linux-kernel - [PATCH 5/5] clk: Get runtime PM before walking tree for clk

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Date: Sun, 24 Mar 2024 22:44:02 -0700
From: Stephen Boyd <sboyd@...nel.org>
To: Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	linux-clk@...r.kernel.org,
	patches@...ts.linux.dev,
	linux-arm-msm@...r.kernel.org,
	Taniya Das <quic_tdas@...cinc.com>,
	Douglas Anderson <dianders@...omium.org>
Subject: [PATCH 5/5] clk: Get runtime PM before walking tree for clk_summary

Similar to the previous commit, we should make sure that all devices are
runtime resumed before printing the clk_summary through debugfs. Failure
to do so would result in a deadlock if the thread is resuming a device
to print clk state and that device is also runtime resuming in another
thread, e.g the screen is turning on and the display driver is starting
up.

Fixes: 1bb294a7981c ("clk: Enable/Disable runtime PM for clk_summary")
Cc: Taniya Das <quic_tdas@...cinc.com>
Cc: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Stephen Boyd <sboyd@...nel.org>
---
 drivers/clk/clk.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 31998ca67b1e..10792599bec1 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3332,7 +3332,7 @@ static int clk_summary_show(struct seq_file *s, void *data)
 	seq_puts(s, "   clock                          count    count    count        rate   accuracy phase  cycle    enable   consumer                         id\n");
 	seq_puts(s, "---------------------------------------------------------------------------------------------------------------------------------------------\n");
 
-
+	clk_pm_runtime_get_all();
 	clk_prepare_lock();
 
 	for (; *lists; lists++)
@@ -3340,6 +3340,7 @@ static int clk_summary_show(struct seq_file *s, void *data)
 			clk_summary_show_subtree(s, c, 0);
 
 	clk_prepare_unlock();
+	clk_pm_runtime_put_all();
 
 	return 0;
 }
@@ -3389,6 +3390,8 @@ static int clk_dump_show(struct seq_file *s, void *data)
 	struct hlist_head **lists = s->private;
 
 	seq_putc(s, '{');
+
+	clk_pm_runtime_get_all();
 	clk_prepare_lock();
 
 	for (; *lists; lists++) {
@@ -3401,6 +3404,7 @@ static int clk_dump_show(struct seq_file *s, void *data)
 	}
 
 	clk_prepare_unlock();
+	clk_pm_runtime_put_all();
 
 	seq_puts(s, "}\n");
 	return 0;
-- 
https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git/
https://git.kernel.org/pub/scm/linux/kernel/git/sboyd/spmi.git