clk: Add tracepoints for hardware operations

It's useful to have tracepoints around operations that change the
hardware state so that we can debug clock hardware performance
and operations. Four basic types of events are supported: on/off
events for enable, disable, prepare, unprepare that only record
an event and a clock name, rate changing events for
clk_set_{min_,max_}rate{_range}(), phase changing events for
clk_set_phase() and parent changing events for clk_set_parent().

Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>

drivers/clk/clk.c

@@ -77,6 +77,9 @@ struct clk_core {
 	struct kref		ref;
 };
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/clk.h>
+
 struct clk {
 	struct clk_core	*core;
 	const char *dev_id;
@@ -492,10 +495,12 @@ static void clk_unprepare_unused_subtree(struct clk_core *clk)
 		return;
 
 	if (clk_core_is_prepared(clk)) {
+		trace_clk_unprepare(clk);
 		if (clk->ops->unprepare_unused)
 			clk->ops->unprepare_unused(clk->hw);
 		else if (clk->ops->unprepare)
 			clk->ops->unprepare(clk->hw);
+		trace_clk_unprepare_complete(clk);
 	}
 }
 
@@ -524,10 +529,12 @@ static void clk_disable_unused_subtree(struct clk_core *clk)
 	 * back to .disable
 	 */
 	if (clk_core_is_enabled(clk)) {
+		trace_clk_disable(clk);
 		if (clk->ops->disable_unused)
 			clk->ops->disable_unused(clk->hw);
 		else if (clk->ops->disable)
 			clk->ops->disable(clk->hw);
+		trace_clk_disable_complete(clk);
 	}
 
 unlock_out:
@@ -907,9 +914,12 @@ static void clk_core_unprepare(struct clk_core *clk)
 
 	WARN_ON(clk->enable_count > 0);
 
+	trace_clk_unprepare(clk);
+
 	if (clk->ops->unprepare)
 		clk->ops->unprepare(clk->hw);
 
+	trace_clk_unprepare_complete(clk);
 	clk_core_unprepare(clk->parent);
 }
 
@@ -947,12 +957,16 @@ static int clk_core_prepare(struct clk_core *clk)
 		if (ret)
 			return ret;
 
-		if (clk->ops->prepare) {
+		trace_clk_prepare(clk);
+
+		if (clk->ops->prepare)
 			ret = clk->ops->prepare(clk->hw);
-			if (ret) {
-				clk_core_unprepare(clk->parent);
-				return ret;
-			}
+
+		trace_clk_prepare_complete(clk);
+
+		if (ret) {
+			clk_core_unprepare(clk->parent);
+			return ret;
 		}
 	}
 
@@ -999,9 +1013,13 @@ static void clk_core_disable(struct clk_core *clk)
 	if (--clk->enable_count > 0)
 		return;
 
+	trace_clk_disable(clk);
+
 	if (clk->ops->disable)
 		clk->ops->disable(clk->hw);
 
+	trace_clk_disable_complete(clk);
+
 	clk_core_disable(clk->parent);
 }
 
@@ -1054,12 +1072,16 @@ static int clk_core_enable(struct clk_core *clk)
 		if (ret)
 			return ret;
 
-		if (clk->ops->enable) {
+		trace_clk_enable(clk);
+
+		if (clk->ops->enable)
 			ret = clk->ops->enable(clk->hw);
-			if (ret) {
-				clk_core_disable(clk->parent);
-				return ret;
-			}
+
+		trace_clk_enable_complete(clk);
+
+		if (ret) {
+			clk_core_disable(clk->parent);
+			return ret;
 		}
 	}
 
@@ -1490,10 +1512,14 @@ static int __clk_set_parent(struct clk_core *clk, struct clk_core *parent,
 
 	old_parent = __clk_set_parent_before(clk, parent);
 
+	trace_clk_set_parent(clk, parent);
+
 	/* change clock input source */
 	if (parent && clk->ops->set_parent)
 		ret = clk->ops->set_parent(clk->hw, p_index);
 
+	trace_clk_set_parent_complete(clk, parent);
+
 	if (ret) {
 		flags = clk_enable_lock();
 		clk_reparent(clk, old_parent);
@@ -1719,6 +1745,7 @@ static void clk_change_rate(struct clk_core *clk)
 
 	if (clk->new_parent && clk->new_parent != clk->parent) {
 		old_parent = __clk_set_parent_before(clk, clk->new_parent);
+		trace_clk_set_parent(clk, clk->new_parent);
 
 		if (clk->ops->set_rate_and_parent) {
 			skip_set_rate = true;
@@ -1729,12 +1756,17 @@ static void clk_change_rate(struct clk_core *clk)
 			clk->ops->set_parent(clk->hw, clk->new_parent_index);
 		}
 
