[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: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Ben Dooks 2008-10-21 14:06:37 +01:00
parent 3055547680
commit c3391e36d6
3 changed files with 23 additions and 18 deletions

View file

@ -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;
}

View file

@ -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);

View file

@ -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;