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mbed-os/targets/TARGET_STM/lp_ticker.c

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/* mbed Microcontroller Library
*******************************************************************************
* Copyright (c) 2018, STMicroelectronics
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*******************************************************************************
*/
#if DEVICE_LPTICKER
/***********************************************************************/
/* lpticker_lptim config is 1 in json config file */
/* LPTICKER is based on LPTIM feature from ST drivers. RTC is not used */
#if MBED_CONF_TARGET_LPTICKER_LPTIM
#include "lp_ticker_api.h"
#include "mbed_error.h"
#include "mbed_power_mgmt.h"
#include "platform/mbed_critical.h"
#include <stdbool.h>
/* lpticker delay is for using C++ Low Power Ticker wrapper,
* which introduces extra delays. We rather want to use the
* low level implementation from this file */
#if defined(LPTICKER_DELAY_TICKS) && (LPTICKER_DELAY_TICKS > 0)
#warning "lpticker_delay_ticks usage not recommended"
#endif
#define LP_TIMER_WRAP(val) (val & 0xFFFF)
/* Safe guard is the number of ticks between the current tick and the next
* tick we want to program an interrupt for. Programing an interrupt in
* between is unreliable */
#define LP_TIMER_SAFE_GUARD 5
LPTIM_HandleTypeDef LptimHandle;
const ticker_info_t *lp_ticker_get_info()
{
static const ticker_info_t info = {
#if MBED_CONF_TARGET_LSE_AVAILABLE
LSE_VALUE / MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK,
#else
LSI_VALUE / MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK,
#endif
16
};
return &info;
}
volatile uint8_t lp_Fired = 0;
/* Flag and stored counter to handle delayed programing at low level */
volatile bool lp_delayed_prog = false;
volatile bool future_event_flag = false;
volatile bool roll_over_flag = false;
volatile bool lp_cmpok = false;
volatile timestamp_t lp_delayed_counter = 0;
volatile bool sleep_manager_locked = false;
static int LPTICKER_inited = 0;
static void LPTIM1_IRQHandler(void);
void lp_ticker_init(void)
{
/* Check if LPTIM is already configured */
if (LPTICKER_inited) {
lp_ticker_disable_interrupt();
return;
}
LPTICKER_inited = 1;
RCC_PeriphCLKInitTypeDef RCC_PeriphCLKInitStruct = {0};
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
#if MBED_CONF_TARGET_LSE_AVAILABLE
/* Enable LSE clock */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSE;
RCC_OscInitStruct.LSEState = RCC_LSE_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
/* Select the LSE clock as LPTIM peripheral clock */
RCC_PeriphCLKInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPTIM1;
#if (TARGET_STM32L0)
RCC_PeriphCLKInitStruct.LptimClockSelection = RCC_LPTIM1CLKSOURCE_LSE;
#else
RCC_PeriphCLKInitStruct.Lptim1ClockSelection = RCC_LPTIM1CLKSOURCE_LSE;
#endif
#else /* MBED_CONF_TARGET_LSE_AVAILABLE */
/* Enable LSI clock */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI;
RCC_OscInitStruct.LSIState = RCC_LSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
/* Select the LSI clock as LPTIM peripheral clock */
RCC_PeriphCLKInitStruct.PeriphClockSelection = RCC_PERIPHCLK_LPTIM1;
#if (TARGET_STM32L0)
RCC_PeriphCLKInitStruct.LptimClockSelection = RCC_LPTIM1CLKSOURCE_LSI;
#else
RCC_PeriphCLKInitStruct.Lptim1ClockSelection = RCC_LPTIM1CLKSOURCE_LSI;
#endif
#endif /* MBED_CONF_TARGET_LSE_AVAILABLE */
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
error("HAL_RCC_OscConfig ERROR\n");
return;
}
if (HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphCLKInitStruct) != HAL_OK) {
error("HAL_RCCEx_PeriphCLKConfig ERROR\n");
return;
}
