1 | /* mbed Microcontroller Library
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2 | * Copyright (c) 2015 ARM Limited
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3 | *
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4 | * Licensed under the Apache License, Version 2.0 (the "License");
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5 | * you may not use this file except in compliance with the License.
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6 | * You may obtain a copy of the License at
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7 | *
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8 | * http://www.apache.org/licenses/LICENSE-2.0
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9 | *
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10 | * Unless required by applicable law or agreed to in writing, software
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11 | * distributed under the License is distributed on an "AS IS" BASIS,
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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13 | * See the License for the specific language governing permissions and
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14 | * limitations under the License.
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15 | */
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16 | #include <stddef.h>
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17 | #include "hal/ticker_api.h"
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18 | #include "platform/mbed_critical.h"
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19 |
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20 | void ticker_set_handler(const ticker_data_t *const data, ticker_event_handler handler) {
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21 | data->interface->init();
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22 |
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23 | data->queue->event_handler = handler;
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24 | }
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25 |
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26 | void ticker_irq_handler(const ticker_data_t *const data) {
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27 | data->interface->clear_interrupt();
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28 |
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29 | /* Go through all the pending TimerEvents */
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30 | while (1) {
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31 | if (data->queue->head == NULL) {
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32 | // There are no more TimerEvents left, so disable matches.
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33 | data->interface->disable_interrupt();
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34 | return;
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35 | }
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36 |
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37 | if ((int)(data->queue->head->timestamp - data->interface->read()) <= 0) {
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38 | // This event was in the past:
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39 | // point to the following one and execute its handler
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40 | ticker_event_t *p = data->queue->head;
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41 | data->queue->head = data->queue->head->next;
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42 | if (data->queue->event_handler != NULL) {
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43 | (*data->queue->event_handler)(p->id); // NOTE: the handler can set new events
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44 | }
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45 | /* Note: We continue back to examining the head because calling the
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46 | * event handler may have altered the chain of pending events. */
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47 | } else {
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48 | // This event and the following ones in the list are in the future:
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49 | // set it as next interrupt and return
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50 | data->interface->set_interrupt(data->queue->head->timestamp);
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51 | return;
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52 | }
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53 | }
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54 | }
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55 |
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56 | void ticker_insert_event(const ticker_data_t *const data, ticker_event_t *obj, timestamp_t timestamp, uint32_t id) {
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57 | /* disable interrupts for the duration of the function */
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58 | core_util_critical_section_enter();
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59 |
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60 | // initialise our data
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61 | obj->timestamp = timestamp;
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62 | obj->id = id;
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63 |
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64 | /* Go through the list until we either reach the end, or find
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65 | an element this should come before (which is possibly the
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66 | head). */
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67 | ticker_event_t *prev = NULL, *p = data->queue->head;
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68 | while (p != NULL) {
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69 | /* check if we come before p */
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70 | if ((int)(timestamp - p->timestamp) < 0) {
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71 | break;
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72 | }
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73 | /* go to the next element */
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74 | prev = p;
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75 | p = p->next;
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76 | }
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77 |
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78 | /* if we're at the end p will be NULL, which is correct */
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79 | obj->next = p;
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80 |
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81 | /* if prev is NULL we're at the head */
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82 | if (prev == NULL) {
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83 | data->queue->head = obj;
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84 | data->interface->set_interrupt(timestamp);
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85 | } else {
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86 | prev->next = obj;
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87 | }
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88 |
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89 | core_util_critical_section_exit();
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90 | }
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91 |
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92 | void ticker_remove_event(const ticker_data_t *const data, ticker_event_t *obj) {
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93 | core_util_critical_section_enter();
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94 |
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95 | // remove this object from the list
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96 | if (data->queue->head == obj) {
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97 | // first in the list, so just drop me
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98 | data->queue->head = obj->next;
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99 | if (data->queue->head == NULL) {
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100 | data->interface->disable_interrupt();
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101 | } else {
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102 | data->interface->set_interrupt(data->queue->head->timestamp);
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103 | }
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104 | } else {
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105 | // find the object before me, then drop me
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106 | ticker_event_t* p = data->queue->head;
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107 | while (p != NULL) {
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108 | if (p->next == obj) {
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109 | p->next = obj->next;
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110 | break;
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111 | }
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112 | p = p->next;
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113 | }
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114 | }
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115 |
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116 | core_util_critical_section_exit();
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117 | }
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118 |
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119 | timestamp_t ticker_read(const ticker_data_t *const data)
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120 | {
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121 | return data->interface->read();
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122 | }
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123 |
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124 | int ticker_get_next_timestamp(const ticker_data_t *const data, timestamp_t *timestamp)
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125 | {
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126 | int ret = 0;
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127 |
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128 | /* if head is NULL, there are no pending events */
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129 | core_util_critical_section_enter();
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130 | if (data->queue->head != NULL) {
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131 | *timestamp = data->queue->head->timestamp;
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132 | ret = 1;
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133 | }
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134 | core_util_critical_section_exit();
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135 |
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136 | return ret;
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137 | }
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