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hal/mbed_ticker_api.c@181:96ed750bd169, 2018-01-17 (annotated)

Committer:
Anna Bridge
Date:
Wed Jan 17 15:23:54 2018 +0000
Revision:
181:96ed750bd169
Parent:
176:af195413fb11
Child:
182:57724642e740
mbed-dev libray. Release version 158

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 149:156823d33999 1 /* mbed Microcontroller Library
<> 149:156823d33999 2 * Copyright (c) 2015 ARM Limited
<> 149:156823d33999 3 *
<> 149:156823d33999 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 149:156823d33999 5 * you may not use this file except in compliance with the License.
<> 149:156823d33999 6 * You may obtain a copy of the License at
<> 149:156823d33999 7 *
<> 149:156823d33999 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 149:156823d33999 9 *
<> 149:156823d33999 10 * Unless required by applicable law or agreed to in writing, software
<> 149:156823d33999 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 149:156823d33999 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 149:156823d33999 13 * See the License for the specific language governing permissions and
<> 149:156823d33999 14 * limitations under the License.
<> 149:156823d33999 15 */
AnnaBridge 167:e84263d55307 16 #include <stdio.h>
<> 149:156823d33999 17 #include <stddef.h>
<> 149:156823d33999 18 #include "hal/ticker_api.h"
<> 160:d5399cc887bb 19 #include "platform/mbed_critical.h"
Anna Bridge 181:96ed750bd169 20 #include "mbed_assert.h"
<> 149:156823d33999 21
AnnaBridge 167:e84263d55307 22 static void schedule_interrupt(const ticker_data_t *const ticker);
AnnaBridge 167:e84263d55307 23 static void update_present_time(const ticker_data_t *const ticker);
AnnaBridge 167:e84263d55307 24
AnnaBridge 167:e84263d55307 25 /*
AnnaBridge 167:e84263d55307 26 * Initialize a ticker instance.
AnnaBridge 167:e84263d55307 27 */
AnnaBridge 167:e84263d55307 28 static void initialize(const ticker_data_t *ticker)
AnnaBridge 167:e84263d55307 29 {
AnnaBridge 167:e84263d55307 30 // return if the queue has already been initialized, in that case the
AnnaBridge 167:e84263d55307 31 // interface used by the queue is already initialized.
AnnaBridge 167:e84263d55307 32 if (ticker->queue->initialized) {
AnnaBridge 167:e84263d55307 33 return;
AnnaBridge 167:e84263d55307 34 }
<> 149:156823d33999 35
AnnaBridge 167:e84263d55307 36 ticker->interface->init();
Anna Bridge 181:96ed750bd169 37
Anna Bridge 181:96ed750bd169 38 const ticker_info_t *info = ticker->interface->get_info();
Anna Bridge 181:96ed750bd169 39 uint32_t frequency = info->frequency;
Anna Bridge 181:96ed750bd169 40 if (info->frequency == 0) {
Anna Bridge 181:96ed750bd169 41 MBED_ASSERT(0);
Anna Bridge 181:96ed750bd169 42 frequency = 1000000;
Anna Bridge 181:96ed750bd169 43 }
Anna Bridge 181:96ed750bd169 44
Anna Bridge 181:96ed750bd169 45 uint32_t bits = info->bits;
Anna Bridge 181:96ed750bd169 46 if ((info->bits > 32) || (info->bits < 4)) {
Anna Bridge 181:96ed750bd169 47 MBED_ASSERT(0);
Anna Bridge 181:96ed750bd169 48 bits = 32;
Anna Bridge 181:96ed750bd169 49 }
Anna Bridge 181:96ed750bd169 50 uint32_t max_delta = 0x7 << (bits - 4); // 7/16th
Anna Bridge 181:96ed750bd169 51 uint64_t max_delta_us =
Anna Bridge 181:96ed750bd169 52 ((uint64_t)max_delta * 1000000 + frequency - 1) / frequency;
Anna Bridge 181:96ed750bd169 53
AnnaBridge 167:e84263d55307 54 ticker->queue->event_handler = NULL;
AnnaBridge 167:e84263d55307 55 ticker->queue->head = NULL;
Anna Bridge 181:96ed750bd169 56 ticker->queue->tick_last_read = ticker->interface->read();
Anna Bridge 181:96ed750bd169 57 ticker->queue->tick_remainder = 0;
Anna Bridge 181:96ed750bd169 58 ticker->queue->frequency = frequency;
Anna Bridge 181:96ed750bd169 59 ticker->queue->bitmask = ((uint64_t)1 << bits) - 1;
Anna Bridge 181:96ed750bd169 60 ticker->queue->max_delta = max_delta;
Anna Bridge 181:96ed750bd169 61 ticker->queue->max_delta_us = max_delta_us;
AnnaBridge 167:e84263d55307 62 ticker->queue->present_time = 0;
AnnaBridge 167:e84263d55307 63 ticker->queue->initialized = true;
AnnaBridge 167:e84263d55307 64
AnnaBridge 167:e84263d55307 65 update_present_time(ticker);
AnnaBridge 167:e84263d55307 66 schedule_interrupt(ticker);
AnnaBridge 167:e84263d55307 67 }
AnnaBridge 167:e84263d55307 68
AnnaBridge 167:e84263d55307 69 /**
AnnaBridge 167:e84263d55307 70 * Set the event handler function of a ticker instance.
