__get_free_pages分配DMA buffer

void *dxt_dma_contig_alloc(unsigned int size)
{
    struct page *page;
    void *addr = (void *)__get_free_pages( GFP_DMA, get_order(size));

    for (page = virt_to_page(addr); page <= virt_to_page(addr + size - 1); page++)
        //SetPageReserved(page);
    return addr;
}

void dxt_dma_contig_free(void *addr, unsigned int size)
{
    struct page *page;
    for (page = virt_to_page(addr); page <= virt_to_page(addr + size - 1); page++)
        //ClearPageReserved(page);
    free_pages((unsigned long)addr, get_order(size));
}

 

1. 在PC上可以分配8M

2. __get_free_pages( GFP_DMA | GFP_KERNEL, )有问题

3. 不能SetPageReserved（）