1/*
2 * ACPI device specific properties support.
3 *
4 * Copyright (C) 2014, Intel Corporation
5 * All rights reserved.
6 *
7 * Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
8 *          Darren Hart <dvhart@linux.intel.com>
9 *          Rafael J. Wysocki <rafael.j.wysocki@intel.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16#include <linux/acpi.h>
17#include <linux/device.h>
18#include <linux/export.h>
19
20#include "internal.h"
21
22/* ACPI _DSD device properties UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301 */
23static const u8 prp_uuid[16] = {
24	0x14, 0xd8, 0xff, 0xda, 0xba, 0x6e, 0x8c, 0x4d,
25	0x8a, 0x91, 0xbc, 0x9b, 0xbf, 0x4a, 0xa3, 0x01
26};
27
28static bool acpi_property_value_ok(const union acpi_object *value)
29{
30	int j;
31
32	/*
33	 * The value must be an integer, a string, a reference, or a package
34	 * whose every element must be an integer, a string, or a reference.
35	 */
36	switch (value->type) {
37	case ACPI_TYPE_INTEGER:
38	case ACPI_TYPE_STRING:
39	case ACPI_TYPE_LOCAL_REFERENCE:
40		return true;
41
42	case ACPI_TYPE_PACKAGE:
43		for (j = 0; j < value->package.count; j++)
44			switch (value->package.elements[j].type) {
45			case ACPI_TYPE_INTEGER:
46			case ACPI_TYPE_STRING:
47			case ACPI_TYPE_LOCAL_REFERENCE:
48				continue;
49
50			default:
51				return false;
52			}
53
54		return true;
55	}
56	return false;
57}
58
59static bool acpi_properties_format_valid(const union acpi_object *properties)
60{
61	int i;
62
63	for (i = 0; i < properties->package.count; i++) {
64		const union acpi_object *property;
65
66		property = &properties->package.elements[i];
67		/*
68		 * Only two elements allowed, the first one must be a string and
69		 * the second one has to satisfy certain conditions.
70		 */
71		if (property->package.count != 2
72		    || property->package.elements[0].type != ACPI_TYPE_STRING
73		    || !acpi_property_value_ok(&property->package.elements[1]))
74			return false;
75	}
76	return true;
77}
78
79static void acpi_init_of_compatible(struct acpi_device *adev)
80{
81	const union acpi_object *of_compatible;
82	struct acpi_hardware_id *hwid;
83	bool acpi_of = false;
84	int ret;
85
86	/*
87	 * Check if the special PRP0001 ACPI ID is present and in that
88	 * case we fill in Device Tree compatible properties for this
89	 * device.
90	 */
91	list_for_each_entry(hwid, &adev->pnp.ids, list) {
92		if (!strcmp(hwid->id, "PRP0001")) {
93			acpi_of = true;
94			break;
95		}
96	}
97
98	if (!acpi_of)
99		return;
100
101	ret = acpi_dev_get_property_array(adev, "compatible", ACPI_TYPE_STRING,
102					  &of_compatible);
103	if (ret) {
104		ret = acpi_dev_get_property(adev, "compatible",
105					    ACPI_TYPE_STRING, &of_compatible);
106		if (ret) {
107			acpi_handle_warn(adev->handle,
108					 "PRP0001 requires compatible property\n");
109			return;
110		}
111	}
112	adev->data.of_compatible = of_compatible;
113}
114
115void acpi_init_properties(struct acpi_device *adev)
116{
117	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
118	const union acpi_object *desc;
119	acpi_status status;
120	int i;
121
122	status = acpi_evaluate_object_typed(adev->handle, "_DSD", NULL, &buf,
123					    ACPI_TYPE_PACKAGE);
124	if (ACPI_FAILURE(status))
125		return;
126
127	desc = buf.pointer;
128	if (desc->package.count % 2)
129		goto fail;
130
131	/* Look for the device properties UUID. */
132	for (i = 0; i < desc->package.count; i += 2) {
133		const union acpi_object *uuid, *properties;
134
135		uuid = &desc->package.elements[i];
136		properties = &desc->package.elements[i + 1];
137
138		/*
139		 * The first element must be a UUID and the second one must be
140		 * a package.
