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/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 "intel_pmt_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
  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         return 0;
  65 }
  66
  67 static DEFINE_XARRAY_ALLOC(telem_array);
  68 static struct intel_pmt_namespace pmt_telem_ns = {
  69         .name = "telem",
  70         .xa = &telem_array,
  71         .pmt_header_decode = pmt_telem_header_decode,
  72 };
  73
  74 static int pmt_telem_remove(struct platform_device *pdev)
  75 {
  76         struct pmt_telem_priv *priv = platform_get_drvdata(pdev);
  77         int i;
  78
  79         for (i = 0; i < priv->num_entries; i++)
  80                 intel_pmt_dev_destroy(&priv->entry[i], &pmt_telem_ns);
  81
  82         return 0;
  83 }
  84
  85 static int pmt_telem_probe(struct platform_device *pdev)
  86 {
  87         struct pmt_telem_priv *priv;
  88         size_t size;
  89         int i, ret;
  90
  91         size = struct_size(priv, entry, pdev->num_resources);
  92         priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
  93         if (!priv)
  94                 return -ENOMEM;
  95
  96         platform_set_drvdata(pdev, priv);
  97
  98         for (i = 0; i < pdev->num_resources; i++) {
  99                 struct intel_pmt_entry *entry = &priv->entry[i];
 100
 101                 ret = intel_pmt_dev_create(entry, &pmt_telem_ns, pdev, i);
 102                 if (ret < 0)
 103                         goto abort_probe;
 104                 if (ret)
 105                         continue;
 106
 107                 priv->num_entries++;
 108         }
 109
 110         return 0;
 111 abort_probe:
 112         pmt_telem_remove(pdev);
 113         return ret;
 114 }
 115
 116 static struct platform_driver pmt_telem_driver = {
 117         .driver = {
 118                 .name   = TELEM_DEV_NAME,
 119         },
 120         .remove = pmt_telem_remove,
 121         .probe  = pmt_telem_probe,
 122 };
 123
 124 static int __init pmt_telem_init(void)
 125 {
 126         return platform_driver_register(&pmt_telem_driver);
 127 }
 128 module_init(pmt_telem_init);
 129
 130 static void __exit pmt_telem_exit(void)
 131 {
 132         platform_driver_unregister(&pmt_telem_driver);
 133         xa_destroy(&telem_array);
 134 }
 135 module_exit(pmt_telem_exit);
 136
 137 MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
 138 MODULE_DESCRIPTION("Intel PMT Telemetry driver");
 139 MODULE_ALIAS("platform:" TELEM_DEV_NAME);
 140 MODULE_LICENSE("GPL v2");