drivers/gpu/drm/drm_privacy_screen_x86.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright (C) 2020 Red Hat, Inc.
   4  *
   5  * Authors:
   6  * Hans de Goede <hdegoede@redhat.com>
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <drm/drm_privacy_screen_machine.h>
  11
  12 #ifdef CONFIG_X86
  13 static struct drm_privacy_screen_lookup arch_lookup;
  14
  15 struct arch_init_data {
  16         struct drm_privacy_screen_lookup lookup;
  17         bool (*detect)(void);
  18 };
  19
  20 #if IS_ENABLED(CONFIG_THINKPAD_ACPI)
  21 static acpi_status __init acpi_set_handle(acpi_handle handle, u32 level,
  22                                           void *context, void **return_value)
  23 {
  24         *(acpi_handle *)return_value = handle;
  25         return AE_CTRL_TERMINATE;
  26 }
  27
  28 static bool __init detect_thinkpad_privacy_screen(void)
  29 {
  30         union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
  31         struct acpi_object_list args = { .count = 1, .pointer = &obj, };
  32         acpi_handle ec_handle = NULL;
  33         unsigned long long output;
  34         acpi_status status;
  35
  36         if (acpi_disabled)
  37                 return false;
  38
  39         /* Get embedded-controller handle */
  40         status = acpi_get_devices("PNP0C09", acpi_set_handle, NULL, &ec_handle);
  41         if (ACPI_FAILURE(status) || !ec_handle)
  42                 return false;
  43
  44         /* And call the privacy-screen get-status method */
  45         status = acpi_evaluate_integer(ec_handle, "HKEY.GSSS", &args, &output);
  46         if (ACPI_FAILURE(status))
  47                 return false;
  48
  49         return (output & 0x10000) ? true : false;
  50 }
  51 #endif
  52
  53 #if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
  54 static bool __init detect_chromeos_privacy_screen(void)
  55 {
  56         return acpi_dev_present("GOOG0010", NULL, -1);
  57 }
  58 #endif
  59
  60 static const struct arch_init_data arch_init_data[] __initconst = {
  61 #if IS_ENABLED(CONFIG_THINKPAD_ACPI)
  62         {
  63                 .lookup = {
  64                         .dev_id = NULL,
  65                         .con_id = NULL,
  66                         .provider = "privacy_screen-thinkpad_acpi",
  67                 },
  68                 .detect = detect_thinkpad_privacy_screen,
  69         },
  70 #endif
  71 #if IS_ENABLED(CONFIG_CHROMEOS_PRIVACY_SCREEN)
  72         {
  73                 .lookup = {
  74                         .dev_id = NULL,
  75                         .con_id = NULL,
  76                         .provider = "privacy_screen-GOOG0010:00",
  77                 },
  78                 .detect = detect_chromeos_privacy_screen,
  79         },
  80 #endif
  81 };
  82
  83 void __init drm_privacy_screen_lookup_init(void)
  84 {
  85         int i;
  86
  87         for (i = 0; i < ARRAY_SIZE(arch_init_data); i++) {
  88                 if (!arch_init_data[i].detect())
  89                         continue;
  90
  91                 pr_info("Found '%s' privacy-screen provider\n",
  92                         arch_init_data[i].lookup.provider);
  93
  94                 /* Make a copy because arch_init_data is __initconst */
  95                 arch_lookup = arch_init_data[i].lookup;
  96                 drm_privacy_screen_lookup_add(&arch_lookup);
  97                 break;
  98         }
  99 }
 100
 101 void drm_privacy_screen_lookup_exit(void)
 102 {
 103         if (arch_lookup.provider)
 104                 drm_privacy_screen_lookup_remove(&arch_lookup);
 105 }
 106 #endif /* ifdef CONFIG_X86 */