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

hi Arnd

just a ping, on Alex's proposal (below) about armv7m_restart
(Currently "restart" is not functional on stm32 MCU).

BR
Ludo
On 12/19/2017 03:38 PM, Alexandre Torgue wrote:

On 12/18/2017 09:24 PM, Arnd Bergmann wrote:

quoted

On Mon, Dec 18, 2017 at 4:17 PM, Ludovic Barre [off-list ref] 
wrote:

quoted

From: Ludovic Barre <redacted>

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 <redacted>

Looks good overall. Two more small comments:

quoted

+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.

quoted

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.

I resend

regards
Alex

quoted

      Arnd

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