btstack_run_loop_freertos.c

/*
 * Copyright (C) 2017 BlueKitchen GmbH
 *
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 * modification, are permitted provided that the following conditions
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 *
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 *    from this software without specific prior written permission.
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 *    personal benefit and not for any commercial purpose or for
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 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
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/*
 *  btstack_run_loop_freertos.c
 *
 *  Run loop on dedicated thread on FreeRTOS
 *  The run loop is triggered from other task/ISRs either via Event Groups
 *  or Task Notifications if HAVE_FREERTOS_TASK_NOTIFICATIONS is defined
 */

#define BTSTACK_FILE__ "btstack_run_loop_freertos.c"

#include <stddef.h> // NULL

#include "btstack_run_loop_freertos.h"

#include "btstack_linked_list.h"
#include "btstack_debug.h"
#include "btstack_util.h"
#include <platform/embedded/hal_time_ms.h>

// some SDKs, e.g. esp-idf, place FreeRTOS headers into an 'freertos' folder to avoid name collisions (e.g. list.h, queue.h, ..)
// wih this flag, the headers are properly found

#ifdef HAVE_FREERTOS_INCLUDE_PREFIX
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/event_groups.h"
#else
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "event_groups.h"
#endif

typedef struct function_call {
    void (*fn)(void * arg);
    void * arg;
} function_call_t;

// pick allocation style, prefer static
#if( configSUPPORT_STATIC_ALLOCATION == 1 )
#define USE_STATIC_ALLOC
#elif( configSUPPORT_DYNAMIC_ALLOCATION == 1 )
// ok, nothing to do
#else
#error "Either configSUPPORT_STATIC_ALLOCATION or configSUPPORT_DYNAMIC_ALLOCATION in FreeRTOSConfig.h must be 1"
#endif

// queue to receive events: up to 2 calls from transport, rest for app
#define RUN_LOOP_QUEUE_LENGTH 20
#define RUN_LOOP_QUEUE_ITEM_SIZE sizeof(function_call_t)

#ifdef USE_STATIC_ALLOC
static StaticQueue_t btstack_run_loop_queue_object;
static uint8_t btstack_run_loop_queue_storage[ RUN_LOOP_QUEUE_LENGTH * RUN_LOOP_QUEUE_ITEM_SIZE ];
#endif

static QueueHandle_t        btstack_run_loop_queue;
static TaskHandle_t         btstack_run_loop_task;

#ifndef HAVE_FREERTOS_TASK_NOTIFICATIONS
static EventGroupHandle_t   btstack_run_loop_event_group;
#endif

// bit 0 event group reserved to wakeup run loop
#define EVENT_GROUP_FLAG_RUN_LOOP 1

// the run loop
static btstack_linked_list_t timers;
static btstack_linked_list_t data_sources;

static uint32_t btstack_run_loop_freertos_get_time_ms(void){
    return hal_time_ms();
}

// set timer
static void btstack_run_loop_freertos_set_timer(btstack_timer_source_t *ts, uint32_t timeout_in_ms){
    ts->timeout = btstack_run_loop_freertos_get_time_ms() + timeout_in_ms + 1;
}

/**
 * Add timer to run_loop (keep list sorted)
 */
static void btstack_run_loop_freertos_add_timer(btstack_timer_source_t *ts){
    btstack_linked_item_t *it;
    for (it = (btstack_linked_item_t *) &timers; it->next ; it = it->next){
        // don't add timer that's already in there
        btstack_timer_source_t * next = (btstack_timer_source_t *) it->next;
        if (next == ts){
            log_error( "btstack_run_loop_timer_add error: timer to add already in list!");
            return;
        }
        // exit if new timeout before list timeout
        int32_t delta = btstack_time_delta(ts->timeout, next->timeout);
        if (delta < 0) break;
    }
    ts->item.next = it->next;
    it->next = (btstack_linked_item_t *) ts;
}

