Ermanno Brusadin / mbed-src

mbed library sources

common/us_ticker_api.c@0:0a673c671a56, 2016-07-27 (annotated)

Committer:
ebrus
Date:
Wed Jul 27 18:35:32 2016 +0000
Revision:
0:0a673c671a56
4

Who changed what in which revision?

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ebrus 0:0a673c671a56 1 /* mbed Microcontroller Library
ebrus 0:0a673c671a56 2 * Copyright (c) 2006-2013 ARM Limited
ebrus 0:0a673c671a56 3 *
ebrus 0:0a673c671a56 4 * Licensed under the Apache License, Version 2.0 (the "License");
ebrus 0:0a673c671a56 5 * you may not use this file except in compliance with the License.
ebrus 0:0a673c671a56 6 * You may obtain a copy of the License at
ebrus 0:0a673c671a56 7 *
ebrus 0:0a673c671a56 8 * http://www.apache.org/licenses/LICENSE-2.0
ebrus 0:0a673c671a56 9 *
ebrus 0:0a673c671a56 10 * Unless required by applicable law or agreed to in writing, software
ebrus 0:0a673c671a56 11 * distributed under the License is distributed on an "AS IS" BASIS,
ebrus 0:0a673c671a56 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
ebrus 0:0a673c671a56 13 * See the License for the specific language governing permissions and
ebrus 0:0a673c671a56 14 * limitations under the License.
ebrus 0:0a673c671a56 15 */
ebrus 0:0a673c671a56 16 #include <stddef.h>
ebrus 0:0a673c671a56 17 #include "us_ticker_api.h"
ebrus 0:0a673c671a56 18 #include "cmsis.h"
ebrus 0:0a673c671a56 19
ebrus 0:0a673c671a56 20 static ticker_event_handler event_handler;
ebrus 0:0a673c671a56 21 static ticker_event_t *head = NULL;
ebrus 0:0a673c671a56 22
ebrus 0:0a673c671a56 23 void us_ticker_set_handler(ticker_event_handler handler) {
ebrus 0:0a673c671a56 24 us_ticker_init();
ebrus 0:0a673c671a56 25
ebrus 0:0a673c671a56 26 event_handler = handler;
ebrus 0:0a673c671a56 27 }
ebrus 0:0a673c671a56 28
ebrus 0:0a673c671a56 29 void us_ticker_irq_handler(void) {
ebrus 0:0a673c671a56 30 us_ticker_clear_interrupt();
ebrus 0:0a673c671a56 31
ebrus 0:0a673c671a56 32 /* Go through all the pending TimerEvents */
ebrus 0:0a673c671a56 33 while (1) {
ebrus 0:0a673c671a56 34 if (head == NULL) {
ebrus 0:0a673c671a56 35 // There are no more TimerEvents left, so disable matches.
ebrus 0:0a673c671a56 36 us_ticker_disable_interrupt();
ebrus 0:0a673c671a56 37 return;
ebrus 0:0a673c671a56 38 }
ebrus 0:0a673c671a56 39
ebrus 0:0a673c671a56 40 if ((int)(head->timestamp - us_ticker_read()) <= 0) {
ebrus 0:0a673c671a56 41 // This event was in the past:
ebrus 0:0a673c671a56 42 // point to the following one and execute its handler
ebrus 0:0a673c671a56 43 ticker_event_t *p = head;
ebrus 0:0a673c671a56 44 head = head->next;
ebrus 0:0a673c671a56 45 if (event_handler != NULL) {
ebrus 0:0a673c671a56 46 event_handler(p->id); // NOTE: the handler can set new events
ebrus 0:0a673c671a56 47 }
ebrus 0:0a673c671a56 48 /* Note: We continue back to examining the head because calling the
ebrus 0:0a673c671a56 49 * event handler may have altered the chain of pending events. */
ebrus 0:0a673c671a56 50 } else {
