1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * apple.c - Apple ACPI quirks
  4 * Copyright (C) 2017 Lukas Wunner <lukas@wunner.de>
  5 */
  6
  7#include <linux/acpi.h>
  8#include <linux/bitmap.h>
  9#include <linux/platform_data/x86/apple.h>
 10#include <linux/uuid.h>
 11
 12/* Apple _DSM device properties GUID */
 13static const guid_t apple_prp_guid =
 14	GUID_INIT(0xa0b5b7c6, 0x1318, 0x441c,
 15		  0xb0, 0xc9, 0xfe, 0x69, 0x5e, 0xaf, 0x94, 0x9b);
 16
 17/**
 18 * acpi_extract_apple_properties - retrieve and convert Apple _DSM properties
 19 * @adev: ACPI device for which to retrieve the properties
 20 *
 21 * Invoke Apple's custom _DSM once to check the protocol version and once more
 22 * to retrieve the properties.  They are marshalled up in a single package as
 23 * alternating key/value elements, unlike _DSD which stores them as a package
 24 * of 2-element packages.  Convert to _DSD format and make them available under
 25 * the primary fwnode.
 26 */
 27void acpi_extract_apple_properties(struct acpi_device *adev)
 28{
 29	unsigned int i, j = 0, newsize = 0, numprops, numvalid;
 30	union acpi_object *props, *newprops;
 31	unsigned long *valid = NULL;
 32	void *free_space;
 33
 34	if (!x86_apple_machine)
 35		return;
 36
 37	props = acpi_evaluate_dsm_typed(adev->handle, &apple_prp_guid, 1, 0,
 38					NULL, ACPI_TYPE_BUFFER);
 39	if (!props)
 40		return;
 41
 42	if (!props->buffer.length)
 43		goto out_free;
 44
 45	if (props->buffer.pointer[0] != 3) {
 46		acpi_handle_info(adev->handle, FW_INFO
 47				 "unsupported properties version %*ph\n",
 48				 props->buffer.length, props->buffer.pointer);
 49		goto out_free;
 50	}
 51
 52	ACPI_FREE(props);
 53	props = acpi_evaluate_dsm_typed(adev->handle, &apple_prp_guid, 1, 1,
 54					NULL, ACPI_TYPE_PACKAGE);
 55	if (!props)
 56		return;
 57
 58	numprops = props->package.count / 2;
 59	if (!numprops)
 60		goto out_free;
 61
 62	valid = bitmap_zalloc(numprops, GFP_KERNEL);
 63	if (!valid)
 64		goto out_free;
 65
 66	/* newsize = key length + value length of each tuple */
 67	for (i = 0; i < numprops; i++) {
 68		union acpi_object *key = &props->package.elements[i * 2];
 69		union acpi_object *val = &props->package.elements[i * 2 + 1];
 70
 71		if ( key->type != ACPI_TYPE_STRING ||
 72		    (val->type != ACPI_TYPE_INTEGER &&
 73		     val->type != ACPI_TYPE_BUFFER))
 74			continue; /* skip invalid properties */
 75
 76		__set_bit(i, valid);
 77		newsize += key->string.length + 1;
 78		if ( val->type == ACPI_TYPE_BUFFER)
 79			newsize += val->buffer.length;
 80	}
 81
 82	numvalid = bitmap_weight(valid, numprops);
 83	if (numprops > numvalid)
 84		acpi_handle_info(adev->handle, FW_INFO
 85				 "skipped %u properties: wrong type\n",
 86				 numprops - numvalid);
 87	if (numvalid == 0)
 88		goto out_free;
 89
 90	/* newsize += top-level package + 3 objects for each key/value tuple */
 91	newsize	+= (1 + 3 * numvalid) * sizeof(union acpi_object);
 92	newprops = ACPI_ALLOCATE_ZEROED(newsize);
 93	if (!newprops)
 94		goto out_free;
 95
 96	/* layout: top-level package | packages | key/value tuples | strings */
 97	newprops->type = ACPI_TYPE_PACKAGE;
 98	newprops->package.count = numvalid;
 99	newprops->package.elements = &newprops[1];
100	free_space = &newprops[1 + 3 * numvalid];
101
102	for_each_set_bit(i, valid, numprops) {
103		union acpi_object *key = &props->package.elements[i * 2];
104		union acpi_object *val = &props->package.elements[i * 2 + 1];
105		unsigned int k = 1 + numvalid + j * 2; /* index into newprops */
106		unsigned int v = k + 1;
107
108		newprops[1 + j].type = ACPI_TYPE_PACKAGE;
109		newprops[1 + j].package.count = 2;
110		newprops[1 + j].package.elements = &newprops[k];
111
112		newprops[k].type = ACPI_TYPE_STRING;
113		newprops[k].string.length = key->string.length;
114		newprops[k].string.pointer = free_space;
115		memcpy(free_space, key->string.pointer, key->string.length);
116		free_space += key->string.length + 1;
117
118		newprops[v].type = val->type;
119		if (val->type == ACPI_TYPE_INTEGER) {
120			newprops[v].integer.value = val->integer.value;
121		} else {
122			newprops[v].buffer.length = val->buffer.length;
123			newprops[v].buffer.pointer = free_space;
124			memcpy(free_space, val->buffer.pointer,
125			       val->buffer.length);
126			free_space += val->buffer.length;
127		}
128		j++; /* count valid properties */
129	}
130	WARN_ON(free_space != (void *)newprops + newsize);
131
132	adev->data.pointer = newprops;
133	acpi_data_add_props(&adev->data, &apple_prp_guid, newprops);
134
135out_free:
136	ACPI_FREE(props);
137	bitmap_free(valid);
138}