__pa() vs. virt_to_phys()

[Martin Maletinsky <maletinsky@scs.ch>]

Hi,

Is there any reason to use __pa() rather than virt_to_phys() or vice versa?

On i386 virt_to_phys() is just a function that returns the value returned by __pa(); on Alpha virt_to_phys() is a function that subtracts IDENT_ADDR from the argument,
whereas __pa() is a macro that subtracts PAGE_OFFSET from its argument - however PAGE_OFFSET and IDENT_ADDR expand to the same value; on Sparc virt_to_phys() is a macro
that expands to __pa().

So the two things look to be pretty much the same on different platforms - is there any reason
for having __pa() as well as virt_to_phys(), and which one is to be used by device drivers?

thanks for your help
regards
Martin
--
Supercomputing System AG          email: maletinsky@scs.ch
Martin Maletinsky                 phone: +41 (0)1 445 16 05
Technoparkstrasse 1               fax:   +41 (0)1 445 16 10
CH-8005 Zurich


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