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mbed-os/libraries/ble/nRF51822/nordic/app_common/app_timer.cpp

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/* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
*
* The information contained herein is property of Nordic Semiconductor ASA.
* Terms and conditions of usage are described in detail in NORDIC
* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
*
* Licensees are granted free, non-transferable use of the information. NO
* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
* the file.
*
*/
#include "app_timer.h"
#include <stdlib.h>
#include "nrf51.h"
#include "nrf51_bitfields.h"
#include "nrf_soc.h"
#include "app_error.h"
//#include "nrf_delay.h"
#include "mbed.h"
#include "app_util.h"
#define RTC1_IRQ_PRI APP_IRQ_PRIORITY_LOW /**< Priority of the RTC1 interrupt (used for checking for timeouts and executing timeout handlers). */
#define SWI0_IRQ_PRI APP_IRQ_PRIORITY_LOW /**< Priority of the SWI0 interrupt (used for updating the timer list). */
// The current design assumes that both interrupt handlers run at the same interrupt level.
// If this is to be changed, protection must be added to prevent them from interrupting each other
// (e.g. by using guard/trigger flags).
STATIC_ASSERT(RTC1_IRQ_PRI == SWI0_IRQ_PRI);
#define MAX_RTC_COUNTER_VAL 0x00FFFFFF /**< Maximum value of the RTC counter. */
#define APP_HIGH_USER_ID 0 /**< User Id for the Application High "user". */
#define APP_LOW_USER_ID 1 /**< User Id for the Application Low "user". */
#define THREAD_MODE_USER_ID 2 /**< User Id for the Thread Mode "user". */
#define RTC_COMPARE_OFFSET_MIN 3 /**< Minimum offset between the current RTC counter value and the Capture Compare register. Although the nRF51 Series User Specification recommends this value to be 2, we use 3 to be safer.*/
#define MAX_RTC_TASKS_DELAY 47 /**< Maximum delay until an RTC task is executed. */
/**@brief Timer allocation state type. */
typedef enum
{
STATE_FREE, /**< The timer node is available. */
STATE_ALLOCATED /**< The timer node has been allocated. */
} timer_alloc_state_t;
/**@brief Timer node type. The nodes will be used form a linked list of running timers. */
typedef struct
{
timer_alloc_state_t state; /**< Timer allocation state. */
app_timer_mode_t mode; /**< Timer mode. */
uint32_t ticks_to_expire; /**< Number of ticks from previous timer interrupt to timer expiry. */
uint32_t ticks_at_start; /**< Current RTC counter value when the timer was started. */
uint32_t ticks_first_interval; /**< Number of ticks in the first timer interval. */
uint32_t ticks_periodic_interval; /**< Timer period (for repeating timers). */
bool is_running; /**< True if timer is running, False otherwise. */
app_timer_timeout_handler_t p_timeout_handler; /**< Pointer to function to be executed when the timer expires. */
void * p_context; /**< General purpose pointer. Will be passed to the timeout handler when the timer expires. */
app_timer_id_t next; /**< Id of next timer in list of running timers. */
} timer_node_t;
STATIC_ASSERT(sizeof(timer_node_t) <= APP_TIMER_NODE_SIZE);
STATIC_ASSERT(sizeof(timer_node_t) % 4 == 0);
/**@brief Set of available timer operation types. */
typedef enum
{
TIMER_USER_OP_TYPE_NONE, /**< Invalid timer operation type. */
TIMER_USER_OP_TYPE_START, /**< Timer operation type Start. */
TIMER_USER_OP_TYPE_STOP, /**< Timer operation type Stop. */
TIMER_USER_OP_TYPE_STOP_ALL /**< Timer operation type Stop All. */
} timer_user_op_type_t;
/**@brief Structure describing a timer start operation. */
typedef struct
{
uint32_t ticks_at_start; /**< Current RTC counter value when the timer was started. */
uint32_t ticks_first_interval; /**< Number of ticks in the first timer interval. */
uint32_t ticks_periodic_interval; /**< Timer period (for repeating timers). */
void * p_context; /**< General purpose pointer. Will be passed to the timeout handler when the timer expires. */
} timer_user_op_start_t;
/**@brief Structure describing a timer operation. */
typedef struct
{
timer_user_op_type_t op_type; /**< Timer operation type. */
app_timer_id_t timer_id; /**< Id of timer on which the operation is to be performed. */
union
{
timer_user_op_start_t start; /**< Structure describing a timer start operation. */
} params;
} timer_user_op_t;
STATIC_ASSERT(sizeof(timer_user_op_t) <= APP_TIMER_USER_OP_SIZE);
STATIC_ASSERT(sizeof(timer_user_op_t) % 4 == 0);
/**@brief Structure describing a timer user.
