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Diff: hal/mbed_ticker_api.c
- Revision:
- 149:156823d33999
diff -r 21d94c44109e -r 156823d33999 hal/mbed_ticker_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hal/mbed_ticker_api.c Fri Oct 28 11:17:30 2016 +0100 @@ -0,0 +1,135 @@ +/* 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 "hal/ticker_api.h" +#include "platform/critical.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 */ + core_util_critical_section_enter(); + + // 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; + + core_util_critical_section_exit(); +} + +void ticker_remove_event(const ticker_data_t *const data, ticker_event_t *obj) { + core_util_critical_section_enter(); + + // 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; + } + } + + core_util_critical_section_exit(); +} + +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 */ + core_util_critical_section_enter(); + if (data->queue->head != NULL) { + *timestamp = data->queue->head->timestamp; + ret = 1; + } + core_util_critical_section_exit(); + + return ret; +}