diff options
Diffstat (limited to 'arch/arm/mach-ep93xx')
| -rw-r--r-- | arch/arm/mach-ep93xx/core.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c index e85bf17f2d2a..6f48b87a1ace 100644 --- a/arch/arm/mach-ep93xx/core.c +++ b/arch/arm/mach-ep93xx/core.c @@ -140,11 +140,29 @@ static struct irqaction ep93xx_timer_irq = { .handler = ep93xx_timer_interrupt, }; +static u32 ep93xx_gettimeoffset(void) +{ + int offset; + + offset = __raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time; + + /* + * Timer 4 is based on a 983.04 kHz reference clock, + * so dividing by 983040 gives the fraction of a second, + * so dividing by 0.983040 converts to uS. + * Refactor the calculation to avoid overflow. + * Finally, multiply by 1000 to give nS. + */ + return (offset + (53 * offset / 3072)) * 1000; +} + static void __init ep93xx_timer_init(void) { u32 tmode = EP93XX_TIMER123_CONTROL_MODE | EP93XX_TIMER123_CONTROL_CLKSEL; + arch_gettimeoffset = ep93xx_gettimeoffset; + /* Enable periodic HZ timer. */ __raw_writel(tmode, EP93XX_TIMER1_CONTROL); __raw_writel(TIMER1_RELOAD, EP93XX_TIMER1_LOAD); @@ -158,19 +176,8 @@ static void __init ep93xx_timer_init(void) setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq); } -static unsigned long ep93xx_gettimeoffset(void) -{ - int offset; - - offset = __raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time; - - /* Calculate (1000000 / 983040) * offset. */ - return offset + (53 * offset / 3072); -} - struct sys_timer ep93xx_timer = { .init = ep93xx_timer_init, - .offset = ep93xx_gettimeoffset, }; |