Subject: Re: [linux-audio-dev] Linux Driver for Creamware Luna II
From: Erik de Castro Lopo (erikd-lad_AT_mega-nerd.com)
Date: Fri Nov 09 2001 - 09:05:06 EET
It really blew my mind when Paul Davis <pbd_AT_Op.Net> said:
> >> unless you can figure out what the interesting address ranges are and
> >> then find only the assignments to locations within those ranges, no
> >> debugger or anything will help reverse engineer this kind of design.
> >
> >Ah, but we can (with PCI at least). /proc/pci is your friend.
>
> Ah, but you can't :) First of all, there is no guarantee that the PCI
> addresses will be the same under Windows, so /proc/pci may not be much
> of a guide. Secondly, and more significantly, /proc/pci tells you the
> physical addresses where PCI devices live. When a driver is writing to
> the device, its typically writing to the virtual address to which the
> physaddr has been mapped. I believe this is true under Windows; its
> nearly always true under Linux.
If someone hs access to a Logic Analyser with a PCI bus probe (I have seen
one) then this becomes possible reverse engineering task.
You run the card under Linux and watch the Logic Analyser trace. Then you
start peeking an poking registers under Linux.
Erik
-- +-----------------------------------------------------------+ Erik de Castro Lopo nospam_AT_mega-nerd.com (Yes it's valid) +-----------------------------------------------------------+ "What is freedom of expression? Without the freedom to offend, it ceases to exist." - Salman Rushdie
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