embox

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/**
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 * @file
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 * @brief Core clocking device in Cortex ARM-M
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 *
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 * @date 25.03.2014
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 * @author Anton Kozlov
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 */
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#include <errno.h>
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#include <hal/clock.h>
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#include <hal/system.h>
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#include <arm/exception.h>
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#include <kernel/irq.h>
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#include <kernel/time/clock_source.h>
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#include <hal/reg.h>
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#include <embox/unit.h>
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#define CLOCK_DIVIDER 1
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#define SYSTICK_IRQ 15
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#include <module/embox/arch/arm/cmsis.h>
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static irq_return_t cmsis_systick_clock_handler(unsigned int irq_nr, void *data) {
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	struct clock_source *cs = data;
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	clock_tick_handler(data);
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	if (cs->event_device->flags & CLOCK_EVENT_ONESHOT_MODE) {
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		/* Systick do not support one-shot mode, so we do
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		 * it by shutting Systick down. */
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		REG_STORE(SysTick->CTRL, 0);
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		REG_STORE(SysTick->VAL, 0);
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	}
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	return IRQ_HANDLED;
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}
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static int cmsis_systick_set_periodic(struct clock_source *cs) {
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	int reload = SYS_CLOCK / (CLOCK_DIVIDER * 1000);
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	return 0 == SysTick_Config(reload) ? 0 : -EINVAL;
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}
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static struct time_event_device cmsis_systick_event = {
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	.set_periodic = cmsis_systick_set_periodic,
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	.irq_nr = SYSTICK_IRQ,
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};
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#if 0
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static cycle_t this_read(struct clock_source *cs) {
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	return 0;
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}
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static struct time_counter_device this_counter = {
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	.read = this_read,
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	.cycles_hz = SYS_CLOCK / CLOCK_DIVIDER,
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};
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#endif
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CLOCK_SOURCE_DEF(cmsis_systick, NULL, NULL,
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	&cmsis_systick_event, NULL);
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STATIC_EXC_ATTACH(SYSTICK_IRQ, cmsis_systick_clock_handler,  &CLOCK_SOURCE_NAME(cmsis_systick));
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