141		 */
142		if (uuid->type != ACPI_TYPE_BUFFER || uuid->buffer.length != 16
143		    || properties->type != ACPI_TYPE_PACKAGE)
144			break;
145
146		if (memcmp(uuid->buffer.pointer, prp_uuid, sizeof(prp_uuid)))
147			continue;
148
149		/*
150		 * We found the matching UUID. Now validate the format of the
151		 * package immediately following it.
152		 */
153		if (!acpi_properties_format_valid(properties))
154			break;
155
156		adev->data.pointer = buf.pointer;
157		adev->data.properties = properties;
158
159		acpi_init_of_compatible(adev);
160		return;
161	}
162
163 fail:
164	dev_warn(&adev->dev, "Returned _DSD data is not valid, skipping\n");
165	ACPI_FREE(buf.pointer);
166}
167
168void acpi_free_properties(struct acpi_device *adev)
169{
170	ACPI_FREE((void *)adev->data.pointer);
171	adev->data.of_compatible = NULL;
172	adev->data.pointer = NULL;
173	adev->data.properties = NULL;
174}
175
176/**
177 * acpi_dev_get_property - return an ACPI property with given name
178 * @adev: ACPI device to get property
179 * @name: Name of the property
180 * @type: Expected property type
181 * @obj: Location to store the property value (if not %NULL)
182 *
183 * Look up a property with @name and store a pointer to the resulting ACPI
184 * object at the location pointed to by @obj if found.
185 *
186 * Callers must not attempt to free the returned objects.  These objects will be
187 * freed by the ACPI core automatically during the removal of @adev.
188 *
189 * Return: %0 if property with @name has been found (success),
190 *         %-EINVAL if the arguments are invalid,
191 *         %-ENODATA if the property doesn't exist,
192 *         %-EPROTO if the property value type doesn't match @type.
193 */
194int acpi_dev_get_property(struct acpi_device *adev, const char *name,
195			  acpi_object_type type, const union acpi_object **obj)
196{
197	const union acpi_object *properties;
198	int i;
199
200	if (!adev || !name)
201		return -EINVAL;
202
203	if (!adev->data.pointer || !adev->data.properties)
204		return -ENODATA;
205
206	properties = adev->data.properties;
207	for (i = 0; i < properties->package.count; i++) {
208		const union acpi_object *propname, *propvalue;
209		const union acpi_object *property;
210
211		property = &properties->package.elements[i];
212
213		propname = &property->package.elements[0];
214		propvalue = &property->package.elements[1];
215
216		if (!strcmp(name, propname->string.pointer)) {
217			if (type != ACPI_TYPE_ANY && propvalue->type != type)
218				return -EPROTO;
219			else if (obj)
220				*obj = propvalue;
221
222			return 0;
223		}
224	}
225	return -ENODATA;
226}
227EXPORT_SYMBOL_GPL(acpi_dev_get_property);
228
229/**
230 * acpi_dev_get_property_array - return an ACPI array property with given name
231 * @adev: ACPI device to get property
232 * @name: Name of the property
233 * @type: Expected type of array elements
234 * @obj: Location to store a pointer to the property value (if not NULL)
235 *
236 * Look up an array property with @name and store a pointer to the resulting
237 * ACPI object at the location pointed to by @obj if found.
238 *
239 * Callers must not attempt to free the returned objects.  Those objects will be
240 * freed by the ACPI core automatically during the removal of @adev.
241 *
242 * Return: %0 if array property (package) with @name has been found (success),
243 *         %-EINVAL if the arguments are invalid,
244 *         %-ENODATA if the property doesn't exist,
245 *         %-EPROTO if the property is not a package or the type of its elements
246 *           doesn't match @type.