*
* @details For each user of the timer module, there will be a timer operations queue. This queue
* will hold timer operations issued by this user until the timer interrupt handler
* processes these operations. For the current implementation, there will be one user for
* each interrupt level available to the application (APP_HIGH, APP_LOW and THREAD_MODE),
* but the module can easily be modified to e.g. have one queue per process when using an
* RTOS. The purpose of the queues is to be able to have a completely lockless timer
* implementation.
*/
typedef struct
{
uint8_t first; /**< Index of first entry to have been inserted in the queue (i.e. the next entry to be executed). */
uint8_t last; /**< Index of last entry to have been inserted in the queue. */
uint8_t user_op_queue_size; /**< Queue size. */
timer_user_op_t * p_user_op_queue; /**< Queue buffer. */
} timer_user_t;
STATIC_ASSERT(sizeof(timer_user_t) == APP_TIMER_USER_SIZE);
STATIC_ASSERT(sizeof(timer_user_t) % 4 == 0);
/**@brief User id type.
*
* @details In the current implementation, this will automatically be generated from the current
* interrupt level.
*/
typedef uint32_t timer_user_id_t;
#define TIMER_NULL ((app_timer_id_t)(0 - 1)) /**< Invalid timer id. */
#define CONTEXT_QUEUE_SIZE_MAX (2) /**< Timer internal elapsed ticks queue size. */
static uint8_t m_node_array_size; /**< Size of timer node array. */
static timer_node_t * mp_nodes = NULL; /**< Array of timer nodes. */
static uint8_t m_user_array_size; /**< Size of timer user array. */
static timer_user_t * mp_users; /**< Array of timer users. */
static app_timer_id_t m_timer_id_head; /**< First timer in list of running timers. */
static uint32_t m_ticks_latest; /**< Last known RTC counter value. */
static uint32_t m_ticks_elapsed[CONTEXT_QUEUE_SIZE_MAX]; /**< Timer internal elapsed ticks queue. */
static uint8_t m_ticks_elapsed_q_read_ind; /**< Timer internal elapsed ticks queue read index. */
static uint8_t m_ticks_elapsed_q_write_ind; /**< Timer internal elapsed ticks queue write index. */
static app_timer_evt_schedule_func_t m_evt_schedule_func; /**< Pointer to function for propagating timeout events to the scheduler. */
/**@brief Function for initializing the RTC1 counter.
*
* @param[in] prescaler Value of the RTC1 PRESCALER register. Set to 0 for no prescaling.
*/
static void rtc1_init(uint32_t prescaler)
{
NRF_RTC1->PRESCALER = prescaler;
NVIC_SetPriority(RTC1_IRQn, RTC1_IRQ_PRI);
}
/**@brief Function for starting the RTC1 timer.
*/
static void rtc1_start(void)
{
NRF_RTC1->EVTENSET = RTC_EVTEN_COMPARE0_Msk;
NRF_RTC1->INTENSET = RTC_INTENSET_COMPARE0_Msk;
NVIC_ClearPendingIRQ(RTC1_IRQn);
NVIC_EnableIRQ(RTC1_IRQn);
NRF_RTC1->TASKS_START = 1;
wait(0.0000001 * MAX_RTC_TASKS_DELAY);
}
/**@brief Function for stopping the RTC1 timer.
*/
static void rtc1_stop(void)
{
NVIC_DisableIRQ(RTC1_IRQn);
NRF_RTC1->EVTENCLR = RTC_EVTEN_COMPARE0_Msk;
NRF_RTC1->INTENCLR = RTC_INTENSET_COMPARE0_Msk;
NRF_RTC1->TASKS_STOP = 1;
wait(0.0000001 * MAX_RTC_TASKS_DELAY);
}
/**@brief Function for returning the current value of the RTC1 counter.
*
* @return Current value of the RTC1 counter.
*/
static __INLINE uint32_t rtc1_counter_get(void)
{
return NRF_RTC1->COUNTER;
}
/**@brief Function for computing the difference between two RTC1 counter values.
*
* @return Number of ticks elapsed from ticks_old to ticks_now.
