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common/ticker_api.c
- Committer:
- fwndz
- Date:
- 2016-12-21
- Revision:
- 636:de8f3520e5c1
- Parent:
- 525:c320967f86b9
File content as of revision 636:de8f3520e5c1:
/* mbed Microcontroller Library * Copyright (c) 2015 ARM Limited * * Licensed 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. */ #include <stddef.h> #include "ticker_api.h" #include "cmsis.h" void ticker_set_handler(const ticker_data_t *const data, ticker_event_handler handler) { data->interface->init(); data->queue->event_handler = handler; } void ticker_irq_handler(const ticker_data_t *const data) { data->interface->clear_interrupt(); /* Go through all the pending TimerEvents */ while (1) { if (data->queue->head == NULL) { // There are no more TimerEvents left, so disable matches. data->interface->disable_interrupt(); return; } if ((int)(data->queue->head->timestamp - data->interface->read()) <= 0) { // This event was in the past: // point to the following one and execute its handler ticker_event_t *p = data->queue->head; data->queue->head = data->queue->head->next; if (data->queue->event_handler != NULL) { (*data->queue->event_handler)(p->id); // NOTE: the handler can set new events } /* Note: We continue back to examining the head because calling the * event handler may have altered the chain of pending events. */ } else { // This event and the following ones in the list are in the future: // set it as next interrupt and return data->interface->set_interrupt(data->queue->head->timestamp); return; } } } void ticker_insert_event(const ticker_data_t *const data, ticker_event_t *obj, timestamp_t timestamp, uint32_t id) { /* disable interrupts for the duration of the function */ __disable_irq(); // initialise our data obj->timestamp = timestamp; obj->id = id; /* Go through the list until we either reach the end, or find an element this should come before (which is possibly the head). */ ticker_event_t *prev = NULL, *p = data->queue->head; while (p != NULL) { /* check if we come before p */ if ((int)(timestamp - p->timestamp) < 0) { break; } /* go to the next element */ prev = p; p = p->next; } /* if prev is NULL we're at the head */ if (prev == NULL) { data->queue->head = obj; data->interface->set_interrupt(timestamp); } else { prev->next = obj; } /* if we're at the end p will be NULL, which is correct */ obj->next = p; __enable_irq(); } void ticker_remove_event(const ticker_data_t *const data, ticker_event_t *obj) { __disable_irq(); // remove this object from the list if (data->queue->head == obj) { // first in the list, so just drop me data->queue->head = obj->next; if (data->queue->head == NULL) { data->interface->disable_interrupt(); } else { data->interface->set_interrupt(data->queue->head->timestamp); } } else { // find the object before me, then drop me ticker_event_t* p = data->queue->head; while (p != NULL) { if (p->next == obj) { p->next = obj->next; break; } p = p->next; } } __enable_irq(); } timestamp_t ticker_read(const ticker_data_t *const data) { return data->interface->read(); } int ticker_get_next_timestamp(const ticker_data_t *const data, timestamp_t *timestamp) { int ret = 0; /* if head is NULL, there are no pending events */ __disable_irq(); if (data->queue->head != NULL) { *timestamp = data->queue->head->timestamp; ret = 1; } __enable_irq(); return ret; }