drivers/acpi/x86/apple.c

   1 /*
   2  * apple.c - Apple ACPI quirks
   3  * Copyright (C) 2017 Lukas Wunner <lukas@wunner.de>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License (version 2) as
   7  * published by the Free Software Foundation.
   8  */
   9
  10 #include <linux/acpi.h>
  11 #include <linux/bitmap.h>
  12 #include <linux/platform_data/x86/apple.h>
  13 #include <linux/uuid.h>
  14
  15 /* Apple _DSM device properties GUID */
  16 static const guid_t apple_prp_guid =
  17         GUID_INIT(0xa0b5b7c6, 0x1318, 0x441c,
  18                   0xb0, 0xc9, 0xfe, 0x69, 0x5e, 0xaf, 0x94, 0x9b);
  19
  20 /**
  21  * acpi_extract_apple_properties - retrieve and convert Apple _DSM properties
  22  * @adev: ACPI device for which to retrieve the properties
  23  *
  24  * Invoke Apple's custom _DSM once to check the protocol version and once more
  25  * to retrieve the properties.  They are marshalled up in a single package as
  26  * alternating key/value elements, unlike _DSD which stores them as a package
  27  * of 2-element packages.  Convert to _DSD format and make them available under
  28  * the primary fwnode.
  29  */
  30 void acpi_extract_apple_properties(struct acpi_device *adev)
  31 {
  32         unsigned int i, j = 0, newsize = 0, numprops, numvalid;
  33         union acpi_object *props, *newprops;
  34         unsigned long *valid = NULL;
  35         void *free_space;
  36
  37         if (!x86_apple_machine)
  38                 return;
  39
  40         props = acpi_evaluate_dsm_typed(adev->handle, &apple_prp_guid, 1, 0,
  41                                         NULL, ACPI_TYPE_BUFFER);
  42         if (!props)
  43                 return;
  44
  45         if (!props->buffer.length)
  46                 goto out_free;
  47
  48         if (props->buffer.pointer[0] != 3) {
  49                 acpi_handle_info(adev->handle, FW_INFO
  50                                  "unsupported properties version %*ph\n",
  51                                  props->buffer.length, props->buffer.pointer);
  52                 goto out_free;
  53         }
  54
  55         ACPI_FREE(props);
  56         props = acpi_evaluate_dsm_typed(adev->handle, &apple_prp_guid, 1, 1,
  57                                         NULL, ACPI_TYPE_PACKAGE);
  58         if (!props)
  59                 return;
  60
  61         numprops = props->package.count / 2;
  62         if (!numprops)
  63                 goto out_free;
  64
  65         valid = kcalloc(BITS_TO_LONGS(numprops), sizeof(long), GFP_KERNEL);
  66         if (!valid)
  67                 goto out_free;
  68
  69         /* newsize = key length + value length of each tuple */
  70         for (i = 0; i < numprops; i++) {
  71                 union acpi_object *key = &props->package.elements[i * 2];
  72                 union acpi_object *val = &props->package.elements[i * 2 + 1];
  73
  74                 if ( key->type != ACPI_TYPE_STRING ||
  75                     (val->type != ACPI_TYPE_INTEGER &&
  76                      val->type != ACPI_TYPE_BUFFER))
  77                         continue; /* skip invalid properties */
  78
  79                 __set_bit(i, valid);
  80                 newsize += key->string.length + 1;
  81                 if ( val->type == ACPI_TYPE_BUFFER)
  82                         newsize += val->buffer.length;
  83         }
  84
  85         numvalid = bitmap_weight(valid, numprops);
  86         if (numprops > numvalid)
  87                 acpi_handle_info(adev->handle, FW_INFO
  88                                  "skipped %u properties: wrong type\n",
  89                                  numprops - numvalid);
  90         if (numvalid == 0)
  91                 goto out_free;
  92
  93         /* newsize += top-level package + 3 objects for each key/value tuple */
  94         newsize += (1 + 3 * numvalid) * sizeof(union acpi_object);
  95         newprops = ACPI_ALLOCATE_ZEROED(newsize);
  96         if (!newprops)
  97                 goto out_free;
  98
  99         /* layout: top-level package | packages | key/value tuples | strings */
 100         newprops->type = ACPI_TYPE_PACKAGE;
 101         newprops->package.count = numvalid;
 102         newprops->package.elements = &newprops[1];
 103         free_space = &newprops[1 + 3 * numvalid];
 104
 105         for_each_set_bit(i, valid, numprops) {
 106                 union acpi_object *key = &props->package.elements[i * 2];
 107                 union acpi_object *val = &props->package.elements[i * 2 + 1];
 108                 unsigned int k = 1 + numvalid + j * 2; /* index into newprops */
 109                 unsigned int v = k + 1;
 110
 111                 newprops[1 + j].type = ACPI_TYPE_PACKAGE;
 112                 newprops[1 + j].package.count = 2;
 113                 newprops[1 + j].package.elements = &newprops[k];
 114
 115                 newprops[k].type = ACPI_TYPE_STRING;
 116                 newprops[k].string.length = key->string.length;
 117                 newprops[k].string.pointer = free_space;
 118                 memcpy(free_space, key->string.pointer, key->string.length);
 119                 free_space += key->string.length + 1;
 120
 121                 newprops[v].type = val->type;
 122                 if (val->type == ACPI_TYPE_INTEGER) {
 123                         newprops[v].integer.value = val->integer.value;
 124                 } else {
 125                         newprops[v].buffer.length = val->buffer.length;
 126                         newprops[v].buffer.pointer = free_space;
 127                         memcpy(free_space, val->buffer.pointer,
 128                                val->buffer.length);
 129                         free_space += val->buffer.length;
 130                 }
 131                 j++; /* count valid properties */
 132         }
 133         WARN_ON(free_space != (void *)newprops + newsize);
 134
 135         adev->data.properties = newprops;
 136         adev->data.pointer = newprops;
 137
 138 out_free:
 139         ACPI_FREE(props);
 140         kfree(valid);
 141 }