LXR linux/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 "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
  32struct pmt_telem_priv {
  33        int                             num_entries;
  34        struct intel_pmt_entry          entry[];
  35};
  36
  37static 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
  48static 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
  75static DEFINE_XARRAY_ALLOC(telem_array);
  76static struct intel_pmt_namespace pmt_telem_ns = {
  77        .name = "telem",
  78        .xa = &telem_array,
  79        .pmt_header_decode = pmt_telem_header_decode,
  80};
  81
  82static 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
  93static 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;
 119abort_probe:
 120        pmt_telem_remove(pdev);
 121        return ret;
 122}
 123
 124static 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
 132static int __init pmt_telem_init(void)
 133{
 134        return platform_driver_register(&pmt_telem_driver);
 135}
 136module_init(pmt_telem_init);
 137
 138static void __exit pmt_telem_exit(void)
 139{
 140        platform_driver_unregister(&pmt_telem_driver);
 141        xa_destroy(&telem_array);
 142}
 143module_exit(pmt_telem_exit);
 144
 145MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
 146MODULE_DESCRIPTION("Intel PMT Telemetry driver");
 147MODULE_ALIAS("platform:" TELEM_DEV_NAME);
 148MODULE_LICENSE("GPL v2");
 149