 		of_amba_device_create(bus, bus_id, platform_data, parent);
395 		return 0;
396 	}
397 
398 	dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
399 	if (!dev || !of_match_node(matches, bus))
400 		return 0;
401 
402 	for_each_child_of_node(bus, child) {
403 		pr_debug("   create child: %pOF\n", child);
404 		rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
405 		if (rc) {
406 			of_node_put(child);
407 			break;
408 		}
409 	}
410 	of_node_set_flag(bus, OF_POPULATED_BUS);
411 	return rc;
412 }
413 
414 /**
415  * of_platform_bus_probe() - Probe the device-tree for platform buses
416  * @root: parent of the first level to probe or NULL for the root of the tree
417  * @matches: match table for bus nodes
418  * @parent: parent to hook devices from, NULL for toplevel
419  *
420  * Note that children of the provided root are not instantiated as devices
421  * unless the specified root itself matches the bus list and is not NULL.
422  */
of_platform_bus_probe(struct device_node * root,const struct of_device_id * matches,struct device * parent)423 int of_platform_bus_probe(struct device_node *root,
424 			  const struct of_device_id *matches,
425 			  struct device *parent)
426 {
427 	struct device_node *child;
428 	int rc = 0;
429 
430 	root = root ? of_node_get(root) : of_find_node_by_path("/");
431 	if (!root)
432 		return -EINVAL;
433 
434 	pr_debug("%s()\n", __func__);
435 	pr_debug(" starting at: %pOF\n", root);
436 
437 	/* Do a self check of bus type, if there's a match, create children */
438 	if (of_match_node(matches, root)) {
439 		rc = of_platform_bus_create(root, matches, NULL, parent, false);
440 	} else for_each_child_of_node(root, child) {
441 		if (!of_match_node(matches, child))
442 			continue;
443 		rc = of_platform_bus_create(child, matches, NULL, parent, false);
444 		if (rc) {
445 			of_node_put(child);
446 			break;
447 		}
448 	}
449 
450 	of_node_put(root);
451 	return rc;
452 }
453 EXPORT_SYMBOL(of_platform_bus_probe);
454 
455 /**
456  * of_platform_populate() - Populate platform_devices from device tree data
457  * @root: parent of the first level to probe or NULL for the root of the tree
458  * @matches: match table, NULL to use the default
459  * @lookup: auxdata table for matching id and platform_data with device nodes
460  * @parent: parent to hook devices from, NULL for toplevel
461  *
462  * Similar to of_platform_bus_probe(), this function walks the device tree
463  * and creates devices from nodes.  It differs in that it follows the modern
464  * convention of requiring all device nodes to have a 'compatible' property,
465  * and it is suitable for creating devices which are children of the root
466  * node (of_platform_bus_probe will only create children of the root which
467  * are selected by the @matches argument).
468  *
469  * New board support should be using this function instead of
470  * of_platform_bus_probe().
471  *
472  * Returns 0 on success, < 0 on failure.