247 */
248int acpi_dev_get_property_array(struct acpi_device *adev, const char *name,
249				acpi_object_type type,
250				const union acpi_object **obj)
251{
252	const union acpi_object *prop;
253	int ret, i;
254
255	ret = acpi_dev_get_property(adev, name, ACPI_TYPE_PACKAGE, &prop);
256	if (ret)
257		return ret;
258
259	if (type != ACPI_TYPE_ANY) {
260		/* Check that all elements are of correct type. */
261		for (i = 0; i < prop->package.count; i++)
262			if (prop->package.elements[i].type != type)
263				return -EPROTO;
264	}
265	if (obj)
266		*obj = prop;
267
268	return 0;
269}
270EXPORT_SYMBOL_GPL(acpi_dev_get_property_array);
271
272/**
273 * acpi_dev_get_property_reference - returns handle to the referenced object
274 * @adev: ACPI device to get property
275 * @name: Name of the property
276 * @index: Index of the reference to return
277 * @args: Location to store the returned reference with optional arguments
278 *
279 * Find property with @name, verifify that it is a package containing at least
280 * one object reference and if so, store the ACPI device object pointer to the
281 * target object in @args->adev.  If the reference includes arguments, store
282 * them in the @args->args[] array.
283 *
284 * If there's more than one reference in the property value package, @index is
285 * used to select the one to return.
286 *
287 * Return: %0 on success, negative error code on failure.
288 */
289int acpi_dev_get_property_reference(struct acpi_device *adev,
290				    const char *name, size_t index,
291				    struct acpi_reference_args *args)
292{
293	const union acpi_object *element, *end;
294	const union acpi_object *obj;
295	struct acpi_device *device;
296	int ret, idx = 0;
297
298	ret = acpi_dev_get_property(adev, name, ACPI_TYPE_ANY, &obj);
299	if (ret)
300		return ret;
301
302	/*
303	 * The simplest case is when the value is a single reference.  Just
304	 * return that reference then.
305	 */
306	if (obj->type == ACPI_TYPE_LOCAL_REFERENCE) {
307		if (index)
308			return -EINVAL;
309
310		ret = acpi_bus_get_device(obj->reference.handle, &device);
311		if (ret)
312			return ret;
313
314		args->adev = device;
315		args->nargs = 0;
316		return 0;
317	}
318
319	/*
320	 * If it is not a single reference, then it is a package of
321	 * references followed by number of ints as follows:
322	 *
323	 *  Package () { REF, INT, REF, INT, INT }
324	 *
325	 * The index argument is then used to determine which reference
326	 * the caller wants (along with the arguments).
327	 */
328	if (obj->type != ACPI_TYPE_PACKAGE || index >= obj->package.count)
329		return -EPROTO;
330
331	element = obj->package.elements;
332	end = element + obj->package.count;
333
334	while (element < end) {
335		u32 nargs, i;
336
337		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
338			return -EPROTO;
339
340		ret = acpi_bus_get_device(element->reference.handle, &device);
341		if (ret)
342			return -ENODEV;
343
344		element++;
345		nargs = 0;
346
347		/* assume following integer elements are all args */
348		for (i = 0; element + i < end; i++) {
349			int type = element[i].type;
350
351			if (type == ACPI_TYPE_INTEGER)
352				nargs++;
353			else if (type == ACPI_TYPE_LOCAL_REFERENCE)
354				break;
355			else
356				return -EPROTO;
357		}
358
359		if (idx++ == index) {
360			args->adev = device;
361			args->nargs = nargs;
362			for (i = 0; i < nargs; i++)
363				args->args[i] = element[i].integer.value;
364
365			return 0;
366		}
367
368		element += nargs;
369	}
370
371	return -EPROTO;
372}
373EXPORT_SYMBOL_GPL(acpi_dev_get_property_reference);
374
375int acpi_dev_prop_get(struct acpi_device *adev, const char *propname,
376		      void **valptr)
377{
378	return acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
379				     (const union acpi_object **)valptr);
380}
381
382int acpi_dev_prop_read_single(struct acpi_device *adev, const char *propname,
383			      enum dev_prop_type proptype, void *val)
384{
385	const union acpi_object *obj;