AnnaBridge 167:e84263d55307 71 */
AnnaBridge 167:e84263d55307 72 static void set_handler(const ticker_data_t *const ticker, ticker_event_handler handler)
AnnaBridge 167:e84263d55307 73 {
AnnaBridge 167:e84263d55307 74 ticker->queue->event_handler = handler;
<> 149:156823d33999 75 }
<> 149:156823d33999 76
AnnaBridge 167:e84263d55307 77 /*
AnnaBridge 167:e84263d55307 78 * Convert a 32 bit timestamp into a 64 bit timestamp.
AnnaBridge 167:e84263d55307 79 *
AnnaBridge 167:e84263d55307 80 * A 64 bit timestamp is used as the point of time of reference while the
AnnaBridge 167:e84263d55307 81 * timestamp to convert is relative to this point of time.
AnnaBridge 167:e84263d55307 82 *
AnnaBridge 167:e84263d55307 83 * The lower 32 bits of the timestamp returned will be equal to the timestamp to
AnnaBridge 167:e84263d55307 84 * convert.
AnnaBridge 167:e84263d55307 85 *
AnnaBridge 167:e84263d55307 86 * If the timestamp to convert is less than the lower 32 bits of the time
AnnaBridge 167:e84263d55307 87 * reference then the timestamp to convert is seen as an overflowed value and
AnnaBridge 167:e84263d55307 88 * the upper 32 bit of the timestamp returned will be equal to the upper 32 bit
AnnaBridge 167:e84263d55307 89 * of the reference point + 1.
AnnaBridge 167:e84263d55307 90 * Otherwise, the upper 32 bit returned will be equal to the upper 32 bit of the
AnnaBridge 167:e84263d55307 91 * reference point.
AnnaBridge 167:e84263d55307 92 *
AnnaBridge 167:e84263d55307 93 * @param ref: The 64 bit timestamp of reference.
AnnaBridge 167:e84263d55307 94 * @param timestamp: The timestamp to convert.
AnnaBridge 167:e84263d55307 95 */
AnnaBridge 167:e84263d55307 96 static us_timestamp_t convert_timestamp(us_timestamp_t ref, timestamp_t timestamp)
AnnaBridge 167:e84263d55307 97 {
AnnaBridge 167:e84263d55307 98 bool overflow = timestamp < ((timestamp_t) ref) ? true : false;
AnnaBridge 167:e84263d55307 99
AnnaBridge 167:e84263d55307 100 us_timestamp_t result = (ref & ~((us_timestamp_t)UINT32_MAX)) | timestamp;
AnnaBridge 167:e84263d55307 101 if (overflow) {
AnnaBridge 167:e84263d55307 102 result += (1ULL<<32);
AnnaBridge 167:e84263d55307 103 }
AnnaBridge 167:e84263d55307 104
AnnaBridge 167:e84263d55307 105 return result;
AnnaBridge 167:e84263d55307 106 }
AnnaBridge 167:e84263d55307 107
AnnaBridge 167:e84263d55307 108 /**
AnnaBridge 167:e84263d55307 109 * Update the present timestamp value of a ticker.
