Re: Buffer at fixed memory address ?

[Vova <vova-ls@xxxxxxxxx>]

Hello !
Sorry, may be I do not explain it correct, but I what to allocate buffer at 
fixed address in RAM. RAM of my board is visible to another computer, with 
which I want to make connection using this buffer. I do not know how second 
computer will find the buffer if it will not be at fixed address.

-- 
      Vladimir

On Monday 10 January 2005 23:02, Om wrote:
> Vova wote:
> > But what will happen if memory which I try to remap are already in use ?
> > Will kernel automatically free that memory ?
>
> Kernel will not free it because it is not allocated. Actually kernel
> will not even see it as normal memory. If the PCI device is programmed
> to exhibit the internal memory to the outside (i.e, In the BAR registers
> and prefetchable/non-prefetchable registers), then only this memory
> becomes visible to the kernel as PCI accessible memory. You will have to
> map this memory to some address space and have your own routines to
> allocate and deallocate memory from this pool.
>
> I hope things are more clear.
> I wouls strongly suggest reading the "pci system architecture" by
> shanley and anderson.
>
> HTH,
> Om.
>

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