/**
 * Remove timer from run loop
 */
static bool btstack_run_loop_freertos_remove_timer(btstack_timer_source_t *ts){
    return btstack_linked_list_remove(&timers, (btstack_linked_item_t *) ts);
}

static void btstack_run_loop_freertos_dump_timer(void){
#ifdef ENABLE_LOG_INFO 
    btstack_linked_item_t *it;
    int i = 0;
    for (it = (btstack_linked_item_t *) timers; it ; it = it->next){
        btstack_timer_source_t *ts = (btstack_timer_source_t*) it;
        log_info("timer %u, timeout %u\n", i, (unsigned int) ts->timeout);
    }
#endif
}

// schedules execution from regular thread
void btstack_run_loop_freertos_trigger(void){
#ifdef HAVE_FREERTOS_TASK_NOTIFICATIONS
    xTaskNotify(btstack_run_loop_task, EVENT_GROUP_FLAG_RUN_LOOP, eSetBits);
#else
    xEventGroupSetBits(btstack_run_loop_event_group, EVENT_GROUP_FLAG_RUN_LOOP);
#endif
}

void btstack_run_loop_freertos_execute_code_on_main_thread(void (*fn)(void *arg), void * arg){

    // directly call function if already on btstack task
    if (xTaskGetCurrentTaskHandle() == btstack_run_loop_task){
        (*fn)(arg);
        return;
    }

    function_call_t message;
    message.fn  = fn;
    message.arg = arg;
    BaseType_t res = xQueueSendToBack(btstack_run_loop_queue, &message, 0); // portMAX_DELAY);
    if (res != pdTRUE){
        log_error("Failed to post fn %p", fn);
    }
    btstack_run_loop_freertos_trigger();
}

#if defined(HAVE_FREERTOS_TASK_NOTIFICATIONS) || (INCLUDE_xEventGroupSetBitFromISR == 1)
void btstack_run_loop_freertos_trigger_from_isr(void){
    BaseType_t xHigherPriorityTaskWoken;
#ifdef HAVE_FREERTOS_TASK_NOTIFICATIONS
    xTaskNotifyFromISR(btstack_run_loop_task, EVENT_GROUP_FLAG_RUN_LOOP, eSetBits, &xHigherPriorityTaskWoken);
    if (xHigherPriorityTaskWoken) {
#ifdef ESP_PLATFORM
        portYIELD_FROM_ISR();
#else
        portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
#endif
    }
#else
    xEventGroupSetBitsFromISR(btstack_run_loop_event_group, EVENT_GROUP_FLAG_RUN_LOOP, &xHigherPriorityTaskWoken);
#endif
}

void btstack_run_loop_freertos_execute_code_on_main_thread_from_isr(void (*fn)(void *arg), void * arg){
    function_call_t message;
    message.fn  = fn;
    message.arg = arg;
    BaseType_t xHigherPriorityTaskWoken;
    xQueueSendToBackFromISR(btstack_run_loop_queue, &message, &xHigherPriorityTaskWoken);
    btstack_run_loop_freertos_trigger_from_isr();
}
#endif

/**
 * Execute run_loop
 */
static void btstack_run_loop_freertos_execute(void) {
    log_debug("RL: execute");
    
    while (true) {

        // process data sources
        btstack_data_source_t *ds;
        btstack_data_source_t *next;
        for (ds = (btstack_data_source_t *) data_sources; ds != NULL ; ds = next){
            next = (btstack_data_source_t *) ds->item.next; // cache pointer to next data_source to allow data source to remove itself
            if (ds->flags & DATA_SOURCE_CALLBACK_POLL){
                ds->process(ds, DATA_SOURCE_CALLBACK_POLL);
            }
        }

        // process registered function calls on run loop thread
        while (true){
            function_call_t message = { NULL, NULL };
            BaseType_t res = xQueueReceive( btstack_run_loop_queue, &message, 0);
            if (res == pdFALSE) break;
            if (message.fn){
                message.fn(message.arg);
            }
        }

