1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Intel PMC PWRM ACPI driver
4 *
5 * Copyright (C) 2025, Intel Corporation
6 */
7
8 #include <linux/acpi.h>
9 #include <linux/bits.h>
10 #include <linux/bitfield.h>
11 #include <linux/cleanup.h>
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/errno.h>
15 #include <linux/intel_vsec.h>
16 #include <linux/limits.h>
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/resource.h>
20 #include <linux/slab.h>
21 #include <linux/types.h>
22 #include <linux/uuid.h>
23
24 #include "core.h"
25
26 #define ENTRY_LEN 5
27
28 /* DWORD2 */
29 #define DVSEC_ID_MASK GENMASK(15, 0)
30 #define NUM_ENTRIES_MASK GENMASK(23, 16)
31 #define ENTRY_SIZE_MASK GENMASK(31, 24)
32
33 /* DWORD3 */
34 #define TBIR_MASK GENMASK(2, 0)
35 #define DISC_TBL_OFF_MASK GENMASK(31, 3)
36
37 const guid_t intel_vsec_guid =
38 GUID_INIT(0x294903fb, 0x634d, 0x4fc7, 0xaf, 0x1f, 0x0f, 0xb9,
39 0x56, 0xb0, 0x4f, 0xc1);
40
is_valid_entry(union acpi_object * pkg)41 static bool is_valid_entry(union acpi_object *pkg)
42 {
43 int i;
44
45 if (!pkg || pkg->type != ACPI_TYPE_PACKAGE || pkg->package.count != ENTRY_LEN)
46 return false;
47
48 if (pkg->package.elements[0].type != ACPI_TYPE_STRING)
49 return false;
50
51 for (i = 1; i < ENTRY_LEN; i++)
52 if (pkg->package.elements[i].type != ACPI_TYPE_INTEGER)
53 return false;
54
55 return true;
56 }
57
pmc_parse_telem_dsd(union acpi_object * obj,struct intel_vsec_header * header)58 acpi_disc_t pmc_parse_telem_dsd(union acpi_object *obj,
59 struct intel_vsec_header *header)
60 {
61 union acpi_object *vsec_pkg;
62 union acpi_object *disc_pkg;
63 u64 hdr0, hdr1;
64 int num_regions;
65 int i;
66
67 if (!header)
68 return ERR_PTR(-EINVAL);
69
70 if (!obj || obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 2)
71 return ERR_PTR(-EINVAL);
72
73 /* First Package is DVSEC info */
74 vsec_pkg = &obj->package.elements[0];
75 if (!is_valid_entry(vsec_pkg))
76 return ERR_PTR(-EINVAL);
77
78 hdr0 = vsec_pkg->package.elements[3].integer.value;
79 hdr1 = vsec_pkg->package.elements[4].integer.value;
80
81 header->id = FIELD_GET(DVSEC_ID_MASK, hdr0);
82 header->num_entries = FIELD_GET(NUM_ENTRIES_MASK, hdr0);
83 header->entry_size = FIELD_GET(ENTRY_SIZE_MASK, hdr0);
84 header->tbir = FIELD_GET(TBIR_MASK, hdr1);
85 header->offset = hdr1 & DISC_TBL_OFF_MASK;
86
87 /* Second Package contains the discovery tables */
88 disc_pkg = &obj->package.elements[1];
89 if (disc_pkg->type != ACPI_TYPE_PACKAGE || disc_pkg->package.count < 1)
90 return ERR_PTR(-EINVAL);
91
92 num_regions = disc_pkg->package.count;
93 if (header->num_entries != num_regions)
94 return ERR_PTR(-EINVAL);
95
96 acpi_disc_t disc __free(kfree) = kmalloc_objs(*disc, num_regions);
97 if (!disc)
98 return ERR_PTR(-ENOMEM);
99
100 for (i = 0; i < num_regions; i++) {
101 union acpi_object *pkg;
102 u64 value;
103 int j;
104
105 pkg = &disc_pkg->package.elements[i];
106 if (!is_valid_entry(pkg))
107 return ERR_PTR(-EINVAL);
108
109 /* Element 0 is a descriptive string; DWORD values start at index 1. */
