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/*
* Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of ARM nor the names of its contributors may be used
* to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <m0_param.h>
#include "rk3399_mcu.h"
/* use 24MHz SysTick */
#define US_TO_CYCLE(US) (US * 24)
#define SYST_CST 0xe000e010
/* enable counter */
#define ENABLE (1 << 0)
/* count down to 0 does not cause SysTick exception to pend */
#define TICKINT (1 << 1)
/* core clock used for SysTick */
#define CLKSOURCE (1 << 2)
#define COUNTFLAG (1 << 16)
#define SYST_RVR 0xe000e014
#define MAX_VALUE 0xffffff
#define MAX_USECS (MAX_VALUE / US_TO_CYCLE(1))
#define SYST_CVR 0xe000e018
#define SYST_CALIB 0xe000e01c
unsigned int remaining_usecs;
static inline void stopwatch_set_usecs(void)
{
unsigned int cycle;
unsigned int usecs = MIN(MAX_USECS, remaining_usecs);
remaining_usecs -= usecs;
cycle = US_TO_CYCLE(usecs);
mmio_write_32(SYST_RVR, cycle);
mmio_write_32(SYST_CVR, 0);
mmio_write_32(SYST_CST, ENABLE | TICKINT | CLKSOURCE);
}
void stopwatch_init_usecs_expire(unsigned int usecs)
{
/*
* Enter an inifite loop if the stopwatch is in use. This will allow the
* state to be analyzed with a debugger.
*/
if (mmio_read_32(SYST_CST) & ENABLE)
while (1)
;
remaining_usecs = usecs;
stopwatch_set_usecs();
}
int stopwatch_expired(void)
{
int val = mmio_read_32(SYST_CST);
if ((val & COUNTFLAG) || !(val & ENABLE)) {
if (!remaining_usecs)
return 1;
stopwatch_set_usecs();
}
return 0;
}
void stopwatch_reset(void)
{
mmio_clrbits_32(SYST_CST, ENABLE);
remaining_usecs = 0;
}
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