*/
static __INLINE uint32_t ticks_diff_get(uint32_t ticks_now, uint32_t ticks_old)
{
return ((ticks_now - ticks_old) & MAX_RTC_COUNTER_VAL);
}
/**@brief Function for setting the RTC1 Capture Compare register 0, and enabling the corresponding
* event.
*
* @param[in] value New value of Capture Compare register 0.
*/
static __INLINE void rtc1_compare0_set(uint32_t value)
{
NRF_RTC1->CC[0] = value;
}
/**@brief Function for inserting a timer in the timer list.
*
* @param[in] timer_id Id of timer to insert.
*/
static void timer_list_insert(app_timer_id_t timer_id)
{
timer_node_t * p_timer = &mp_nodes[timer_id];
if (m_timer_id_head == TIMER_NULL)
{
m_timer_id_head = timer_id;
}
else
{
if (p_timer->ticks_to_expire <= mp_nodes[m_timer_id_head].ticks_to_expire)
{
mp_nodes[m_timer_id_head].ticks_to_expire -= p_timer->ticks_to_expire;
p_timer->next = m_timer_id_head;
m_timer_id_head = timer_id;
}
else
{
app_timer_id_t previous;
app_timer_id_t current;
uint32_t ticks_to_expire;
ticks_to_expire = p_timer->ticks_to_expire;
previous = m_timer_id_head;
current = m_timer_id_head;
while ((current != TIMER_NULL) && (ticks_to_expire > mp_nodes[current].ticks_to_expire))
{
ticks_to_expire -= mp_nodes[current].ticks_to_expire;
previous = current;
current = mp_nodes[current].next;
}
if (current != TIMER_NULL)
{
mp_nodes[current].ticks_to_expire -= ticks_to_expire;
}
p_timer->ticks_to_expire = ticks_to_expire;
p_timer->next = current;
mp_nodes[previous].next = timer_id;
}
}
}
/**@brief Function for removing a timer from the timer queue.
*
* @param[in] timer_id Id of timer to remove.
*/
static void timer_list_remove(app_timer_id_t timer_id)
{
app_timer_id_t previous;
app_timer_id_t current;
uint32_t timeout;
// Find the timer's position in timer list
previous = m_timer_id_head;
current = previous;
while (current != TIMER_NULL)
{
if (current == timer_id)
{
break;
}
previous = current;
current = mp_nodes[current].next;
}
// Timer not in active list
if (current == TIMER_NULL)
{
return;
}
// Timer is the first in the list
if (previous == current)
{
m_timer_id_head = mp_nodes[m_timer_id_head].next;
}
// Remaining timeout between next timeout
timeout = mp_nodes[current].ticks_to_expire;
// Link previous timer with next of this timer, i.e. removing the timer from list
mp_nodes[previous].next = mp_nodes[current].next;
// If this is not the last timer, increment the next timer by this timer timeout
current = mp_nodes[previous].next;
if (current != TIMER_NULL)
{
mp_nodes[current].ticks_to_expire += timeout;
}
}
/**@brief Function for scheduling a check for timeouts by generating a RTC1 interrupt.
*/
static void timer_timeouts_check_sched(void)
{
NVIC_SetPendingIRQ(RTC1_IRQn);
}
/**@brief Function for scheduling a timer list update by generating a SWI0 interrupt.
*/
static void timer_list_handler_sched(void)
{
NVIC_SetPendingIRQ(SWI0_IRQn);
}
/**@brief Function for executing an application timeout handler, either by calling it directly, or
* by passing an event to the @ref app_scheduler.
*
* @param[in] p_timer Pointer to expired timer.
*/
static void timeout_handler_exec(timer_node_t * p_timer)
{
if (m_evt_schedule_func != NULL)
{
uint32_t err_code = m_evt_schedule_func(p_timer->p_timeout_handler, p_timer->p_context);
APP_ERROR_CHECK(err_code);
}
else
{
p_timer->p_timeout_handler(p_timer->p_context);
}
}
/**@brief Function for checking for expired timers.
