Re: [PATCH V2 3/9] ARM: stm32: prepare stm32 family to welcome armv7 architecture

[Alexandre Torgue]

On 12/18/2017 09:24 PM, Arnd Bergmann wrote:
> On Mon, Dec 18, 2017 at 4:17 PM, Ludovic Barre <ludovic.Barre@xxxxxx> wrote:
> > From: Ludovic Barre <ludovic.barre@xxxxxx>
> >
> > This patch prepares the STM32 machine for the integration of Cortex-A
> > based microprocessor (MPU), on top of the existing Cortex-M
> > microcontroller family (MCU). Since both MCUs and MPUs are sharing
> > common hardware blocks we can keep using ARCH_STM32 flag for most of
> > them. If a hardware block is specific to one family we can use either
> > ARM_SINGLE_ARMV7M or ARCH_MULTI_V7 flag.
> >
> > Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
>
> Looks good overall. Two more small comments:
>
>
> > +if ARCH_STM32
> > +
> >   config MACH_STM32F429
> > -       bool "STMicrolectronics STM32F429"
> > -       depends on ARCH_STM32
> > +       bool "STMicroelectronics STM32F429"
> > +       depends on ARM_SINGLE_ARMV7M
> >          default y
>
> Instead of the explicit dependency for each board, I'd leave the surrounding
> 'if ARM_SINGLE_ARMV7M'. I think you had in v1.
>
> > diff --git a/arch/arm/mach-stm32/Makefile b/arch/arm/mach-stm32/Makefile
> > index bd0b7b5..5940af1 100644
> > --- a/arch/arm/mach-stm32/Makefile
> > +++ b/arch/arm/mach-stm32/Makefile
> > @@ -1 +1 @@
> > -obj-y += board-dt.o
> > +obj-$(CONFIG_ARM_SINGLE_ARMV7M) += board-mcu-dt.o
> > diff --git a/arch/arm/mach-stm32/board-dt.c b/arch/arm/mach-stm32/board-mcu-dt.c
> > similarity index 100%
> > rename from arch/arm/mach-stm32/board-dt.c
> > rename to arch/arm/mach-stm32/board-mcu-dt.c
>
> Why the rename? I don't expect the new machines to have any notable
> contents in a board file, if any at all, so just use one file for both.
> I see the board-dt.c file refers to armv7m_restart, we can either put
> that in an #ifdef, or find a way to make it the default for all armv7-m
> platforms that don't provide any other restart method.
Currently "restart" is not functional on stm32 MCU (at least for 
stm32f746, I will check on others MCU). My fear is if Ludovic made some 
patches to make "armv7m_restart" the default ".restart" function for all 
armv7-m platform, he will not be able to test it on stm32 MCU (as it is 
not currently working). I propose to do it in 2 steps:

1-Keep as you suggest only one board-dt.c file for both (MCU and MPU) 
and remove ".restart" function.

2-Investigate and send patches around ".restart" for both in an other 
series.

regards
Alex


>       Arnd