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(virt_addr: residency_info_mem.iomem_addr, value: &count,
34 width: residency_info_mem.gaddr.bit_width);
35 if (error)
36 return error;
37
38 *counter = div64_u64(dividend: count * 1000000ULL, divisor: residency_info_mem.frequency);
39 return 0;
40 }
41
42 err = rdmsrq_safe(msr: residency_info_ffh.gaddr.address, p: 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(dividend: *counter * 1000000ULL, divisor: 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: &counter, io_mem: true);
65 if (ret)
66 return ret;
67
68 return sprintf(buf, fmt: "%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: &counter, io_mem: false);
80 if (ret)
81 return ret;
82
83 return sprintf(buf, fmt: "%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(bus: &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(a: tsc_khz, b: 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(offset: info->gaddr.address,
115 size: info->gaddr.bit_width / 8);
116 if (!info->iomem_addr)
117 goto exit;
118
119 sysfs_add_file_to_group(kobj: &dev_root->kobj,
120 attr: &dev_attr_low_power_idle_system_residency_us.attr,
121 group: "cpuidle");
122 } else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
123 sysfs_add_file_to_group(kobj: &dev_root->kobj,
124 attr: &dev_attr_low_power_idle_cpu_residency_us.attr,
125 group: "cpuidle");
126 }
127exit:
128 put_device(dev: 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(info: &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(info: &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, instance: 0, out_table: (struct acpi_table_header **)&lpit);
155 if (ACPI_FAILURE(status))
156 return;
157
158 lpit_process(begin: (u64)lpit + sizeof(*lpit),
159 end: (u64)lpit + lpit->header.length);
160
161 acpi_put_table(table: (struct acpi_table_header *)lpit);
162}
163