On Wed, 2 Jun 2021, Michael Schmitz wrote: > Hi Geert, > > Am 02.06.2021 um 19:09 schrieb Geert Uytterhoeven: > > Hi Michael, > > > > On Wed, Jun 2, 2021 at 7:21 AM Michael Schmitz <schmitzmic@xxxxxxxxx> wrote: > > > For multiplatform kernels where CONFIG_ATARI_ROM_ISA is not set, > > > at least isa_sex must be set correctly to allow for correct I/O > > > primitive selection in shared drivers. > > > > > > Signed-off-by: Michael Schmitz <schmitzmic@xxxxxxxxx> > > > > Thanks for your patch! > > > > > > > --- a/arch/m68k/kernel/setup_mm.c > > > +++ b/arch/m68k/kernel/setup_mm.c > > > @@ -386,6 +386,10 @@ void __init setup_arch(char **cmdline_p) > > > isa_type = ISA_TYPE_ENEC; > > > isa_sex = 0; > > > } > > > +#else > > > + if (MACH_IS_ATARI) { > > > + isa_sex = 0; > > > > I find it strange that you set isa_sex, but not isa_type? > > Yes, as I said this is only to ensure isa_sex has the correct value (0) so > isa_readw() resolves to in_le16() for the Atari IDE driver after the change at > the end of the first patch. Might have been better to rather say > > int isa_sex=0; > > at the start of setup_mm.c ... or rely on that variable being initialized as > zero anyway. > > > However, this is inside the CONFIG_ISA && MULTI_ISA block, so what > > kind of ISA does this correspond to? > > No ISA at all in that case, but since we have to route all readw() calls > through isa_readw() for the sake of generality if we want to support Q40 > ISA and Atari MMIO in the same kernel image, we need to make sure > isa_readw() does the right thing on Atari if CONFIG_ISA is set. > > I know io_mm.h says it's about various ISA bridges, but as I found out, > drivers using only MMIO are also affected by these definitions. > > 'Maze' does not begin to describe it, 'mess' might be getting closer, > but I can't see how we would avoid use of definitions in io_mm.h by > non-ISA drivers. > It seems that the need for explicit zero initialization has more to do with subtelty over in asm/io_mm.h than anything else. If so, it would be better to add commentary there than to add redundant code here. > Cheers, > > Michael > > > > > > + } > > > #endif > > > #endif > > > > Gr{oetje,eeting}s, > > > > Geert > > >