AnnaBridge 167:e84263d55307 110 */
AnnaBridge 167:e84263d55307 111 static void update_present_time(const ticker_data_t *const ticker)
Anna Bridge 181:96ed750bd169 112 {
Anna Bridge 181:96ed750bd169 113
Anna Bridge 181:96ed750bd169 114 ticker_event_queue_t *queue = ticker->queue;
Anna Bridge 181:96ed750bd169 115 uint32_t ticker_time = ticker->interface->read();
Anna Bridge 181:96ed750bd169 116 if (ticker_time == ticker->queue->tick_last_read) {
Anna Bridge 181:96ed750bd169 117 // No work to do
Anna Bridge 181:96ed750bd169 118 return;
Anna Bridge 181:96ed750bd169 119 }
Anna Bridge 181:96ed750bd169 120
Anna Bridge 181:96ed750bd169 121 uint64_t elapsed_ticks = (ticker_time - queue->tick_last_read) & queue->bitmask;
Anna Bridge 181:96ed750bd169 122 queue->tick_last_read = ticker_time;
Anna Bridge 181:96ed750bd169 123
Anna Bridge 181:96ed750bd169 124 uint64_t elapsed_us;
Anna Bridge 181:96ed750bd169 125 if (1000000 == queue->frequency) {
Anna Bridge 181:96ed750bd169 126 // Optimized for 1MHz
Anna Bridge 181:96ed750bd169 127
Anna Bridge 181:96ed750bd169 128 elapsed_us = elapsed_ticks;
Anna Bridge 181:96ed750bd169 129 } else if (32768 == queue->frequency) {
Anna Bridge 181:96ed750bd169 130 // Optimized for 32KHz
Anna Bridge 181:96ed750bd169 131
Anna Bridge 181:96ed750bd169 132 uint64_t us_x_ticks = elapsed_ticks * 1000000;
Anna Bridge 181:96ed750bd169 133 elapsed_us = us_x_ticks >> 15;
Anna Bridge 181:96ed750bd169 134
Anna Bridge 181:96ed750bd169 135 // Update remainder
Anna Bridge 181:96ed750bd169 136 queue->tick_remainder += us_x_ticks - (elapsed_us << 15);
Anna Bridge 181:96ed750bd169 137 if (queue->tick_remainder >= queue->frequency) {
Anna Bridge 181:96ed750bd169 138 elapsed_us += 1;
Anna Bridge 181:96ed750bd169 139 queue->tick_remainder -= queue->frequency;
Anna Bridge 181:96ed750bd169 140 }
Anna Bridge 181:96ed750bd169 141 } else {
Anna Bridge 181:96ed750bd169 142 // General case
Anna Bridge 181:96ed750bd169 143
Anna Bridge 181:96ed750bd169 144 uint64_t us_x_ticks = elapsed_ticks * 1000000;
Anna Bridge 181:96ed750bd169 145 elapsed_us = us_x_ticks / queue->frequency;
Anna Bridge 181:96ed750bd169 146
Anna Bridge 181:96ed750bd169 147 // Update remainder
Anna Bridge 181:96ed750bd169 148 queue->tick_remainder += us_x_ticks - elapsed_us * queue->frequency;
Anna Bridge 181:96ed750bd169 149 if (queue->tick_remainder >= queue->frequency) {
Anna Bridge 181:96ed750bd169 150 elapsed_us += 1;
Anna Bridge 181:96ed750bd169 151 queue->tick_remainder -= queue->frequency;
Anna Bridge 181:96ed750bd169 152 }
Anna Bridge 181:96ed750bd169 153 }
Anna Bridge 181:96ed750bd169 154
Anna Bridge 181:96ed750bd169 155 // Update current time
Anna Bridge 181:96ed750bd169 156 queue->present_time += elapsed_us;
Anna Bridge 181:96ed750bd169 157 }
Anna Bridge 181:96ed750bd169 158
Anna Bridge 181:96ed750bd169 159 /**
Anna Bridge 181:96ed750bd169 160 * Given the absolute timestamp compute the hal tick timestamp.
