resources/acpi_cpu/fra_acpi_cpu.c

   1 /**
   2  * @file   fres_acpi_cpu.c
   3  * @author Dario Faggioli <faggioli@gandalf.sssup.it>
   4  *         Michael Trimarchi <trimarchimichael@yahoo.it>
   5  *
   6  * @brief  Implementation of shared CPU related ACPI functions.
   7  *
   8  */
   9
  10 #include "fra_acpi_cpu.h"
  11
  12 static int frequency_initialized = 0;
  13
  14 static unsigned long freqs[3];
  15
  16 int fra_CPU_power_init(int cpu)
  17 {
  18         int ret;
  19         int i, j, freq_num = 0;
  20         struct cpufreq_available_governors *governors, *g;
  21         struct cpufreq_available_frequencies *frequencies, *f;
  22
  23         if (frequency_initialized == 1) return 0;
  24
  25         ret = cpufreq_cpu_exists(cpu);
  26         if (ret) return EINVAL;
  27
  28         governors = cpufreq_get_available_governors(cpu);
  29         if (!governors) return EINVAL;
  30         for (g = governors; g != NULL; g = g->next)
  31                 if (strncmp("userspace", g->governor, sizeof(*g->governor)) == 0)
  32                         break;
  33         cpufreq_put_available_governors(governors);
  34
  35         if (g == NULL) return EINVAL;
  36
  37         ret = cpufreq_modify_policy_governor(cpu, "userspace");
  38         if (ret) return EPERM;
  39
  40
  41         frequencies = cpufreq_get_available_frequencies(cpu);
  42         if (!frequencies) return EINVAL;
  43         for (f = frequencies; f; f = f->next, freq_num++)
  44                 ;
  45
  46         f = frequencies;
  47         i = j = 0;
  48         while (f) {
  49                 if (i == 0 ||
  50                     i == ((int)ceil((double)freq_num / 2.0f)) ||
  51                     i == freq_num - 1) {
  52                         freqs[j] = f->frequency;
  53                         j++;
  54                 }
  55                 i++;
  56                 f = f->next;
  57         }
  58         cpufreq_put_available_frequencies(frequencies);
  59
  60         frequency_initialized = 1;
  61
  62         return 0;
  63 }
  64
  65 int fra_CPU_get_power(int cpu, int *level)
  66 {
  67         unsigned long freq;
  68         int i;
  69
  70         if (!frequency_initialized) return EINVAL;
  71
  72         freq = cpufreq_get(cpu);
  73         for (i = 0; i < 3; i++)
  74                 if (freqs[i] == freq) {
  75                         *level = i;
  76                         return 0;
  77                 }
  78
  79         return EINVAL;
  80 }
  81
  82 int fra_CPU_set_power(int cpu, int level)
  83 {
  84         if (!frequency_initialized || level >= 3)
  85                 return EINVAL;
  86
  87         return cpufreq_set_frequency(cpu, freqs[level]);
  88 }
  89
  90 int fra_CPU_get_speed(int cpu, int level, double *ratio)
  91 {
  92         if (!frequency_initialized || level >= 3)
  93                 return EINVAL;
  94
  95         *ratio = (double) freqs[level] / freqs[0];
  96
  97         return 0;
  98 }
  99