386	int ret;
387
388	if (!val)
389		return -EINVAL;
390
391	if (proptype >= DEV_PROP_U8 && proptype <= DEV_PROP_U64) {
392		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_INTEGER, &obj);
393		if (ret)
394			return ret;
395
396		switch (proptype) {
397		case DEV_PROP_U8:
398			if (obj->integer.value > U8_MAX)
399				return -EOVERFLOW;
400			*(u8 *)val = obj->integer.value;
401			break;
402		case DEV_PROP_U16:
403			if (obj->integer.value > U16_MAX)
404				return -EOVERFLOW;
405			*(u16 *)val = obj->integer.value;
406			break;
407		case DEV_PROP_U32:
408			if (obj->integer.value > U32_MAX)
409				return -EOVERFLOW;
410			*(u32 *)val = obj->integer.value;
411			break;
412		default:
413			*(u64 *)val = obj->integer.value;
414			break;
415		}
416	} else if (proptype == DEV_PROP_STRING) {
417		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_STRING, &obj);
418		if (ret)
419			return ret;
420
421		*(char **)val = obj->string.pointer;
422	} else {
423		ret = -EINVAL;
424	}
425	return ret;
426}
427
428static int acpi_copy_property_array_u8(const union acpi_object *items, u8 *val,
429				       size_t nval)
430{
431	int i;
432
433	for (i = 0; i < nval; i++) {
434		if (items[i].type != ACPI_TYPE_INTEGER)
435			return -EPROTO;
436		if (items[i].integer.value > U8_MAX)
437			return -EOVERFLOW;
438
439		val[i] = items[i].integer.value;
440	}
441	return 0;
442}
443
444static int acpi_copy_property_array_u16(const union acpi_object *items,
445					u16 *val, size_t nval)
446{
447	int i;
448
449	for (i = 0; i < nval; i++) {
450		if (items[i].type != ACPI_TYPE_INTEGER)
451			return -EPROTO;
452		if (items[i].integer.value > U16_MAX)
453			return -EOVERFLOW;
454
455		val[i] = items[i].integer.value;
456	}
457	return 0;
458}
459
460static int acpi_copy_property_array_u32(const union acpi_object *items,
461					u32 *val, size_t nval)
462{
463	int i;
464
465	for (i = 0; i < nval; i++) {
466		if (items[i].type != ACPI_TYPE_INTEGER)
467			return -EPROTO;
468		if (items[i].integer.value > U32_MAX)
469			return -EOVERFLOW;
470
471		val[i] = items[i].integer.value;
472	}
473	return 0;
474}
475
476static int acpi_copy_property_array_u64(const union acpi_object *items,
477					u64 *val, size_t nval)
478{
479	int i;
480
481	for (i = 0; i < nval; i++) {
482		if (items[i].type != ACPI_TYPE_INTEGER)
483			return -EPROTO;
484
485		val[i] = items[i].integer.value;
486	}
487	return 0;
488}
489
490static int acpi_copy_property_array_string(const union acpi_object *items,
491					   char **val, size_t nval)
492{
493	int i;
494
495	for (i = 0; i < nval; i++) {
496		if (items[i].type != ACPI_TYPE_STRING)
497			return -EPROTO;
498
499		val[i] = items[i].string.pointer;
500	}
501	return 0;
502}
503
504int acpi_dev_prop_read(struct acpi_device *adev, const char *propname,
505		       enum dev_prop_type proptype, void *val, size_t nval)
506{
507	const union acpi_object *obj;
508	const union acpi_object *items;
509	int ret;
510
511	if (val && nval == 1) {
512		ret = acpi_dev_prop_read_single(adev, propname, proptype, val);
513		if (!ret)
514			return ret;
515	}
516
517	ret = acpi_dev_get_property_array(adev, propname, ACPI_TYPE_ANY, &obj);
518	if (ret)
519		return ret;
520
521	if (!val)
522		return obj->package.count;
523	else if (nval <= 0)
524		return -EINVAL;
525
526	if (nval > obj->package.count)
527		return -EOVERFLOW;
528
529	items = obj->package.elements;
530	switch (proptype) {
531	case DEV_PROP_U8:
532		ret = acpi_copy_property_array_u8(items, (u8 *)val, nval);
533		break;
534	case DEV_PROP_U16:
535		ret = acpi_copy_property_array_u16(items, (u16 *)val, nval);
536		break;
537	case DEV_PROP_U32:
538		ret = acpi_copy_property_array_u32(items, (u32 *)val, nval);
539		break;
540	case DEV_PROP_U64:
541		ret = acpi_copy_property_array_u64(items, (u64 *)val, nval);
542		break;
543	case DEV_PROP_STRING:
544		ret = acpi_copy_property_array_string(items, (char **)val, nval);
545		break;
546	default:
547		ret = -EINVAL;
548		break;
549	}
550	return ret;
551}
552