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arch/arm/src/stm32h7: add support for oneshot timer

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The code is ported from arch/arm/src/stm32
This commit is contained in:
Pierre-Olivier Vauboin 2020-05-05 17:44:14 +02:00 committed by patacongo
parent 1ef0fe36c4
commit d96565a765
5 changed files with 949 additions and 0 deletions
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18
arch/arm/src/stm32h7/Kconfig
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@ -1625,6 +1625,24 @@ config STM32H7_DMACAPABLE
menu "Timer Configuration"
config STM32H7_ONESHOT
bool "TIM one-shot wrapper"
default n
---help---
Enable a wrapper around the low level timer/counter functions to
support one-shot timer.
config STM32H7_ONESHOT_MAXTIMERS
int "Maximum number of oneshot timers"
default 1
range 1 8
depends on STM32H7_ONESHOT
---help---
Determines the maximum number of oneshot timers that can be
supported. This setting pre-allocates some minimal support for each
of the timers and places an upper limit on the number of oneshot
timers that you can use.
config STM32H7_PWM_LL_OPS
bool "PWM low-level operations"
default n

4
arch/arm/src/stm32h7/Make.defs
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@ -117,6 +117,10 @@ ifneq ($(CONFIG_SCHED_TICKLESS),y)
CHIP_CSRCS += stm32_timerisr.c
endif
ifeq ($(CONFIG_STM32H7_ONESHOT),y)
CHIP_CSRCS += stm32_oneshot.c stm32_oneshot_lowerhalf.c
endif
ifeq ($(CONFIG_BUILD_PROTECTED),y)
CHIP_CSRCS += stm32_userspace.c stm32_mpuinit.c
endif

402
arch/arm/src/stm32h7/stm32_oneshot.c Normal file
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@ -0,0 +1,402 @@
/****************************************************************************
* arch/arm/src/stm32h7/stm32_oneshot.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* 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_STM32H7_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_STM32H7_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 (Interrupt)...\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, GTIM_DIER_UIE);
STM32_TIM_SETMODE(oneshot->tch, STM32_TIM_MODE_DISABLED);
STM32_TIM_ACKINT(oneshot->tch, GTIM_SR_UIF);
/* 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_STM32H7_ONESHOT_MAXTIMERS.
*
****************************************************************************/
static inline int stm32_allocate_handler(struct stm32_oneshot_s *oneshot)
{
#if CONFIG_STM32H7_ONESHOT_MAXTIMERS > 1
int ret = -EBUSY;
int i;
/* Search for an unused handler */
sched_lock();
for (i = 0; i < CONFIG_STM32H7_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, USEC_PER_SEC:%d\n", chan, resolution, USEC_PER_SEC);
DEBUGASSERT(oneshot && resolution > 0);
/* Get the TC frequency the corresponds to the requested resolution */
frequency = USEC_PER_SEC / (uint32_t)resolution;
tmrinfo("frequency: %d\n", frequency);
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);
tmrinfo("frequency: %d, USEC_PER_SEC: %d\n", oneshot->frequency, USEC_PER_SEC);
*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");
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, GTIM_SR_UIF);
STM32_TIM_ENABLEINT(oneshot->tch, GTIM_DIER_UIE);
/* 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;
/* 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;
}
tmrinfo("Cancelling...\n");
/* Now we can disable the interrupt and stop the timer. */
STM32_TIM_DISABLEINT(oneshot->tch, GTIM_DIER_UIE);
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)
{
/* Not implemented */
ts->tv_sec = 0;
ts->tv_nsec = 0;
}
return OK;
}
#endif /* CONFIG_STM32H7_ONESHOT */