__HAL_RCC_LPTIM1_CLK_ENABLE();
__HAL_RCC_LPTIM1_FORCE_RESET();
__HAL_RCC_LPTIM1_RELEASE_RESET();
/* Initialize the LPTIM peripheral */
LptimHandle.Instance = LPTIM1;
LptimHandle.State = HAL_LPTIM_STATE_RESET;
LptimHandle.Init.Clock.Source = LPTIM_CLOCKSOURCE_APBCLOCK_LPOSC;
#if defined(MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK)
#if (MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK == 4)
LptimHandle.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV4;
#elif (MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK == 2)
LptimHandle.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV2;
#else
LptimHandle.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV1;
#endif
#else
LptimHandle.Init.Clock.Prescaler = LPTIM_PRESCALER_DIV1;
#endif /* MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK */
LptimHandle.Init.Trigger.Source = LPTIM_TRIGSOURCE_SOFTWARE;
#if defined (LPTIM_ACTIVEEDGE_FALLING)
LptimHandle.Init.Trigger.ActiveEdge = LPTIM_ACTIVEEDGE_FALLING;
#endif
#if defined (LPTIM_TRIGSAMPLETIME_DIRECTTRANSITION)
LptimHandle.Init.Trigger.SampleTime = LPTIM_TRIGSAMPLETIME_DIRECTTRANSITION;
#endif
LptimHandle.Init.OutputPolarity = LPTIM_OUTPUTPOLARITY_HIGH;
LptimHandle.Init.UpdateMode = LPTIM_UPDATE_IMMEDIATE;
LptimHandle.Init.CounterSource = LPTIM_COUNTERSOURCE_INTERNAL;
#if defined (LPTIM_INPUT1SOURCE_GPIO) /* STM32L4 */
LptimHandle.Init.Input1Source = LPTIM_INPUT1SOURCE_GPIO;
LptimHandle.Init.Input2Source = LPTIM_INPUT2SOURCE_GPIO;
#endif /* LPTIM_INPUT1SOURCE_GPIO */
if (HAL_LPTIM_Init(&LptimHandle) != HAL_OK) {
error("HAL_LPTIM_Init ERROR\n");
return;
}
NVIC_SetVector(LPTIM1_IRQn, (uint32_t)LPTIM1_IRQHandler);
#if defined (__HAL_LPTIM_WAKEUPTIMER_EXTI_ENABLE_IT)
/* EXTI lines are not configured by default */
__HAL_LPTIM_WAKEUPTIMER_EXTI_ENABLE_IT();
#endif
#if defined (__HAL_LPTIM_WAKEUPTIMER_EXTI_ENABLE_RISING_EDGE)
__HAL_LPTIM_WAKEUPTIMER_EXTI_ENABLE_RISING_EDGE();
#endif
__HAL_LPTIM_ENABLE_IT(&LptimHandle, LPTIM_IT_CMPM);
__HAL_LPTIM_ENABLE_IT(&LptimHandle, LPTIM_IT_CMPOK);
HAL_LPTIM_Counter_Start(&LptimHandle, 0xFFFF);
/* Need to write a compare value in order to get LPTIM_FLAG_CMPOK in set_interrupt */
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK);
__HAL_LPTIM_COMPARE_SET(&LptimHandle, 0);
while (__HAL_LPTIM_GET_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK) == RESET) {
}
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK);
/* Init is called with Interrupts disabled, so the CMPOK interrupt
* will not be handled. Let's mark it is now safe to write to LP counter */
lp_cmpok = true;
}
static void LPTIM1_IRQHandler(void)
{
core_util_critical_section_enter();
if (lp_Fired) {
lp_Fired = 0;
/* We're already in handler and interrupt might be pending,
* so clear the flag, to avoid calling irq_handler twice */
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPM);
lp_ticker_irq_handler();
}
/* Compare match interrupt */
if (__HAL_LPTIM_GET_FLAG(&LptimHandle, LPTIM_FLAG_CMPM) != RESET) {
if (__HAL_LPTIM_GET_IT_SOURCE(&LptimHandle, LPTIM_IT_CMPM) != RESET) {
/* Clear Compare match flag */
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPM);
lp_ticker_irq_handler();
}
}
if (__HAL_LPTIM_GET_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK) != RESET) {
if (__HAL_LPTIM_GET_IT_SOURCE(&LptimHandle, LPTIM_IT_CMPOK) != RESET) {
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK);
lp_cmpok = true;
if (sleep_manager_locked) {
sleep_manager_unlock_deep_sleep();
sleep_manager_locked = false;
}
if (lp_delayed_prog) {
if (roll_over_flag) {
/* If we were close to the roll over of the ticker counter
* change current tick so it can be compared with buffer.
