[Gc-linux-devel] dvd kernelmodule: memory address problem

[JockyW <joc...@ho...>]

Thanks for your assistance Arthur,

My simple dvd characterdevice works quite well. I rewrote the linux IRQ2
handler to handle all dvd irqs (not just the cover int).

But now I stumbled on a memory problem. My devicedriver uses a read buffer
which is a 2048 bytes static char array. When I print the address, it sits
on 0xC200EB24. That address doesn't work when I pass it to the DMA Memory
Address Register. It is a strange address, because in "yagcd"
http://www.gc-linux.org/docs/yagcd/chap4.html#sec4 it is written that
uncached logical ram addresses run from 0xc0000000-0xc17fffff

What kind of address translation should I apply to get the dma to work?


"Arthur Othieno" <a.o...@bl...> wrote in message
news:20040410170241.GA29363@mars...
> On Sat, Apr 10, 2004 at 04:59:51PM +0200, JockyW wrote:
> >
> > Thanks for your reply, but fttb it doesn't really help me.
> >
> > I have tried with this Makefile:
> >     obj-m := gcdvd.o
> >     module-objs := gcdvd.o cache.o
> >
> > But unfortunately cache.o isn't linked. After insmod gcdvd.o I get a
unknown
> > symbol, tho it is defined in cache.o
>
> s/module-objs/gcdvd-objs/
>
> > A bit strange is that insmod gcdvd.ko doesn't work at all because of a
bad
> > format or so. Only insmod gcdvd.o is accepted.
>
> You'll need module-init-tools for that. Grab them from
> http://kernel.org/pub/linux/utils/kernel/module-init-tools/
>
> See also http://lwn.net/Articles/22197/
>
> > As alternative to above Makefile I can take:
> > TARGET  := gcdvd
> > WARN    := -W -Wall -Wstrict-prototypes -Wmissing-prototypes
> > INCLUDE := -I/usr/src/linux/include
> > CFLAGS  := -c -O2 -DMODULE -D__KERNEL__ -DKBUILD_MODNAME="${TARGET}"
${WARN}
> > ${INCLUDE}
> > CC      := gcc-3.0
> >
> > ${TARGET}.o: ${TARGET}.c
> > cache.o: cache.S
> >
> > .PHONY: clean
> >
> > clean:
> >  rm -rf ${TARGET}.ko
> >  rm -rf ${TARGET}.o
> >
> > But there is again the problem that I don't know how to extend it such
that
> > it also links cache.o
> >
> > Any help is appreciated!
>
> See http://lwn.net/Articles/21823/ for how to properly compile external
> modules.
>
> Arthur
>
>
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