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nuttx/arch/arm/src/stm32/stm32_oneshot.c

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/****************************************************************************
* arch/arm/src/stm32/stm32_oneshot.c
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 names NuttX nor Atmel 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 OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/clock.h>
#include "stm32_oneshot.h"
#ifdef CONFIG_STM32_ONESHOT
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int stm32_oneshot_handler(int irg_num, void * context, void *arg);
/****************************************************************************
* Private Data
****************************************************************************/
static struct stm32_oneshot_s *g_oneshot[CONFIG_STM32_ONESHOT_MAXTIMERS];
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_oneshot_handler
*
* Description:
* Common timer interrupt callback. When any oneshot timer interrupt
* expires, this function will be called. It will forward the call to
* the next level up.
*
* Input Parameters:
* oneshot - The state associated with the expired timer
*
* Returned Value:
* Always returns OK
*
****************************************************************************/
static int stm32_oneshot_handler(int irg_num, void * context, void *arg)
{
struct stm32_oneshot_s * oneshot = (struct stm32_oneshot_s *) arg;
oneshot_handler_t oneshot_handler;
void *oneshot_arg;
tmrinfo("Expired...\n");
DEBUGASSERT(oneshot != NULL && oneshot->handler);
/* The clock was stopped, but not disabled when the RC match occurred.
* Disable the TC now and disable any further interrupts.
*/
STM32_TIM_SETISR(oneshot->tch, NULL, NULL, 0);
STM32_TIM_DISABLEINT(oneshot->tch, 0);
STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_DISABLED);
STM32_TIM_ACKINT(oneshot->tch, 0);
/* The timer is no longer running */
oneshot->running = false;
/* Forward the event, clearing out any vestiges */
oneshot_handler = (oneshot_handler_t)oneshot->handler;
oneshot->handler = NULL;
oneshot_arg = (void *)oneshot->arg;
oneshot->arg = NULL;
oneshot_handler(oneshot_arg);
return OK;
}
/****************************************************************************
* Name: stm32_allocate_handler
*
* Description:
* Allocate a timer callback handler for the oneshot instance.
*
* Input Parameters:
* oneshot - The state instance the new oneshot timer
*
* Returned Value:
* Returns zero (OK) on success. This can only fail if the number of
* timers exceeds CONFIG_STM32_ONESHOT_MAXTIMERS.
*
****************************************************************************/
static inline int stm32_allocate_handler(struct stm32_oneshot_s *oneshot)
{
#if CONFIG_STM32_ONESHOT_MAXTIMERS > 1
int ret = -EBUSY;
int i;
/* Search for an unused handler */
sched_lock();
for (i = 0; i < CONFIG_STM32_ONESHOT_MAXTIMERS; i++)
{
/* Is this handler available? */
if (g_oneshot[i] == NULL)
{
/* Yes... assign it to this oneshot */
g_oneshot[i] = oneshot;
oneshot->cbndx = i;
ret = OK;
break;
}
}
sched_unlock();
return ret;
#else
if (g_oneshot[0] == NULL)
{
g_oneshot[0] = oneshot;
return OK;
}
return -EBUSY;
#endif
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_oneshot_initialize
*
* Description:
* Initialize the oneshot timer wrapper
*
* Input Parameters:
* oneshot Caller allocated instance of the oneshot state structure
* chan Timer counter channel to be used.
* resolution The required resolution of the timer in units of
* microseconds. NOTE that the range is restricted to the
* range of uint16_t (excluding zero).
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int stm32_oneshot_initialize(struct stm32_oneshot_s *oneshot, int chan,
uint16_t resolution)
{
uint32_t frequency;
tmrinfo("chan=%d resolution=%d usec\n", chan, resolution);
DEBUGASSERT(oneshot && resolution > 0);
/* Get the TC frequency the corresponds to the requested resolution */
frequency = USEC_PER_SEC / (uint32_t)resolution;
oneshot->frequency = frequency;
oneshot->tch = stm32_tim_init(chan);
if (!oneshot->tch)
{
tmrerr("ERROR: Failed to allocate TIM%d\n", chan);
return -EBUSY;
}
STM32_TIM_SETCLOCK(oneshot->tch, frequency);
/* Initialize the remaining fields in the state structure. */
oneshot->chan = chan;
oneshot->running = false;
oneshot->handler = NULL;
oneshot->arg = NULL;
/* Assign a callback handler to the oneshot */
return stm32_allocate_handler(oneshot);
}
/****************************************************************************
* Name: stm32_oneshot_max_delay
*
* Description:
* Determine the maximum delay of the one-shot timer (in microseconds)
*
****************************************************************************/
int stm32_oneshot_max_delay(struct stm32_oneshot_s *oneshot, uint64_t *usec)
{
DEBUGASSERT(oneshot != NULL && usec != NULL);
*usec = (uint64_t)(UINT32_MAX / oneshot->frequency) *
(uint64_t)USEC_PER_SEC;
return OK;
}
/****************************************************************************
* Name: stm32_oneshot_start
*
* Description:
* Start the oneshot timer
*
* Input Parameters:
* oneshot Caller allocated instance of the oneshot state structure. This
* structure must have been previously initialized via a call to
* stm32_oneshot_initialize();
* handler The function to call when when the oneshot timer expires.
* arg An opaque argument that will accompany the callback.
