drivers/acpi/x86/apple.c

   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 */
  13 static 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  */
  27 void 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
 135 out_free:
 136         ACPI_FREE(props);
 137         bitmap_free(valid);
 138 }