1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Intel ACPI functions
  4 *
  5 * _DSM related code stolen from nouveau_acpi.c.
  6 */
  7#include <linux/pci.h>
  8#include <linux/acpi.h>
  9#include <drm/drmP.h>
 10#include "i915_drv.h"
 11
 12#define INTEL_DSM_REVISION_ID 1 /* For Calpella anyway... */
 13#define INTEL_DSM_FN_PLATFORM_MUX_INFO 1 /* No args */
 14
 15static struct intel_dsm_priv {
 16	acpi_handle dhandle;
 17} intel_dsm_priv;
 18
 19static const guid_t intel_dsm_guid =
 20	GUID_INIT(0x7ed873d3, 0xc2d0, 0x4e4f,
 21		  0xa8, 0x54, 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c);
 22
 23static char *intel_dsm_port_name(u8 id)
 24{
 25	switch (id) {
 26	case 0:
 27		return "Reserved";
 28	case 1:
 29		return "Analog VGA";
 30	case 2:
 31		return "LVDS";
 32	case 3:
 33		return "Reserved";
 34	case 4:
 35		return "HDMI/DVI_B";
 36	case 5:
 37		return "HDMI/DVI_C";
 38	case 6:
 39		return "HDMI/DVI_D";
 40	case 7:
 41		return "DisplayPort_A";
 42	case 8:
 43		return "DisplayPort_B";
 44	case 9:
 45		return "DisplayPort_C";
 46	case 0xa:
 47		return "DisplayPort_D";
 48	case 0xb:
 49	case 0xc:
 50	case 0xd:
 51		return "Reserved";
 52	case 0xe:
 53		return "WiDi";
 54	default:
 55		return "bad type";
 56	}
 57}
 58
 59static char *intel_dsm_mux_type(u8 type)
 60{
 61	switch (type) {
 62	case 0:
 63		return "unknown";
 64	case 1:
 65		return "No MUX, iGPU only";
 66	case 2:
 67		return "No MUX, dGPU only";
 68	case 3:
 69		return "MUXed between iGPU and dGPU";
 70	default:
 71		return "bad type";
 72	}
 73}
 74
 75static void intel_dsm_platform_mux_info(void)
 76{
 77	int i;
 78	union acpi_object *pkg, *connector_count;
 79
 80	pkg = acpi_evaluate_dsm_typed(intel_dsm_priv.dhandle, &intel_dsm_guid,
 81			INTEL_DSM_REVISION_ID, INTEL_DSM_FN_PLATFORM_MUX_INFO,
 82			NULL, ACPI_TYPE_PACKAGE);
 83	if (!pkg) {
 84		DRM_DEBUG_DRIVER("failed to evaluate _DSM\n");
 85		return;
 86	}
 87
 88	connector_count = &pkg->package.elements[0];
 89	DRM_DEBUG_DRIVER("MUX info connectors: %lld\n",
 90		  (unsigned long long)connector_count->integer.value);
 91	for (i = 1; i < pkg->package.count; i++) {
 92		union acpi_object *obj = &pkg->package.elements[i];
 93		union acpi_object *connector_id = &obj->package.elements[0];
 94		union acpi_object *info = &obj->package.elements[1];
 95		DRM_DEBUG_DRIVER("Connector id: 0x%016llx\n",
 96			  (unsigned long long)connector_id->integer.value);
 97		DRM_DEBUG_DRIVER("  port id: %s\n",
 98		       intel_dsm_port_name(info->buffer.pointer[0]));
 99		DRM_DEBUG_DRIVER("  display mux info: %s\n",
100		       intel_dsm_mux_type(info->buffer.pointer[1]));
101		DRM_DEBUG_DRIVER("  aux/dc mux info: %s\n",
102		       intel_dsm_mux_type(info->buffer.pointer[2]));
103		DRM_DEBUG_DRIVER("  hpd mux info: %s\n",
104		       intel_dsm_mux_type(info->buffer.pointer[3]));
105	}
106
107	ACPI_FREE(pkg);
108}
109
110static bool intel_dsm_pci_probe(struct pci_dev *pdev)
111{
112	acpi_handle dhandle;
113
114	dhandle = ACPI_HANDLE(&pdev->dev);
115	if (!dhandle)
116		return false;
117
118	if (!acpi_check_dsm(dhandle, &intel_dsm_guid, INTEL_DSM_REVISION_ID,
119			    1 << INTEL_DSM_FN_PLATFORM_MUX_INFO)) {
120		DRM_DEBUG_KMS("no _DSM method for intel device\n");
121		return false;
122	}
123
124	intel_dsm_priv.dhandle = dhandle;
125	intel_dsm_platform_mux_info();
126
127	return true;
128}
129
130static bool intel_dsm_detect(void)
131{
132	char acpi_method_name[255] = { 0 };
133	struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name};
134	struct pci_dev *pdev = NULL;
135	bool has_dsm = false;
136	int vga_count = 0;
137
138	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
139		vga_count++;
140		has_dsm |= intel_dsm_pci_probe(pdev);
141	}
142
143	if (vga_count == 2 && has_dsm) {
144		acpi_get_name(intel_dsm_priv.dhandle, ACPI_FULL_PATHNAME, &buffer);
145		DRM_DEBUG_DRIVER("vga_switcheroo: detected DSM switching method %s handle\n",
146				 acpi_method_name);
147		return true;
148	}
149
150	return false;
151}
152
153void intel_register_dsm_handler(void)
154{
155	if (!intel_dsm_detect())
156		return;
157}
158
159void intel_unregister_dsm_handler(void)
160{
161}