Re: Excellent job on the firewire support!

On Tue, Jul 20, 2004 at 11:41:52AM +0900, Hidetoshi Shimokawa wrote:
> It is not enough :-< I lack the knowledge of BIOS/PCI(and ACPI?).
> Once we can access the OHCI register via PCI in the loader,
> the remaining part is relatively easy as you described.
> I need some help for this part. I suppose that implementing dcons 
> in the loader is architecture dependent.

Very much so, to begin with. Let's consider the i386 case.

libi386/biospci.c wants FireWire device classes added to it for its probe.
Some BIOS wrapper functions to manipulate PCI configuration registers need
to be added too.

Then a fwconsole driver much like comconsole could be written, i.e.
fwc_probe(), fwc_init() etc. I believe it's safe to assume that V==P
for address space at this point. I guess this could act as a shim before
the driver actually gets loaded. kenv could be used to tell dcons where
the loader had allocated the buffer before the kernel actually starts.

There would have to be a comfortable handover between loader and dcons
in the kernel, but because it just uses a ring buffer, I imagine this is
somewhat easier than it would be otherwise.

I am about to get some long overdue sleep, otherwise I'd begin hacking this
myself. ;-)

BMS