473  */
of_platform_populate(struct device_node * root,const struct of_device_id * matches,const struct of_dev_auxdata * lookup,struct device * parent)474 int of_platform_populate(struct device_node *root,
475 			const struct of_device_id *matches,
476 			const struct of_dev_auxdata *lookup,
477 			struct device *parent)
478 {
479 	struct device_node *child;
480 	int rc = 0;
481 
482 	root = root ? of_node_get(root) : of_find_node_by_path("/");
483 	if (!root)
484 		return -EINVAL;
485 
486 	pr_debug("%s()\n", __func__);
487 	pr_debug(" starting at: %pOF\n", root);
488 
489 	for_each_child_of_node(root, child) {
490 		rc = of_platform_bus_create(child, matches, lookup, parent, true);
491 		if (rc) {
492 			of_node_put(child);
493 			break;
494 		}
495 	}
496 	of_node_set_flag(root, OF_POPULATED_BUS);
497 
498 	of_node_put(root);
499 	return rc;
500 }
501 EXPORT_SYMBOL_GPL(of_platform_populate);
502 
of_platform_default_populate(struct device_node * root,const struct of_dev_auxdata * lookup,struct device * parent)503 int of_platform_default_populate(struct device_node *root,
504 				 const struct of_dev_auxdata *lookup,
505 				 struct device *parent)
506 {
507 	return of_platform_populate(root, of_default_bus_match_table, lookup,
508 				    parent);
509 }
510 EXPORT_SYMBOL_GPL(of_platform_default_populate);
511 
512 #ifndef CONFIG_PPC
513 static const struct of_device_id reserved_mem_matches[] = {
514 	{ .compatible = "qcom,rmtfs-mem" },
515 	{ .compatible = "qcom,cmd-db" },
516 	{ .compatible = "ramoops" },
517 	{}
518 };
519 
of_platform_default_populate_init(void)520 static int __init of_platform_default_populate_init(void)
521 {
522 	struct device_node *node;
523 
524 	if (!of_have_populated_dt())
525 		return -ENODEV;
526 
527 	/*
528 	 * Handle certain compatibles explicitly, since we don't want to create
529 	 * platform_devices for every node in /reserved-memory with a
530 	 * "compatible",
531 	 */
532 	for_each_matching_node(node, reserved_mem_matches)
533 		of_platform_device_create(node, NULL, NULL);
534 
535 	node = of_find_node_by_path("/firmware");
536 	if (node) {
537 		of_platform_populate(node, NULL, NULL, NULL);
538 		of_node_put(node);
539 	}
540 
541 	/* Populate everything else. */
542 	of_platform_default_populate(NULL, NULL, NULL);
543 
544 	return 0;
545 }
546 arch_initcall_sync(of_platform_default_populate_init);
547 #endif
548 
of_platform_device_destroy(struct device * dev,void * data)549 int of_platform_device_destroy(struct device *dev, void *data)
550 {
551 	/* Do not touch devices not populated from the device tree */
552 	if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
553 		return 0;
554 
555 	/* Recurse for any nodes that were treated as busses */
556 	if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
557 		device_for_each_child(dev, NULL, of_platform_device_destroy);
558 
559 	of_node_clear_flag(dev->of_node, OF_POPULATED);
560 	of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
561 
562 	if (dev->bus == &platform_bus_type)
563 		platform_device_unregister(to_platform_device(dev));
564 #ifdef CONFIG_ARM_AMBA
565 	else if (dev->bus == &amba_bustype)
566 		amba_device_unregister(to_amba_device(dev));
567 #endif
568 
569 	return 0;
570 }
571 EXPORT_SYMBOL_GPL(of_platform_device_destroy);
572 
573 /**
574  * of_platform_depopulate() - Remove devices populated from device tree
575  * @parent: device which children will be removed
576  *
577  * Complementary to of_platform_populate(), this function removes children
578  * of the given device (and, recurrently, their children) that have been
579  * created from their respective device tree nodes (and only those,
580  * leaving others - eg. manually created - unharmed).
581  */
of_platform_depopulate(struct device * parent)582 void of_platform_depopulate(struct device *parent)
583 {
584 	if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
585 		device_for_each_child(parent, NULL, of_platform_device_destroy);
586 		of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
587 	}
588 }
589 EXPORT_SYMBOL_GPL(of_platform_depopulate);
590 
devm_of_platform_populate_release(struct device * dev,void * res)591 static void devm_of_platform_populate_release(struct device *dev, void *res)
592 {
593 	of_platform_depopulate(*(struct device **)res);
594 }
595 
596 /**
597  * devm_of_platform_populate() - Populate platform_devices from device tree data
598  * @dev: device that requested to populate from device tree data
599  *
600  * Similar to of_platform_populate(), but will automatically call
601  * of_platform_depopulate() when the device is unbound from the bus.
602  *
603  * Returns 0 on success, < 0 on failure.
