Clean up the DMA interface too much unneeded stuff crept in with
the busdma code back when.
Modify the ATA_IN* / ATA_OUT* macros so that resource and offset
are gotten from a table. That allows for new chipsets that doesn't
nessesarily have things ordered the good old way. This also removes
the need for the wierd PC98 resource functions.
Tested on: i386, PC98, Alpha, Sparc64
This moves all chipset specific code to a new file 'ata-chipset.c'.
Extensive use of tables and pointers to avoid having the same switch
on chipset type in several places, and to allow substituting various
functions for different HW arch needs.
Added PIO mode setup and all DMA modes.
Support for all known SiS chipsets. Thanks to Christoph Kukulies for
sponsoring a nice ASUS P4S8X SiS648 based board for this work!
Tested on: i386, PC98, alpha and sparc64
