mirror of
https://github.com/oliverschmidt/contiki.git
synced 2024-12-23 16:29:34 +00:00
262 lines
8.5 KiB
C
262 lines
8.5 KiB
C
/*
|
|
* Copyright (c) 2012, Texas Instruments Incorporated - http://www.ti.com/
|
|
* 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 copyright holder 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.
|
|
*/
|
|
/**
|
|
* \addtogroup cc2538
|
|
* @{
|
|
*
|
|
* \defgroup cc2538-clock cc2538 Clock
|
|
*
|
|
* Implementation of the clock module for the cc2538
|
|
*
|
|
* To implement the clock functionality, we use the SysTick peripheral on the
|
|
* cortex-M3. We run the system clock at a configurable speed and set the
|
|
* SysTick to give us 128 interrupts / sec. However, the Sleep Timer counter
|
|
* value is used for the number of elapsed ticks in order to avoid a
|
|
* significant time drift caused by PM1/2. Contrary to the Sleep Timer, the
|
|
* SysTick peripheral is indeed frozen during PM1/2, so adjusting upon wake-up
|
|
* a tick counter based on this peripheral would hardly be accurate.
|
|
* @{
|
|
*
|
|
* \file
|
|
* Clock driver implementation for the TI cc2538
|
|
*/
|
|
#include "contiki.h"
|
|
#include "systick.h"
|
|
#include "reg.h"
|
|
#include "cpu.h"
|
|
#include "dev/gptimer.h"
|
|
#include "dev/sys-ctrl.h"
|
|
|
|
#include "sys/energest.h"
|
|
#include "sys/etimer.h"
|
|
#include "sys/rtimer.h"
|
|
|
|
#include <stdint.h>
|
|
/*---------------------------------------------------------------------------*/
|
|
#define RTIMER_CLOCK_TICK_RATIO (RTIMER_SECOND / CLOCK_SECOND)
|
|
|
|
/* Prescaler for GPT0:Timer A used for clock_delay_usec(). */
|
|
#if SYS_CTRL_SYS_CLOCK < SYS_CTRL_1MHZ
|
|
#error System clock speeds below 1MHz are not supported
|
|
#endif
|
|
#define PRESCALER_VALUE (SYS_CTRL_SYS_CLOCK / SYS_CTRL_1MHZ - 1)
|
|
|
|
/* Reload value for SysTick counter */
|
|
#if SYS_CTRL_SYS_CLOCK % CLOCK_SECOND
|
|
/* Too low clock speeds will lead to reduced accurracy */
|
|
#error System clock speed too slow for CLOCK_SECOND, accuracy reduced
|
|
#endif
|
|
#define RELOAD_VALUE (SYS_CTRL_SYS_CLOCK / CLOCK_SECOND - 1)
|
|
|
|
static volatile uint64_t rt_ticks_startup = 0, rt_ticks_epoch = 0;
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief Arch-specific implementation of clock_init for the cc2538
|
|
*
|
|
* We initialise the SysTick to fire 128 interrupts per second, giving us a
|
|
* value of 128 for CLOCK_SECOND
|
|
*
|
|
* We also initialise GPT0:Timer A, which is used by clock_delay_usec().
|
|
* We use 16-bit range (individual), count-down, one-shot, no interrupts.
|
|
* The prescaler is computed according to the system clock in order to get 1
|
|
* tick per usec.
|
|
*/
|
|
void
|
|
clock_init(void)
|
|
{
|
|
REG(SYSTICK_STRELOAD) = RELOAD_VALUE;
|
|
|
|
/* System clock source, Enable */
|
|
REG(SYSTICK_STCTRL) |= SYSTICK_STCTRL_CLK_SRC | SYSTICK_STCTRL_ENABLE;
|
|
|
|
/* Enable the SysTick Interrupt */
|
|
REG(SYSTICK_STCTRL) |= SYSTICK_STCTRL_INTEN;
|
|
|
|
/*
|
|
* Remove the clock gate to enable GPT0 and then initialise it
|
|
* We only use GPT0 for clock_delay_usec. We initialise it here so we can
|
|
* have it ready when it's needed
|
|
*/
|
|
REG(SYS_CTRL_RCGCGPT) |= SYS_CTRL_RCGCGPT_GPT0;
|
|
|
|
/* Make sure GPT0 is off */
|
|
REG(GPT_0_BASE + GPTIMER_CTL) = 0;
|
|
|
|
/* 16-bit */
|
|
REG(GPT_0_BASE + GPTIMER_CFG) = 0x04;
|
|
|
|
/* One-Shot, Count Down, No Interrupts */
|
|
REG(GPT_0_BASE + GPTIMER_TAMR) = GPTIMER_TAMR_TAMR_ONE_SHOT;
|
|
|
|
/* Prescale depending on system clock used */
|
|
REG(GPT_0_BASE + GPTIMER_TAPR) = PRESCALER_VALUE;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
CCIF clock_time_t
|
|
clock_time(void)
|
|
{
|
|
return rt_ticks_startup / RTIMER_CLOCK_TICK_RATIO;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