604  */
devm_of_platform_populate(struct device * dev)605 int devm_of_platform_populate(struct device *dev)
606 {
607 	struct device **ptr;
608 	int ret;
609 
610 	if (!dev)
611 		return -EINVAL;
612 
613 	ptr = devres_alloc(devm_of_platform_populate_release,
614 			   sizeof(*ptr), GFP_KERNEL);
615 	if (!ptr)
616 		return -ENOMEM;
617 
618 	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
619 	if (ret) {
620 		devres_free(ptr);
621 	} else {
622 		*ptr = dev;
623 		devres_add(dev, ptr);
624 	}
625 
626 	return ret;
627 }
628 EXPORT_SYMBOL_GPL(devm_of_platform_populate);
629 
devm_of_platform_match(struct device * dev,void * res,void * data)630 static int devm_of_platform_match(struct device *dev, void *res, void *data)
631 {
632 	struct device **ptr = res;
633 
634 	if (!ptr) {
635 		WARN_ON(!ptr);
636 		return 0;
637 	}
638 
639 	return *ptr == data;
640 }
641 
642 /**
643  * devm_of_platform_depopulate() - Remove devices populated from device tree
644  * @dev: device that requested to depopulate from device tree data
645  *
646  * Complementary to devm_of_platform_populate(), this function removes children
647  * of the given device (and, recurrently, their children) that have been
648  * created from their respective device tree nodes (and only those,
649  * leaving others - eg. manually created - unharmed).
650  */
devm_of_platform_depopulate(struct device * dev)651 void devm_of_platform_depopulate(struct device *dev)
652 {
653 	int ret;
654 
655 	ret = devres_release(dev, devm_of_platform_populate_release,
656 			     devm_of_platform_match, dev);
657 
658 	WARN_ON(ret);
659 }
660 EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
661 
662 #ifdef CONFIG_OF_DYNAMIC
of_platform_notify(struct notifier_block * nb,unsigned long action,void * arg)663 static int of_platform_notify(struct notifier_block *nb,
664 				unsigned long action, void *arg)
665 {
666 	struct of_reconfig_data *rd = arg;
667 	struct platform_device *pdev_parent, *pdev;
668 	bool children_left;
669 
670 	switch (of_reconfig_get_state_change(action, rd)) {
671 	case OF_RECONFIG_CHANGE_ADD:
672 		/* verify that the parent is a bus */
673 		if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
674 			return NOTIFY_OK;	/* not for us */
675 
676 		/* already populated? (driver using of_populate manually) */
677 		if (of_node_check_flag(rd->dn, OF_POPULATED))
678 			return NOTIFY_OK;
679 
680 		/* pdev_parent may be NULL when no bus platform device */
681 		pdev_parent = of_find_device_by_node(rd->dn->parent);
682 		pdev = of_platform_device_create(rd->dn, NULL,
683 				pdev_parent ? &pdev_parent->dev : NULL);
684 		of_dev_put(pdev_parent);
685 
686 		if (pdev == NULL) {
687 			pr_err("%s: failed to create for '%pOF'\n",
688 					__func__, rd->dn);
689 			/* of_platform_device_create tosses the error code */
690 			return notifier_from_errno(-EINVAL);
691 		}
692 		break;
693 
694 	case OF_RECONFIG_CHANGE_REMOVE:
695 
696 		/* already depopulated? */
697 		if (!of_node_check_flag(rd->dn, OF_POPULATED))
698 			return NOTIFY_OK;
699 
700 		/* find our device by node */
701 		pdev = of_find_device_by_node(rd->dn);
702 		if (pdev == NULL)
703 			return NOTIFY_OK;	/* no? not meant for us */
704 
705 		/* unregister takes one ref away */
706 		of_platform_device_destroy(&pdev->dev, &children_left);
707 
708 		/* and put the reference of the find */
709 		of_dev_put(pdev);
710 		break;
711 	}
712 
713 	return NOTIFY_OK;
714 }
715 
716 static struct notifier_block platform_of_notifier = {
717 	.notifier_call = of_platform_notify,
718 };
719 
of_platform_register_reconfig_notifier(void)720 void of_platform_register_reconfig_notifier(void)
721 {
722 	WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
723 }
724 #endif /* CONFIG_OF_DYNAMIC */
725 
726 #endif /* CONFIG_OF_ADDRESS */
727