[PATCH v4 3/4] clocksource: orion: Use atomic access for shared registers

From: Ezequiel Garcia
Date: Sat Aug 24 2013 - 11:35:58 EST


Replace the driver-specific thread-safe shared register API
by the recently introduced atomic_io_modify().

Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxxxxxxxxxx>
---
drivers/clocksource/time-orion.c | 29 +++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/drivers/clocksource/time-orion.c b/drivers/clocksource/time-orion.c
index ecbeb68..f69f697 100644
--- a/drivers/clocksource/time-orion.c
+++ b/drivers/clocksource/time-orion.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
+#include <linux/io.h>
#include <linux/spinlock.h>
#include <asm/sched_clock.h>

@@ -35,20 +36,6 @@
#define ORION_ONESHOT_MAX 0xfffffffe

static void __iomem *timer_base;
-static DEFINE_SPINLOCK(timer_ctrl_lock);
-
-/*
- * Thread-safe access to TIMER_CTRL register
- * (shared with watchdog timer)
- */
-void orion_timer_ctrl_clrset(u32 clr, u32 set)
-{
- spin_lock(&timer_ctrl_lock);
- writel((readl(timer_base + TIMER_CTRL) & ~clr) | set,
- timer_base + TIMER_CTRL);
- spin_unlock(&timer_ctrl_lock);
-}
-EXPORT_SYMBOL(orion_timer_ctrl_clrset);

/*
* Free-running clocksource handling.
@@ -68,7 +55,8 @@ static int orion_clkevt_next_event(unsigned long delta,
{
/* setup and enable one-shot timer */
writel(delta, timer_base + TIMER1_VAL);
- orion_timer_ctrl_clrset(TIMER1_RELOAD_EN, TIMER1_EN);
+ atomic_io_modify(timer_base + TIMER_CTRL,
+ TIMER1_RELOAD_EN | TIMER1_EN, TIMER1_EN);

return 0;
}
@@ -80,10 +68,13 @@ static void orion_clkevt_mode(enum clock_event_mode mode,
/* setup and enable periodic timer at 1/HZ intervals */
writel(ticks_per_jiffy - 1, timer_base + TIMER1_RELOAD);
writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL);
- orion_timer_ctrl_clrset(0, TIMER1_RELOAD_EN | TIMER1_EN);
+ atomic_io_modify(timer_base + TIMER_CTRL,
+ TIMER1_RELOAD_EN | TIMER1_EN,
+ TIMER1_RELOAD_EN | TIMER1_EN);
} else {
/* disable timer */
- orion_timer_ctrl_clrset(TIMER1_RELOAD_EN | TIMER1_EN, 0);
+ atomic_io_modify(timer_base + TIMER_CTRL,
+ TIMER1_RELOAD_EN | TIMER1_EN, 0);
}
}

@@ -131,7 +122,9 @@ static void __init orion_timer_init(struct device_node *np)
/* setup timer0 as free-running clocksource */
writel(~0, timer_base + TIMER0_VAL);
writel(~0, timer_base + TIMER0_RELOAD);
- orion_timer_ctrl_clrset(0, TIMER0_RELOAD_EN | TIMER0_EN);
+ atomic_io_modify(timer_base + TIMER_CTRL,
+ TIMER0_RELOAD_EN | TIMER0_EN,
+ TIMER0_RELOAD_EN | TIMER0_EN);
clocksource_mmio_init(timer_base + TIMER0_VAL, "orion_clocksource",
clk_get_rate(clk), 300, 32,
clocksource_mmio_readl_down);
--
1.8.1.5

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