Anna Bridge 181:96ed750bd169 161 */
Anna Bridge 181:96ed750bd169 162 static timestamp_t compute_tick(const ticker_data_t *const ticker, us_timestamp_t timestamp)
Anna Bridge 181:96ed750bd169 163 {
Anna Bridge 181:96ed750bd169 164 ticker_event_queue_t *queue = ticker->queue;
Anna Bridge 181:96ed750bd169 165 us_timestamp_t delta_us = timestamp - queue->present_time;
Anna Bridge 181:96ed750bd169 166
Anna Bridge 181:96ed750bd169 167 timestamp_t delta = ticker->queue->max_delta;
Anna Bridge 181:96ed750bd169 168 if (delta_us <= ticker->queue->max_delta_us) {
Anna Bridge 181:96ed750bd169 169 // Checking max_delta_us ensures the operation will not overflow
Anna Bridge 181:96ed750bd169 170
Anna Bridge 181:96ed750bd169 171 if (1000000 == queue->frequency) {
Anna Bridge 181:96ed750bd169 172 // Optimized for 1MHz
Anna Bridge 181:96ed750bd169 173
Anna Bridge 181:96ed750bd169 174 delta = delta_us;
Anna Bridge 181:96ed750bd169 175 if (delta > ticker->queue->max_delta) {
Anna Bridge 181:96ed750bd169 176 delta = ticker->queue->max_delta;
Anna Bridge 181:96ed750bd169 177 }
Anna Bridge 181:96ed750bd169 178 } else if (32768 == queue->frequency) {
Anna Bridge 181:96ed750bd169 179 // Optimized for 32KHz
Anna Bridge 181:96ed750bd169 180
Anna Bridge 181:96ed750bd169 181 delta = (delta_us << 15) / 1000000;
Anna Bridge 181:96ed750bd169 182 if (delta > ticker->queue->max_delta) {
Anna Bridge 181:96ed750bd169 183 delta = ticker->queue->max_delta;
Anna Bridge 181:96ed750bd169 184 }
Anna Bridge 181:96ed750bd169 185 } else {
Anna Bridge 181:96ed750bd169 186 // General case
Anna Bridge 181:96ed750bd169 187
Anna Bridge 181:96ed750bd169 188 delta = delta_us * queue->frequency / 1000000;
Anna Bridge 181:96ed750bd169 189 if (delta > ticker->queue->max_delta) {
Anna Bridge 181:96ed750bd169 190 delta = ticker->queue->max_delta;
Anna Bridge 181:96ed750bd169 191 }
Anna Bridge 181:96ed750bd169 192 }
Anna Bridge 181:96ed750bd169 193 }
Anna Bridge 181:96ed750bd169 194 return (queue->tick_last_read + delta) & queue->bitmask;
Anna Bridge 181:96ed750bd169 195 }
Anna Bridge 181:96ed750bd169 196
Anna Bridge 181:96ed750bd169 197 /**
Anna Bridge 181:96ed750bd169 198 * Return 1 if the tick has incremented to or past match_tick, otherwise 0.
Anna Bridge 181:96ed750bd169 199 */
Anna Bridge 181:96ed750bd169 200 int _ticker_match_interval_passed(timestamp_t prev_tick, timestamp_t cur_tick, timestamp_t match_tick)
Anna Bridge 181:96ed750bd169 201 {
Anna Bridge 181:96ed750bd169 202 if (match_tick > prev_tick) {
Anna Bridge 181:96ed750bd169 203 return (cur_tick >= match_tick) || (cur_tick < prev_tick);
Anna Bridge 181:96ed750bd169 204 } else {
Anna Bridge 181:96ed750bd169 205 return (cur_tick < prev_tick) && (cur_tick >= match_tick);
Anna Bridge 181:96ed750bd169 206 }
AnnaBridge 167:e84263d55307 207 }
AnnaBridge 167:e84263d55307 208
AnnaBridge 167:e84263d55307 209 /**
AnnaBridge 167:e84263d55307 210 * Compute the time when the interrupt has to be triggered and schedule it.