195
arch/arm/src/stm32h7/stm32_oneshot.h Normal file
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@ -0,0 +1,195 @@
/****************************************************************************
* arch/arm/src/stm32h7/stm32_oneshot.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
#ifndef __ARCH_ARM_SRC_STM32_ONESHOT_H
#define __ARCH_ARM_SRC_STM32_ONESHOT_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <time.h>
#include <nuttx/irq.h>
#include "stm32_tim.h"
#ifdef CONFIG_STM32H7_ONESHOT
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#if !defined(CONFIG_STM32H7_ONESHOT_MAXTIMERS) || \
CONFIG_STM32H7_ONESHOT_MAXTIMERS < 1
# undef CONFIG_STM32H7_ONESHOT_MAXTIMERS
# define CONFIG_STM32H7_ONESHOT_MAXTIMERS 1
#endif
#if CONFIG_STM32H7_ONESHOT_MAXTIMERS > 8
# warning Additional logic required to handle more than 8 timers
# undef CONFIG_STM32H7_ONESHOT_MAXTIMERS
# define CONFIG_STM32H7_ONESHOT_MAXTIMERS 8
#endif
/****************************************************************************
* Public Types
****************************************************************************/
/* This describes the callback function that will be invoked when the oneshot
* timer expires. The oneshot fires, the client will receive:
*
* arg - The opaque argument provided when the interrupt was registered
*/
typedef void (*oneshot_handler_t)(void *arg);
/* The oneshot client must allocate an instance of this structure and called
* stm32_oneshot_initialize() before using the oneshot facilities. The client
* should not access the contents of this structure directly since the
* contents are subject to change.
*/
struct stm32_oneshot_s
{
uint8_t chan; /* The timer/counter in use */
#if CONFIG_STM32H7_ONESHOT_MAXTIMERS > 1
uint8_t cbndx; /* Timer callback handler index */
#endif
volatile bool running; /* True: the timer is running */
FAR struct stm32_tim_dev_s *tch; /* Pointer returned by
* stm32_tim_init() */
volatile oneshot_handler_t handler; /* Oneshot expiration callback */
volatile void *arg; /* The argument that will accompany
* the callback */
uint32_t frequency;
uint32_t period;
};
/****************************************************************************
* Public Data
****************************************************************************/
#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
/****************************************************************************
* 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);
/****************************************************************************
* 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);
/****************************************************************************
* 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);
/****************************************************************************
* 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.
*
* 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);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_STM32H7_ONESHOT */
#endif /* __ARCH_ARM_SRC_STM32_ONESHOT_H */