*/
static void timer_timeouts_check(void)
{
// Handle expired of timer
if (m_timer_id_head != TIMER_NULL)
{
app_timer_id_t timer_id;
uint32_t ticks_elapsed;
uint32_t ticks_expired;
// Initialize actual elapsed ticks being consumed to 0
ticks_expired = 0;
// ticks_elapsed is collected here, job will use it
ticks_elapsed = ticks_diff_get(rtc1_counter_get(), m_ticks_latest);
// Auto variable containing the head of timers expiring
timer_id = m_timer_id_head;
// Expire all timers within ticks_elapsed and collect ticks_expired
while (timer_id != TIMER_NULL)
{
timer_node_t * p_timer;
// Auto variable for current timer node
p_timer = &mp_nodes[timer_id];
// Do nothing if timer did not expire
if (ticks_elapsed < p_timer->ticks_to_expire)
{
break;
}
// Decrement ticks_elapsed and collect expired ticks
ticks_elapsed -= p_timer->ticks_to_expire;
ticks_expired += p_timer->ticks_to_expire;
// Move to next timer
timer_id = p_timer->next;
// Execute Task
timeout_handler_exec(p_timer);
}
// Prepare to queue the ticks expired in the m_ticks_elapsed queue.
if (m_ticks_elapsed_q_read_ind == m_ticks_elapsed_q_write_ind)
{
// The read index of the queue is equal to the write index. This means the new
// value of ticks_expired should be stored at a new location in the m_ticks_elapsed
// queue (which is implemented as a double buffer).
// Check if there will be a queue overflow.
if (++m_ticks_elapsed_q_write_ind == CONTEXT_QUEUE_SIZE_MAX)
{
// There will be a queue overflow. Hence the write index should point to the start
// of the queue.
m_ticks_elapsed_q_write_ind = 0;
}
}
// Queue the ticks expired.
m_ticks_elapsed[m_ticks_elapsed_q_write_ind] = ticks_expired;
timer_list_handler_sched();
}
}
/**@brief Function for acquiring the number of ticks elapsed.
*
* @param[out] p_ticks_elapsed Number of ticks elapsed.
*
* @return TRUE if elapsed ticks was read from queue, FALSE otherwise.
*/
static bool elapsed_ticks_acquire(uint32_t * p_ticks_elapsed)
{
// Pick the elapsed value from queue
if (m_ticks_elapsed_q_read_ind != m_ticks_elapsed_q_write_ind)
{
// Dequeue elapsed value
m_ticks_elapsed_q_read_ind++;
if (m_ticks_elapsed_q_read_ind == CONTEXT_QUEUE_SIZE_MAX)
{
m_ticks_elapsed_q_read_ind = 0;
}
*p_ticks_elapsed = m_ticks_elapsed[m_ticks_elapsed_q_read_ind];
m_ticks_latest += *p_ticks_elapsed;
m_ticks_latest &= MAX_RTC_COUNTER_VAL;
return true;
}
else
{
// No elapsed value in queue
*p_ticks_elapsed = 0;
return false;
}
}
/**@brief Function for handling the timer list deletions.
*
* @return TRUE if Capture Compare register must be updated, FALSE otherwise.
*/
static bool list_deletions_handler(void)
{
app_timer_id_t timer_id_old_head;
uint8_t user_id;
// Remember the old head, so as to decide if new compare needs to be set
timer_id_old_head = m_timer_id_head;
user_id = m_user_array_size;
while (user_id--)
{
timer_user_t * p_user = &mp_users[user_id];
uint8_t user_ops_first = p_user->first;
while (user_ops_first != p_user->last)
{
timer_node_t * p_timer;
timer_user_op_t * p_user_op = &p_user->p_user_op_queue[user_ops_first];
// Traverse to next operation in queue
user_ops_first++;
if (user_ops_first == p_user->user_op_queue_size)
{
user_ops_first = 0;
}
switch (p_user_op->op_type)
{
case TIMER_USER_OP_TYPE_STOP:
// Delete node if timer is running
p_timer = &mp_nodes[p_user_op->timer_id];
if (p_timer->is_running)
{
timer_list_remove(p_user_op->timer_id);
p_timer->is_running = false;
}
break;
case TIMER_USER_OP_TYPE_STOP_ALL:
// Delete list of running timers, and mark all timers as not running
while (m_timer_id_head != TIMER_NULL)
{
timer_node_t * p_head = &mp_nodes[m_timer_id_head];
p_head->is_running = false;
m_timer_id_head = p_head->next;
}
break;
default:
// No implementation needed.
break;
}
}
}
// Detect change in head of the list
return (m_timer_id_head != timer_id_old_head);
}
/**@brief Function for updating the timer list for expired timers.
*
* @param[in] ticks_elapsed Number of elapsed ticks.
* @param[in] ticks_previous Previous known value of the RTC counter.