        // process timers and get next timeout
        uint32_t timeout_ms = portMAX_DELAY;
        log_debug("RL: portMAX_DELAY %u", portMAX_DELAY);
        while (timers) {
            btstack_timer_source_t * ts = (btstack_timer_source_t *) timers;
            uint32_t now = btstack_run_loop_freertos_get_time_ms();
            int32_t delta_ms = btstack_time_delta(ts->timeout, now);
            log_debug("RL: now %u, expires %u -> delta %d", now, ts->timeout, delta_ms);
            if (delta_ms > 0){
                timeout_ms = delta_ms;
                break;
            }
            // remove timer before processing it to allow handler to re-register with run loop
            btstack_run_loop_freertos_remove_timer(ts);
            log_debug("RL: first timer %p", ts->process);
            ts->process(ts);
        }

        // wait for timeout or event group/task notification
        log_debug("RL: wait with timeout %u", (int) timeout_ms);
#ifdef HAVE_FREERTOS_TASK_NOTIFICATIONS
        xTaskNotifyWait(pdFALSE, 0xffffffff, NULL, pdMS_TO_TICKS(timeout_ms));
#else
        xEventGroupWaitBits(btstack_run_loop_event_group, EVENT_GROUP_FLAG_RUN_LOOP, 1, 0, pdMS_TO_TICKS(timeout_ms));
#endif
    }
}

static void btstack_run_loop_freertos_add_data_source(btstack_data_source_t *ds){
    btstack_linked_list_add(&data_sources, (btstack_linked_item_t *) ds);
}

static bool btstack_run_loop_freertos_remove_data_source(btstack_data_source_t *ds){
    return btstack_linked_list_remove(&data_sources, (btstack_linked_item_t *) ds);
}

static void btstack_run_loop_freertos_enable_data_source_callbacks(btstack_data_source_t * ds, uint16_t callback_types){
    ds->flags |= callback_types;
}

static void btstack_run_loop_freertos_disable_data_source_callbacks(btstack_data_source_t * ds, uint16_t callback_types){
    ds->flags &= ~callback_types;
}

static void btstack_run_loop_freertos_init(void){
    timers = NULL;

#ifdef USE_STATIC_ALLOC
    btstack_run_loop_queue = xQueueCreateStatic(RUN_LOOP_QUEUE_LENGTH, RUN_LOOP_QUEUE_ITEM_SIZE, btstack_run_loop_queue_storage, &btstack_run_loop_queue_object);
#else
    btstack_run_loop_queue = xQueueCreate(RUN_LOOP_QUEUE_LENGTH, RUN_LOOP_QUEUE_ITEM_SIZE);
#endif

#ifndef HAVE_FREERTOS_TASK_NOTIFICATIONS
    // event group to wake run loop
    btstack_run_loop_event_group = xEventGroupCreate();
#endif

    // task to handle to optimize 'run on main thread'
    btstack_run_loop_task = xTaskGetCurrentTaskHandle();

    log_info("run loop init, task %p, queue item size %u", btstack_run_loop_task, (int) sizeof(function_call_t));
}

/**
 * @brief Provide btstack_run_loop_posix instance for use with btstack_run_loop_init
 */

static const btstack_run_loop_t btstack_run_loop_freertos = {
    &btstack_run_loop_freertos_init,
    &btstack_run_loop_freertos_add_data_source,
    &btstack_run_loop_freertos_remove_data_source,
    &btstack_run_loop_freertos_enable_data_source_callbacks,
    &btstack_run_loop_freertos_disable_data_source_callbacks,
    &btstack_run_loop_freertos_set_timer,
    &btstack_run_loop_freertos_add_timer,
    &btstack_run_loop_freertos_remove_timer,
    &btstack_run_loop_freertos_execute,
    &btstack_run_loop_freertos_dump_timer,
    &btstack_run_loop_freertos_get_time_ms,
};

const btstack_run_loop_t * btstack_run_loop_freertos_get_instance(void){
    return &btstack_run_loop_freertos;
}