Commit c3391e36 authored by Ben Dooks's avatar Ben Dooks
Browse files

[ARM] S3C24XX: Change clock locking to use spinlocks. 



We cannot sleep if we have cpufreq pm enabled during some
of the clock operations, so change to use a spinlock to
protect the clock system.

Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent 30555476

arch/arm/plat-s3c24xx/clock.c

+18 −14
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ 
#include <linux/interrupt.h>

#include <linux/ioport.h>

#include <linux/clk.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>

#include <linux/delay.h>

#include <linux/io.h>
@@ -55,7 +55,11 @@ 


static LIST_HEAD(clocks);



DEFINE_MUTEX(clocks_mutex);

/* We originally used an mutex here, but some contexts (see resume)

 * are calling functions such as clk_set_parent() with IRQs disabled

 * causing an BUG to be triggered.

 */

DEFINE_SPINLOCK(clocks_lock);



/* enable and disable calls for use with the clk struct */
@@ -77,7 +81,7 @@ struct clk *clk_get(struct device *dev, const char *id) 
	else

		idno = to_platform_device(dev)->id;



	mutex_lock(&clocks_mutex);

	spin_lock(&clocks_lock);



	list_for_each_entry(p, &clocks, list) {

		if (p->id == idno &&
@@ -101,7 +105,7 @@ struct clk *clk_get(struct device *dev, const char *id) 
		}

	}



	mutex_unlock(&clocks_mutex);

	spin_unlock(&clocks_lock);

	return clk;

}
@@ -117,12 +121,12 @@ int clk_enable(struct clk *clk) 


	clk_enable(clk->parent);



	mutex_lock(&clocks_mutex);

	spin_lock(&clocks_lock);



	if ((clk->usage++) == 0)

		(clk->enable)(clk, 1);



	mutex_unlock(&clocks_mutex);

	spin_unlock(&clocks_lock);

	return 0;

}
@@ -131,12 +135,12 @@ void clk_disable(struct clk *clk) 
	if (IS_ERR(clk) || clk == NULL)

		return;



	mutex_lock(&clocks_mutex);

	spin_lock(&clocks_lock);



	if ((--clk->usage) == 0)

		(clk->enable)(clk, 0);



	mutex_unlock(&clocks_mutex);

	spin_unlock(&clocks_lock);

	clk_disable(clk->parent);

}
@@ -182,9 +186,9 @@ int clk_set_rate(struct clk *clk, unsigned long rate) 
	if (clk->set_rate == NULL)

		return -EINVAL;



	mutex_lock(&clocks_mutex);

	spin_lock(&clocks_lock);

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

	mutex_unlock(&clocks_mutex);

	spin_unlock(&clocks_lock);



	return ret;

}
@@ -201,12 +205,12 @@ int clk_set_parent(struct clk *clk, struct clk *parent) 
	if (IS_ERR(clk))

		return -EINVAL;



	mutex_lock(&clocks_mutex);

	spin_lock(&clocks_lock);



	if (clk->set_parent)

		ret = (clk->set_parent)(clk, parent);



	mutex_unlock(&clocks_mutex);

	spin_unlock(&clocks_lock);



	return ret;

}
@@ -302,9 +306,9 @@ int s3c24xx_register_clock(struct clk *clk) 


	/* add to the list of available clocks */



	mutex_lock(&clocks_mutex);

	spin_lock(&clocks_lock);

	list_add(&clk->list, &clocks);

	mutex_unlock(&clocks_mutex);

	spin_unlock(&clocks_lock);



	return 0;

}

arch/arm/plat-s3c24xx/include/plat/clock.h

+3 −1
Original line number Diff line number Diff line
@@ -10,6 +10,8 @@ 
 * published by the Free Software Foundation.

*/



#include <linux/spinlock.h>



struct clk {

	struct list_head      list;

	struct module        *owner;
@@ -51,7 +53,7 @@ extern struct clk clk_xtal; 
 * Please DO NOT use these outside of arch/arm/mach-s3c2410

*/



extern struct mutex clocks_mutex;

extern spinlock_t clocks_lock;



extern int s3c2410_clkcon_enable(struct clk *clk, int enable);

arch/arm/plat-s3c24xx/s3c244x-clock.c

+2 −3
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ 
#include <linux/sysdev.h>

#include <linux/interrupt.h>

#include <linux/ioport.h>

#include <linux/mutex.h>

#include <linux/clk.h>

#include <linux/io.h>
@@ -102,13 +101,13 @@ static int s3c244x_clk_add(struct sys_device *sysdev) 
	if (clk_get_rate(clock_upll) > (94 * MHZ)) {

		clk_usb_bus.rate = clk_get_rate(clock_upll) / 2;



		mutex_lock(&clocks_mutex);

		spin_lock(&clocks_lock);



		clkdivn = __raw_readl(S3C2410_CLKDIVN);

		clkdivn |= S3C2440_CLKDIVN_UCLK;

		__raw_writel(clkdivn, S3C2410_CLKDIVN);



		mutex_unlock(&clocks_mutex);

		spin_unlock(&clocks_lock);

	}



	return 0;