* @param[out] p_restart_list_head List of repeating timers to be restarted.
*/
static void expired_timers_handler(uint32_t ticks_elapsed,
uint32_t ticks_previous,
app_timer_id_t * p_restart_list_head)
{
uint32_t ticks_expired = 0;
while (m_timer_id_head != TIMER_NULL)
{
timer_node_t * p_timer;
app_timer_id_t id_expired;
// Auto variable for current timer node
p_timer = &mp_nodes[m_timer_id_head];
// Do nothing if timer did not expire
if (ticks_elapsed < p_timer->ticks_to_expire)
{
p_timer->ticks_to_expire -= ticks_elapsed;
break;
}
// Decrement ticks_elapsed and collect expired ticks
ticks_elapsed -= p_timer->ticks_to_expire;
ticks_expired += p_timer->ticks_to_expire;
// Timer expired, set ticks_to_expire zero
p_timer->ticks_to_expire = 0;
p_timer->is_running = false;
// Remove the expired timer from head
id_expired = m_timer_id_head;
m_timer_id_head = p_timer->next;
// Timer will be restarted if periodic
if (p_timer->ticks_periodic_interval != 0)
{
p_timer->ticks_at_start = (ticks_previous + ticks_expired) & MAX_RTC_COUNTER_VAL;
p_timer->ticks_first_interval = p_timer->ticks_periodic_interval;
p_timer->next = *p_restart_list_head;
*p_restart_list_head = id_expired;
}
}
}
/**@brief Function for handling timer list insertions.
*
* @param[in] p_restart_list_head List of repeating timers to be restarted.
*
* @return TRUE if Capture Compare register must be updated, FALSE otherwise.
*/
static bool list_insertions_handler(app_timer_id_t restart_list_head)
{
app_timer_id_t timer_id_old_head;
uint8_t user_id;
// Remember the old head, so as to decide if new compare needs to be set
timer_id_old_head = m_timer_id_head;
user_id = m_user_array_size;
while (user_id--)
{
timer_user_t * p_user = &mp_users[user_id];
// Handle insertions of timers
while ((restart_list_head != TIMER_NULL) || (p_user->first != p_user->last))
{
app_timer_id_t id_start;
timer_node_t * p_timer;
if (restart_list_head != TIMER_NULL)
{
id_start = restart_list_head;
p_timer = &mp_nodes[id_start];
restart_list_head = p_timer->next;
}
else
{
timer_user_op_t * p_user_op = &p_user->p_user_op_queue[p_user->first];
p_user->first++;
if (p_user->first == p_user->user_op_queue_size)
{
p_user->first = 0;
}
id_start = p_user_op->timer_id;
p_timer = &mp_nodes[id_start];
if ((p_user_op->op_type != TIMER_USER_OP_TYPE_START) || p_timer->is_running)
{
continue;
}
p_timer->ticks_at_start = p_user_op->params.start.ticks_at_start;
p_timer->ticks_first_interval = p_user_op->params.start.ticks_first_interval;
p_timer->ticks_periodic_interval = p_user_op->params.start.ticks_periodic_interval;
p_timer->p_context = p_user_op->params.start.p_context;
}
// Prepare the node to be inserted
if (
((p_timer->ticks_at_start - m_ticks_latest) & MAX_RTC_COUNTER_VAL)
<
(MAX_RTC_COUNTER_VAL / 2)
)
{
p_timer->ticks_to_expire = ticks_diff_get(p_timer->ticks_at_start, m_ticks_latest) +
p_timer->ticks_first_interval;
}
else
{
uint32_t delta_current_start;
delta_current_start = ticks_diff_get(m_ticks_latest, p_timer->ticks_at_start);
if (p_timer->ticks_first_interval > delta_current_start)
{
p_timer->ticks_to_expire = p_timer->ticks_first_interval - delta_current_start;
}
else
{
p_timer->ticks_to_expire = 0;
}
}
p_timer->ticks_at_start = 0;
p_timer->ticks_first_interval = 0;
p_timer->is_running = true;
p_timer->next = TIMER_NULL;
// Insert into list
timer_list_insert(id_start);
}
}
return (m_timer_id_head != timer_id_old_head);
}
/**@brief Function for updating the Capture Compare register.
