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 
17 static const guid_t intel_dsm_guid =
18 	GUID_INIT(0x7ed873d3, 0xc2d0, 0x4e4f,
19 		  0xa8, 0x54, 0x0f, 0x13, 0x17, 0xb0, 0x1c, 0x2c);
20 
21 static 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 
57 static 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 
73 static 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 
108 static 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 
127 static 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 
150 void intel_register_dsm_handler(void)
151 {
152 	if (!intel_dsm_detect())
153 		return;
154 }
155 
156 void intel_unregister_dsm_handler(void)
157 {
158 }
159