Finn Thain found out that our multiplatform support is broken when attempting to build a kernel with support for both Q40 and Atari (when setting CONFIG_ISA through CONFIG_Q40, but not CONFIG_ATARI_ROM_ISA). Inspection of the code in io_mm.h reveals that in that case, ISA I/O accessors with address translation are used for the Atari IDE driver, where MMIO accessors with no address translation would have been appropriate. Setting CONFIG_ATARI_ROM_ISA will fix the issue for Atari, but then force the use of I/O accessors without address translation for Q40. The code in io_mm.h is fundamentally broken for kernels that have both Q40 and Atari support. Address this by adding a check for address < 1024 to the Atari address translation case, changing the default address translation to return the untranslated address, and changing the CONFIG_ATARI_ROM_ISA section to use ISA I/O accessors for addresses > 1024 (i.e., those not intended to map to the ROM port). Tested on ARAnyM with all combinations of CONFIG_ATARI_ROM_ISA and CONFIG_ISA. Earlier versions tested on my Falcon hardware, all using pata_falcon. A thorough review in particular in regard to ramifications for Q40 and Amiga would be welcome. If there is a better way to implement these changes, I'd appreciate a hint. This is all academic as long as support for Q40 and Atari in the same kernel image is not needed, of course. I suspect patch 2 may not be needed, since the isa_sex variable should always be zero? Cheers, Michael