*/
static void compare_reg_update(app_timer_id_t timer_id_head_old)
{
// Setup the timeout for timers on the head of the list
if (m_timer_id_head != TIMER_NULL)
{
uint32_t ticks_to_expire = mp_nodes[m_timer_id_head].ticks_to_expire;
uint32_t pre_counter_val = rtc1_counter_get();
uint32_t cc = m_ticks_latest;
uint32_t ticks_elapsed = ticks_diff_get(pre_counter_val, cc) + RTC_COMPARE_OFFSET_MIN;
if (timer_id_head_old == TIMER_NULL)
{
// No timers were already running, start RTC
rtc1_start();
}
cc += (ticks_elapsed < ticks_to_expire) ? ticks_to_expire : ticks_elapsed;
cc &= MAX_RTC_COUNTER_VAL;
rtc1_compare0_set(cc);
uint32_t post_counter_val = rtc1_counter_get();
if (
(ticks_diff_get(post_counter_val, pre_counter_val) + RTC_COMPARE_OFFSET_MIN)
>
ticks_diff_get(cc, pre_counter_val)
)
{
// When this happens the COMPARE event may not be triggered by the RTC.
// The nRF51 Series User Specification states that if the COUNTER value is N
// (i.e post_counter_val = N), writing N or N+1 to a CC register may not trigger a
// COMPARE event. Hence the RTC interrupt is forcefully pended by calling the following
// function.
timer_timeouts_check_sched();
}
}
else
{
// No timers are running, stop RTC
rtc1_stop();
}
}
/**@brief Function for handling changes to the timer list.
*/
static void timer_list_handler(void)
{
app_timer_id_t restart_list_head = TIMER_NULL;
uint32_t ticks_elapsed;
uint32_t ticks_previous;
bool ticks_have_elapsed;
bool compare_update;
app_timer_id_t timer_id_head_old;
// Back up the previous known tick and previous list head
ticks_previous = m_ticks_latest;
timer_id_head_old = m_timer_id_head;
// Get number of elapsed ticks
ticks_have_elapsed = elapsed_ticks_acquire(&ticks_elapsed);
// Handle list deletions
compare_update = list_deletions_handler();
// Handle expired timers
if (ticks_have_elapsed)
{
expired_timers_handler(ticks_elapsed, ticks_previous, &restart_list_head);
compare_update = true;
}
// Handle list insertions
if (list_insertions_handler(restart_list_head))
{
compare_update = true;
}
// Update compare register if necessary
if (compare_update)
{
compare_reg_update(timer_id_head_old);
}
}
/**@brief Function for enqueueing a new operations queue entry.
*
* @param[in] p_user User that the entry is to be enqueued for.
* @param[in] last_index Index of the next last index to be enqueued.
*/
static void user_op_enque(timer_user_t * p_user, app_timer_id_t last_index)
{
p_user->last = last_index;
}
/**@brief Function for allocating a new operations queue entry.
*
* @param[in] p_user User that the entry is to be allocated for.
* @param[out] p_last_index Index of the next last index to be enqueued.
*
* @return Pointer to allocated queue entry, or NULL if queue is full.
*/
static timer_user_op_t * user_op_alloc(timer_user_t * p_user, app_timer_id_t * p_last_index)
{
app_timer_id_t last;
timer_user_op_t * p_user_op;
last = p_user->last + 1;
if (last == p_user->user_op_queue_size)
{
// Overflow case.
last = 0;
}
if (last == p_user->first)
{
// Queue is full.
return NULL;
}
*p_last_index = last;
p_user_op = &p_user->p_user_op_queue[p_user->last];
return p_user_op;
}
/**@brief Function for scheduling a Timer Start operation.
*
* @param[in] user_id Id of user calling this function.
* @param[in] timer_id Id of timer to start.
* @param[in] timeout_initial Time (in ticks) to first timer expiry.
* @param[in] timeout_periodic Time (in ticks) between periodic expiries.
* @param[in] p_context General purpose pointer. Will be passed to the timeout handler when
* the timer expires.
* @return NRF_SUCCESS on success, otherwise an error code.
