Function dma_pool_alloc

components/drivers/dma/dma_pool.c:267–691

}

static rt_ubase_t dma_pool_alloc(struct rt_dma_pool *pool, rt_size_t size)
{
    rt_size_t bit, next_bit, end_bit, max_bits;

    size = RT_DIV_ROUND_UP(size, ARCH_PAGE_SIZE);
    max_bits = pool->bits - size;

    rt_bitmap_for_each_clear_bit(pool->map, bit, max_bits)
    {
        end_bit = bit + size;

        for (next_bit = bit + 1; next_bit < end_bit; ++next_bit)
        {
            if (rt_bitmap_test_bit(pool->map, next_bit))
            {
                bit = next_bit;
                goto _next;
            }
        }

        if (next_bit == end_bit)
        {
            while (next_bit --> bit)
            {
                rt_bitmap_set_bit(pool->map, next_bit);
            }

            return pool->start + bit * ARCH_PAGE_SIZE;
        }
    _next:
    }

    return RT_NULL;
}

static void dma_pool_free(struct rt_dma_pool *pool, rt_ubase_t offset, rt_size_t size)
{
    rt_size_t bit = (offset - pool->start) / ARCH_PAGE_SIZE, end_bit;

    size = RT_DIV_ROUND_UP(size, ARCH_PAGE_SIZE);
    end_bit = bit + size;

    for (; bit < end_bit; ++bit)
    {
        rt_bitmap_clear_bit(pool->map, bit);
    }
}

static void *dma_alloc(struct rt_device *dev, rt_size_t size,
        rt_ubase_t *dma_handle, rt_ubase_t flags)
{
    void *dma_buffer = RT_NULL;
    struct rt_dma_pool *pool;

    region_pool_lock();

    rt_list_for_each_entry(pool, &dma_pool_nodes, list)
    {