kumquat-buildroot/arch/Config.in.xtensa
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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choice
prompt "Target Architecture Variant"
default BR2_xtensa_fsf
depends on BR2_xtensa
config BR2_XTENSA_CUSTOM
bool "Custom Xtensa processor configuration"
config BR2_xtensa_fsf
bool "fsf - Default configuration"
select BR2_USE_MMU
endchoice
config BR2_XTENSA_OVERLAY_FILE
string "Overlay file for custom configuration"
depends on BR2_XTENSA_CUSTOM
help
Enter the path to the overlay tarball for a custom processor
configuration.
These overlay files are tar packages with updated
configuration files for various toolchain packages and Xtensa
processor configurations. They are provided by the processor
vendor or directly from Tensilica.
The path can be either absolute, or relative to the top
directory of buildroot.
choice
prompt "Target Architecture Endianness"
default BR2_XTENSA_LITTLE_ENDIAN
depends on BR2_XTENSA_CUSTOM
config BR2_XTENSA_LITTLE_ENDIAN
bool "Little endian"
config BR2_XTENSA_BIG_ENDIAN
bool "Big endian"
endchoice
config BR2_XTENSA_USE_MMU
bool "MMU support"
default y
depends on BR2_XTENSA_CUSTOM
select BR2_USE_MMU
help
Enable this option if your Xtensa core has a MMU (Memory
Management Unit).
config BR2_ENDIAN
default "LITTLE" if BR2_XTENSA_LITTLE_ENDIAN
default "BIG" if BR2_xtensa_fsf || BR2_XTENSA_BIG_ENDIAN
config BR2_ARCH
default "xtensa" if BR2_xtensa
config BR2_NORMALIZED_ARCH
default "xtensa"
config BR2_READELF_ARCH_NAME
default "Tensilica Xtensa Processor"
# vim: ft=kconfig
# -*- mode:kconfig; -*-