Hi

I've PCI device which uses DMA engines and runs on 64 bit Linux with 512MB RAM.

It has 32 bit register used to specify DMA buffer address so as far as I understand I need to restrict it DMA buffers addresses to 32 bit.

I tried the following:

err = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));

if (err) {

    exit...

}

dma_alloc_coherent(dev, 0x1000, &dma_handle, GFP_KERNEL)

but when I print allocated buffer address I get the following 0x409993216

What am I missing here?

Thanks,

Tal