Re: Question about ioremap and io_remap_page_range

Ingo Molnar (mingo@elte.hu)
Thu, 27 Sep 2001 08:52:02 +0200 (CEST)


On Thu, 27 Sep 2001, [GB2312] ǿ wrote:

> Here is some rather basic questions I want ask ,any reply or comment
> please CC to my emailbox,thank you very much.
>
> When I work with kernel 2.4.2 in Intel X86 , I use
>
> VIRT_ADDR = ioremap(BUS_ADDR); to map a section of PCI memory, and
> X_ADDR = virt_to_phys(VIRT_ADDR);

i'd suggest to read Documentation/DMA-mapping.txt in any recent kernel
source, the bus_to_virt()/virt_to_phys() interface is obsolete and has
been replaced by the pci_alloc_*/pci_map_*/pci_free_*() dynamic
DMA-mapping API. You can find some nice examples of usage in
drivers/net/*.c.

Ingo

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