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
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
lpit_read_residency_counter_us(u64 * counter,bool io_mem)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
low_power_idle_system_residency_us_show(struct device * dev,struct device_attribute * attr,char * buf)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
low_power_idle_cpu_residency_us_show(struct device * dev,struct device_attribute * attr,char * buf)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
lpit_read_residency_count_address(u64 * address)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 }
95 EXPORT_SYMBOL_GPL(lpit_read_residency_count_address);
96
lpit_update_residency(struct lpit_residency_info * info,struct acpi_lpit_native * lpit_native)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 : mul_u32_u32(tsc_khz, 1000U);
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) {
107 info->iomem_addr = ioremap(info->gaddr.address,
108 info->gaddr.bit_width / 8);
109 if (!info->iomem_addr)
110 return;
111
112 /* Silently fail, if cpuidle attribute group is not present */
113 sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
114 &dev_attr_low_power_idle_system_residency_us.attr,
115 "cpuidle");
116 } else if (info->gaddr.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) {
117 /* Silently fail, if cpuidle attribute group is not present */
118 sysfs_add_file_to_group(&cpu_subsys.dev_root->kobj,
119 &dev_attr_low_power_idle_cpu_residency_us.attr,
120 "cpuidle");
121 }
122 }
123
lpit_process(u64 begin,u64 end)124 static void lpit_process(u64 begin, u64 end)
125 {
126 while (begin + sizeof(struct acpi_lpit_native) <= end) {
127 struct acpi_lpit_native *lpit_native = (struct acpi_lpit_native *)begin;
128
129 if (!lpit_native->header.type && !lpit_native->header.flags) {
130 if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY &&
131 !residency_info_mem.gaddr.address) {
132 lpit_update_residency(&residency_info_mem, lpit_native);
133 } else if (lpit_native->residency_counter.space_id == ACPI_ADR_SPACE_FIXED_HARDWARE &&
134 !residency_info_ffh.gaddr.address) {
135 lpit_update_residency(&residency_info_ffh, lpit_native);
136 }
137 }
138 begin += lpit_native->header.length;
139 }
140 }
141
acpi_init_lpit(void)142 void acpi_init_lpit(void)
143 {
144 acpi_status status;
145 struct acpi_table_lpit *lpit;
146
147 status = acpi_get_table(ACPI_SIG_LPIT, 0, (struct acpi_table_header **)&lpit);
148 if (ACPI_FAILURE(status))
149 return;
150
151 lpit_process((u64)lpit + sizeof(*lpit),
152 (u64)lpit + lpit->header.length);
153
154 acpi_put_table((struct acpi_table_header *)lpit);
155 }
156