cpufreq_userspace.c 3.6 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * linux/drivers/cpufreq/cpufreq_userspace.c
  4. *
  5. * Copyright (C) 2001 Russell King
  6. * (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
  7. */
  8. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  9. #include <linux/cpufreq.h>
  10. #include <linux/init.h>
  11. #include <linux/module.h>
  12. #include <linux/mutex.h>
  13. #include <linux/slab.h>
  14. static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
  15. static DEFINE_MUTEX(userspace_mutex);
  16. /**
  17. * cpufreq_set - set the CPU frequency
  18. * @policy: pointer to policy struct where freq is being set
  19. * @freq: target frequency in kHz
  20. *
  21. * Sets the CPU frequency to freq.
  22. */
  23. static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
  24. {
  25. int ret = -EINVAL;
  26. unsigned int *setspeed = policy->governor_data;
  27. pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
  28. mutex_lock(&userspace_mutex);
  29. if (!per_cpu(cpu_is_managed, policy->cpu))
  30. goto err;
  31. *setspeed = freq;
  32. ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
  33. err:
  34. mutex_unlock(&userspace_mutex);
  35. return ret;
  36. }
  37. static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
  38. {
  39. return sprintf(buf, "%u\n", policy->cur);
  40. }
  41. static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
  42. {
  43. unsigned int *setspeed;
  44. setspeed = kzalloc(sizeof(*setspeed), GFP_KERNEL);
  45. if (!setspeed)
  46. return -ENOMEM;
  47. policy->governor_data = setspeed;
  48. return 0;
  49. }
  50. static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
  51. {
  52. mutex_lock(&userspace_mutex);
  53. kfree(policy->governor_data);
  54. policy->governor_data = NULL;
  55. mutex_unlock(&userspace_mutex);
  56. }
  57. static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
  58. {
  59. unsigned int *setspeed = policy->governor_data;
  60. BUG_ON(!policy->cur);
  61. pr_debug("started managing cpu %u\n", policy->cpu);
  62. mutex_lock(&userspace_mutex);
  63. per_cpu(cpu_is_managed, policy->cpu) = 1;
  64. *setspeed = policy->cur;
  65. mutex_unlock(&userspace_mutex);
  66. return 0;
  67. }
  68. static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
  69. {
  70. unsigned int *setspeed = policy->governor_data;
  71. pr_debug("managing cpu %u stopped\n", policy->cpu);
  72. mutex_lock(&userspace_mutex);
  73. per_cpu(cpu_is_managed, policy->cpu) = 0;
  74. *setspeed = 0;
  75. mutex_unlock(&userspace_mutex);
  76. }
  77. static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
  78. {
  79. unsigned int *setspeed = policy->governor_data;
  80. mutex_lock(&userspace_mutex);
  81. pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
  82. policy->cpu, policy->min, policy->max, policy->cur, *setspeed);
  83. if (policy->max < *setspeed)
  84. __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
  85. else if (policy->min > *setspeed)
  86. __cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
  87. else
  88. __cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L);
  89. mutex_unlock(&userspace_mutex);
  90. }
  91. static struct cpufreq_governor cpufreq_gov_userspace = {
  92. .name = "userspace",
  93. .init = cpufreq_userspace_policy_init,
  94. .exit = cpufreq_userspace_policy_exit,
  95. .start = cpufreq_userspace_policy_start,
  96. .stop = cpufreq_userspace_policy_stop,
  97. .limits = cpufreq_userspace_policy_limits,
  98. .store_setspeed = cpufreq_set,
  99. .show_setspeed = show_speed,
  100. .owner = THIS_MODULE,
  101. };
  102. MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
  103. "Russell King <rmk@arm.linux.org.uk>");
  104. MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
  105. MODULE_LICENSE("GPL");
  106. #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
  107. struct cpufreq_governor *cpufreq_default_governor(void)
  108. {
  109. return &cpufreq_gov_userspace;
  110. }
  111. #endif
  112. cpufreq_governor_init(cpufreq_gov_userspace);
  113. cpufreq_governor_exit(cpufreq_gov_userspace);