Merge branch 'pm-cpufreq'
[muen/linux.git] / drivers / base / arch_topology.c
1 /*
2  * Arch specific cpu topology information
3  *
4  * Copyright (C) 2016, ARM Ltd.
5  * Written by: Juri Lelli, ARM Ltd.
6  *
7  * This file is subject to the terms and conditions of the GNU General Public
8  * License.  See the file "COPYING" in the main directory of this archive
9  * for more details.
10  *
11  * Released under the GPLv2 only.
12  * SPDX-License-Identifier: GPL-2.0
13  */
14
15 #include <linux/acpi.h>
16 #include <linux/arch_topology.h>
17 #include <linux/cpu.h>
18 #include <linux/cpufreq.h>
19 #include <linux/device.h>
20 #include <linux/of.h>
21 #include <linux/slab.h>
22 #include <linux/string.h>
23 #include <linux/sched/topology.h>
24
25 DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
26
27 void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
28                          unsigned long max_freq)
29 {
30         unsigned long scale;
31         int i;
32
33         scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
34
35         for_each_cpu(i, cpus)
36                 per_cpu(freq_scale, i) = scale;
37 }
38
39 static DEFINE_MUTEX(cpu_scale_mutex);
40 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
41
42 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
43 {
44         per_cpu(cpu_scale, cpu) = capacity;
45 }
46
47 static ssize_t cpu_capacity_show(struct device *dev,
48                                  struct device_attribute *attr,
49                                  char *buf)
50 {
51         struct cpu *cpu = container_of(dev, struct cpu, dev);
52
53         return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id));
54 }
55
56 static ssize_t cpu_capacity_store(struct device *dev,
57                                   struct device_attribute *attr,
58                                   const char *buf,
59                                   size_t count)
60 {
61         struct cpu *cpu = container_of(dev, struct cpu, dev);
62         int this_cpu = cpu->dev.id;
63         int i;
64         unsigned long new_capacity;
65         ssize_t ret;
66
67         if (!count)
68                 return 0;
69
70         ret = kstrtoul(buf, 0, &new_capacity);
71         if (ret)
72                 return ret;
73         if (new_capacity > SCHED_CAPACITY_SCALE)
74                 return -EINVAL;
75
76         mutex_lock(&cpu_scale_mutex);
77         for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
78                 topology_set_cpu_scale(i, new_capacity);
79         mutex_unlock(&cpu_scale_mutex);
80
81         return count;
82 }
83
84 static DEVICE_ATTR_RW(cpu_capacity);
85
86 static int register_cpu_capacity_sysctl(void)
87 {
88         int i;
89         struct device *cpu;
90
91         for_each_possible_cpu(i) {
92                 cpu = get_cpu_device(i);
93                 if (!cpu) {
94                         pr_err("%s: too early to get CPU%d device!\n",
95                                __func__, i);
96                         continue;
97                 }
98                 device_create_file(cpu, &dev_attr_cpu_capacity);
99         }
100
101         return 0;
102 }
103 subsys_initcall(register_cpu_capacity_sysctl);
104
105 static u32 capacity_scale;
106 static u32 *raw_capacity;
107
108 static int __init free_raw_capacity(void)
109 {
110         kfree(raw_capacity);
111         raw_capacity = NULL;
112
113         return 0;
114 }
115
116 void topology_normalize_cpu_scale(void)
117 {
118         u64 capacity;
119         int cpu;
120
121         if (!raw_capacity)
122                 return;
123
124         pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
125         mutex_lock(&cpu_scale_mutex);
126         for_each_possible_cpu(cpu) {
127                 pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
128                          cpu, raw_capacity[cpu]);
129                 capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
130                         / capacity_scale;
131                 topology_set_cpu_scale(cpu, capacity);
132                 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
133                         cpu, topology_get_cpu_scale(NULL, cpu));
134         }
135         mutex_unlock(&cpu_scale_mutex);
136 }
137
138 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
139 {
140         static bool cap_parsing_failed;
141         int ret;
142         u32 cpu_capacity;
143
144         if (cap_parsing_failed)
145                 return false;
146
147         ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
148                                    &cpu_capacity);
149         if (!ret) {
150                 if (!raw_capacity) {
151                         raw_capacity = kcalloc(num_possible_cpus(),
152                                                sizeof(*raw_capacity),
153                                                GFP_KERNEL);
154                         if (!raw_capacity) {
155                                 pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
156                                 cap_parsing_failed = true;
157                                 return false;
158                         }
159                 }
160                 capacity_scale = max(cpu_capacity, capacity_scale);
161                 raw_capacity[cpu] = cpu_capacity;
162                 pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
163                         cpu_node, raw_capacity[cpu]);
164         } else {
165                 if (raw_capacity) {
166                         pr_err("cpu_capacity: missing %pOF raw capacity\n",
167                                 cpu_node);
168                         pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
169                 }
170                 cap_parsing_failed = true;
171                 free_raw_capacity();
172         }
173
174         return !ret;
175 }
176
177 #ifdef CONFIG_CPU_FREQ
178 static cpumask_var_t cpus_to_visit __initdata;
179 static void __init parsing_done_workfn(struct work_struct *work);
180 static __initdata DECLARE_WORK(parsing_done_work, parsing_done_workfn);
181
182 static int __init
183 init_cpu_capacity_callback(struct notifier_block *nb,
184                            unsigned long val,
185                            void *data)
186 {
187         struct cpufreq_policy *policy = data;
188         int cpu;
189
190         if (!raw_capacity)
191                 return 0;
192
193         if (val != CPUFREQ_NOTIFY)
194                 return 0;
195
196         pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
197                  cpumask_pr_args(policy->related_cpus),
198                  cpumask_pr_args(cpus_to_visit));
199
200         cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
201
202         for_each_cpu(cpu, policy->related_cpus) {
203                 raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) *
204                                     policy->cpuinfo.max_freq / 1000UL;
205                 capacity_scale = max(raw_capacity[cpu], capacity_scale);
206         }
207
208         if (cpumask_empty(cpus_to_visit)) {
209                 topology_normalize_cpu_scale();
210                 free_raw_capacity();
211                 pr_debug("cpu_capacity: parsing done\n");
212                 schedule_work(&parsing_done_work);
213         }
214
215         return 0;
216 }
217
218 static struct notifier_block init_cpu_capacity_notifier __initdata = {
219         .notifier_call = init_cpu_capacity_callback,
220 };
221
222 static int __init register_cpufreq_notifier(void)
223 {
224         int ret;
225
226         /*
227          * on ACPI-based systems we need to use the default cpu capacity
228          * until we have the necessary code to parse the cpu capacity, so
229          * skip registering cpufreq notifier.
230          */
231         if (!acpi_disabled || !raw_capacity)
232                 return -EINVAL;
233
234         if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
235                 pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
236                 return -ENOMEM;
237         }
238
239         cpumask_copy(cpus_to_visit, cpu_possible_mask);
240
241         ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
242                                         CPUFREQ_POLICY_NOTIFIER);
243
244         if (ret)
245                 free_cpumask_var(cpus_to_visit);
246
247         return ret;
248 }
249 core_initcall(register_cpufreq_notifier);
250
251 static void __init parsing_done_workfn(struct work_struct *work)
252 {
253         cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
254                                          CPUFREQ_POLICY_NOTIFIER);
255         free_cpumask_var(cpus_to_visit);
256 }
257
258 #else
259 core_initcall(free_raw_capacity);
260 #endif