[U-Boot-Users] [PATCH 6/6] cfi_flash: Use map_physmem() and unmap_physmem()

Stefan Roese sr at denx.de
Wed Dec 12 07:09:34 CET 2007


On Tuesday 11 December 2007, Andrew Dyer wrote:
> > Virtual addresses? We don't have virtual memory in U-Boot...
>
> Virtual addesses don't imply demand paged virtual memory.
>
> For example on MIPS all software addresses are virtual and go through
> a translation to a physical address (granted for some regions of
> memory it's just forcing some address bits).  Some procs (Au1xxx) go
> as far as to require using the TLB to access all of the 36-bit
> physical space in the 32-bit virtual space.  For u-boot we can usually
> get away with a static mapping, but the mapping is still there.

Right. 

We already have this static mapping on most PPC440 platforms too. But here we 
currently try to match the low 32bits of the physical and the "virtual" 
address. How should we call such a resulting address if not "virtual 
address"?

Best regards,
Stefan

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