driver/gator_trace_power.c

   1 /**
   2  * Copyright (C) ARM Limited 2011-2013. 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 kernel v2.6.38
  26 // the now deprecated power_frequency trace point was available prior to 2.6.38, but only for x86
  27 #if GATOR_CPU_FREQ_SUPPORT
  28 enum {
  29         POWER_CPU_FREQ,
  30         POWER_CPU_IDLE,
  31         POWER_TOTAL
  32 };
  33
  34 static DEFINE_PER_CPU(ulong, idle_prev_state);
  35 static ulong power_cpu_enabled[POWER_TOTAL];
  36 static ulong power_cpu_key[POWER_TOTAL];
  37
  38 static int gator_trace_power_create_files(struct super_block *sb, struct dentry *root)
  39 {
  40         struct dentry *dir;
  41         int cpu;
  42         bool found_nonzero_freq = false;
  43
  44         // Even if CONFIG_CPU_FREQ is defined, it still may not be used. Check
  45         // for non-zero values from cpufreq_quick_get
  46         for_each_online_cpu(cpu) {
  47                 if (cpufreq_quick_get(cpu) > 0) {
  48                         found_nonzero_freq = true;
  49                         break;
  50                 }
  51         }
  52
  53         if (found_nonzero_freq) {
  54                 // cpu_frequency
  55                 dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_freq");
  56                 if (!dir) {
  57                         return -1;
  58                 }
  59                 gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_FREQ]);
  60                 gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_FREQ]);
  61         }
  62
  63         // cpu_idle
  64         dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_idle");
  65         if (!dir) {
  66                 return -1;
  67         }
  68         gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_IDLE]);
  69         gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_IDLE]);
  70
  71         return 0;
  72 }
  73
  74 // 'cpu' may not equal smp_processor_id(), i.e. may not be running on the core that is having the freq/idle state change
  75 GATOR_DEFINE_PROBE(cpu_frequency, TP_PROTO(unsigned int frequency, unsigned int cpu))
  76 {
  77         cpu = lcpu_to_pcpu(cpu);
  78         marshal_event_single(cpu, power_cpu_key[POWER_CPU_FREQ], frequency * 1000);
  79 }
  80
  81 GATOR_DEFINE_PROBE(cpu_idle, TP_PROTO(unsigned int state, unsigned int cpu))
  82 {
  83         cpu = lcpu_to_pcpu(cpu);
  84
  85         if (state == per_cpu(idle_prev_state, cpu)) {
  86                 return;
  87         }
  88
  89         if (implements_wfi()) {
  90                 if (state == PWR_EVENT_EXIT) {
  91                         // transition from wfi to non-wfi
  92                         marshal_idle(cpu, MESSAGE_IDLE_EXIT);
  93                 } else {
  94                         // transition from non-wfi to wfi
  95                         marshal_idle(cpu, MESSAGE_IDLE_ENTER);
  96                 }
  97         }
  98
  99         per_cpu(idle_prev_state, cpu) = state;
 100
 101         if (power_cpu_enabled[POWER_CPU_IDLE]) {
 102                 // Increment state so that no negative numbers are sent
 103                 marshal_event_single(cpu, power_cpu_key[POWER_CPU_IDLE], state + 1);
 104         }
 105 }
 106
 107 static void gator_trace_power_online(void)
 108 {
 109         int pcpu = get_physical_cpu();
 110         int lcpu = get_logical_cpu();
 111         if (power_cpu_enabled[POWER_CPU_FREQ]) {
 112                 marshal_event_single(pcpu, power_cpu_key[POWER_CPU_FREQ], cpufreq_quick_get(lcpu) * 1000);
 113         }
 114 }
 115
 116 static void gator_trace_power_offline(void)
 117 {
 118         // Set frequency to zero on an offline
 119         int cpu = get_physical_cpu();
 120         if (power_cpu_enabled[POWER_CPU_FREQ]) {
 121                 marshal_event_single(cpu, power_cpu_key[POWER_CPU_FREQ], 0);
 122         }
 123 }
 124
 125 static int gator_trace_power_start(void)
 126 {
 127         int cpu;
 128
 129         // register tracepoints
 130         if (power_cpu_enabled[POWER_CPU_FREQ])
 131                 if (GATOR_REGISTER_TRACE(cpu_frequency))
 132                         goto fail_cpu_frequency_exit;
 133
 134         // Always register for cpu:idle for detecting WFI, independent of power_cpu_enabled[POWER_CPU_IDLE]
 135         if (GATOR_REGISTER_TRACE(cpu_idle))
 136                 goto fail_cpu_idle_exit;
 137         pr_debug("gator: registered power event tracepoints\n");
 138
 139         for_each_present_cpu(cpu) {
 140                 per_cpu(idle_prev_state, cpu) = 0;
 141         }
 142
 143         return 0;
 144
 145         // unregister tracepoints on error
 146 fail_cpu_idle_exit:
 147         if (power_cpu_enabled[POWER_CPU_FREQ])
 148                 GATOR_UNREGISTER_TRACE(cpu_frequency);
 149 fail_cpu_frequency_exit:
 150         pr_err("gator: power event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
 151
 152         return -1;
 153 }
 154
 155 static void gator_trace_power_stop(void)
 156 {
 157         int i;
 158
 159         if (power_cpu_enabled[POWER_CPU_FREQ])
 160                 GATOR_UNREGISTER_TRACE(cpu_frequency);
 161         GATOR_UNREGISTER_TRACE(cpu_idle);
 162         pr_debug("gator: unregistered power event tracepoints\n");
 163
 164         for (i = 0; i < POWER_TOTAL; i++) {
 165                 power_cpu_enabled[i] = 0;
 166         }
 167 }
 168
 169 void gator_trace_power_init(void)
 170 {
 171         int i;
 172         for (i = 0; i < POWER_TOTAL; i++) {
 173                 power_cpu_enabled[i] = 0;
 174                 power_cpu_key[i] = gator_events_get_key();
 175         }
 176 }
 177 #else
 178 static int gator_trace_power_create_files(struct super_block *sb, struct dentry *root)
 179 {
 180         return 0;
 181 }
 182
 183 static void gator_trace_power_online(void)
 184 {
 185 }
 186
 187 static void gator_trace_power_offline(void)
 188 {
 189 }
 190
 191 static int gator_trace_power_start(void)
 192 {
 193         return 0;
 194 }
 195
 196 static void gator_trace_power_stop(void)
 197 {
 198 }
 199
 200 void gator_trace_power_init(void)
 201 {
 202 }
 203 #endif