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#define TELEM_TYPE(v)		(((v) & GENMASK(7, 4)) >> 4)
 27/* size is in bytes */
 28#define TELEM_SIZE(v)		(((v) & GENMASK(27, 12)) >> 10)
 29
 30/* Used by client hardware to identify a fixed telemetry entry*/
 31#define TELEM_CLIENT_FIXED_BLOCK_GUID	0x10000000
 32
 33enum telem_type {
 34	TELEM_TYPE_PUNIT = 0,
 35	TELEM_TYPE_CRASHLOG,
 36	TELEM_TYPE_PUNIT_FIXED,
 37};
 38
 39struct pmt_telem_priv {
 40	int				num_entries;
 41	struct intel_pmt_entry		entry[];
 42};
 43
 44static bool pmt_telem_region_overlaps(struct intel_pmt_entry *entry,
 45				      struct device *dev)
 46{
 47	u32 guid = readl(entry->disc_table + TELEM_GUID_OFFSET);
 48
 49	if (intel_pmt_is_early_client_hw(dev)) {
 50		u32 type = TELEM_TYPE(readl(entry->disc_table));
 51
 52		if ((type == TELEM_TYPE_PUNIT_FIXED) ||
 53		    (guid == TELEM_CLIENT_FIXED_BLOCK_GUID))
 54			return true;
 55	}
 56
 57	return false;
 58}
 59
 60static int pmt_telem_header_decode(struct intel_pmt_entry *entry,
 61				   struct intel_pmt_header *header,
 62				   struct device *dev)
 63{
 64	void __iomem *disc_table = entry->disc_table;
 65
 66	if (pmt_telem_region_overlaps(entry, dev))
 67		return 1;
 68
 69	header->access_type = TELEM_ACCESS(readl(disc_table));
 70	header->guid = readl(disc_table + TELEM_GUID_OFFSET);
 71	header->base_offset = readl(disc_table + TELEM_BASE_OFFSET);
 72
 73	/* Size is measured in DWORDS, but accessor returns bytes */
 74	header->size = TELEM_SIZE(readl(disc_table));
 75
 76	/*
 77	 * Some devices may expose non-functioning entries that are
 78	 * reserved for future use. They have zero size. Do not fail
 79	 * probe for these. Just ignore them.
 80	 */
 81	if (header->size == 0)
 82		return 1;
 83
 84	return 0;
 85}
 86
 87static DEFINE_XARRAY_ALLOC(telem_array);
 88static struct intel_pmt_namespace pmt_telem_ns = {
 89	.name = "telem",
 90	.xa = &telem_array,
 91	.pmt_header_decode = pmt_telem_header_decode,
 92};
 93
 94static void pmt_telem_remove(struct auxiliary_device *auxdev)
 95{
 96	struct pmt_telem_priv *priv = auxiliary_get_drvdata(auxdev);
 97	int i;
 98
 99	for (i = 0; i < priv->num_entries; i++)
100		intel_pmt_dev_destroy(&priv->entry[i], &pmt_telem_ns);
101}
102
103static int pmt_telem_probe(struct auxiliary_device *auxdev, const struct auxiliary_device_id *id)
104{
105	struct intel_vsec_device *intel_vsec_dev = auxdev_to_ivdev(auxdev);
106	struct pmt_telem_priv *priv;
107	size_t size;
108	int i, ret;
109
110	size = struct_size(priv, entry, intel_vsec_dev->num_resources);
111	priv = devm_kzalloc(&auxdev->dev, size, GFP_KERNEL);
112	if (!priv)
113		return -ENOMEM;
114
115	auxiliary_set_drvdata(auxdev, priv);
116
117	for (i = 0; i < intel_vsec_dev->num_resources; i++) {
118		struct intel_pmt_entry *entry = &priv->entry[priv->num_entries];
119
120		ret = intel_pmt_dev_create(entry, &pmt_telem_ns, intel_vsec_dev, i);
121		if (ret < 0)
122			goto abort_probe;
123		if (ret)
124			continue;
125
126		priv->num_entries++;
127	}
128
129	return 0;
130abort_probe:
131	pmt_telem_remove(auxdev);
132	return ret;
133}
134
135static const struct auxiliary_device_id pmt_telem_id_table[] = {
136	{ .name = "intel_vsec.telemetry" },
137	{}
138};
139MODULE_DEVICE_TABLE(auxiliary, pmt_telem_id_table);
140
141static struct auxiliary_driver pmt_telem_aux_driver = {
142	.id_table	= pmt_telem_id_table,
143	.remove		= pmt_telem_remove,
144	.probe		= pmt_telem_probe,
145};
146
147static int __init pmt_telem_init(void)
148{
149	return auxiliary_driver_register(&pmt_telem_aux_driver);
150}
151module_init(pmt_telem_init);
152
153static void __exit pmt_telem_exit(void)
154{
155	auxiliary_driver_unregister(&pmt_telem_aux_driver);
156	xa_destroy(&telem_array);
157}
158module_exit(pmt_telem_exit);
159
160MODULE_AUTHOR("David E. Box <david.e.box@linux.intel.com>");
161MODULE_DESCRIPTION("Intel PMT Telemetry driver");
162MODULE_LICENSE("GPL v2");