AnnaBridge 167:e84263d55307 211 *
AnnaBridge 167:e84263d55307 212 * If there is no event in the queue or the next event to execute is in more
Anna Bridge 181:96ed750bd169 213 * than ticker.queue.max_delta ticks from now then the ticker irq will be
Anna Bridge 181:96ed750bd169 214 * scheduled in ticker.queue.max_delta ticks. Otherwise the irq will be
Anna Bridge 181:96ed750bd169 215 * scheduled to happen when the running counter reach the timestamp of the
Anna Bridge 181:96ed750bd169 216 * first event in the queue.
AnnaBridge 167:e84263d55307 217 *
AnnaBridge 167:e84263d55307 218 * @note If there is no event in the queue then the interrupt is scheduled to
Anna Bridge 181:96ed750bd169 219 * in ticker.queue.max_delta. This is necessary to keep track
AnnaBridge 167:e84263d55307 220 * of the timer overflow.
AnnaBridge 167:e84263d55307 221 */
AnnaBridge 167:e84263d55307 222 static void schedule_interrupt(const ticker_data_t *const ticker)
AnnaBridge 167:e84263d55307 223 {
Anna Bridge 181:96ed750bd169 224 ticker_event_queue_t *queue = ticker->queue;
AnnaBridge 167:e84263d55307 225 update_present_time(ticker);
AnnaBridge 167:e84263d55307 226
AnnaBridge 167:e84263d55307 227 if (ticker->queue->head) {
AnnaBridge 167:e84263d55307 228 us_timestamp_t present = ticker->queue->present_time;
Anna Bridge 181:96ed750bd169 229 us_timestamp_t match_time = ticker->queue->head->timestamp;
AnnaBridge 167:e84263d55307 230
AnnaBridge 167:e84263d55307 231 // if the event at the head of the queue is in the past then schedule
AnnaBridge 167:e84263d55307 232 // it immediately.
Anna Bridge 181:96ed750bd169 233 if (match_time <= present) {
AnnaBridge 174:b96e65c34a4d 234 ticker->interface->fire_interrupt();
AnnaBridge 174:b96e65c34a4d 235 return;
AnnaBridge 167:e84263d55307 236 }
Anna Bridge 181:96ed750bd169 237
Anna Bridge 181:96ed750bd169 238 timestamp_t match_tick = compute_tick(ticker, match_time);
Anna Bridge 181:96ed750bd169 239 ticker->interface->set_interrupt(match_tick);
Anna Bridge 181:96ed750bd169 240 timestamp_t cur_tick = ticker->interface->read();
AnnaBridge 167:e84263d55307 241
Anna Bridge 181:96ed750bd169 242 if (_ticker_match_interval_passed(queue->tick_last_read, cur_tick, match_tick)) {
Anna Bridge 181:96ed750bd169 243 ticker->interface->fire_interrupt();
Anna Bridge 181:96ed750bd169 244 }
Anna Bridge 181:96ed750bd169 245 } else {
Anna Bridge 181:96ed750bd169 246 uint32_t match_tick =
Anna Bridge 181:96ed750bd169 247 (queue->tick_last_read + queue->max_delta) & queue->bitmask;
Anna Bridge 181:96ed750bd169 248 ticker->interface->set_interrupt(match_tick);
AnnaBridge 174:b96e65c34a4d 249 }
AnnaBridge 167:e84263d55307 250 }
AnnaBridge 167:e84263d55307 251
AnnaBridge 167:e84263d55307 252 void ticker_set_handler(const ticker_data_t *const ticker, ticker_event_handler handler)
AnnaBridge 167:e84263d55307 253 {
AnnaBridge 167:e84263d55307 254 initialize(ticker);
AnnaBridge 167:e84263d55307 255 set_handler(ticker, handler);
AnnaBridge 167:e84263d55307 256 }
AnnaBridge 167:e84263d55307 257
AnnaBridge 167:e84263d55307 258 void ticker_irq_handler(const ticker_data_t *const ticker)
AnnaBridge 167:e84263d55307 259 {
AnnaBridge 167:e84263d55307 260 ticker->interface->clear_interrupt();
<> 149:156823d33999 261
<> 149:156823d33999 262 /* Go through all the pending TimerEvents */
<> 149:156823d33999 263 while (1) {
