osd-contiki/cpu/pico-rv32/dev/clock.c

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/*
* Copyright (c) 2016, Dr. Ralf Schlatterbeck Open Source Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
*
* This file is part of the Contiki operating system.
*
*/
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/**
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* \brief This module contains PicoRV32-specific code to implement
* the Contiki core clock functions.
*
* \author Ralf Schlatterbeck <rsc@runtux.com>.
*
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*/
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/** \addtogroup picorv32
* @{
*/
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/**
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* \defgroup picorv32clock PicoRV32 clock implementation
* @{
*/
/**
* \file
* This file contains PicoRV32-specific code to implement the Contiki
* core clock functions.
*
*/
/**
* These routines define the PicoRV32-specific calls declared in
* /core/sys/clock.h CLOCK_SECOND is the number of ticks per second.
* It is defined through CONF_CLOCK_SECOND in the contiki-conf.h for
* each platform.
* The usual AVR defaults are 128 or 125 ticks per second, counting a
* prescaled CPU clock using the 8 bit timer0.
*
* clock_time_t is usually declared by the platform as an unsigned 16
* bit data type, thus intervals up to 512 or 524 seconds can be
* measured with ~8 millisecond precision.
* For longer intervals the 32 bit clock_seconds() is available.
*/
#include "sys/clock.h"
#include "sys/etimer.h"
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#include <stdio.h> // FIXME
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static volatile clock_time_t count;
unsigned long offset;
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long sleepseconds;
/*---------------------------------------------------------------------------*/
/**
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* No need to init
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*/
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void
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clock_init(void)
{
}
/*---------------------------------------------------------------------------*/
/**
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* Return the tick counter. We use the full 64bit counter which makes
* computation of seconds etc. easier later.
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*/
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clock_time_t
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clock_time(void)
{
uint32_t low, high;
asm ("1: rdcycleh %1\n"
"rdcycle %0\n"
"rdcycleh t0\n"
"bne %1,t0,1b\n"
: "=r" (low), "=r" (high)
:
: "t0"
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);
return ((clock_time_t)high) << 32 | low;
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}
/*---------------------------------------------------------------------------*/
/**
* Return seconds, default is time since startup.
*/
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unsigned long
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clock_seconds(void)
{
return (unsigned long)(clock_time () / CLOCK_CONF_SECOND) + offset;
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}
/*---------------------------------------------------------------------------*/
/**
* Set seconds, e.g. to a standard epoch for an absolute date/time.
*/
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void
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clock_set_seconds(unsigned long sec)
{
offset = sec - (unsigned long)(clock_time () / CLOCK_CONF_SECOND);
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}
/*---------------------------------------------------------------------------*/
/*
* Wait for a number of clock ticks.
*/
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void
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clock_wait(clock_time_t t)
{
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clock_time_t endticks = clock_time() + t;
while (clock_time () < endticks)
{;}
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}
/*---------------------------------------------------------------------------*/
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void
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clock_delay_usec(uint16_t dt)
{
clock_wait (CLOCK_SECOND * dt / 1000000ULL);
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}
/*---------------------------------------------------------------------------*/
/**
* Adjust the system current clock time.
* \param howmany How many ticks to add
*
* Typically used to add ticks after an MCU sleep
* clock_seconds will increment if necessary to reflect the tick addition.
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* Leap ticks or seconds can (rarely) be introduced if the ISR is not blocked.
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*/
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void
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clock_adjust_ticks(clock_time_t howmany)
{
}
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/** @} */
/** @} */