+		trace_clk_set_parent_complete(clk, clk->new_parent);
 		__clk_set_parent_after(clk, clk->new_parent, old_parent);
 	}
 
+	trace_clk_set_rate(clk, clk->new_rate);
+
 	if (!skip_set_rate && clk->ops->set_rate)
 		clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
 
+	trace_clk_set_rate_complete(clk, clk->new_rate);
+
 	clk->rate = clk_recalc(clk, best_parent_rate);
 
 	if (clk->notifier_count && old_rate != clk->rate)
@@ -2135,9 +2167,13 @@ int clk_set_phase(struct clk *clk, int degrees)
 
 	clk_prepare_lock();
 
+	trace_clk_set_phase(clk->core, degrees);
+
 	if (clk->core->ops->set_phase)
 		ret = clk->core->ops->set_phase(clk->core->hw, degrees);
 
+	trace_clk_set_phase_complete(clk->core, degrees);
+
 	if (!ret)
 		clk->core->phase = degrees;
 

include/trace/events/clk.h

@@ -0,0 +1,198 @@
+/*
+ * Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM clk
+
+#if !defined(_TRACE_CLK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CLK_H
+
+#include <linux/tracepoint.h>
+
+struct clk_core;
+
+DECLARE_EVENT_CLASS(clk,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core),
+
+	TP_STRUCT__entry(
+		__string(        name,           core->name       )
+	),
+
+	TP_fast_assign(
+		__assign_str(name, core->name);
+	),
+
+	TP_printk("%s", __get_str(name))
+);
+
+DEFINE_EVENT(clk, clk_enable,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_enable_complete,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_disable,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_disable_complete,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_prepare,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_prepare_complete,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_unprepare,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DEFINE_EVENT(clk, clk_unprepare_complete,
+
+	TP_PROTO(struct clk_core *core),
+
+	TP_ARGS(core)
+);
+
+DECLARE_EVENT_CLASS(clk_rate,
+
+	TP_PROTO(struct clk_core *core, unsigned long rate),
+
+	TP_ARGS(core, rate),
+
+	TP_STRUCT__entry(
+		__string(        name,           core->name                )
+		__field(unsigned long,           rate                      )
+	),
+
+	TP_fast_assign(
+		__assign_str(name, core->name);
+		__entry->rate = rate;
+	),
+
+	TP_printk("%s %lu", __get_str(name), (unsigned long)__entry->rate)
+);
+
+DEFINE_EVENT(clk_rate, clk_set_rate,
+
+	TP_PROTO(struct clk_core *core, unsigned long rate),
+
+	TP_ARGS(core, rate)
+);
+
+DEFINE_EVENT(clk_rate, clk_set_rate_complete,
+
+	TP_PROTO(struct clk_core *core, unsigned long rate),
+
+	TP_ARGS(core, rate)
+);
+
+DECLARE_EVENT_CLASS(clk_parent,
+
+	TP_PROTO(struct clk_core *core, struct clk_core *parent),
+
+	TP_ARGS(core, parent),
+
+	TP_STRUCT__entry(
+		__string(        name,           core->name                )
+		__string(        pname,          parent->name              )
+	),
+
+	TP_fast_assign(
+		__assign_str(name, core->name);
+		__assign_str(pname, parent->name);
+	),
+
+	TP_printk("%s %s", __get_str(name), __get_str(pname))
+);
+
+DEFINE_EVENT(clk_parent, clk_set_parent,
+
+	TP_PROTO(struct clk_core *core, struct clk_core *parent),
+
+	TP_ARGS(core, parent)
+);
+
+DEFINE_EVENT(clk_parent, clk_set_parent_complete,
+
+	TP_PROTO(struct clk_core *core, struct clk_core *parent),
+
+	TP_ARGS(core, parent)
+);
+
+DECLARE_EVENT_CLASS(clk_phase,
+
+	TP_PROTO(struct clk_core *core, int phase),
+
+	TP_ARGS(core, phase),
+
+	TP_STRUCT__entry(
+		__string(        name,           core->name                )
+		__field(	  int,           phase                     )
+	),
+
+	TP_fast_assign(
+		__assign_str(name, core->name);
+		__entry->phase = phase;
+	),
+
+	TP_printk("%s %d", __get_str(name), (int)__entry->phase)
+);
+
+DEFINE_EVENT(clk_phase, clk_set_phase,
+
+	TP_PROTO(struct clk_core *core, int phase),
+
+	TP_ARGS(core, phase)
+);
+
+DEFINE_EVENT(clk_phase, clk_set_phase_complete,
+
+	TP_PROTO(struct clk_core *core, int phase),
+
+	TP_ARGS(core, phase)
+);
+
+#endif /* _TRACE_CLK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>