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author | Linus Walleij <linus.walleij@linaro.org> | 2015-06-15 14:34:03 +0200 |
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committer | Linus Walleij <linus.walleij@linaro.org> | 2015-07-08 16:22:39 +0200 |
commit | 000bc17817bfe9e7d1fd59cec9e95f6b3638872f (patch) | |
tree | d65d9c92549d82cc5569278324ecadff6757b7a2 /arch/arm/mach-ep93xx | |
parent | 361c81f996707e122bffe95c5a3e6c47611b8a29 (diff) | |
download | linux-000bc17817bfe9e7d1fd59cec9e95f6b3638872f.tar.bz2 |
ARM: ep93xx: switch to GENERIC_CLOCKEVENTS
This switches the EP93xx to use GENERIC_CLOCKEVENTS and
CLKSRC_MMIO. Also implements a sched_clock() hook.
Tested on the SIM.ONE. Use only oneshot events.
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'arch/arm/mach-ep93xx')
-rw-r--r-- | arch/arm/mach-ep93xx/timer-ep93xx.c | 110 |
1 files changed, 70 insertions, 40 deletions
diff --git a/arch/arm/mach-ep93xx/timer-ep93xx.c b/arch/arm/mach-ep93xx/timer-ep93xx.c index 978252c52661..932236b348bc 100644 --- a/arch/arm/mach-ep93xx/timer-ep93xx.c +++ b/arch/arm/mach-ep93xx/timer-ep93xx.c @@ -1,5 +1,8 @@ #include <linux/kernel.h> #include <linux/init.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> +#include <linux/sched_clock.h> #include <linux/interrupt.h> #include <linux/irq.h> #include <linux/io.h> @@ -45,26 +48,68 @@ #define EP93XX_TIMER3_CONTROL EP93XX_TIMER_REG(0x88) #define EP93XX_TIMER3_CLEAR EP93XX_TIMER_REG(0x8c) -#define EP93XX_TIMER123_CLOCK 508469 -#define EP93XX_TIMER4_CLOCK 983040 +#define EP93XX_TIMER123_RATE 508469 +#define EP93XX_TIMER4_RATE 983040 -#define TIMER1_RELOAD ((EP93XX_TIMER123_CLOCK / HZ) - 1) -#define TIMER4_TICKS_PER_JIFFY DIV_ROUND_CLOSEST(EP93XX_TIMER4_CLOCK, HZ) +static u64 notrace ep93xx_read_sched_clock(void) +{ + u64 ret; + + ret = __raw_readl(EP93XX_TIMER4_VALUE_LOW); + ret |= ((u64) (__raw_readl(EP93XX_TIMER4_VALUE_HIGH) & 0xff) << 32); + return ret; +} + +cycle_t ep93xx_clocksource_read(struct clocksource *c) +{ + u64 ret; + + ret = __raw_readl(EP93XX_TIMER4_VALUE_LOW); + ret |= ((u64) (__raw_readl(EP93XX_TIMER4_VALUE_HIGH) & 0xff) << 32); + return (cycle_t) ret; +} + +static int ep93xx_clkevt_set_next_event(unsigned long next, + struct clock_event_device *evt) +{ + /* Default mode: periodic, off, 508 kHz */ + u32 tmode = EP93XX_TIMER123_CONTROL_MODE | + EP93XX_TIMER123_CONTROL_CLKSEL; + + /* Clear timer */ + __raw_writel(tmode, EP93XX_TIMER1_CONTROL); + + /* Set next event */ + __raw_writel(next, EP93XX_TIMER1_LOAD); + __raw_writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE, + EP93XX_TIMER1_CONTROL); + return 0; +} -static unsigned int last_jiffy_time; + +static void ep93xx_clkevt_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + /* Disable timer */ + __raw_writel(0, EP93XX_TIMER1_CONTROL); +} + +static struct clock_event_device ep93xx_clockevent = { + .name = "timer1", + .features = CLOCK_EVT_FEAT_ONESHOT, + .set_mode = ep93xx_clkevt_set_mode, + .set_next_event = ep93xx_clkevt_set_next_event, + .rating = 300, +}; static irqreturn_t ep93xx_timer_interrupt(int irq, void *dev_id) { + struct clock_event_device *evt = dev_id; + /* Writing any value clears the timer interrupt */ __raw_writel(1, EP93XX_TIMER1_CLEAR); - /* Recover lost jiffies */ - while ((signed long) - (__raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time) - >= TIMER4_TICKS_PER_JIFFY) { - last_jiffy_time += TIMER4_TICKS_PER_JIFFY; - timer_tick(); - } + evt->event_handler(evt); return IRQ_HANDLED; } @@ -73,40 +118,25 @@ static struct irqaction ep93xx_timer_irq = { .name = "ep93xx timer", .flags = IRQF_TIMER | IRQF_IRQPOLL, .handler = ep93xx_timer_interrupt, + .dev_id = &ep93xx_clockevent, }; -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; -} - 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); - __raw_writel(tmode | EP93XX_TIMER123_CONTROL_ENABLE, - EP93XX_TIMER1_CONTROL); - - /* Enable lost jiffy timer. */ + /* Enable and register clocksource and sched_clock on timer 4 */ __raw_writel(EP93XX_TIMER4_VALUE_HIGH_ENABLE, EP93XX_TIMER4_VALUE_HIGH); + clocksource_mmio_init(NULL, "timer4", + EP93XX_TIMER4_RATE, 200, 40, + ep93xx_clocksource_read); + sched_clock_register(ep93xx_read_sched_clock, 40, + EP93XX_TIMER4_RATE); + /* Set up clockevent on timer 1 */ setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq); + // FIXME: timer one is 16 bits 1-ffff use timer 3 1-ffffffff */ + clockevents_config_and_register(&ep93xx_clockevent, + EP93XX_TIMER123_RATE, + 1, + 0xffffU); } |