Re: [PATCH 1/4] hw/sh4/Kconfig: Rename CONFIG_SH4 -> CONFIG_SH4_DEVICES

[Peter Maydell]

On Mon, 8 Feb 2021 at 20:04, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>
> We want to be able to use the 'SH4' config for architecture
> specific features. As CONFIG_SH4 is only used to select
> peripherals, rename it CONFIG_SH4_DEVICES.
>
> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  hw/block/meson.build | 2 +-
>  hw/char/meson.build  | 2 +-
>  hw/intc/meson.build  | 2 +-
>  hw/sh4/Kconfig       | 6 +++---
>  hw/timer/meson.build | 2 +-
>  5 files changed, 7 insertions(+), 7 deletions(-)

We could if we wished be more fine-grained about this, eg by
adding new CONFIG options for each device:
 CONFIG_TC58128
 CONFIG_SH_SERIAL
 CONFIG_SH_INTC
 CONFIG_SH_TIMER
 CONFIG_SH_PCI

and then in hw/sh4/Kconfig
 * config SH7750:
   add 'select SH_SERIAL', 'select SH_INTC', 'select SH_TIMER'
 * config R2D:
   add 'select SH7750' (it's a pre-existing bug that it doesn't, since
   r2d.c has a call to sh7750_init(). Harmless at the moment because
   nothing actually uses CONFIG_SH7750 -- hw/sh4/meson.build always
   compiles sh7750.c and sh7750_regnames.c unconditionally...)
   add 'select SH_PCI' (and make hw/sh4/meson.build build sh_pci.c
   only if it is set...)
 * config SHIX
   add 'select TC58128'

Do we have a general preference for how fine-grained we go with the
Kconfig switches ? Looking at the arm code, in some cases we have
a CONFIG_ for the SoC that uses 'select' to turn on a separate
CONFIG_ for each device (the STM32 SoCs are done this way), and
in some cases we just have the meson.build use the SoC's CONFIG_*
to control whether we compile its devices (the Xilinx and Exynos4
SoCs are done this way). When reviewing new code it would be helpful
to know whether to suggest doing it one way or the other :-)

thanks
-- PMM