* ts Provides the duration of the one shot timer.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
int stm32_oneshot_start(struct stm32_oneshot_s *oneshot,
oneshot_handler_t handler, void *arg,
const struct timespec *ts)
{
uint64_t usec;
uint64_t period;
irqstate_t flags;
tmrinfo("handler=%p arg=%p, ts=(%lu, %lu)\n",
handler, arg, (unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec);
DEBUGASSERT(oneshot && handler && ts);
DEBUGASSERT(oneshot->tch);
/* Was the oneshot already running? */
flags = enter_critical_section();
if (oneshot->running)
{
/* Yes.. then cancel it */
tmrinfo("Already running... cancelling\n");
(void)stm32_oneshot_cancel(oneshot, NULL);
}
/* Save the new handler and its argument */
oneshot->handler = handler;
oneshot->arg = arg;
/* Express the delay in microseconds */
usec = (uint64_t)ts->tv_sec * USEC_PER_SEC +
(uint64_t)(ts->tv_nsec / NSEC_PER_USEC);
/* Get the timer counter frequency and determine the number of counts need
* to achieve the requested delay.
*
* frequency = ticks / second
* ticks = seconds * frequency
* = (usecs * frequency) / USEC_PER_SEC;
*/
period = (usec * (uint64_t)oneshot->frequency) / USEC_PER_SEC;
tmrinfo("usec=%llu period=%08llx\n", usec, period);
DEBUGASSERT(period <= UINT32_MAX);
/* Set up to receive the callback when the interrupt occurs */
STM32_TIM_SETISR(oneshot->tch, stm32_oneshot_handler, oneshot, 0);
/* Set timer period */
oneshot->period = (uint32_t)period;
STM32_TIM_SETPERIOD(oneshot->tch, (uint32_t)period);
/* Start the counter */
STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_PULSE);
STM32_TIM_ACKINT(oneshot->tch, 0);
STM32_TIM_ENABLEINT(oneshot->tch, 0);
/* Enable interrupts. We should get the callback when the interrupt
* occurs.
*/
oneshot->running = true;
leave_critical_section(flags);
return OK;
}
/****************************************************************************
* Name: stm32_oneshot_cancel
*
* Description:
* Cancel the oneshot timer and return the time remaining on the timer.
*
* NOTE: This function may execute at a high rate with no timer running (as
* when pre-emption is enabled and disabled).
*
* Input Parameters:
* oneshot Caller allocated instance of the oneshot state structure. This
* structure must have been previously initialized via a call to
* stm32_oneshot_initialize();
* ts The location in which to return the time remaining on the
* oneshot timer. A time of zero is returned if the timer is
* not running. ts may be zero in which case the time remaining
* is not returned.
*
* Returned Value:
* Zero (OK) is returned on success. A call to up_timer_cancel() when
* the timer is not active should also return success; a negated errno
* value is returned on any failure.
*
****************************************************************************/
int stm32_oneshot_cancel(struct stm32_oneshot_s *oneshot,
struct timespec *ts)
{
irqstate_t flags;
uint64_t usec;
uint64_t sec;
uint64_t nsec;
uint32_t count;
uint32_t period;
/* Was the timer running? */
flags = enter_critical_section();
if (!oneshot->running)
{
/* No.. Just return zero timer remaining and successful cancellation.
* This function may execute at a high rate with no timer running
* (as when pre-emption is enabled and disabled).
*/
ts->tv_sec = 0;
ts->tv_nsec = 0;
leave_critical_section(flags);
return OK;
}
/* Yes.. Get the timer counter and period registers and stop the counter.
* If the counter expires while we are doing this, the counter clock will
* be stopped, but the clock will not be disabled.
*
* The expected behavior is that the counter register will freezes at
* a value equal to the RC register when the timer expires. The counter
* should have values between 0 and RC in all other cased.
*
* REVISIT: This does not appear to be the case.
*/
tmrinfo("Cancelling...\n");
count = STM32_TIM_GETCOUNTER(oneshot->tch);
period = oneshot->period;
/* Now we can disable the interrupt and stop the timer. */
STM32_TIM_DISABLEINT(oneshot->tch, 0);
STM32_TIM_SETISR(oneshot->tch, NULL, NULL, 0);
STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_DISABLED);
oneshot->running = false;
oneshot->handler = NULL;
oneshot->arg = NULL;
leave_critical_section(flags);
/* Did the caller provide us with a location to return the time
* remaining?
*/
if (ts)
{
/* Yes.. then calculate and return the time remaining on the
* oneshot timer.
*/
tmrinfo("period=%lu count=%lu\n",
(unsigned long)period, (unsigned long)count);
/* REVISIT: I am not certain why the timer counter value sometimes
* exceeds RC. Might be a bug, or perhaps the counter does not stop
* in all cases.
*/
if (count >= period)
{
/* No time remaining (?) */
ts->tv_sec = 0;
ts->tv_nsec = 0;
}
else
{
/* The total time remaining is the difference. Convert the that
* to units of microseconds.
*
* frequency = ticks / second
* seconds = ticks * frequency
* usecs = (ticks * USEC_PER_SEC) / frequency;
*/
usec = (((uint64_t)(period - count)) * USEC_PER_SEC) /
oneshot->frequency;
/* Return the time remaining in the correct form */
sec = usec / USEC_PER_SEC;
nsec = ((usec) - (sec * USEC_PER_SEC)) * NSEC_PER_USEC;
ts->tv_sec = (time_t)sec;
ts->tv_nsec = (unsigned long)nsec;
}
tmrinfo("remaining (%lu, %lu)\n",
(unsigned long)ts->tv_sec, (unsigned long)ts->tv_nsec);
}
return OK;
}
#endif /* CONFIG_STM32_ONESHOT */
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