linux-kernel - [RFC PATCH] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate

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Date:	Sun, 10 Jul 2016 21:55:56 -0700
From:	<jiada_wang@...tor.com>
To:	<mturquette@...libre.com>, <sboyd@...eaurora.org>,
	<linux-clk@...r.kernel.org>
CC:	<linux-kernel@...r.kernel.org>, <joshua_frkuska@...tor.com>,
	<vladimir_zapolskiy@...tor.com>, <jiada_wang@...tor.com>
Subject: [RFC PATCH] clk: move check of CLK_SET_RATE_GATE flag to clk_propagate_rate_change()

From: Jiada Wang <jiada_wang@...tor.com>

Previously CLK_SET_RATE_GATE flag is only checked in clk_set_rate()
which only ensures the clock being called by clk_set_rate() won't
change rate when it has been prepared if CLK_SET_RATE_GATE flag is set.
But a clk_set_rate() request may propagate rate change to these clocks
from the requested clock's topmost parent clock to all its offsprings,
when any one of these clocks has CLK_SET_RATE_GATE flag set
and it has been prepared, the clk_set_rate() request should fail.

This patch moves check of CLK_SET_RATE_GATE flag to
clk_propagate_rate_change() to ensure all affected clocks will
be checked if their rate will be changed after clk_set_rate().

Signed-off-by: Jiada Wang <jiada_wang@...tor.com>
---
 drivers/clk/clk.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 820a939..aa5e4c3 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1437,6 +1437,9 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core,
 	if (core->rate == core->new_rate)
 		return NULL;

+	if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
+		return -EBUSY;
+
 	if (core->notifier_count) {
 		ret = __clk_notify(core, event, core->rate, core->new_rate);
 		if (ret & NOTIFY_STOP_MASK)
@@ -1571,9 +1574,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core,
 	if (rate == clk_core_get_rate_nolock(core))
 		return 0;

-	if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count)
-		return -EBUSY;
-
 	/* calculate new rates and get the topmost changed clock */
 	top = clk_calc_new_rates(core, rate);
 	if (!top)
-- 
1.7.9.5