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 --- cpu/arm920t/ep93xx/timer.c | 52 ++++++++++++++++++++----------------------- 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 */