drivers/cpufreq/cppc_cpufreq.c

   1 /*
   2  * CPPC (Collaborative Processor Performance Control) driver for
   3  * interfacing with the CPUfreq layer and governors. See
   4  * cppc_acpi.c for CPPC specific methods.
   5  *
   6  * (C) Copyright 2014, 2015 Linaro Ltd.
   7  * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; version 2
  12  * of the License.
  13  */
  14
  15 #define pr_fmt(fmt)     "CPPC Cpufreq:" fmt
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/delay.h>
  20 #include <linux/cpu.h>
  21 #include <linux/cpufreq.h>
  22 #include <linux/vmalloc.h>
  23
  24 #include <acpi/cppc_acpi.h>
  25
  26 /*
  27  * These structs contain information parsed from per CPU
  28  * ACPI _CPC structures.
  29  * e.g. For each CPU the highest, lowest supported
  30  * performance capabilities, desired performance level
  31  * requested etc.
  32  */
  33 static struct cpudata **all_cpu_data;
  34
  35 static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
  36                 unsigned int target_freq,
  37                 unsigned int relation)
  38 {
  39         struct cpudata *cpu;
  40         struct cpufreq_freqs freqs;
  41         int ret = 0;
  42
  43         cpu = all_cpu_data[policy->cpu];
  44
  45         cpu->perf_ctrls.desired_perf = target_freq;
  46         freqs.old = policy->cur;
  47         freqs.new = target_freq;
  48
  49         cpufreq_freq_transition_begin(policy, &freqs);
  50         ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
  51         cpufreq_freq_transition_end(policy, &freqs, ret != 0);
  52
  53         if (ret)
  54                 pr_debug("Failed to set target on CPU:%d. ret:%d\n",
  55                                 cpu->cpu, ret);
  56
  57         return ret;
  58 }
  59
  60 static int cppc_verify_policy(struct cpufreq_policy *policy)
  61 {
  62         cpufreq_verify_within_cpu_limits(policy);
  63         return 0;
  64 }
  65
  66 static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
  67 {
  68         int cpu_num = policy->cpu;
  69         struct cpudata *cpu = all_cpu_data[cpu_num];
  70         int ret;
  71
  72         cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
  73
  74         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
  75         if (ret)
  76                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
  77                                 cpu->perf_caps.lowest_perf, cpu_num, ret);
  78 }
  79
  80 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
  81 {
  82         struct cpudata *cpu;
  83         unsigned int cpu_num = policy->cpu;
  84         int ret = 0;
  85
  86         cpu = all_cpu_data[policy->cpu];
  87
  88         cpu->cpu = cpu_num;
  89         ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
  90
  91         if (ret) {
  92                 pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
  93                                 cpu_num, ret);
  94                 return ret;
  95         }
  96
  97         policy->min = cpu->perf_caps.lowest_perf;
  98         policy->max = cpu->perf_caps.highest_perf;
  99         policy->cpuinfo.min_freq = policy->min;
 100         policy->cpuinfo.max_freq = policy->max;
 101         policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
 102         policy->shared_type = cpu->shared_type;
 103
 104         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
 105                 cpumask_copy(policy->cpus, cpu->shared_cpu_map);
 106         else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
 107                 /* Support only SW_ANY for now. */
 108                 pr_debug("Unsupported CPU co-ord type\n");
 109                 return -EFAULT;
 110         }
 111
 112         cpumask_set_cpu(policy->cpu, policy->cpus);
 113         cpu->cur_policy = policy;
 114
 115         /* Set policy->cur to max now. The governors will adjust later. */
 116         policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
 117
 118         ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
 119         if (ret)
 120                 pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
 121                                 cpu->perf_caps.highest_perf, cpu_num, ret);
 122
 123         return ret;
 124 }
 125
 126 static struct cpufreq_driver cppc_cpufreq_driver = {
 127         .flags = CPUFREQ_CONST_LOOPS,
 128         .verify = cppc_verify_policy,
 129         .target = cppc_cpufreq_set_target,
 130         .init = cppc_cpufreq_cpu_init,
 131         .stop_cpu = cppc_cpufreq_stop_cpu,
 132         .name = "cppc_cpufreq",
 133 };
 134
 135 static int __init cppc_cpufreq_init(void)
 136 {
 137         int i, ret = 0;
 138         struct cpudata *cpu;
 139
 140         if (acpi_disabled)
 141                 return -ENODEV;
 142
 143         all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
 144         if (!all_cpu_data)
 145                 return -ENOMEM;
 146
 147         for_each_possible_cpu(i) {
 148                 all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
 149                 if (!all_cpu_data[i])
 150                         goto out;
 151
 152                 cpu = all_cpu_data[i];
 153                 if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
 154                         goto out;
 155         }
 156
 157         ret = acpi_get_psd_map(all_cpu_data);
 158         if (ret) {
 159                 pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
 160                 goto out;
 161         }
 162
 163         ret = cpufreq_register_driver(&cppc_cpufreq_driver);
 164         if (ret)
 165                 goto out;
 166
 167         return ret;
 168
 169 out:
 170         for_each_possible_cpu(i)
 171                 kfree(all_cpu_data[i]);
 172
 173         kfree(all_cpu_data);
 174         return -ENODEV;
 175 }
 176
 177 static void __exit cppc_cpufreq_exit(void)
 178 {
 179         struct cpudata *cpu;
 180         int i;
 181
 182         cpufreq_unregister_driver(&cppc_cpufreq_driver);
 183
 184         for_each_possible_cpu(i) {
 185                 cpu = all_cpu_data[i];
 186                 free_cpumask_var(cpu->shared_cpu_map);
 187                 kfree(cpu);
 188         }
 189
 190         kfree(all_cpu_data);
 191 }
 192
 193 module_exit(cppc_cpufreq_exit);
 194 MODULE_AUTHOR("Ashwin Chaugule");
 195 MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
 196 MODULE_LICENSE("GPL");
 197
 198 late_initcall(cppc_cpufreq_init);