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