linux-kernel - [PATCH] clk: Fix CLK_SET_RATE_GATE flag validation in clk_set

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Message-Id: <1337114622-11292-1-git-send-email-skannan@codeaurora.org>
Date:	Tue, 15 May 2012 13:43:42 -0700
From:	Saravana Kannan <skannan@...eaurora.org>
To:	linux-arm-kernel@...ts.infradead.org,
	Mike Turquette <mturquette@...aro.org>,
	Paul Walmsley <paul@...an.com>,
	Shawn Guo <shawn.guo@...escale.com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Rob Herring <rob.herring@...xeda.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Russell King <linux@....linux.org.uk>
Cc:	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	Andrew Lunn <andrew@...n.ch>,
	Jeremy Kerr <jeremy.kerr@...onical.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Arnd Bergman <arnd.bergmann@...aro.org>,
	Jamie Iles <jamie@...ieiles.com>,
	Richard Zhao <richard.zhao@...aro.org>,
	Magnus Damm <magnus.damm@...il.com>,
	Linus Walleij <linus.walleij@...ricsson.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Amit Kucheria <amit.kucheria@...aro.org>,
	Deepak Saxena <dsaxena@...aro.org>,
	Grant Likely <grant.likely@...retlab.ca>
Subject: [PATCH] clk: Fix CLK_SET_RATE_GATE flag validation in clk_set_rate().

The clk_set_rate() code shouldn't check the clock's enable count when
validating CLK_SET_RATE_GATE flag since the enable count could change after
the validation. Similar to clk_set_parent(), it should instead check the
prepare count. The prepare count should go to zero only when the end user
expects the clock to not be enabled in the future. Since the code already
grabs the prepare count before validation, it's not possible for prepare
count to change after validation and by association not possible for a well
behaving end user to enable the clock while the set rate is in progress.

Signed-off-by: Saravana Kannan <skannan@...eaurora.org>
---
Please let me know if you don't want me to directly email or CC you in my
clock related patches. I don't want to spam anyone. Also, let me know if
you want me add you to my standard list of people to cc in my clock
patches.

 drivers/clk/clk.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 09b9112..f5b9d3c 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -903,7 +903,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
 	if (rate == clk->rate)
 		goto out;
 
-	if ((clk->flags & CLK_SET_RATE_GATE) && __clk_is_enabled(clk)) {
+	if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
 		ret = -EBUSY;
 		goto out;
 	}
-- 
1.7.8.3

Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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