* If this event got outdated fire interrupt right now,
* else schedule it normally. */
if (lp_delayed_counter <= ((lp_ticker_read() + LP_TIMER_SAFE_GUARD + 1) & 0xFFFF)) {
lp_ticker_fire_interrupt();
} else {
lp_ticker_set_interrupt((lp_delayed_counter - LP_TIMER_SAFE_GUARD - 1) & 0xFFFF);
}
roll_over_flag = false;
} else {
if (future_event_flag && (lp_delayed_counter <= lp_ticker_read())) {
/* If this event got outdated fire interrupt right now,
* else schedule it normally. */
lp_ticker_fire_interrupt();
future_event_flag = false;
} else {
lp_ticker_set_interrupt(lp_delayed_counter);
}
}
lp_delayed_prog = false;
}
}
}
#if defined (__HAL_LPTIM_WAKEUPTIMER_EXTI_CLEAR_FLAG)
/* EXTI lines are not configured by default */
__HAL_LPTIM_WAKEUPTIMER_EXTI_CLEAR_FLAG();
#endif
core_util_critical_section_exit();
}
uint32_t lp_ticker_read(void)
{
uint32_t lp_time = LPTIM1->CNT;
/* Reading the LPTIM_CNT register may return unreliable values.
It is necessary to perform two consecutive read accesses and verify that the two returned values are identical */
while (lp_time != LPTIM1->CNT) {
lp_time = LPTIM1->CNT;
}
return lp_time;
}
/* This function should always be called from critical section */
void lp_ticker_set_interrupt(timestamp_t timestamp)
{
core_util_critical_section_enter();
timestamp_t last_read_counter = lp_ticker_read();
/* Always store the last requested timestamp */
lp_delayed_counter = timestamp;
NVIC_EnableIRQ(LPTIM1_IRQn);
/* CMPOK is set by hardware to inform application that the APB bus write operation to the
* LPTIM_CMP register has been successfully completed.
* Any successive write before the CMPOK flag be set, will lead to unpredictable results
* We need to prevent to set a new comparator value before CMPOK flag is set by HW */
if (lp_cmpok == false) {
/* if this is not safe to write, then delay the programing to the
* time when CMPOK interrupt will trigger */
/* If this target timestamp is close to the roll over of the ticker counter
* and current tick is also close to the roll over, then we are in danger zone.*/
if (((0xFFFF - LP_TIMER_SAFE_GUARD < timestamp) || (timestamp < LP_TIMER_SAFE_GUARD)) && (0xFFFA < last_read_counter)) {
roll_over_flag = true;
/* Change the lp_delayed_counter buffer in that way so the value of (0xFFFF - LP_TIMER_SAFE_GUARD) is equal to 0.
* By doing this it is easy to check if the value of timestamp get outdated by delaying its programming
* For example if LP_TIMER_SAFE_GUARD is set to 5
* (0xFFFA + LP_TIMER_SAFE_GUARD + 1) & 0xFFFF = 0
* (0xFFFF + LP_TIMER_SAFE_GUARD + 1) & 0xFFFF = 5
* (0x0000 + LP_TIMER_SAFE_GUARD + 1) & 0xFFFF = 6
* (0x0005 + LP_TIMER_SAFE_GUARD + 1) & 0xFFFF = 11*/
lp_delayed_counter = (timestamp + LP_TIMER_SAFE_GUARD + 1) & 0xFFFF;
} else {
roll_over_flag = false;
/* Check if event was meant to be in the past. */
if (lp_delayed_counter >= last_read_counter) {
future_event_flag = true;
} else {
future_event_flag = false;
}
}
lp_delayed_prog = true;
} else {
lp_ticker_clear_interrupt();
/* HW is not able to trig a very short term interrupt, that is
* not less than few ticks away (LP_TIMER_SAFE_GUARD). So let's make sure it'
* s at least current tick + LP_TIMER_SAFE_GUARD */
for (uint8_t i = 0; i < LP_TIMER_SAFE_GUARD; i++) {
if (LP_TIMER_WRAP((last_read_counter + i)) == timestamp) {
timestamp = LP_TIMER_WRAP((timestamp + LP_TIMER_SAFE_GUARD));
}
}
/* Then check if this target timestamp is not in the past, or close to wrap-around
* Let's assume last_read_counter = 0xFFFC, and we want to program timestamp = 0x100
* The interrupt will not fire before the CMPOK flag is OK, so there are 2 cases:
* in case CMPOK flag is set by HW after or at wrap-around, then this will fire only @0x100
* in case CMPOK flag is set before, it will indeed fire early, as for the wrap-around case.
