Messages in this thread | | | Subject | Re: [PULL] Add support for Texas Instruments C6X architecture | From | Mark Salter <> | Date | Sun, 06 Nov 2011 15:05:27 -0500 |
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On Sun, 2011-11-06 at 11:07 -0800, Linus Torvalds wrote: > > > > I think the best counter argument is that it leads to paddr != vaddr > > in the case of NOMMU with a non-zero memory base. My view is that in > > all NOMMU cases, physical and virtual addresses should be the same. > > Otherwise, you end up breaking drivers which need to pass physical > > addresses to devices. > > That's a totally insane argument.
Not *totally* insane. Forget the last sentence. You're right that its a driver problem. Creating a physical address space separate from the "virtual" space on a NOMMU arch where the hw uses a one-to-one mapping seems a long way to go. My point here is that the simplest NOMMU case is paddr == vaddr. Right now, the generic headers are broken in that regard for hardware that maps RAM at a non-zero address.
So, okay. Let's have some more discussion among more people. There is certainly more than one approach to fix the currently broken bits and I sure don't claim to have the one true way. I just want to do what needs to be done to make the port acceptable for upstream inclusion.
--Mark
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