[ARM] 3303/1: S3C24XX - add clock enable usage counting
Patch from Ben Dooks
Move to using an enable count for the shared clocks
and protect the clock system using a mutex instead
of just disabling IRQs during the clock update.
Since there is little more code in the path for
non-shared clocks, the enable and disable calls
use the same code for each.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-s3c2410/clock.c b/arch/arm/mach-s3c2410/clock.c
index af2f3d5..08489ef 100644
--- a/arch/arm/mach-s3c2410/clock.c
+++ b/arch/arm/mach-s3c2410/clock.c
@@ -40,7 +40,6 @@
#include <linux/mutex.h>
#include <asm/hardware.h>
-#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/io.h>
@@ -59,22 +58,18 @@
void inline s3c24xx_clk_enable(unsigned int clocks, unsigned int enable)
{
unsigned long clkcon;
- unsigned long flags;
-
- local_irq_save(flags);
clkcon = __raw_readl(S3C2410_CLKCON);
- clkcon &= ~clocks;
if (enable)
clkcon |= clocks;
+ else
+ clkcon &= ~clocks;
/* ensure none of the special function bits set */
clkcon &= ~(S3C2410_CLKCON_IDLE|S3C2410_CLKCON_POWER);
__raw_writel(clkcon, S3C2410_CLKCON);
-
- local_irq_restore(flags);
}
/* enable and disable calls for use with the clk struct */
@@ -138,16 +133,32 @@
int clk_enable(struct clk *clk)
{
- if (IS_ERR(clk))
+ if (IS_ERR(clk) || clk == NULL)
return -EINVAL;
- return (clk->enable)(clk, 1);
+ clk_enable(clk->parent);
+
+ mutex_lock(&clocks_mutex);
+
+ if ((clk->usage++) == 0)
+ (clk->enable)(clk, 1);
+
+ mutex_unlock(&clocks_mutex);
+ return 0;
}
void clk_disable(struct clk *clk)
{
- if (!IS_ERR(clk))
+ if (IS_ERR(clk) || clk == NULL)
+ return;
+
+ mutex_lock(&clocks_mutex);
+
+ if ((--clk->usage) == 0)
(clk->enable)(clk, 0);
+
+ mutex_unlock(&clocks_mutex);
+ clk_disable(clk->parent);
}
@@ -361,6 +372,14 @@
if (clk->enable == NULL)
clk->enable = clk_null_enable;
+ /* if this is a standard clock, set the usage state */
+
+ if (clk->ctrlbit) {
+ unsigned long clkcon = __raw_readl(S3C2410_CLKCON);
+
+ clk->usage = (clkcon & clk->ctrlbit) ? 1 : 0;
+ }
+
/* add to the list of available clocks */
mutex_lock(&clocks_mutex);
@@ -402,6 +421,8 @@
* the LCD clock if it is not needed.
*/
+ mutex_lock(&clocks_mutex);
+
s3c24xx_clk_enable(S3C2410_CLKCON_NAND, 0);
s3c24xx_clk_enable(S3C2410_CLKCON_USBH, 0);
s3c24xx_clk_enable(S3C2410_CLKCON_USBD, 0);
@@ -409,6 +430,8 @@
s3c24xx_clk_enable(S3C2410_CLKCON_IIC, 0);
s3c24xx_clk_enable(S3C2410_CLKCON_SPI, 0);
+ mutex_unlock(&clocks_mutex);
+
/* assume uart clocks are correctly setup */
/* register our clocks */