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
 13static struct drm_privacy_screen_lookup arch_lookup;
 14
 15struct arch_init_data {
 16	struct drm_privacy_screen_lookup lookup;
 17	bool (*detect)(void);
 18};
 19
 20#if IS_ENABLED(CONFIG_THINKPAD_ACPI)
 21static 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
 28static 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)
 54static bool __init detect_chromeos_privacy_screen(void)
 55{
 56	return acpi_dev_present("GOOG0010", NULL, -1);
 57}
 58#endif
 59
 60static 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
 83void __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
101void 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 */