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path: root/drivers/gator/gator_trace_power.c
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Diffstat (limited to 'drivers/gator/gator_trace_power.c')
-rw-r--r--drivers/gator/gator_trace_power.c203
1 files changed, 203 insertions, 0 deletions
diff --git a/drivers/gator/gator_trace_power.c b/drivers/gator/gator_trace_power.c
new file mode 100644
index 000000000000..f2754b1c2b56
--- /dev/null
+++ b/drivers/gator/gator_trace_power.c
@@ -0,0 +1,203 @@
+/**
+ * Copyright (C) ARM Limited 2011-2014. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/cpufreq.h>
+#include <trace/events/power.h>
+
+#if defined(__arm__)
+
+#include <asm/mach-types.h>
+
+#define implements_wfi() (!machine_is_omap3_beagle())
+
+#else
+
+#define implements_wfi() false
+
+#endif
+
+// cpu_frequency and cpu_idle trace points were introduced in Linux kernel v2.6.38
+// the now deprecated power_frequency trace point was available prior to 2.6.38, but only for x86
+#if GATOR_CPU_FREQ_SUPPORT
+enum {
+ POWER_CPU_FREQ,
+ POWER_CPU_IDLE,
+ POWER_TOTAL
+};
+
+static DEFINE_PER_CPU(ulong, idle_prev_state);
+static ulong power_cpu_enabled[POWER_TOTAL];
+static ulong power_cpu_key[POWER_TOTAL];
+
+static int gator_trace_power_create_files(struct super_block *sb, struct dentry *root)
+{
+ struct dentry *dir;
+ int cpu;
+ bool found_nonzero_freq = false;
+
+ // Even if CONFIG_CPU_FREQ is defined, it still may not be used. Check
+ // for non-zero values from cpufreq_quick_get
+ for_each_online_cpu(cpu) {
+ if (cpufreq_quick_get(cpu) > 0) {
+ found_nonzero_freq = true;
+ break;
+ }
+ }
+
+ if (found_nonzero_freq) {
+ // cpu_frequency
+ dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_freq");
+ if (!dir) {
+ return -1;
+ }
+ gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_FREQ]);
+ gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_FREQ]);
+ }
+
+ // cpu_idle
+ dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_idle");
+ if (!dir) {
+ return -1;
+ }
+ gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_IDLE]);
+ gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_IDLE]);
+
+ return 0;
+}
+
+// 'cpu' may not equal smp_processor_id(), i.e. may not be running on the core that is having the freq/idle state change
+GATOR_DEFINE_PROBE(cpu_frequency, TP_PROTO(unsigned int frequency, unsigned int cpu))
+{
+ cpu = lcpu_to_pcpu(cpu);
+ marshal_event_single64(cpu, power_cpu_key[POWER_CPU_FREQ], frequency * 1000L);
+}
+
+GATOR_DEFINE_PROBE(cpu_idle, TP_PROTO(unsigned int state, unsigned int cpu))
+{
+ cpu = lcpu_to_pcpu(cpu);
+
+ if (state == per_cpu(idle_prev_state, cpu)) {
+ return;
+ }
+
+ if (implements_wfi()) {
+ if (state == PWR_EVENT_EXIT) {
+ // transition from wfi to non-wfi
+ marshal_idle(cpu, MESSAGE_IDLE_EXIT);
+ } else {
+ // transition from non-wfi to wfi
+ marshal_idle(cpu, MESSAGE_IDLE_ENTER);
+ }
+ }
+
+ per_cpu(idle_prev_state, cpu) = state;
+
+ if (power_cpu_enabled[POWER_CPU_IDLE]) {
+ // Increment state so that no negative numbers are sent
+ marshal_event_single(cpu, power_cpu_key[POWER_CPU_IDLE], state + 1);
+ }
+}
+
+static void gator_trace_power_online(void)
+{
+ int pcpu = get_physical_cpu();
+ int lcpu = get_logical_cpu();
+ if (power_cpu_enabled[POWER_CPU_FREQ]) {
+ marshal_event_single64(pcpu, power_cpu_key[POWER_CPU_FREQ], cpufreq_quick_get(lcpu) * 1000L);
+ }
+}
+
+static void gator_trace_power_offline(void)
+{
+ // Set frequency to zero on an offline
+ int cpu = get_physical_cpu();
+ if (power_cpu_enabled[POWER_CPU_FREQ]) {
+ marshal_event_single(cpu, power_cpu_key[POWER_CPU_FREQ], 0);
+ }
+}
+
+static int gator_trace_power_start(void)
+{
+ int cpu;
+
+ // register tracepoints
+ if (power_cpu_enabled[POWER_CPU_FREQ])
+ if (GATOR_REGISTER_TRACE(cpu_frequency))
+ goto fail_cpu_frequency_exit;
+
+ // Always register for cpu:idle for detecting WFI, independent of power_cpu_enabled[POWER_CPU_IDLE]
+ if (GATOR_REGISTER_TRACE(cpu_idle))
+ goto fail_cpu_idle_exit;
+ pr_debug("gator: registered power event tracepoints\n");
+
+ for_each_present_cpu(cpu) {
+ per_cpu(idle_prev_state, cpu) = 0;
+ }
+
+ return 0;
+
+ // unregister tracepoints on error
+fail_cpu_idle_exit:
+ if (power_cpu_enabled[POWER_CPU_FREQ])
+ GATOR_UNREGISTER_TRACE(cpu_frequency);
+fail_cpu_frequency_exit:
+ pr_err("gator: power event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
+
+ return -1;
+}
+
+static void gator_trace_power_stop(void)
+{
+ int i;
+
+ if (power_cpu_enabled[POWER_CPU_FREQ])
+ GATOR_UNREGISTER_TRACE(cpu_frequency);
+ GATOR_UNREGISTER_TRACE(cpu_idle);
+ pr_debug("gator: unregistered power event tracepoints\n");
+
+ for (i = 0; i < POWER_TOTAL; i++) {
+ power_cpu_enabled[i] = 0;
+ }
+}
+
+static void gator_trace_power_init(void)
+{
+ int i;
+ for (i = 0; i < POWER_TOTAL; i++) {
+ power_cpu_enabled[i] = 0;
+ power_cpu_key[i] = gator_events_get_key();
+ }
+}
+#else
+static int gator_trace_power_create_files(struct super_block *sb, struct dentry *root)
+{
+ return 0;
+}
+
+static void gator_trace_power_online(void)
+{
+}
+
+static void gator_trace_power_offline(void)
+{
+}
+
+static int gator_trace_power_start(void)
+{
+ return 0;
+}
+
+static void gator_trace_power_stop(void)
+{
+}
+
+static void gator_trace_power_init(void)
+{
+}
+#endif