caveats, but works quite well in a lot of MP cases, and all
UP cases that I have tested. Parts of this will hopefully be
reworked in the not-too-distant future.
* need to specify DMA channel for DMACMD_SET_IO
* the upper byte of port was masked incorrectly
also update comment in _mca_bus_dmamap_sync() to current reality
* add flag to explicitly specify if the DMA should be done as 16bit or 8bit
* add flag to specify the DMA should happen via I/O port
* add new function mca_dma_set_ioport(), to set I/O port to be used for the
DMA operation
Also clarify copyright (welcome to 2001 :), and couple other minor nits
interface, using the code from dev/mca/edc_mca.c:edc_setup_dma()
as a base. Use ISA routines for dmamap/dmamem functions, primarily
to get the buffer bouncing for >16MB RAM machines. The MCA DMA
channel is stored in unused upper 4 bits of ISA DMA cookie's
id_flags, hopefully that's not too disgusting :)
Export mca_dmamap_create(), which returns map suitable for further DMA
operations using MCA DMA controller.
mca_busprobe(): also report if machine has 32bit DMA (feature byte 2
bit 1)
Use symbolic names for DMA controller commands - I've finally got
info what they mean from Tymm Twillman's Linux include/asm/mca_dma.h.
No more magic constants! Also fix bug in the way DMA counter has been
setup - for 16bit DMA, it's necessary to tell the controller _half_
the byte count. This was wrong in the former code.
found in some older IBM PS/2 machines.
This code is based upon work by Scott D. Telford, with some minor bits
in arch/i386/mca/mca_machdep.c taken from FreeBSD.
XXX this is still very experimental and development version; use at your
XXX own risk