* But that will take at least 3 cycles and the interrupt fires at the end of a cycle.
* In our case 0xFFFC + 3 => at the transition between 0xFFFF and 0.
* If last_read_counter was 0xFFFB, it should be at the transition between 0xFFFE and 0xFFFF.
* There might be crossing cases where it would also fire @ 0xFFFE, but by the time we read the counter,
* it may already have moved to the next one, so for now we've taken this as margin of error.
*/
if ((timestamp < last_read_counter) && (last_read_counter <= (0xFFFF - LP_TIMER_SAFE_GUARD))) {
/* Workaround, because limitation */
__HAL_LPTIM_COMPARE_SET(&LptimHandle, ~0);
} else {
/* It is safe to write */
__HAL_LPTIM_COMPARE_SET(&LptimHandle, timestamp);
}
/* We just programed the CMP so we'll need to wait for cmpok before
* next programing */
lp_cmpok = false;
/* Prevent from sleeping after compare register was set as we need CMPOK
* interrupt to fire (in ~3x30us cycles) before we can safely enter deep sleep mode */
if (!sleep_manager_locked) {
sleep_manager_lock_deep_sleep();
sleep_manager_locked = true;
}
}
core_util_critical_section_exit();
}
void lp_ticker_fire_interrupt(void)
{
core_util_critical_section_enter();
lp_Fired = 1;
/* In case we fire interrupt now, then cancel pending programing */
lp_delayed_prog = false;
NVIC_SetPendingIRQ(LPTIM1_IRQn);
NVIC_EnableIRQ(LPTIM1_IRQn);
core_util_critical_section_exit();
}
void lp_ticker_disable_interrupt(void)
{
core_util_critical_section_enter();
if (!lp_cmpok) {
while (__HAL_LPTIM_GET_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK) == RESET) {
}
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPOK);
lp_cmpok = true;
}
/* now that CMPOK is set, allow deep sleep again */
if (sleep_manager_locked) {
sleep_manager_unlock_deep_sleep();
sleep_manager_locked = false;
}
lp_delayed_prog = false;
lp_Fired = 0;
NVIC_DisableIRQ(LPTIM1_IRQn);
NVIC_ClearPendingIRQ(LPTIM1_IRQn);
core_util_critical_section_exit();
}
void lp_ticker_clear_interrupt(void)
{
core_util_critical_section_enter();
__HAL_LPTIM_CLEAR_FLAG(&LptimHandle, LPTIM_FLAG_CMPM);
NVIC_ClearPendingIRQ(LPTIM1_IRQn);
core_util_critical_section_exit();
}
void lp_ticker_free(void)
{
lp_ticker_disable_interrupt();
}
/*****************************************************************/
/* lpticker_lptim config is 0 or not defined in json config file */
/* LPTICKER is based on RTC wake up feature from ST drivers */
#else /* MBED_CONF_TARGET_LPTICKER_LPTIM */
#include "rtc_api_hal.h"
const ticker_info_t *lp_ticker_get_info()
{
static const ticker_info_t info = {
RTC_CLOCK / 4, // RTC_WAKEUPCLOCK_RTCCLK_DIV4
32
};
return &info;
}
void lp_ticker_init(void)
{
rtc_init();
lp_ticker_disable_interrupt();
}
uint32_t lp_ticker_read(void)
{
return rtc_read_lp();
}
void lp_ticker_set_interrupt(timestamp_t timestamp)
{
rtc_set_wake_up_timer(timestamp);
}
void lp_ticker_fire_interrupt(void)
{
rtc_fire_interrupt();
}
void lp_ticker_disable_interrupt(void)
{
rtc_deactivate_wake_up_timer();
}
void lp_ticker_clear_interrupt(void)
{
lp_ticker_disable_interrupt();
}
void lp_ticker_free(void)
{
lp_ticker_disable_interrupt();
}
#endif /* MBED_CONF_TARGET_LPTICKER_LPTIM */
#endif /* DEVICE_LPTICKER */
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