Messages in this thread | | | Subject | Re: [2.6 patch] mark virt_to_bus/bus_to_virt as __deprecated on i386 | From | Arjan van de Ven <> | Date | Wed, 19 Apr 2006 21:23:45 +0200 |
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On Wed, 2006-04-19 at 14:21 -0400, linux-os (Dick Johnson) wrote: > On Wed, 19 Apr 2006, Adrian Bunk wrote: > > > On Wed, Apr 19, 2006 at 08:13:55AM +0300, Muli Ben-Yehuda wrote: > >> On Wed, Apr 19, 2006 at 12:07:15AM +0200, Adrian Bunk wrote: > >>> virt_to_bus/bus_to_virt are long deprecated, mark them as __deprecated > >>> on i386. > >> > >> You should probably update Documentation/ while you're at it. > > > > Which file under Documentation/ are you referring to? > > > >> Also, IIRC Xen uses virt_to_phys to return guest physical addresses > >> and virt_to_bus to return machine physical addresses, so the > >> difference is useful at least in some scenarios. > > > > Solving this should be easy. > > > > And this still doesn't make it right for architecture independent > > drivers to use virt_to_bus/bus_to_virt. > > Then what would you use to return the proper bus address to put > into a DMA scatter list and, conversely, how would you convert > those bus addresses into something a virtual mode CPU could > access? These macros used to be the link that made such driver > coding architecture independent. You cannot just claim that > one can't make such conversions anymore. The CPU uses virtual > addresses and the DMA uses physical (bus) addresses. Do we > throw away DMA altogether?
since a long time the kernel has proper dma mapping API's for this, in 2.4 it's pci specific in 2.6 it's generic and bus agnostic.
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