/**
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 *
 * \author Francesco Sacchi <batt@develer.com>
 *
 * \brief Low-level timer module for Atmel AT91 (inplementation).
 */

#include "timer_at91.h"
#include <io/arm.h>
#include "sysirq_at91.h"

#include <cfg/macros.h> // BV()
#include <cfg/module.h>
#include <cpu/irq.h>
#include <cpu/types.h>


/** HW dependent timer initialization  */
#if (CONFIG_TIMER == TIMER_ON_PIT)

	ISR_PROTO_CONTEXT_SWITCH(timer_handler);

	void timer_hw_init(void)
	{
		sysirq_init();

		cpu_flags_t flags;

		MOD_CHECK(sysirq);

		IRQ_SAVE_DISABLE(flags);

		PIT_MR = TIMER_HW_CNT;
		/* Register system interrupt handler. */
		sysirq_setHandler(SYSIRQ_PIT, timer_handler);

		/* Enable interval timer and interval timer interrupts */
		PIT_MR |= BV(PITEN);
		sysirq_setEnable(SYSIRQ_PIT, true);

		/* Reset counters, this is needed to start timer and interrupt flags */
		uint32_t dummy = PIVR;
		(void) dummy;

		IRQ_RESTORE(flags);
	}

#else
	#error Unimplemented value for CONFIG_TIMER
#endif /* CONFIG_TIMER */