kumquat-buildroot/arch/Config.in.m68k
Thomas Petazzoni 874916567a arch: rework MMU option handling and move to "Target architecture" menu
The MMU option is currently located in the "Toolchain" menu, but it
doesn't make sense as it's really architecture related. In addition,
the selection of MMU has an impact on the choice of binary format
available, which is visible in the architecture menu.

Therefore, this commit moves the MMU option into the architecture
menu.

However, if we simply move it in arch/Config.in, it means that we
would have the following order of options:

 Target architecture
 Target architecture variant
 ABI
 MMU
 Binary format

But really, the MMU option should be right below the Target
architecture variant, and the available ABIs derived from that.

The variant and ABI are arch-specfic, and defined in the per-arch
Config.in fragments; a Kconfig option can have only one prompt defined,
even under conditions, and appears at the place in the menu where its
prompt was defined. So, there is no (easy) possibility to have a
generic option appear where we want it.

Since in fact only 2 architectures show a visible prompt for the MMU
option (RISC-V and Xtensa), we move this option in
arch/Config.in.riscv and arch/Config.in.xtensa.

Some walkthrough the commit:

 - BR2_ARCH_HAS_MMU_MANDATORY and BR2_ARCH_HAS_MMU_OPTIONAL are
   removed as they are no longer needed

 - BR2_USE_MMU becomes a hidden boolean

 - All the places where we used to select BR2_ARCH_HAS_MMU_MANDATORY
   now select BR2_USE_MMU directly.

 - Introduce BR2_RISCV_USE_MMU and BR2_XTENSA_USE_MMU.

 - All defconfigs that used "# BR2_USE_MMU is not set" are switched to
   using the new option.

All in all, this simplifies things quite a bit, and allows to have a
good option ordering in the Target architecture menu.

This commit might raise a concern in terms of backward compatibility
with existing configurations. The only configurations that will be
broken by this change are RISC-V noMMU (which was very recently
introduced) and Xtensa noMMU (which we can probably agree is not such
a widely popular configuration).

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
[yann.morin.1998@free.fr:
  - expand further why we need per-arch MMU options
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
2022-07-27 11:38:07 +02:00

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config BR2_ARCH
default "m68k" if BR2_m68k
config BR2_NORMALIZED_ARCH
default "m68k"
config BR2_ENDIAN
default "BIG"
# symbols used to distinguish between m68k and coldfire
# for gcc multilib
config BR2_m68k_m68k
bool
config BR2_m68k_cf
bool
# coldfire variants will be added later
choice
prompt "Target CPU"
default BR2_m68k_68040
depends on BR2_m68k
help
Specific CPU variant to use
config BR2_m68k_68040
bool "68040"
select BR2_m68k_m68k
select BR2_USE_MMU
config BR2_m68k_cf5208
bool "5208"
select BR2_m68k_cf
select BR2_SOFT_FLOAT
endchoice
config BR2_GCC_TARGET_CPU
default "68040" if BR2_m68k_68040
default "5208" if BR2_m68k_cf5208
config BR2_READELF_ARCH_NAME
default "MC68000"
# vim: ft=kconfig
# -*- mode:kconfig; -*-