330
arch/arm/src/stm32h7/stm32_oneshot_lowerhalf.c Normal file
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@ -0,0 +1,330 @@
/****************************************************************************
* arch/arm/src/stm32h7/stm32_oneshot_lowerhalf.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <time.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/kmalloc.h>
#include <nuttx/timers/oneshot.h>
#include "stm32_oneshot.h"
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure describes the state of the oneshot timer lower-half driver */
struct stm32_oneshot_lowerhalf_s
{
/* This is the part of the lower half driver that is visible to the upper-
* half client of the driver. This must be the first thing in this
* structure so that pointers to struct oneshot_lowerhalf_s are cast
* compatible to struct stm32_oneshot_lowerhalf_s and vice versa.
*/
struct oneshot_lowerhalf_s lh; /* Common lower-half driver fields */
/* Private lower half data follows */
struct stm32_oneshot_s oneshot; /* STM32-specific oneshot state */
oneshot_callback_t callback; /* Internal handler that receives callback */
FAR void *arg; /* Argument that is passed to the handler */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static void stm32_oneshot_handler(void *arg);
static int stm32_max_delay(FAR struct oneshot_lowerhalf_s *lower,
FAR struct timespec *ts);
static int stm32_start(FAR struct oneshot_lowerhalf_s *lower,
oneshot_callback_t callback, FAR void *arg,
FAR const struct timespec *ts);
static int stm32_cancel(FAR struct oneshot_lowerhalf_s *lower,
FAR struct timespec *ts);
/****************************************************************************
* Private Data
****************************************************************************/
/* Lower half operations */
static const struct oneshot_operations_s g_oneshot_ops =
{
.max_delay = stm32_max_delay,
.start = stm32_start,
.cancel = stm32_cancel,
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_oneshot_handler
*
* Description:
* Timer expiration handler
*
* Input Parameters:
* arg - Should be the same argument provided when stm32_oneshot_start()
* was called.
*
* Returned Value:
* None
*
****************************************************************************/
static void stm32_oneshot_handler(void *arg)
{
FAR struct stm32_oneshot_lowerhalf_s *priv =
(FAR struct stm32_oneshot_lowerhalf_s *)arg;
oneshot_callback_t callback;
FAR void *cbarg;
DEBUGASSERT(priv != NULL);
/* Perhaps the callback was nullified in a race condition with
* stm32_cancel?
*/
if (priv->callback)
{
/* Sample and nullify BEFORE executing callback (in case the callback
* restarts the oneshot).
*/
callback = priv->callback;
cbarg = priv->arg;
priv->callback = NULL;
priv->arg = NULL;
/* Then perform the callback */
callback(&priv->lh, cbarg);
}
}
/****************************************************************************
* Name: stm32_max_delay
*
* Description:
* Determine the maximum delay of the one-shot timer (in microseconds)
*
* Input Parameters:
* lower An instance of the lower-half oneshot state structure. This
* structure must have been previously initialized via a call to
* oneshot_initialize();
* ts The location in which to return the maximum delay.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure.
*
****************************************************************************/
static int stm32_max_delay(FAR struct oneshot_lowerhalf_s *lower,
FAR struct timespec *ts)
{
FAR struct stm32_oneshot_lowerhalf_s *priv =
(FAR struct stm32_oneshot_lowerhalf_s *)lower;
uint64_t usecs;
int ret;
DEBUGASSERT(priv != NULL && ts != NULL);
ret = stm32_oneshot_max_delay(&priv->oneshot, &usecs);
if (ret >= 0)
{
uint64_t sec = usecs / 1000000;
usecs -= 1000000 * sec;
ts->tv_sec = (time_t)sec;
ts->tv_nsec = (long)(usecs * 1000);
}
return ret;
}
/****************************************************************************
* Name: stm32_start
*
* Description:
* Start the oneshot timer
*
* Input Parameters:
* lower An instance of the lower-half oneshot state structure. This
* structure must have been previously initialized via a call to
* 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.
*
****************************************************************************/
static int stm32_start(FAR struct oneshot_lowerhalf_s *lower,
oneshot_callback_t callback, FAR void *arg,
FAR const struct timespec *ts)
{
FAR struct stm32_oneshot_lowerhalf_s *priv =
(FAR struct stm32_oneshot_lowerhalf_s *)lower;
irqstate_t flags;
int ret;
DEBUGASSERT(priv != NULL && callback != NULL && ts != NULL);
/* Save the callback information and start the timer */
flags = enter_critical_section();
priv->callback = callback;
priv->arg = arg;
ret = stm32_oneshot_start(&priv->oneshot,
stm32_oneshot_handler, priv, ts);
leave_critical_section(flags);
if (ret < 0)
{
tmrerr("ERROR: stm32_oneshot_start failed: %d\n", flags);
}
return ret;
}
/****************************************************************************
* Name: stm32_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:
* lower Caller allocated instance of the oneshot state structure. This
* structure must have been previously initialized via a call to
* 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.
*
* 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.
*
****************************************************************************/
static int stm32_cancel(FAR struct oneshot_lowerhalf_s *lower,
FAR struct timespec *ts)
{
FAR struct stm32_oneshot_lowerhalf_s *priv =
(FAR struct stm32_oneshot_lowerhalf_s *)lower;
irqstate_t flags;
int ret;
DEBUGASSERT(priv != NULL);
/* Cancel the timer */
flags = enter_critical_section();
ret = stm32_oneshot_cancel(&priv->oneshot, ts);
priv->callback = NULL;
priv->arg = NULL;
leave_critical_section(flags);
if (ret < 0)
{
tmrerr("ERROR: stm32_oneshot_cancel failed: %d\n", flags);
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: oneshot_initialize
*
* Description:
* Initialize the oneshot timer and return a oneshot lower half driver
* instance.
*
* Input Parameters:
* 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:
* On success, a non-NULL instance of the oneshot lower-half driver is
* returned. NULL is return on any failure.
*
****************************************************************************/
FAR struct oneshot_lowerhalf_s *oneshot_initialize(int chan,
uint16_t resolution)
{
FAR struct stm32_oneshot_lowerhalf_s *priv;
int ret;
/* Allocate an instance of the lower half driver */
priv = (FAR struct stm32_oneshot_lowerhalf_s *)
kmm_zalloc(sizeof(struct stm32_oneshot_lowerhalf_s));
if (priv == NULL)
{
tmrerr("ERROR: Failed to initialized state structure\n");
return NULL;
}
/* Initialize the lower-half driver structure */
priv->lh.ops = &g_oneshot_ops;
/* Initialize the contained STM32 oneshot timer */
ret = stm32_oneshot_initialize(&priv->oneshot, chan, resolution);
if (ret < 0)
{
tmrerr("ERROR: stm32_oneshot_initialize failed: %d\n", ret);
kmm_free(priv);
return NULL;
}
return &priv->lh;
}