malloc_threadx.c

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/*
 * Copyright © 2017 Embedded Artistry LLC.
 * License: MIT. See LICENSE file for details.
 */

#include <assert.h>
#include <malloc.h>
#include <stdbool.h>
#include <stdint.h>
#include <threadx/tx_api.h>

#pragma mark - Declarations -

static TX_BYTE_POOL malloc_pool_;

static volatile bool initialized_ = false;

#pragma mark - APIs -

__attribute__((weak)) void malloc_init(void)
{
    // Unused here, override to specify your own init functin
    // Which includes malloc_addblock calls
}

void malloc_addblock(void* addr, size_t size)
{
    assert(addr && (size > 0));

    unsigned r;

    /*
     * tx_byte_pool_create is ThreadX's API to create a byte pool using a memory block.
     * We are essentially just wrapping ThreadX APIs into a simpler form
     */
    r = tx_byte_pool_create(&malloc_pool_, "Heap Memory Pool", addr, size);
    assert(r == TX_SUCCESS);

    // Signal to any threads waiting on do_malloc that we are done
    initialized_ = true;
}

void* malloc(size_t size)
{
    void* ptr = NULL;

    while(!initialized_)
    {
        tx_thread_sleep(1);
    }

    if(size > 0)
    {
        // We simply wrap the threadX call into a standard form
        unsigned r = tx_byte_allocate(&malloc_pool_, &ptr, size, TX_WAIT_FOREVER);

        // I add the string to provide a more helpful error output.  It's value is always true.
        assert(r == TX_SUCCESS && "malloc failed");
    } // else NULL if there was an error

    return ptr;
}

void free(void* ptr)
{
    assert(initialized_);

    if(ptr)
    {
        // We simply wrap the threadX call into a standard form
        unsigned r = tx_byte_release(ptr);
        assert(r == TX_SUCCESS);
    }
}