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Brian Stecher
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Re: PORT IO functions in*() and out*() will deal with Physical Address or Virtual Address before the Kernel intialization starts?
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Brian Stecher
11/26/2010 8:22 AM
post76113
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Re: PORT IO functions in*() and out*() will deal with Physical Address or Virtual Address before the Kernel intialization starts?
Depends on the architecture. You should always do a startup_io_map() and
the return value from that will be the appriopriate value to feed into
the in* and out* functions for the system that you're running on.
From a theoretical standpoint, program code _always_ operates on virtual
addresses. It's just that if the CPU memory managment unit hasn't been
turned on yet, virtual == physical. As implied above, some architectures
have the MMU on during startup and some don't.
On Fri, Nov 26, 2010 at 05:31:55AM -0500, ravinder are wrote:
> Hi OSTech,
>
> in startup code initialization (before entering to Kernel
> initialization) the port IO fucinons in*() and out*() will work
> directly on physical addresses or virtaul address ?
>
> Thanks,
> Ravinder Are
>
>
>
> _______________________________________________
>
> OSTech
> http://community.qnx.com/sf/go/post76105
>
--
Brian Stecher (bstecher@qnx.com) QNX Software Systems
phone: +1 (613) 591-0931 (voice) 175 Terence Matthews Cr.
+1 (613) 591-3579 (fax) Kanata, Ontario, Canada K2M 1W8
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