AnnaBridge 167:e84263d55307 264 if (ticker->queue->head == NULL) {
AnnaBridge 167:e84263d55307 265 break;
<> 149:156823d33999 266 }
<> 149:156823d33999 267
AnnaBridge 167:e84263d55307 268 // update the current timestamp used by the queue
AnnaBridge 167:e84263d55307 269 update_present_time(ticker);
AnnaBridge 167:e84263d55307 270
AnnaBridge 167:e84263d55307 271 if (ticker->queue->head->timestamp <= ticker->queue->present_time) {
<> 149:156823d33999 272 // This event was in the past:
<> 149:156823d33999 273 // point to the following one and execute its handler
AnnaBridge 167:e84263d55307 274 ticker_event_t *p = ticker->queue->head;
AnnaBridge 167:e84263d55307 275 ticker->queue->head = ticker->queue->head->next;
AnnaBridge 167:e84263d55307 276 if (ticker->queue->event_handler != NULL) {
AnnaBridge 167:e84263d55307 277 (*ticker->queue->event_handler)(p->id); // NOTE: the handler can set new events
<> 149:156823d33999 278 }
<> 149:156823d33999 279 /* Note: We continue back to examining the head because calling the
<> 149:156823d33999 280 * event handler may have altered the chain of pending events. */
<> 149:156823d33999 281 } else {
AnnaBridge 167:e84263d55307 282 break;
AnnaBridge 167:e84263d55307 283 }
<> 149:156823d33999 284 }
AnnaBridge 167:e84263d55307 285
AnnaBridge 167:e84263d55307 286 schedule_interrupt(ticker);
<> 149:156823d33999 287 }
<> 149:156823d33999 288
AnnaBridge 167:e84263d55307 289 void ticker_insert_event(const ticker_data_t *const ticker, ticker_event_t *obj, timestamp_t timestamp, uint32_t id)
AnnaBridge 167:e84263d55307 290 {
<> 149:156823d33999 291 core_util_critical_section_enter();
<> 149:156823d33999 292
AnnaBridge 167:e84263d55307 293 // update the current timestamp
AnnaBridge 167:e84263d55307 294 update_present_time(ticker);
AnnaBridge 167:e84263d55307 295 us_timestamp_t absolute_timestamp = convert_timestamp(
AnnaBridge 167:e84263d55307 296 ticker->queue->present_time,
AnnaBridge 167:e84263d55307 297 timestamp
AnnaBridge 167:e84263d55307 298 );
AnnaBridge 167:e84263d55307 299 core_util_critical_section_exit();
AnnaBridge 167:e84263d55307 300
AnnaBridge 167:e84263d55307 301 // defer to ticker_insert_event_us
AnnaBridge 167:e84263d55307 302 ticker_insert_event_us(
AnnaBridge 167:e84263d55307 303 ticker,
AnnaBridge 167:e84263d55307 304 obj, absolute_timestamp, id
AnnaBridge 167:e84263d55307 305 );
AnnaBridge 167:e84263d55307 306 }
AnnaBridge 167:e84263d55307 307
AnnaBridge 167:e84263d55307 308 void ticker_insert_event_us(const ticker_data_t *const ticker, ticker_event_t *obj, us_timestamp_t timestamp, uint32_t id)
AnnaBridge 167:e84263d55307 309 {
AnnaBridge 167:e84263d55307 310 core_util_critical_section_enter();
AnnaBridge 167:e84263d55307 311
AnnaBridge 167:e84263d55307 312 // update the current timestamp
AnnaBridge 167:e84263d55307 313 update_present_time(ticker);
AnnaBridge 167:e84263d55307 314
<> 149:156823d33999 315 // initialise our data
<> 149:156823d33999 316 obj->timestamp = timestamp;
<> 149:156823d33999 317 obj->id = id;
<> 149:156823d33999 318
<> 149:156823d33999 319 /* Go through the list until we either reach the end, or find
<> 149:156823d33999 320 an element this should come before (which is possibly the
<> 149:156823d33999 321 head). */
AnnaBridge 167:e84263d55307 322 ticker_event_t *prev = NULL, *p = ticker->queue->head;
<> 149:156823d33999 323 while (p != NULL) {
