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1802d0be | 1 | // SPDX-License-Identifier: GPL-2.0-only |
eeb2d80d SP |
2 | |
3 | /* | |
4 | * acpi_lpit.c - LPIT table processing functions | |
5 | * | |
6 | * Copyright (C) 2017 Intel Corporation. All rights reserved. | |
eeb2d80d SP |
7 | */ |
8 | ||
9 | #include <linux/cpu.h> | |
10 | #include <linux/acpi.h> | |
11 | #include <asm/msr.h> | |
12 | #include <asm/tsc.h> | |
13 | ||
14 | struct lpit_residency_info { | |
15 | struct acpi_generic_address gaddr; | |
16 | u64 frequency; | |
17 | void __iomem *iomem_addr; | |
18 | }; | |
19 | ||
20 | /* Storage for an memory mapped and FFH based entries */ | |
21 | static struct lpit_residency_info residency_info_mem; | |
22 | static struct lpit_residency_info residency_info_ffh; | |
23 | ||
24 | static int lpit_read_residency_counter_us(u64 *counter, bool io_mem) | |
25 | { | |
26 | int err; | |
27 | ||
28 | if (io_mem) { | |
29 | u64 count = 0; | |
30 | int error; | |
31 | ||
32 | error = acpi_os_read_iomem(residency_info_mem.iomem_addr, &count, | |
33 | residency_info_mem.gaddr.bit_width); | |
34 | if (error) | |
35 | return error; | |
36 | ||
37 | *counter = div64_u64(count * 1000000ULL, residency_info_mem.frequency); | |
38 | return 0; | |
39 | } | |
40 | ||
41 | err = rdmsrl_safe(residency_info_ffh.gaddr.address, counter); | |
42 | if (!err) { | |
43 | u64 mask = GENMASK_ULL(residency_info_ffh.gaddr.bit_offset + | |
44 | residency_info_ffh.gaddr. bit_width - 1, | |
45 | residency_info_ffh.gaddr.bit_offset); | |
46 | ||
47 | *counter &= mask; | |
48 | *counter >>= residency_info_ffh.gaddr.bit_offset; | |
49 | *counter = div64_u64(*counter * 1000000ULL, residency_info_ffh.frequency); | |
50 | return 0; | |
51 | } | |
52 | ||
53 | return -ENODATA; | |
54 | } | |
55 | ||
56 | static ssize_t low_power_idle_system_residency_us_show(struct device *dev, | |
57 | struct device_attribute *attr, | |
58 | char *buf) | |
59 | { | |
60 | u64 counter; | |
61 | int ret; | |
62 | ||
63 | ret = lpit_read_residency_counter_us(&counter, true); | |
64 | if (ret) | |
65 | return ret; | |
66 | ||
67 | return sprintf(buf, "%llu\n", counter); | |
68 | } | |
69 | static DEVICE_ATTR_RO(low_power_idle_system_residency_us); | |
70 | ||
71 | static ssize_t low_power_idle_cpu_residency_us_show(struct device *dev, | |
72 | struct device_attribute *attr, | |
73 | char *buf) | |
74 | { | |
75 | u64 counter; | |
76 | int ret; | |
77 | ||
78 | ret = lpit_read_residency_counter_us(&counter, false); | |
79 | if (ret) | |
80 | return ret; | |
81 | ||
82 | return sprintf(buf, "%llu\n", counter); | |
83 | } | |
84 | static DEVICE_ATTR_RO(low_power_idle_cpu_residency_us); | |
85 | ||
86 | int lpit_read_residency_count_address(u64 *address) | |
87 | { | |
88 | if (!residency_info_mem.gaddr.address) | |
89 | return -EINVAL; | |
90 | ||
91 | *address = residency_info_mem.gaddr.address; | |
92 | ||
93 | return 0; | |
94 | } | |
9383bbad | 95 | EXPORT_SYMBOL_GPL(lpit_read_residency_count_address); |
eeb2d80d SP |
96 | |
97 | static void lpit_update_residency(struct lpit_residency_info *info, | |
98 | struct acpi_lpit_native *lpit_native) | |
99 | { | |
100 | info->frequency = lpit_native->counter_frequency ? | |
101 | lpit_native->counter_frequency : tsc_khz * 1000; | |
102 | if (!info->frequency) | |
103 | info->frequency = 1; | |
104 | ||
105 | info->gaddr = lpit_native->residency_counter; | |
106 | if (info->gaddr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { | |
4bdc0d67 | 107 | info->iomem_addr = ioremap(info->gaddr.address, |
eeb2d80d SP |
108 | info->gaddr.bit_width / 8); |
109 | if (!info->iomem_addr) | |
110 | return; | |
111 | ||
1cdda948 RB |
112 | if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) |
113 | return; | |
114 | ||
eeb2d80d SP |
115 | /* Silently fail, if cpuidle attribute group is not present */ |
116 | sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj, | |
117 | &dev_attr_low_power_idle_system_residency_us.attr, | |
118 | "cpuidle"); | |
119 | } else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) { | |
1cdda948 RB |
120 | if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)) |
121 | return; | |
122 | ||
eeb2d80d SP |
123 | /* Silently fail, if cpuidle attribute group is not present */ |
124 | sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj, | |
125 | &dev_attr_low_power_idle_cpu_residency_us.attr, | |
126 | "cpuidle"); | |
127 | } | |
128 | } | |
129 | ||
130 | static void lpit_process(u64 begin, u64 end) | |
131 | { | |
32865e3e | 132 | while (begin + sizeof(struct acpi_lpit_native) <= end) { |
eeb2d80d SP |
133 | struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin; |
134 | ||
135 | if (!lpit_native->header.type && !lpit_native->header.flags) { | |
136 | if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && | |
137 | !residency_info_mem.gaddr.address) { | |
138 | lpit_update_residency(&residency_info_mem, lpit_native); | |
139 | } else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE && | |
140 | !residency_info_ffh.gaddr.address) { | |
141 | lpit_update_residency(&residency_info_ffh, lpit_native); | |
142 | } | |
143 | } | |
144 | begin += lpit_native->header.length; | |
145 | } | |
146 | } | |
147 | ||
148 | void acpi_init_lpit(void) | |
149 | { | |
150 | acpi_status status; | |
eeb2d80d SP |
151 | struct acpi_table_lpit *lpit; |
152 | ||
153 | status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit); | |
154 | ||
155 | if (ACPI_FAILURE(status)) | |
156 | return; | |
157 | ||
32865e3e LS |
158 | lpit_process((u64)lpit + sizeof(*lpit), |
159 | (u64)lpit + lpit->header.length); | |
eeb2d80d | 160 | } |