I'd like to ask some questions about floppy driver. I am owner of Pegasos-II PowerPC-based mainboard (http://www.pegasosppc.com) and floppy drive doesn't work on my machine. It doesn't read any data, sometimes even causes random crashes. Sometimes operation looks like completed ok but wrong data are read from/written to disk. Everything points to DMA problem - wrong region is used.
I tried to turn off DMA by specifying floppy=nodma but then it doesn't work at all.
I investigated the problem and discovered that virtual DMA for PowerPC is not implemented at all and hardware DMA is also handled differently. So here is my question:
In include/asm-ppc/floppy.h i see the following:
--- cut ---
/*
* The PowerPC has no problems with floppy DMA crossing 64k borders.
*/
#define CROSS_64KB(a,s) (0)
--- cut ---
What architectures was this tested on? Only Macintoshes or also something else? Does this work on CHRP-based machines? Pegasos is a CHRP-based machine and i'd like to know if ISA DMA is restricted in the same way as on x86. If yes, i will try to replace this macro with one taken from include/asm-i386/floppy.h but i'm afraid of reducing functionality or even breaking support for some machines which i don't know about. I guess i should use some #ifdef's here but i don't know conditions for them.
P. S. For information: Pegasos uses Discovery II MV64361 as a northbridge and VIA 8231 as southbridge. For full technical specifications see: http://www.pegasosppc.com/tech_specs.php
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Best regards,
Pavel Fedin, mailto:[email protected]