ebrus 0:0a673c671a56 51 // This event and the following ones in the list are in the future:
ebrus 0:0a673c671a56 52 // set it as next interrupt and return
ebrus 0:0a673c671a56 53 us_ticker_set_interrupt(head->timestamp);
ebrus 0:0a673c671a56 54 return;
ebrus 0:0a673c671a56 55 }
ebrus 0:0a673c671a56 56 }
ebrus 0:0a673c671a56 57 }
ebrus 0:0a673c671a56 58
ebrus 0:0a673c671a56 59 void us_ticker_insert_event(ticker_event_t *obj, timestamp_t timestamp, uint32_t id) {
ebrus 0:0a673c671a56 60 /* disable interrupts for the duration of the function */
ebrus 0:0a673c671a56 61 __disable_irq();
ebrus 0:0a673c671a56 62
ebrus 0:0a673c671a56 63 // initialise our data
ebrus 0:0a673c671a56 64 obj->timestamp = timestamp;
ebrus 0:0a673c671a56 65 obj->id = id;
ebrus 0:0a673c671a56 66
ebrus 0:0a673c671a56 67 /* Go through the list until we either reach the end, or find
ebrus 0:0a673c671a56 68 an element this should come before (which is possibly the
ebrus 0:0a673c671a56 69 head). */
ebrus 0:0a673c671a56 70 ticker_event_t *prev = NULL, *p = head;
ebrus 0:0a673c671a56 71 while (p != NULL) {
ebrus 0:0a673c671a56 72 /* check if we come before p */
ebrus 0:0a673c671a56 73 if ((int)(timestamp - p->timestamp) <= 0) {
ebrus 0:0a673c671a56 74 break;
ebrus 0:0a673c671a56 75 }
ebrus 0:0a673c671a56 76 /* go to the next element */
ebrus 0:0a673c671a56 77 prev = p;
ebrus 0:0a673c671a56 78 p = p->next;
ebrus 0:0a673c671a56 79 }
ebrus 0:0a673c671a56 80 /* if prev is NULL we're at the head */
ebrus 0:0a673c671a56 81 if (prev == NULL) {
ebrus 0:0a673c671a56 82 head = obj;
ebrus 0:0a673c671a56 83 us_ticker_set_interrupt(timestamp);
ebrus 0:0a673c671a56 84 } else {
ebrus 0:0a673c671a56 85 prev->next = obj;
ebrus 0:0a673c671a56 86 }
ebrus 0:0a673c671a56 87 /* if we're at the end p will be NULL, which is correct */
ebrus 0:0a673c671a56 88 obj->next = p;
ebrus 0:0a673c671a56 89
ebrus 0:0a673c671a56 90 __enable_irq();
ebrus 0:0a673c671a56 91 }
ebrus 0:0a673c671a56 92
ebrus 0:0a673c671a56 93 void us_ticker_remove_event(ticker_event_t *obj) {
ebrus 0:0a673c671a56 94 __disable_irq();
ebrus 0:0a673c671a56 95
ebrus 0:0a673c671a56 96 // remove this object from the list
ebrus 0:0a673c671a56 97 if (head == obj) {
ebrus 0:0a673c671a56 98 // first in the list, so just drop me
ebrus 0:0a673c671a56 99 head = obj->next;
ebrus 0:0a673c671a56 100 if (head == NULL) {
ebrus 0:0a673c671a56 101 us_ticker_disable_interrupt();
ebrus 0:0a673c671a56 102 } else {
ebrus 0:0a673c671a56 103 us_ticker_set_interrupt(head->timestamp);
ebrus 0:0a673c671a56 104 }
ebrus 0:0a673c671a56 105 } else {
ebrus 0:0a673c671a56 106 // find the object before me, then drop me
ebrus 0:0a673c671a56 107 ticker_event_t* p = head;
ebrus 0:0a673c671a56 108 while (p != NULL) {
ebrus 0:0a673c671a56 109 if (p->next == obj) {
ebrus 0:0a673c671a56 110 p->next = obj->next;
ebrus 0:0a673c671a56 111 break;
ebrus 0:0a673c671a56 112 }
ebrus 0:0a673c671a56 113 p = p->next;
ebrus 0:0a673c671a56 114 }
ebrus 0:0a673c671a56 115 }
ebrus 0:0a673c671a56 116
ebrus 0:0a673c671a56 117 __enable_irq();
ebrus 0:0a673c671a56 118 }