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authorMatthias Kaehlcke <matthias@kaehlcke.net>2010-03-09 22:13:56 +0100
committertrix <trix@windriver.com>2010-04-03 15:24:26 -0500
commitb032698ff687034286c98c09fd4830d804cd1786 (patch)
treee93108dafef991a0f74aa816dea100d3b038517e /cpu/arm920t
parent33eef04bf8541f7b15d4f694ad10f9b912b9caa6 (diff)
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ep93xx timer: refactoring
ep93xx timer: Simplified the timer code by eliminating clk_to_systicks() and performing (almost) all manipulation of the timer structure in read_timer() Signed-off-by: Matthias Kaehlcke <matthias@kaehlcke.net>
Diffstat (limited to 'cpu/arm920t')
-rw-r--r--cpu/arm920t/ep93xx/timer.c52
1 files changed, 24 insertions, 28 deletions
diff --git a/cpu/arm920t/ep93xx/timer.c b/cpu/arm920t/ep93xx/timer.c
index 943f193..4a0ce4d 100644
--- a/cpu/arm920t/ep93xx/timer.c
+++ b/cpu/arm920t/ep93xx/timer.c
@@ -1,8 +1,7 @@
/*
* Cirrus Logic EP93xx timer support.
*
- * Copyright (C) 2009, 2010
- * Matthias Kaehlcke <matthias@kaehlcke.net>
+ * Copyright (C) 2009, 2010 Matthias Kaehlcke <matthias@kaehlcke.net>
*
* Copyright (C) 2004, 2005
* Cory T. Tusar, Videon Central, Inc., <ctusar@videon-central.com>
@@ -42,17 +41,9 @@
static struct ep93xx_timer
{
unsigned long long ticks;
- unsigned long last_update;
+ unsigned long last_read;
} timer;
-static inline unsigned long clk_to_systicks(unsigned long long clk_ticks)
-{
- unsigned long long sys_ticks = (clk_ticks * CONFIG_SYS_HZ);
- do_div(sys_ticks, TIMER_FREQ);
-
- return (unsigned long)sys_ticks;
-}
-
static inline unsigned long long usecs_to_ticks(unsigned long usecs)
{
unsigned long long ticks = (unsigned long long)usecs * TIMER_FREQ;
@@ -61,11 +52,18 @@ static inline unsigned long long usecs_to_ticks(unsigned long usecs)
return ticks;
}
-static inline unsigned long read_timer(void)
+static inline void read_timer(void)
{
struct timer_regs *timer_regs = (struct timer_regs *)TIMER_BASE;
+ const unsigned long now = TIMER_MAX_VAL - readl(&timer_regs->timer3.value);
+
+ if (now >= timer.last_read)
+ timer.ticks += now - timer.last_read;
+ else
+ /* an overflow occurred */
+ timer.ticks += TIMER_MAX_VAL - timer.last_read + now;
- return TIMER_MAX_VAL - readl(&timer_regs->timer3.value);
+ timer.last_read = now;
}
/*
@@ -73,17 +71,14 @@ static inline unsigned long read_timer(void)
*/
unsigned long long get_ticks(void)
{
- const unsigned long now = read_timer();
+ unsigned long long sys_ticks;
- if (now >= timer.last_update)
- timer.ticks += now - timer.last_update;
- else
- /* an overflow occurred */
- timer.ticks += TIMER_MAX_VAL - timer.last_update + now;
+ read_timer();
- timer.last_update = now;
+ sys_ticks = timer.ticks * CONFIG_SYS_HZ;
+ do_div(sys_ticks, TIMER_FREQ);
- return clk_to_systicks(timer.ticks);
+ return sys_ticks;
}
unsigned long get_timer_masked(void)
@@ -98,7 +93,7 @@ unsigned long get_timer(unsigned long base)
void reset_timer_masked(void)
{
- timer.last_update = read_timer();
+ read_timer();
timer.ticks = 0;
}
@@ -109,23 +104,24 @@ void reset_timer(void)
void __udelay(unsigned long usec)
{
- /* read the timer and update timer.ticks */
- get_ticks();
+ unsigned long long target;
+
+ read_timer();
- const unsigned long long target = timer.ticks + usecs_to_ticks(usec);
+ target = timer.ticks + usecs_to_ticks(usec);
while (timer.ticks < target)
- get_ticks();
+ read_timer();
}
int timer_init(void)
{
struct timer_regs *timer_regs = (struct timer_regs *)TIMER_BASE;
- /* use timer 3 with 508KHz and free running */
+ /* use timer 3 with 508KHz and free running, not enabled now */
writel(TIMER_CLKSEL, &timer_regs->timer3.control);
- /* set initial timer value 3 */
+ /* set initial timer value */
writel(TIMER_MAX_VAL, &timer_regs->timer3.load);
/* Enable the timer */