*/
static uint32_t timer_start_op_schedule(timer_user_id_t user_id,
app_timer_id_t timer_id,
uint32_t timeout_initial,
uint32_t timeout_periodic,
void * p_context)
{
app_timer_id_t last_index;
timer_user_op_t * p_user_op = user_op_alloc(&mp_users[user_id], &last_index);
if (p_user_op == NULL)
{
return NRF_ERROR_NO_MEM;
}
p_user_op->op_type = TIMER_USER_OP_TYPE_START;
p_user_op->timer_id = timer_id;
p_user_op->params.start.ticks_at_start = rtc1_counter_get();
p_user_op->params.start.ticks_first_interval = timeout_initial;
p_user_op->params.start.ticks_periodic_interval = timeout_periodic;
p_user_op->params.start.p_context = p_context;
user_op_enque(&mp_users[user_id], last_index);
timer_list_handler_sched();
return NRF_SUCCESS;
}
/**@brief Function for scheduling a Timer Stop operation.
*
* @param[in] user_id Id of user calling this function.
* @param[in] timer_id Id of timer to stop.
*
* @return NRF_SUCCESS on successful scheduling a timer stop operation. NRF_ERROR_NO_MEM when there
* is no memory left to schedule the timer stop operation.
*/
static uint32_t timer_stop_op_schedule(timer_user_id_t user_id, app_timer_id_t timer_id)
{
app_timer_id_t last_index;
timer_user_op_t * p_user_op = user_op_alloc(&mp_users[user_id], &last_index);
if (p_user_op == NULL)
{
return NRF_ERROR_NO_MEM;
}
p_user_op->op_type = TIMER_USER_OP_TYPE_STOP;
p_user_op->timer_id = timer_id;
user_op_enque(&mp_users[user_id], last_index);
timer_list_handler_sched();
return NRF_SUCCESS;
}
/**@brief Function for scheduling a Timer Stop All operation.
*
* @param[in] user_id Id of user calling this function.
*/
static uint32_t timer_stop_all_op_schedule(timer_user_id_t user_id)
{
app_timer_id_t last_index;
timer_user_op_t * p_user_op = user_op_alloc(&mp_users[user_id], &last_index);
if (p_user_op == NULL)
{
return NRF_ERROR_NO_MEM;
}
p_user_op->op_type = TIMER_USER_OP_TYPE_STOP_ALL;
p_user_op->timer_id = TIMER_NULL;
user_op_enque(&mp_users[user_id], last_index);
timer_list_handler_sched();
return NRF_SUCCESS;
}
/**@brief Function for handling the RTC1 interrupt.
*
* @details Checks for timeouts, and executes timeout handlers for expired timers.
*/
extern "C" void RTC1_IRQHandler(void)
{
// Clear all events (also unexpected ones)
NRF_RTC1->EVENTS_COMPARE[0] = 0;
NRF_RTC1->EVENTS_COMPARE[1] = 0;
NRF_RTC1->EVENTS_COMPARE[2] = 0;
NRF_RTC1->EVENTS_COMPARE[3] = 0;
NRF_RTC1->EVENTS_TICK = 0;
NRF_RTC1->EVENTS_OVRFLW = 0;
// Check for expired timers
timer_timeouts_check();
}
/**@brief Function for handling the SWI0 interrupt.
*
* @details Performs all updates to the timer list.
*/
extern "C" void SWI0_IRQHandler(void)
{
timer_list_handler();
}
uint32_t app_timer_init(uint32_t prescaler,
uint8_t max_timers,
uint8_t op_queues_size,
void * p_buffer,
app_timer_evt_schedule_func_t evt_schedule_func)
{
int i;
// Check that buffer is correctly aligned
if (!is_word_aligned(p_buffer))
{
return NRF_ERROR_INVALID_PARAM;
}
// Check for NULL buffer
if (p_buffer == NULL)
{
return NRF_ERROR_INVALID_PARAM;
}
// Stop RTC to prevent any running timers from expiring (in case of reinitialization)
rtc1_stop();
m_evt_schedule_func = evt_schedule_func;
// Initialize timer node array
m_node_array_size = max_timers;
mp_nodes = (timer_node_t *) p_buffer;
for (i = 0; i < max_timers; i++)
{
mp_nodes[i].state = STATE_FREE;
mp_nodes[i].is_running = false;
}
// Skip timer node array
p_buffer = &((uint8_t *)p_buffer)[max_timers * sizeof(timer_node_t)];
