1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Intel Platform Monitory Technology Telemetry driver
4 *
5 * Copyright (c) 2020, Intel Corporation.
6 * All Rights Reserved.
7 *
8 * Author: "David E. Box" <david.e.box@linux.intel.com>
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/pci.h>
14 #include <linux/slab.h>
15 #include <linux/uaccess.h>
16 #include <linux/overflow.h>
17
18 #include "class.h"
19
20 #define TELEM_DEV_NAME "pmt_telemetry"
21
22 #define TELEM_SIZE_OFFSET 0x0
23 #define TELEM_GUID_OFFSET 0x4
24 #define TELEM_BASE_OFFSET 0x8
25 #define TELEM_ACCESS(v) ((v) & GENMASK(3, 0))
26 /* size is in bytes */
27 #define TELEM_SIZE(v) (((v) & GENMASK(27, 12)) >> 10)
28
29 /* Used by client hardware to identify a fixed telemetry entry*/
30 #define TELEM_CLIENT_FIXED_BLOCK_GUID 0x10000000
31
32 struct pmt_telem_priv {
33 int num_entries;
34 struct intel_pmt_entry entry[];
35 };
36
pmt_telem_region_overlaps(struct intel_pmt_entry * entry,struct device * dev)37 static bool pmt_telem_region_overlaps(struct intel_pmt_entry *entry,
38 struct device *dev)
39 {
40 u32 guid = readl(entry->disc_table + TELEM_GUID_OFFSET);
41
42 if (guid != TELEM_CLIENT_FIXED_BLOCK_GUID)
43 return false;
44
45 return intel_pmt_is_early_client_hw(dev);
46 }
47
pmt_telem_header_decode(struct intel_pmt_entry * entry,struct intel_pmt_header * header,struct device * dev)48 static int pmt_telem_header_decode(struct intel_pmt_entry *entry,
49 struct intel_pmt_header *header,
50 struct device *dev)
51 {
52 void __iomem *disc_table = entry->disc_table;
53
54 if (pmt_telem_region_overlaps(entry, dev))
55 return 1;
56
57 header->access_type = TELEM_ACCESS(readl(disc_table));
58 header->guid = readl(disc_table + TELEM_GUID_OFFSET);
59 header->base_offset = readl(disc_table + TELEM_BASE_OFFSET);
60
61 /* Size is measured in DWORDS, but accessor returns bytes */
62 header->size = TELEM_SIZE(readl(disc_table));
63
64 /*
65 * Some devices may expose non-functioning entries that are
66 * reserved for future use. They have zero size. Do not fail
67 * probe for these. Just ignore them.
68 */
69 if (header->size == 0)
70 return 1;
71
72 return 0;
73 }
74
75 static DEFINE_XARRAY_ALLOC(telem_array);
76 static struct intel_pmt_namespace pmt_telem_ns = {
77 .name = "telem",
78 .xa = &telem_array,
79 .pmt_header_decode = pmt_telem_header_decode,
80 };
81
pmt_telem_remove(struct platform_device * pdev)82 static int pmt_telem_remove(struct platform_device *pdev)
83 {
84 struct pmt_telem_priv *priv = platform_get_drvdata(pdev);
85 int i;
86
87 for (i = 0; i < priv->num_entries; i++)
88 intel_pmt_dev_destroy(&priv->entry[i], &pmt_telem_ns);
89
90 return 0;
91 }
92
pmt_telem_probe(struct platform_device * pdev)93 static int pmt_telem_probe(struct platform_device *pdev)
94 {
95 struct pmt_telem_priv *priv;
96 size_t size;
97 int i, ret;
98
99 size = struct_size(priv, entry, pdev->num_resources);
100 priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
101 if (!priv)
102 return -ENOMEM;
103
104 platform_set_drvdata(pdev, priv);
105
106 for (i = 0; i < pdev->num_resources; i++) {
107 struct intel_pmt_entry *entry = &priv->entry[i];
108
109 ret = intel_pmt_dev_create(entry, &pmt_telem_ns, pdev, i);
110 if (ret < 0)
111 goto abort_probe;
112 if (ret)
113 continue;
114
115 priv->num_entries++;
116 }
117
118 return 0;
119 abort_probe:
120 pmt_telem_remove(pdev);
121 return ret;
122 }
123
124 static struct platform_driver pmt_telem_driver = {
125 .driver = {
126 .name = TELEM_DEV_NAME,
127 },
128 .remove = pmt_telem_remove,
129 .probe = pmt_telem_probe,
130 };
131
pmt_telem_init(void)132 static int __init pmt_telem_init(void)
133 {
134 return platform_driver_register(&pmt_telem_driver);
135 }
136 module_init(pmt_telem_init);
137
pmt_telem_exit(void)138 static void __exit pmt_telem_exit(void)
139 {
140 platform_driver_unregister(&pmt_telem_driver);
141 xa_destroy(&telem_array);
142 }
143 module_exit(pmt_telem_exit);
144
145 MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
146 MODULE_DESCRIPTION("Intel PMT Telemetry driver");
147 MODULE_ALIAS("platform:" TELEM_DEV_NAME);
148 MODULE_LICENSE("GPL v2");
149