[PATCH] clk: Add tracepoints for hardware operations

From: Stephen Boyd
Date: Mon Jun 30 2014 - 19:56:53 EST

It's useful to have tracepoints around operations that change the
hardware state so that we can debug clock hardware performance
and operations. Three 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_rate() and parent changing events for clk_set_parent().

Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---

I see that there are tracepoints for clock_enable/clock_set_rate
in events/power.h but those look to be unused and they also
take cpu_id which seems odd. I'd rather we just make a new set of
events for the common clock framework instead and add the "_complete"
set of events so we know when things have completed.

drivers/clk/clk.c | 28 ++++++++
include/trace/events/clk.h | 165 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 193 insertions(+)
create mode 100644 include/trace/events/clk.h

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 8b73edef151d..f8bf69df3210 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -21,6 +21,9 @@
#include <linux/init.h>
#include <linux/sched.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/clk.h>
+
#include "clk.h"

static DEFINE_SPINLOCK(enable_lock);
@@ -483,10 +486,12 @@ static void clk_unprepare_unused_subtree(struct clk *clk)
return;

if (__clk_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);
}
}

@@ -516,10 +521,12 @@ static void clk_disable_unused_subtree(struct clk *clk)
* back to .disable
*/
if (__clk_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:
@@ -802,9 +809,13 @@ void __clk_unprepare(struct clk *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_unprepare(clk->parent);
}

@@ -842,6 +853,8 @@ int __clk_prepare(struct clk *clk)
if (ret)
return ret;

+ trace_clk_prepare(clk);
+
if (clk->ops->prepare) {
ret = clk->ops->prepare(clk->hw);
if (ret) {
@@ -849,6 +862,8 @@ int __clk_prepare(struct clk *clk)
return ret;
}
}
+
+ trace_clk_prepare_complete(clk);
}

clk->prepare_count++;
@@ -891,9 +906,13 @@ static void __clk_disable(struct clk *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_disable(clk->parent);
}

@@ -938,6 +957,7 @@ static int __clk_enable(struct clk *clk)
if (ret)
return ret;

+ trace_clk_enable(clk);
if (clk->ops->enable) {
ret = clk->ops->enable(clk->hw);
if (ret) {
@@ -945,6 +965,7 @@ static int __clk_enable(struct clk *clk)
return ret;
}
}
+ trace_clk_enable_complete(clk);
}

clk->enable_count++;
@@ -1241,6 +1262,8 @@ static struct clk *__clk_set_parent_before(struct clk *clk, struct clk *parent)
unsigned long flags;
struct clk *old_parent = clk->parent;

+ trace_clk_set_parent(clk, parent);
+
/*
* Migrate prepare state between parents and prevent race with
* clk_enable().
@@ -1285,6 +1308,7 @@ static void __clk_set_parent_after(struct clk *clk, struct clk *parent,
__clk_unprepare(old_parent);
}

+ trace_clk_set_parent_complete(clk, parent);
/* update debugfs with new clk tree topology */
clk_debug_reparent(clk, parent);
}
@@ -1507,6 +1531,8 @@ static void clk_change_rate(struct clk *clk)
else if (clk->parent)
best_parent_rate = clk->parent->rate;

+ trace_clk_set_rate(clk, clk->new_rate);
+
if (clk->new_parent && clk->new_parent != clk->parent) {
old_parent = __clk_set_parent_before(clk, clk->new_parent);

@@ -1525,6 +1551,8 @@ static void clk_change_rate(struct clk *clk)
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)
diff --git a/include/trace/events/clk.h b/include/trace/events/clk.h
new file mode 100644
index 000000000000..8523adce0f73
--- /dev/null
+++ b/include/trace/events/clk.h
@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 2014, 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;
+
+DECLARE_EVENT_CLASS(clk,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk),
+
+ TP_STRUCT__entry(
+ __string( name, __clk_get_name(clk) )
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, __clk_get_name(clk));
+ ),
+
+ TP_printk("%s", __get_str(name))
+);
+
+DEFINE_EVENT(clk, clk_enable,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_enable_complete,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_disable,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_disable_complete,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_prepare,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_prepare_complete,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_unprepare,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DEFINE_EVENT(clk, clk_unprepare_complete,
+
+ TP_PROTO(struct clk *clk),
+
+ TP_ARGS(clk)
+);
+
+DECLARE_EVENT_CLASS(clk_rate,
+
+ TP_PROTO(struct clk *clk, unsigned long rate),
+
+ TP_ARGS(clk, rate),
+
+ TP_STRUCT__entry(
+ __string( name, __clk_get_name(clk) )
+ __field(unsigned long, rate )
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, __clk_get_name(clk));
+ __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 *clk, unsigned long rate),
+
+ TP_ARGS(clk, rate)
+);
+
+DEFINE_EVENT(clk_rate, clk_set_rate_complete,
+
+ TP_PROTO(struct clk *clk, unsigned long rate),
+
+ TP_ARGS(clk, rate)
+);
+
+DECLARE_EVENT_CLASS(clk_parent,
+
+ TP_PROTO(struct clk *clk, struct clk *parent),
+
+ TP_ARGS(clk, parent),
+
+ TP_STRUCT__entry(
+ __string( name, __clk_get_name(clk) )
+ __string( pname, __clk_get_name(parent) )
+ ),
+
+ TP_fast_assign(
+ __assign_str(name, __clk_get_name(clk));
+ __assign_str(pname, __clk_get_name(parent));
+ ),
+
+ TP_printk("%s %s", __get_str(name), __get_str(pname))
+);
+
+DEFINE_EVENT(clk_parent, clk_set_parent,
+
+ TP_PROTO(struct clk *clk, struct clk *parent),
+
+ TP_ARGS(clk, parent)
+);
+
+DEFINE_EVENT(clk_parent, clk_set_parent_complete,
+
+ TP_PROTO(struct clk *clk, struct clk *parent),
+
+ TP_ARGS(clk, parent)
+);
+
+#endif /* _TRACE_CLK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
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