Re: pci_alloc_consistent usage

[Atsushi Nemoto <anemo@mba.ocn.ne.jp>]

>>>>> On Tue, 27 May 2003 13:22:37 +0200, Ralf Baechle <ralf@linux-mips.org> 
>>>>> said:
ralf> While it's officially documented I still don't like it.  A
ralf> double conversion such as page_address(virt_to_page(ptr)) would
ralf> accidently turn a pointer of an uncached mapping into one to a
ralf> cached area for the same object - that will almost certainly not
ralf> work as expected on a non-coherent machine.

Yes, it's dangerous, I agree.

ralf> Whatever - virt_to_page should then be considered a a legacy API
ralf> which we have to try to support as well as possible in the hope
ralf> it's going to fade away ...

I hope so.  For now we can do something like:

     buf = pci_alloc_consistent(dev, size, &dmabuf);
#if defined(__mips__) && defined(CONFIG_NONCOHERENT_IO)
     page = virt_to_page(CAC_ADDR(buf));
#else
     page = virt_to_page(buf);
#endif

Ugly but I do not want to add extra overhead to virt_to_page itself...

---
Atsushi Nemoto