<> 149:156823d33999 324 /* check if we come before p */
AnnaBridge 167:e84263d55307 325 if (timestamp < p->timestamp) {
<> 149:156823d33999 326 break;
<> 149:156823d33999 327 }
<> 149:156823d33999 328 /* go to the next element */
<> 149:156823d33999 329 prev = p;
<> 149:156823d33999 330 p = p->next;
<> 149:156823d33999 331 }
<> 162:e13f6fdb2ac4 332
<> 162:e13f6fdb2ac4 333 /* if we're at the end p will be NULL, which is correct */
<> 162:e13f6fdb2ac4 334 obj->next = p;
<> 162:e13f6fdb2ac4 335
<> 149:156823d33999 336 /* if prev is NULL we're at the head */
<> 149:156823d33999 337 if (prev == NULL) {
AnnaBridge 167:e84263d55307 338 ticker->queue->head = obj;
<> 149:156823d33999 339 } else {
<> 149:156823d33999 340 prev->next = obj;
<> 149:156823d33999 341 }
<> 149:156823d33999 342
AnnaBridge 167:e84263d55307 343 schedule_interrupt(ticker);
AnnaBridge 167:e84263d55307 344
<> 149:156823d33999 345 core_util_critical_section_exit();
<> 149:156823d33999 346 }
<> 149:156823d33999 347
AnnaBridge 167:e84263d55307 348 void ticker_remove_event(const ticker_data_t *const ticker, ticker_event_t *obj)
AnnaBridge 167:e84263d55307 349 {
<> 149:156823d33999 350 core_util_critical_section_enter();
<> 149:156823d33999 351
<> 149:156823d33999 352 // remove this object from the list
AnnaBridge 167:e84263d55307 353 if (ticker->queue->head == obj) {
<> 149:156823d33999 354 // first in the list, so just drop me
AnnaBridge 167:e84263d55307 355 ticker->queue->head = obj->next;
AnnaBridge 167:e84263d55307 356 schedule_interrupt(ticker);
<> 149:156823d33999 357 } else {
<> 149:156823d33999 358 // find the object before me, then drop me
AnnaBridge 167:e84263d55307 359 ticker_event_t* p = ticker->queue->head;
<> 149:156823d33999 360 while (p != NULL) {
<> 149:156823d33999 361 if (p->next == obj) {
<> 149:156823d33999 362 p->next = obj->next;
<> 149:156823d33999 363 break;
<> 149:156823d33999 364 }
<> 149:156823d33999 365 p = p->next;
<> 149:156823d33999 366 }
<> 149:156823d33999 367 }
<> 149:156823d33999 368
<> 149:156823d33999 369 core_util_critical_section_exit();
<> 149:156823d33999 370 }
<> 149:156823d33999 371
AnnaBridge 167:e84263d55307 372 timestamp_t ticker_read(const ticker_data_t *const ticker)
<> 149:156823d33999 373 {
AnnaBridge 167:e84263d55307 374 return ticker_read_us(ticker);
AnnaBridge 167:e84263d55307 375 }
AnnaBridge 167:e84263d55307 376
AnnaBridge 167:e84263d55307 377 us_timestamp_t ticker_read_us(const ticker_data_t *const ticker)
AnnaBridge 167:e84263d55307 378 {
AnnaBridge 176:af195413fb11 379 initialize(ticker);
AnnaBridge 167:e84263d55307 380 update_present_time(ticker);
AnnaBridge 167:e84263d55307 381 return ticker->queue->present_time;
<> 149:156823d33999 382 }
<> 149:156823d33999 383
<> 149:156823d33999 384 int ticker_get_next_timestamp(const ticker_data_t *const data, timestamp_t *timestamp)
<> 149:156823d33999 385 {
<> 149:156823d33999 386 int ret = 0;
<> 149:156823d33999 387
<> 149:156823d33999 388 /* if head is NULL, there are no pending events */
<> 149:156823d33999 389 core_util_critical_section_enter();
<> 149:156823d33999 390 if (data->queue->head != NULL) {
<> 149:156823d33999 391 *timestamp = data->queue->head->timestamp;
<> 149:156823d33999 392 ret = 1;
<> 149:156823d33999 393 }
<> 149:156823d33999 394 core_util_critical_section_exit();
<> 149:156823d33999 395
<> 149:156823d33999 396 return ret;
<> 149:156823d33999 397 }