Restrict DMA Buffer to 32 bit Address

[Tal Lubko]

 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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20210114/9a75cf65/attachment.html>