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/*
* Copyright (c) 2011 Sebastian Huber. All rights reserved.
*
* embedded brains GmbH
* Obere Lagerstr. 30
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#include <rtems.h>
#include <rtems/score/armv7m.h>
/* This is defined in ../../../shared/clockdrv_shell.h */
rtems_isr Clock_isr(rtems_vector_number vector);
static uint64_t _ARMV7M_Systick_factor;
static void _ARMV7M_Systick_at_tick(void)
{
volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
/* Clear COUNTFLAG */
systick->csr;
}
static void _ARMV7M_Systick_handler(void)
{
_ARMV7M_Interrupt_service_enter();
Clock_isr(ARMV7M_VECTOR_SYSTICK);
_ARMV7M_Interrupt_service_leave();
}
static void _ARMV7M_Systick_handler_install(void)
{
_ARMV7M_Set_exception_handler(
ARMV7M_VECTOR_SYSTICK,
_ARMV7M_Systick_handler
);
}
static void _ARMV7M_Systick_initialize(void)
{
volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
uint64_t frequency = ARMV7M_SYSTICK_CALIB_TENMS(systick->calib) * 100ULL;
uint64_t us_per_tick = rtems_configuration_get_microseconds_per_tick();
uint64_t interval = (frequency * us_per_tick) / 1000000ULL;
_ARMV7M_Systick_factor = (1000000000ULL << 32) / frequency;
systick->rvr = (uint32_t) interval;
systick->cvr = 0;
systick->csr = ARMV7M_SYSTICK_CSR_TICKINT | ARMV7M_SYSTICK_CSR_ENABLE;
}
static void _ARMV7M_Systick_cleanup(void)
{
volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
systick->csr = 0;
}
static uint32_t _ARMV7M_Systick_nanoseconds_since_last_tick(void)
{
volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
volatile ARMV7M_SCB *scb = _ARMV7M_SCB;
uint32_t rvr = systick->rvr;
uint32_t c = rvr - systick->cvr;
if ((scb->icsr & ARMV7M_SCB_ICSR_PENDSTSET) != 0) {
c = rvr - systick->cvr + rvr;
}
return (uint32_t) ((c * _ARMV7M_Systick_factor) >> 32);
}
#define Clock_driver_support_at_tick() \
_ARMV7M_Systick_at_tick()
#define Clock_driver_support_initialize_hardware() \
_ARMV7M_Systick_initialize()
#define Clock_driver_support_install_isr(isr, old_isr) \
do { \
_ARMV7M_Systick_handler_install(); \
old_isr = NULL; \
} while (0)
#define Clock_driver_support_shutdown_hardware() \
_ARMV7M_Systick_cleanup()
#define Clock_driver_nanoseconds_since_last_tick \
_ARMV7M_Systick_nanoseconds_since_last_tick
/* Include shared source clock driver code */
#include "../../../shared/clockdrv_shell.h"
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