Re: [PATCH] m68k: move sun3 into a top-level platform option

["Arnd Bergmann" <arnd@arndb.de>]

On Sun, Aug 18, 2024, at 13:08, Geert Uytterhoeven wrote:
> On Sat, Aug 3, 2024 at 4:01 PM Arnd Bergmann <arnd@kernel.org> wrote:

>> +       help
>> +         This option enables support for the Sun 3 series of workstations
>> +         (3/50, 3/60, 3/1xx, 3/2xx systems). These use a classic 68020 CPU
>> +         but the custom memory management unit makes them incompatible with
>> +         all other classic m68k machines, including Sun 3x.
>
> Yes, it's a good idea to factor out at the top level machines that
> need special handling.
>
> However, the name of the choice now sounds a bit odd. Perhaps it should
> be changed to "CPU/machine family support"?
> Likewise for M68KCLASSIC.

Changed for v3 now.

>> -if M68KCLASSIC
>> +endchoice
>>
>>  config M68000
>> -       def_bool y
>> -       depends on !MMU
>> +       def_bool M68KCLASSIC && !MMU
>
> I think this is unrelated, and should be spun-off into a separate patch
> to fix the "no CPU type selected" issue?

This change is actually needed here since I'm moving
it out of the 'if M68KCLASSIC' block. There is no change
in behavior here, only adapting to the other changes.

>>         select CPU_HAS_NO_BITFIELDS
>>         select CPU_HAS_NO_CAS
>>         select CPU_HAS_NO_MULDIV64
>> @@ -56,7 +66,8 @@ config M68000
>>           a paging MMU.
>>
>>  config M68020
>> -       bool "68020 support"
>> +       bool "68020 support" if M68KCLASSIC
>> +       default !(M68030 || M68040 || M68060)
>
> Part of the "no CPU type selected" fix?

It turns out this was just wrong an broke COLDFIRE builds.
I've replaced it with a separate patch that works.

>>         depends on MMU
>>         select FPU
>>         select CPU_HAS_ADDRESS_SPACES
>
> You also need:
>
>     config M68KFPU_EMU
>             bool "Math emulation support"
>    -        depends on M68KCLASSIC && FPU
>    +        depends on (M68KCLASSIC || SUN3) && FPU

Added.

>> --- a/arch/m68k/kernel/Makefile
>> +++ b/arch/m68k/kernel/Makefile
>> @@ -5,16 +5,8 @@
>>
>>  extra-y                        += vmlinux.lds
>>
>> -obj-$(CONFIG_AMIGA)    := head.o
>> -obj-$(CONFIG_ATARI)    := head.o
>> -obj-$(CONFIG_MAC)      := head.o
>> -obj-$(CONFIG_APOLLO)   := head.o
>> -obj-$(CONFIG_VME)      := head.o
>> -obj-$(CONFIG_HP300)    := head.o
>> -obj-$(CONFIG_Q40)      := head.o
>> -obj-$(CONFIG_SUN3X)    := head.o
>> -obj-$(CONFIG_VIRT)     := head.o
>> -obj-$(CONFIG_SUN3)     := sun3-head.o
>> +obj-$(CONFIG_M68KCLASSIC)      := head.o
>> +obj-$(CONFIG_SUN3)             := sun3-head.o
>
> Nice cleanup ;-)
>

This also needed a small fixuup to not break dragonball,
using CONFIG_MMU_MOTOROLA instead of CONFIG_M68KCLASSIC.

      Arnd