drivers/gator/gator_trace_power.c

   1 /**
   2  * Copyright (C) ARM Limited 2011-2015. All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <linux/cpufreq.h>
  11 #include <trace/events/power.h>
  12
  13 #if defined(__arm__)
  14
  15 #include <asm/mach-types.h>
  16
  17 #define implements_wfi() (!machine_is_omap3_beagle())
  18
  19 #else
  20
  21 #define implements_wfi() false
  22
  23 #endif
  24
  25 /* cpu_frequency and cpu_idle trace points were introduced in Linux
  26  * kernel v2.6.38 the now deprecated power_frequency trace point was
  27  * available prior to 2.6.38, but only for x86
  28  */
  29 #if GATOR_CPU_FREQ_SUPPORT
  30 enum {
  31         POWER_CPU_FREQ,
  32         POWER_TOTAL
  33 };
  34
  35 static DEFINE_PER_CPU(ulong, idle_prev_state);
  36 static ulong power_cpu_enabled[POWER_TOTAL];
  37 static ulong power_cpu_key[POWER_TOTAL];
  38 static ulong power_cpu_cores;
  39
  40 static int gator_trace_power_create_files(struct super_block *sb, struct dentry *root)
  41 {
  42         struct dentry *dir;
  43         int cpu;
  44         bool found_nonzero_freq = false;
  45
  46         /* Even if CONFIG_CPU_FREQ is defined, it still may not be
  47          * used. Check for non-zero values from cpufreq_quick_get
  48          */
  49         for_each_online_cpu(cpu) {
  50                 if (cpufreq_quick_get(cpu) > 0) {
  51                         found_nonzero_freq = true;
  52                         break;
  53                 }
  54         }
  55
  56         if (found_nonzero_freq) {
  57                 /* cpu_frequency */
  58                 dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_freq");
  59                 if (!dir)
  60                         return -1;
  61                 gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_FREQ]);
  62                 gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_FREQ]);
  63         }
  64
  65         return 0;
  66 }
  67
  68 /* 'cpu' may not equal smp_processor_id(), i.e. may not be running on the core that is having the freq/idle state change */
  69 GATOR_DEFINE_PROBE(cpu_frequency, TP_PROTO(unsigned int frequency, unsigned int cpu))
  70 {
  71         cpu = lcpu_to_pcpu(cpu);
  72         marshal_event_single64(cpu, power_cpu_key[POWER_CPU_FREQ], frequency * 1000L);
  73 }
  74
  75 GATOR_DEFINE_PROBE(cpu_idle, TP_PROTO(unsigned int state, unsigned int cpu))
  76 {
  77         cpu = lcpu_to_pcpu(cpu);
  78
  79         if (state == per_cpu(idle_prev_state, cpu))
  80                 return;
  81
  82         if (implements_wfi()) {
  83                 marshal_idle(cpu, state);
  84         }
  85
  86         per_cpu(idle_prev_state, cpu) = state;
  87 }
  88
  89 static void gator_trace_power_online(void)
  90 {
  91         int pcpu = get_physical_cpu();
  92         int lcpu = get_logical_cpu();
  93
  94         if (power_cpu_enabled[POWER_CPU_FREQ])
  95                 marshal_event_single64(pcpu, power_cpu_key[POWER_CPU_FREQ], cpufreq_quick_get(lcpu) * 1000L);
  96 }
  97
  98 static void gator_trace_power_offline(void)
  99 {
 100         /* Set frequency to zero on an offline */
 101         int cpu = get_physical_cpu();
 102
 103         if (power_cpu_enabled[POWER_CPU_FREQ])
 104                 marshal_event_single(cpu, power_cpu_key[POWER_CPU_FREQ], 0);
 105 }
 106
 107 static int gator_trace_power_start(void)
 108 {
 109         int cpu;
 110
 111         /* register tracepoints */
 112         if (power_cpu_enabled[POWER_CPU_FREQ])
 113                 if (GATOR_REGISTER_TRACE(cpu_frequency))
 114                         goto fail_cpu_frequency_exit;
 115
 116         /* Always register for cpu_idle for detecting WFI */
 117         if (GATOR_REGISTER_TRACE(cpu_idle))
 118                 goto fail_cpu_idle_exit;
 119         pr_debug("gator: registered power event tracepoints\n");
 120
 121         for_each_present_cpu(cpu) {
 122                 per_cpu(idle_prev_state, cpu) = 0;
 123         }
 124
 125         return 0;
 126
 127         /* unregister tracepoints on error */
 128 fail_cpu_idle_exit:
 129         if (power_cpu_enabled[POWER_CPU_FREQ])
 130                 GATOR_UNREGISTER_TRACE(cpu_frequency);
 131 fail_cpu_frequency_exit:
 132         pr_err("gator: power event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
 133
 134         return -1;
 135 }
 136
 137 static void gator_trace_power_stop(void)
 138 {
 139         int i;
 140
 141         if (power_cpu_enabled[POWER_CPU_FREQ])
 142                 GATOR_UNREGISTER_TRACE(cpu_frequency);
 143         GATOR_UNREGISTER_TRACE(cpu_idle);
 144         pr_debug("gator: unregistered power event tracepoints\n");
 145
 146         for (i = 0; i < POWER_TOTAL; i++)
 147                 power_cpu_enabled[i] = 0;
 148 }
 149
 150 static void gator_trace_power_init(void)
 151 {
 152         int i;
 153
 154         power_cpu_cores = nr_cpu_ids;
 155         for (i = 0; i < POWER_TOTAL; i++) {
 156                 power_cpu_enabled[i] = 0;
 157                 power_cpu_key[i] = gator_events_get_key();
 158         }
 159 }
 160 #else
 161 static int gator_trace_power_create_files(struct super_block *sb, struct dentry *root)
 162 {
 163         return 0;
 164 }
 165
 166 static void gator_trace_power_online(void)
 167 {
 168 }
 169
 170 static void gator_trace_power_offline(void)
 171 {
 172 }
 173
 174 static int gator_trace_power_start(void)
 175 {
 176         return 0;
 177 }
 178
 179 static void gator_trace_power_stop(void)
 180 {
 181 }
 182
 183 static void gator_trace_power_init(void)
 184 {
 185 }
 186 #endif