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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}
1
2/*
3 * acpi_lpit.c - LPIT table processing functions
4 *
5 * Copyright (C) 2017 Intel Corporation. All rights reserved.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <linux/cpu.h>
18#include <linux/acpi.h>
19#include <asm/msr.h>
20#include <asm/tsc.h>
21
22struct lpit_residency_info {
23 struct acpi_generic_address gaddr;
24 u64 frequency;
25 void __iomem *iomem_addr;
26};
27
28/* Storage for an memory mapped and FFH based entries */
29static struct lpit_residency_info residency_info_mem;
30static struct lpit_residency_info residency_info_ffh;
31
32static int lpit_read_residency_counter_us(u64 *counter, bool io_mem)
33{
34 int err;
35
36 if (io_mem) {
37 u64 count = 0;
38 int error;
39
40 error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count,
41 residency_info_mem.gaddr.bit_width);
42 if (error)
43 return error;
44
45 *counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency);
46 return 0;
47 }
48
49 err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter);
50 if (!err) {
51 u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset +
52 residency_info_ffh.gaddr. bit_width - 1,
53 residency_info_ffh.gaddr.bit_offset);
54
55 *counter &= mask;
56 *counter >>= residency_info_ffh.gaddr.bit_offset;
57 *counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency);
58 return 0;
59 }
60
61 return -ENODATA;
62}
63
64static ssize_t low_power_idle_system_residency_us_show(struct device *dev,
65 struct device_attribute *attr,
66 char *buf)
67{
68 u64 counter;
69 int ret;
70
71 ret = lpit_read_residency_counter_us(&counter, true);
72 if (ret)
73 return ret;
74
75 return sprintf(buf, "%llu\n", counter);
76}
77static DEVICE_ATTR_RO(low_power_idle_system_residency_us);
78
79static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev,
80 struct device_attribute *attr,
81 char *buf)
82{
83 u64 counter;
84 int ret;
85
86 ret = lpit_read_residency_counter_us(&counter, false);
87 if (ret)
88 return ret;
89
90 return sprintf(buf, "%llu\n", counter);
91}
92static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us);
93
94int lpit_read_residency_count_address(u64 *address)
95{
96 if (!residency_info_mem.gaddr.address)
97 return -EINVAL;
98
99 *address = residency_info_mem.gaddr.address;
100
101 return 0;
102}
103EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
104
105static void lpit_update_residency(struct lpit_residency_info *info,
106 struct acpi_lpit_native *lpit_native)
107{
108 info->frequency = lpit_native->counter_frequency ?
109 lpit_native->counter_frequency : tsc_khz * 1000;
110 if (!info->frequency)
111 info->frequency = 1;
112
113 info->gaddr = lpit_native->residency_counter;
114 if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
115 info->iomem_addr = ioremap_nocache(info->gaddr.address,
116 info->gaddr.bit_width / 8);
117 if (!info->iomem_addr)
118 return;
119
120 /* Silently fail, if cpuidle attribute group is not present */
121 sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
122 &dev_attr_low_power_idle_system_residency_us.attr,
123 "cpuidle");
124 } else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
125 /* Silently fail, if cpuidle attribute group is not present */
126 sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
127 &dev_attr_low_power_idle_cpu_residency_us.attr,
128 "cpuidle");
129 }
130}
131
132static void lpit_process(u64 begin, u64 end)
133{
134 while (begin + sizeof(struct acpi_lpit_native) < end) {
135 struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin;
136
137 if (!lpit_native->header.type && !lpit_native->header.flags) {
138 if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
139 !residency_info_mem.gaddr.address) {
140 lpit_update_residency(&residency_info_mem, lpit_native);
141 } else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
142 !residency_info_ffh.gaddr.address) {
143 lpit_update_residency(&residency_info_ffh, lpit_native);
144 }
145 }
146 begin += lpit_native->header.length;
147 }
148}
149
150void acpi_init_lpit(void)
151{
152 acpi_status status;
153 u64 lpit_begin;
154 struct acpi_table_lpit *lpit;
155
156 status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit);
157
158 if (ACPI_FAILURE(status))
159 return;
160
161 lpit_begin = (u64)lpit + sizeof(*lpit);
162 lpit_process(lpit_begin, lpit_begin + lpit->header.length);
163}