drivers/platform/x86/intel/pmt/telemetry.c

   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/auxiliary_bus.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/pci.h>
  15 #include <linux/slab.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/overflow.h>
  18
  19 #include "../vsec.h"
  20 #include "class.h"
  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
  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
  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
  82 static void pmt_telem_remove(struct auxiliary_device *auxdev)
  83 {
  84         struct pmt_telem_priv *priv = auxiliary_get_drvdata(auxdev);
  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
  91 static int pmt_telem_probe(struct auxiliary_device *auxdev, const struct auxiliary_device_id *id)
  92 {
  93         struct intel_vsec_device *intel_vsec_dev = auxdev_to_ivdev(auxdev);
  94         struct pmt_telem_priv *priv;
  95         size_t size;
  96         int i, ret;
  97
  98         size = struct_size(priv, entry, intel_vsec_dev->num_resources);
  99         priv = devm_kzalloc(&auxdev->dev, size, GFP_KERNEL);
 100         if (!priv)
 101                 return -ENOMEM;
 102
 103         auxiliary_set_drvdata(auxdev, priv);
 104
 105         for (i = 0; i < intel_vsec_dev->num_resources; i++) {
 106                 struct intel_pmt_entry *entry = &priv->entry[priv->num_entries];
 107
 108                 ret = intel_pmt_dev_create(entry, &pmt_telem_ns, intel_vsec_dev, i);
 109                 if (ret < 0)
 110                         goto abort_probe;
 111                 if (ret)
 112                         continue;
 113
 114                 priv->num_entries++;
 115         }
 116
 117         return 0;
 118 abort_probe:
 119         pmt_telem_remove(auxdev);
 120         return ret;
 121 }
 122
 123 static const struct auxiliary_device_id pmt_telem_id_table[] = {
 124         { .name = "intel_vsec.telemetry" },
 125         {}
 126 };
 127 MODULE_DEVICE_TABLE(auxiliary, pmt_telem_id_table);
 128
 129 static struct auxiliary_driver pmt_telem_aux_driver = {
 130         .id_table       = pmt_telem_id_table,
 131         .remove         = pmt_telem_remove,
 132         .probe          = pmt_telem_probe,
 133 };
 134
 135 static int __init pmt_telem_init(void)
 136 {
 137         return auxiliary_driver_register(&pmt_telem_aux_driver);
 138 }
 139 module_init(pmt_telem_init);
 140
 141 static void __exit pmt_telem_exit(void)
 142 {
 143         auxiliary_driver_unregister(&pmt_telem_aux_driver);
 144         xa_destroy(&telem_array);
 145 }
 146 module_exit(pmt_telem_exit);
 147
 148 MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
 149 MODULE_DESCRIPTION("Intel PMT Telemetry driver");
 150 MODULE_LICENSE("GPL v2");