Lancaster University / mbed-src

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targets/hal/TARGET_STM/TARGET_STM32F7/us_ticker.c@641:be9b2017785a, 2016-07-13 (annotated)

Committer:
LancasterUniversity
Date:
Wed Jul 13 12:52:54 2016 +0100
Revision:
641:be9b2017785a
Parent:
573:ad23fe03a082 
Synchronized with git rev 1fb8ab4c

Author: James Devine

mbed-classic: BUGFIX for timer when using wait_ms from interrupt context



Previously if a user used wait[_ms,_us] in interrupt context the device would

hang indefinitely. This was due to incrementing overflowCount from

interrupt context only.



This meant that if a user used wait[_ms,_us] in an ISR with

the same or greater interrupt priority, it would result in an infinite

loop as the overflowCount variable would never be incremented, and

wait[_ms,_us] would never return.



This patch simply applies a better solution for the race condition

mentioned in the previous commit. It instead disables the timer1

interrupt and increments the overflowCount variable, preventing

the race condition whilst supporting wait[_ms,_us] in interrupt

context.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 573:ad23fe03a082 1 /* mbed Microcontroller Library
mbed_official 573:ad23fe03a082 2 * Copyright (c) 2015, STMicroelectronics
mbed_official 573:ad23fe03a082 3 * All rights reserved.
mbed_official 573:ad23fe03a082 4 *
mbed_official 573:ad23fe03a082 5 * Redistribution and use in source and binary forms, with or without
mbed_official 573:ad23fe03a082 6 * modification, are permitted provided that the following conditions are met:
mbed_official 573:ad23fe03a082 7 *
mbed_official 573:ad23fe03a082 8 * 1. Redistributions of source code must retain the above copyright notice,
mbed_official 573:ad23fe03a082 9 * this list of conditions and the following disclaimer.
mbed_official 573:ad23fe03a082 10 * 2. Redistributions in binary form must reproduce the above copyright notice,
mbed_official 573:ad23fe03a082 11 * this list of conditions and the following disclaimer in the documentation
mbed_official 573:ad23fe03a082 12 * and/or other materials provided with the distribution.
mbed_official 573:ad23fe03a082 13 * 3. Neither the name of STMicroelectronics nor the names of its contributors
mbed_official 573:ad23fe03a082 14 * may be used to endorse or promote products derived from this software
mbed_official 573:ad23fe03a082 15 * without specific prior written permission.
mbed_official 573:ad23fe03a082 16 *
mbed_official 573:ad23fe03a082 17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
mbed_official 573:ad23fe03a082 18 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
mbed_official 573:ad23fe03a082 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
mbed_official 573:ad23fe03a082 20 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
mbed_official 573:ad23fe03a082 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
mbed_official 573:ad23fe03a082 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
mbed_official 573:ad23fe03a082 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 573:ad23fe03a082 24 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
mbed_official 573:ad23fe03a082 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
mbed_official 573:ad23fe03a082 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
mbed_official 573:ad23fe03a082 27 */
mbed_official 573:ad23fe03a082 28 #include <stddef.h>
mbed_official 573:ad23fe03a082 29 #include "us_ticker_api.h"
mbed_official 573:ad23fe03a082 30 #include "PeripheralNames.h"
mbed_official 573:ad23fe03a082 31 #include "hal_tick.h"
mbed_official 573:ad23fe03a082 32
mbed_official 573:ad23fe03a082 33 #define TIM_MST TIM5
mbed_official 573:ad23fe03a082 34
mbed_official 573:ad23fe03a082 35 static TIM_HandleTypeDef TimMasterHandle;
mbed_official 573:ad23fe03a082 36 static int us_ticker_inited = 0;
mbed_official 573:ad23fe03a082 37
mbed_official 573:ad23fe03a082 38 void us_ticker_init(void)
mbed_official 573:ad23fe03a082 39 {
mbed_official 573:ad23fe03a082 40 if (us_ticker_inited) return;
mbed_official 573:ad23fe03a082 41 us_ticker_inited = 1;
mbed_official 573:ad23fe03a082 42
mbed_official 573:ad23fe03a082 43 TimMasterHandle.Instance = TIM_MST;
mbed_official 573:ad23fe03a082 44
mbed_official 573:ad23fe03a082 45 HAL_InitTick(0); // The passed value is not used
mbed_official 573:ad23fe03a082 46 }
mbed_official 573:ad23fe03a082 47
mbed_official 573:ad23fe03a082 48 uint32_t us_ticker_read()
mbed_official 573:ad23fe03a082 49 {
mbed_official 573:ad23fe03a082 50 if (!us_ticker_inited) us_ticker_init();
mbed_official 573:ad23fe03a082 51 return TIM_MST->CNT;
mbed_official 573:ad23fe03a082 52 }
mbed_official 573:ad23fe03a082 53
mbed_official 573:ad23fe03a082 54 void us_ticker_set_interrupt(timestamp_t timestamp)
mbed_official 573:ad23fe03a082 55 {
mbed_official 573:ad23fe03a082 56 // Set new output compare value
mbed_official 573:ad23fe03a082 57 __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_1, (uint32_t)timestamp);
mbed_official 573:ad23fe03a082 58 // Enable IT
mbed_official 573:ad23fe03a082 59 __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 573:ad23fe03a082 60 }
mbed_official 573:ad23fe03a082 61
mbed_official 573:ad23fe03a082 62 void us_ticker_disable_interrupt(void)
mbed_official 573:ad23fe03a082 63 {
mbed_official 573:ad23fe03a082 64 __HAL_TIM_DISABLE_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 573:ad23fe03a082 65 }
mbed_official 573:ad23fe03a082 66
mbed_official 573:ad23fe03a082 67 void us_ticker_clear_interrupt(void)
mbed_official 573:ad23fe03a082 68 {
mbed_official 573:ad23fe03a082 69 __HAL_TIM_CLEAR_IT(&TimMasterHandle, TIM_IT_CC1);
mbed_official 573:ad23fe03a082 70 }