110 for (j = 1; j < ENTRY_LEN; j++) {
111 value = pkg->package.elements[j].integer.value;
112 if (value > U32_MAX)
113 return ERR_PTR(-ERANGE);
114
115 disc[i][j - 1] = value;
116 }
117 }
118
119 return no_free_ptr(disc);
120 }
121 EXPORT_SYMBOL_NS_GPL(pmc_parse_telem_dsd, "INTEL_PMC_CORE");
122
pmc_find_telem_guid(union acpi_object * dsd)123 union acpi_object *pmc_find_telem_guid(union acpi_object *dsd)
124 {
125 int i;
126
127 if (!dsd || dsd->type != ACPI_TYPE_PACKAGE)
128 return NULL;
129
130 for (i = 0; i + 1 < dsd->package.count; i += 2) {
131 union acpi_object *uuid_obj, *data_obj;
132 guid_t uuid;
133
134 uuid_obj = &dsd->package.elements[i];
135 data_obj = &dsd->package.elements[i + 1];
136
137 if (uuid_obj->type != ACPI_TYPE_BUFFER ||
138 uuid_obj->buffer.length != 16)
139 continue;
140
141 memcpy(&uuid, uuid_obj->buffer.pointer, 16);
142 if (guid_equal(&uuid, &intel_vsec_guid))
143 return data_obj;
144 }
145
146 return NULL;
147 }
148 EXPORT_SYMBOL_NS_GPL(pmc_find_telem_guid, "INTEL_PMC_CORE");
149
pmc_pwrm_acpi_probe(struct platform_device * pdev)150 static int pmc_pwrm_acpi_probe(struct platform_device *pdev)
151 {
152 struct intel_vsec_header header;
153 struct intel_vsec_header *headers[2] = { &header, NULL };
154 struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
155 struct intel_vsec_platform_info info = { };
156 struct device *dev = &pdev->dev;
157 union acpi_object *dsd;
158 struct resource *res;
159 acpi_handle handle;
160 acpi_status status;
161
162 handle = ACPI_HANDLE(&pdev->dev);
163 if (!handle)
164 return -ENODEV;
165
166 status = acpi_evaluate_object(handle, "_DSD", NULL, &buf);
167 if (ACPI_FAILURE(status)) {
168 return dev_err_probe(dev, -ENODEV, "Could not evaluate _DSD: %s\n",
169 acpi_format_exception(status));
170 }
171
172 void *dsd_buf __free(pmc_acpi_free) = buf.pointer;
173
174 dsd = pmc_find_telem_guid(dsd_buf);
175 if (!dsd)
176 return -ENODEV;
177
178 acpi_disc_t acpi_disc __free(kfree) = pmc_parse_telem_dsd(dsd, &header);
179 if (IS_ERR(acpi_disc))
180 return PTR_ERR(acpi_disc);
181
182 res = platform_get_resource(pdev, IORESOURCE_MEM, header.tbir);
183 if (!res)
184 return -EINVAL;
185
186 info.headers = headers;
187 info.caps = VSEC_CAP_TELEMETRY;
188 info.acpi_disc = acpi_disc;
189 info.src = INTEL_VSEC_DISC_ACPI;
190 info.base_addr = res->start;
191
192 return intel_vsec_register(&pdev->dev, &info);
193 }
194
195 static const struct acpi_device_id pmc_pwrm_acpi_ids[] = {
196 { "INTC1122", 0 }, /* Nova Lake */
197 { "INTC1129", 0 }, /* Nova Lake */
198 { }
199 };
200 MODULE_DEVICE_TABLE(acpi, pmc_pwrm_acpi_ids);
201
202 static struct platform_driver pmc_pwrm_acpi_driver = {
203 .probe = pmc_pwrm_acpi_probe,
204 .driver = {
205 .name = "intel_pmc_pwrm_acpi",
206 .acpi_match_table = ACPI_PTR(pmc_pwrm_acpi_ids),
207 },
208 };
209 module_platform_driver(pmc_pwrm_acpi_driver);
210
211 MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
212 MODULE_DESCRIPTION("Intel PMC PWRM ACPI driver");
213 MODULE_LICENSE("GPL");
214 MODULE_IMPORT_NS("INTEL_VSEC");
215