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Commit b8451862 authored by Roland Stigge's avatar Roland Stigge Committed by Olof Johansson
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ARM: LPC32xx: clock.c: Fix mutex lock issues 



This patch fixes the mutex issue in clock.c, as done in Kevin Wells' original
driver update:

In some cases, the clock drivers could grab a mutex twice in an improper
context. This patch changes the mutex mechanism to a simple irq lock/unlock
mechanism and removes un-needed locks from some functions.

(See also git.lpclinux.com)

Signed-off-by: default avatarRoland Stigge <stigge@antcom.de>
Tested-by: default avatarWolfram Sang <w.sang@pengutronix.de>
Acked-by: default avatarKevin Wells <kevin.wells@nxp.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
parent 0cf0d815

arch/arm/mach-lpc32xx/clock.c

+11 −30
Original line number Diff line number Diff line
@@ -97,9 +97,10 @@ 
#include "clock.h"

#include "common.h"



static DEFINE_SPINLOCK(global_clkregs_lock);



static struct clk clk_armpll;

static struct clk clk_usbpll;

static DEFINE_MUTEX(clkm_lock);



/*

 * Post divider values for PLLs based on selected register value
@@ -891,16 +892,6 @@ static struct clk clk_lcd = { 
	.enable_mask	= LPC32XX_CLKPWR_LCDCTRL_CLK_EN,

};



static inline void clk_lock(void)

{

	mutex_lock(&clkm_lock);

}



static inline void clk_unlock(void)

{

	mutex_unlock(&clkm_lock);

}



static void local_clk_disable(struct clk *clk)

{

	/* Don't attempt to disable clock if it has no users */
@@ -945,10 +936,11 @@ static int local_clk_enable(struct clk *clk) 
int clk_enable(struct clk *clk)

{

	int ret;

	unsigned long flags;



	clk_lock();

	spin_lock_irqsave(&global_clkregs_lock, flags);

	ret = local_clk_enable(clk);

	clk_unlock();

	spin_unlock_irqrestore(&global_clkregs_lock, flags);



	return ret;

}
@@ -959,9 +951,11 @@ EXPORT_SYMBOL(clk_enable); 
 */

void clk_disable(struct clk *clk)

{

	clk_lock();

	unsigned long flags;



	spin_lock_irqsave(&global_clkregs_lock, flags);

	local_clk_disable(clk);

	clk_unlock();

	spin_unlock_irqrestore(&global_clkregs_lock, flags);

}

EXPORT_SYMBOL(clk_disable);
@@ -970,13 +964,7 @@ EXPORT_SYMBOL(clk_disable); 
 */

unsigned long clk_get_rate(struct clk *clk)

{

	unsigned long rate;



	clk_lock();

	rate = clk->get_rate(clk);

	clk_unlock();



	return rate;

	return clk->get_rate(clk);

}

EXPORT_SYMBOL(clk_get_rate);
@@ -992,11 +980,8 @@ int clk_set_rate(struct clk *clk, unsigned long rate) 
	 * the actual rate set as part of the peripheral dividers

	 * instead of high level clock control

	 */

	if (clk->set_rate) {

		clk_lock();

	if (clk->set_rate)

		ret = clk->set_rate(clk, rate);

		clk_unlock();

	}



	return ret;

}
@@ -1007,15 +992,11 @@ EXPORT_SYMBOL(clk_set_rate); 
 */

long clk_round_rate(struct clk *clk, unsigned long rate)

{

	clk_lock();



	if (clk->round_rate)

		rate = clk->round_rate(clk, rate);

	else

		rate = clk->get_rate(clk);



	clk_unlock();



	return rate;

}

EXPORT_SYMBOL(clk_round_rate);