// Initialize users array
m_user_array_size = APP_TIMER_INT_LEVELS;
mp_users = (timer_user_t *) p_buffer;
// Skip user array
p_buffer = &((uint8_t *)p_buffer)[APP_TIMER_INT_LEVELS * sizeof(timer_user_t)];
// Initialize operation queues
for (i = 0; i < APP_TIMER_INT_LEVELS; i++)
{
timer_user_t * p_user = &mp_users[i];
p_user->first = 0;
p_user->last = 0;
p_user->user_op_queue_size = op_queues_size;
p_user->p_user_op_queue = (timer_user_op_t *) p_buffer;
// Skip operation queue
p_buffer = &((uint8_t *)p_buffer)[op_queues_size * sizeof(timer_user_op_t)];
}
m_timer_id_head = TIMER_NULL;
m_ticks_elapsed_q_read_ind = 0;
m_ticks_elapsed_q_write_ind = 0;
NVIC_ClearPendingIRQ(SWI0_IRQn);
NVIC_SetPriority(SWI0_IRQn, SWI0_IRQ_PRI);
NVIC_EnableIRQ(SWI0_IRQn);
rtc1_init(prescaler);
m_ticks_latest = rtc1_counter_get();
return NRF_SUCCESS;
}
uint32_t app_timer_create(app_timer_id_t * p_timer_id,
app_timer_mode_t mode,
app_timer_timeout_handler_t timeout_handler)
{
int i;
// Check state and parameters
if (mp_nodes == NULL)
{
return NRF_ERROR_INVALID_STATE;
}
if (timeout_handler == NULL)
{
return NRF_ERROR_INVALID_PARAM;
}
if (p_timer_id == NULL)
{
return NRF_ERROR_INVALID_PARAM;
}
// Find free timer
for (i = 0; i < m_node_array_size; i++)
{
if (mp_nodes[i].state == STATE_FREE)
{
mp_nodes[i].state = STATE_ALLOCATED;
mp_nodes[i].mode = mode;
mp_nodes[i].p_timeout_handler = timeout_handler;
*p_timer_id = i;
return NRF_SUCCESS;
}
}
return NRF_ERROR_NO_MEM;
}
/**@brief Function for creating a timer user id from the current interrupt level.
*
* @return Timer user id.
*/
static timer_user_id_t user_id_get(void)
{
timer_user_id_t ret;
STATIC_ASSERT(APP_TIMER_INT_LEVELS == 3);
switch (current_int_priority_get())
{
case APP_IRQ_PRIORITY_HIGH:
ret = APP_HIGH_USER_ID;
break;
case APP_IRQ_PRIORITY_LOW:
ret = APP_LOW_USER_ID;
break;
default:
ret = THREAD_MODE_USER_ID;
break;
}
return ret;
}
uint32_t app_timer_start(app_timer_id_t timer_id, uint32_t timeout_ticks, void * p_context)
{
uint32_t timeout_periodic;
// Check state and parameters
if (mp_nodes == NULL)
{
return NRF_ERROR_INVALID_STATE;
}
if ((timer_id >= m_node_array_size) || (timeout_ticks < APP_TIMER_MIN_TIMEOUT_TICKS))
{
return NRF_ERROR_INVALID_PARAM;
}
if (mp_nodes[timer_id].state != STATE_ALLOCATED)
{
return NRF_ERROR_INVALID_STATE;
}
// Schedule timer start operation
timeout_periodic = (mp_nodes[timer_id].mode == APP_TIMER_MODE_REPEATED) ? timeout_ticks : 0;
return timer_start_op_schedule(user_id_get(),
timer_id,
timeout_ticks,
timeout_periodic,
p_context);
}
uint32_t app_timer_stop(app_timer_id_t timer_id)
{
// Check state and parameters
if (mp_nodes == NULL)
{
return NRF_ERROR_INVALID_STATE;
}
if (timer_id >= m_node_array_size)
{
return NRF_ERROR_INVALID_PARAM;
}
if (mp_nodes[timer_id].state != STATE_ALLOCATED)
{
return NRF_ERROR_INVALID_STATE;
}
// Schedule timer stop operation
return timer_stop_op_schedule(user_id_get(), timer_id);
}
uint32_t app_timer_stop_all(void)
{
// Check state
if (mp_nodes == NULL)
{
return NRF_ERROR_INVALID_STATE;
}
return timer_stop_all_op_schedule(user_id_get());
}
uint32_t app_timer_cnt_get(uint32_t * p_ticks)
{
*p_ticks = rtc1_counter_get();
return NRF_SUCCESS;
}
uint32_t app_timer_cnt_diff_compute(uint32_t ticks_to,
uint32_t ticks_from,
uint32_t * p_ticks_diff)
{
*p_ticks_diff = ticks_diff_get(ticks_to, ticks_from);
return NRF_SUCCESS;
}
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