clock_set_seconds(unsigned long sec)
|
|
{
|
|
rt_ticks_epoch = (uint64_t)sec * RTIMER_SECOND;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
CCIF unsigned long
|
|
clock_seconds(void)
|
|
{
|
|
return rt_ticks_epoch / RTIMER_SECOND;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
clock_wait(clock_time_t i)
|
|
{
|
|
clock_time_t start;
|
|
|
|
start = clock_time();
|
|
while(clock_time() - start < (clock_time_t)i);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/*
|
|
* Arch-specific implementation of clock_delay_usec for the cc2538
|
|
*
|
|
* See clock_init() for GPT0 Timer A's configuration
|
|
*/
|
|
void
|
|
clock_delay_usec(uint16_t dt)
|
|
{
|
|
REG(GPT_0_BASE + GPTIMER_TAILR) = dt;
|
|
REG(GPT_0_BASE + GPTIMER_CTL) |= GPTIMER_CTL_TAEN;
|
|
|
|
/* One-Shot mode: TAEN will be cleared when the timer reaches 0 */
|
|
while(REG(GPT_0_BASE + GPTIMER_CTL) & GPTIMER_CTL_TAEN);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief Obsolete delay function but we implement it here since some code
|
|
* still uses it
|
|
*/
|
|
void
|
|
clock_delay(unsigned int i)
|
|
{
|
|
clock_delay_usec(i);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief Update the software clock ticks and seconds
|
|
*
|
|
* This function is used to update the software tick counters whenever the
|
|
* system clock might have changed, which can occur upon a SysTick ISR or upon
|
|
* wake-up from PM1/2.
|
|
*
|
|
* For the software clock ticks counter, the Sleep Timer counter value is used
|
|
* as the base tick value, and extended to a 64-bit value thanks to a detection
|
|
* of wraparounds.
|
|
*
|
|
* For the seconds counter, the changes of the Sleep Timer counter value are
|
|
* added to the reference time, which is either the startup time or the value
|
|
* passed to clock_set_seconds().
|
|
*
|
|
* This function polls the etimer process if an etimer has expired.
|
|
*/
|
|
static void
|
|
update_ticks(void)
|
|
{
|
|
rtimer_clock_t now;
|
|
uint64_t prev_rt_ticks_startup, cur_rt_ticks_startup;
|
|
uint32_t cur_rt_ticks_startup_hi;
|
|
|
|
now = RTIMER_NOW();
|
|
prev_rt_ticks_startup = rt_ticks_startup;
|
|
|
|
cur_rt_ticks_startup_hi = prev_rt_ticks_startup >> 32;
|
|
if(now < (rtimer_clock_t)prev_rt_ticks_startup) {
|
|
cur_rt_ticks_startup_hi++;
|
|
}
|
|
cur_rt_ticks_startup = (uint64_t)cur_rt_ticks_startup_hi << 32 | now;
|
|
rt_ticks_startup = cur_rt_ticks_startup;
|
|
|
|
rt_ticks_epoch += cur_rt_ticks_startup - prev_rt_ticks_startup;
|
|
|
|
/*
|
|
* Inform the etimer library that the system clock has changed and that an
|
|
* etimer might have expired.
|
|
*/
|
|
if(etimer_pending()) {
|
|
etimer_request_poll();
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief Adjust the clock following missed SysTick ISRs
|
|
*
|
|
* This function is useful when coming out of PM1/2, during which the system
|
|
* clock is stopped. We adjust the clock counters like after any SysTick ISR.
|
|
*
|
|
* \note This function is only meant to be used by lpm_exit(). Applications
|
|
* should really avoid calling this
|
|
*/
|
|
void
|
|
clock_adjust(void)
|
|
{
|
|
/* Halt the SysTick while adjusting */
|
|
REG(SYSTICK_STCTRL) &= ~SYSTICK_STCTRL_ENABLE;
|
|
|
|
update_ticks();
|
|
|
|
/* Re-Start the SysTick */
|
|
REG(SYSTICK_STCTRL) |= SYSTICK_STCTRL_ENABLE;
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
/**
|
|
* \brief The clock Interrupt Service Routine
|
|
*
|
|
* It polls the etimer process if an etimer has expired. It also updates the
|
|
* software clock tick and seconds counter.
|
|
*/
|
|
void
|
|
clock_isr(void)
|
|
{
|
|
ENERGEST_ON(ENERGEST_TYPE_IRQ);
|
|
|
|
update_ticks();
|
|
|
|
ENERGEST_OFF(ENERGEST_TYPE_IRQ);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
|
|
/**
|
|
* @}
|
|
* @}
|
|
*/
|