1// SPDX-License-Identifier: GPL-2.0-only
2
3/*
4 * acpi_lpit.c - LPIT table processing functions
5 *
6 * Copyright (C) 2017 Intel Corporation. All rights reserved.
7 */
8
9#include <linux/cpu.h>
10#include <linux/acpi.h>
11#include <asm/msr.h>
12#include <asm/tsc.h>
13#include "internal.h"
14
15struct lpit_residency_info {
16	struct acpi_generic_address gaddr;
17	u64 frequency;
18	void __iomem *iomem_addr;
19};
20
21/* Storage for an memory mapped and FFH based entries */
22static struct lpit_residency_info residency_info_mem;
23static struct lpit_residency_info residency_info_ffh;
24
25static int lpit_read_residency_counter_us(u64 *counter, bool io_mem)
26{
27	int err;
28
29	if (io_mem) {
30		u64 count = 0;
31		int error;
32
33		error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count,
34					   residency_info_mem.gaddr.bit_width);
35		if (error)
36			return error;
37
38		*counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency);
39		return 0;
40	}
41
42	err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter);
43	if (!err) {
44		u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset +
45				       residency_info_ffh.gaddr. bit_width - 1,
46				       residency_info_ffh.gaddr.bit_offset);
47
48		*counter &= mask;
49		*counter >>= residency_info_ffh.gaddr.bit_offset;
50		*counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency);
51		return 0;
52	}
53
54	return -ENODATA;
55}
56
57static ssize_t low_power_idle_system_residency_us_show(struct device *dev,
58						       struct device_attribute *attr,
59						       char *buf)
60{
61	u64 counter;
62	int ret;
63
64	ret = lpit_read_residency_counter_us(&counter, true);
65	if (ret)
66		return ret;
67
68	return sprintf(buf, "%llu\n", counter);
69}
70static DEVICE_ATTR_RO(low_power_idle_system_residency_us);
71
72static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev,
73						    struct device_attribute *attr,
74						    char *buf)
75{
76	u64 counter;
77	int ret;
78
79	ret = lpit_read_residency_counter_us(&counter, false);
80	if (ret)
81		return ret;
82
83	return sprintf(buf, "%llu\n", counter);
84}
85static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us);
86
87int lpit_read_residency_count_address(u64 *address)
88{
89	if (!residency_info_mem.gaddr.address)
90		return -EINVAL;
91
92	*address = residency_info_mem.gaddr.address;
93
94	return 0;
95}
96EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
97
98static void lpit_update_residency(struct lpit_residency_info *info,
99				 struct acpi_lpit_native *lpit_native)
100{
101	struct device *dev_root = bus_get_dev_root(&cpu_subsys);
102
103	/* Silently fail, if cpuidle attribute group is not present */
104	if (!dev_root)
105		return;
106
107	info->frequency = lpit_native->counter_frequency ?
108				lpit_native->counter_frequency : mul_u32_u32(tsc_khz, 1000U);
109	if (!info->frequency)
110		info->frequency = 1;
111
112	info->gaddr = lpit_native->residency_counter;
113	if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
114		info->iomem_addr = ioremap(info->gaddr.address,
115						   info->gaddr.bit_width / 8);
116		if (!info->iomem_addr)
117			goto exit;
118
119		sysfs_add_file_to_group(&dev_root->kobj,
120					&dev_attr_low_power_idle_system_residency_us.attr,
121					"cpuidle");
122	} else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
123		sysfs_add_file_to_group(&dev_root->kobj,
124					&dev_attr_low_power_idle_cpu_residency_us.attr,
125					"cpuidle");
126	}
127exit:
128	put_device(dev_root);
129}
130
131static void lpit_process(u64 begin, u64 end)
132{
133	while (begin + sizeof(struct acpi_lpit_native) <= end) {
134		struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin;
135
136		if (!lpit_native->header.type && !lpit_native->header.flags) {
137			if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
138			    !residency_info_mem.gaddr.address) {
139				lpit_update_residency(&residency_info_mem, lpit_native);
140			} else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
141				   !residency_info_ffh.gaddr.address) {
142				lpit_update_residency(&residency_info_ffh, lpit_native);
143			}
144		}
145		begin += lpit_native->header.length;
146	}
147}
148
149void acpi_init_lpit(void)
150{
151	acpi_status status;
152	struct acpi_table_lpit *lpit;
153
154	status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit);
155	if (ACPI_FAILURE(status))
156		return;
157
158	lpit_process((u64)lpit + sizeof(*lpit),
159		     (u64)lpit + lpit->header.length);
160
161	acpi_put_table((struct acpi_table_header *)lpit);
162}
163