[PATCH v2 0/4] Enable DMA on STM32 MCU based on cortex-M7

[Alexandre Torgue]

Hi Vlad

On 02/28/2018 02:22 PM, Vladimir Murzin wrote:
> On 28/02/18 13:10, Alexandre Torgue wrote:
>> This series enable DMA on several STM32 MCU based on cortex-M7.
>> To make it possible, a dedicated dma pool memory area has to be
>> created. This patchset activate also ARM_MPU flag which will configure
>> MPU (Memory Protection Unit) according to devicetree information (mem
>> and dma-pool). Note that on cortex-M7 DMA has to use a NO cache-able
>> memory region.
>>
>>
>> v2:
>> -select ARM_MPU in mach-stm32 Kconfig instead of add it in stm32 defconfig
>> -Remove XIP configuration from stm32_defconfig: ARM_MPU flag imposes XIP image
>> to be aligned on 1MB. It is currently not the case. I had choice to either
>> modify current XIP start address to be aligned on 1MB or to remove global
>> configuration. I make choice to remove XIP configuration. Indeed, SD card
>> support has been recently added for most of STM32 MCU boards (except for
>> stm32f429-disco). As kernel is growing up for stm32 it will be more and more
>> difficult to flash it in embeded flash (max size: 2MB).
> 
> It is sad we are loosing XIP configuration - it used to uncover some bugs
> in a past. Probably, you might consider to have stm32 tiny (+xip) defconfig
> for those who do not want/need all-in-one kernel.

I agree and I don't want to loose XIP configuration. I just want that 
default stm32_defconfig covers the main MCU boards and the maximum 
IPs/driver for those boards. SD cards will be the boot support that will 
be supported in buildroot (except for stm32f429-disco).

But I agree, I could maybe use a frag to have a tiny configuration for 
stm32 to be able to flash xip in embeded flash and provide a "basic" 
support (kernel boot + console).


Regards
Alex
> 
> Cheers
> Vladimir
> 
>> -fix typo in commit message
>>
>> Regards
>> Alex
>>
>> Alexandre Torgue (4):
>>    ARM: dts: stm32: add DMA memory pool on MCU which embed a cortex-M7
>>    ARM: configs: stm32: remove XIP configuration
>>    ARM: stm32: Select ARM_MPU for cortex-M7 machines
>>    ARM: dts: stm32: enable dma on MCU which embed a cortex-M7
>>
>>   arch/arm/boot/dts/stm32746g-eval.dts   | 21 +++++++++++++++++++++
>>   arch/arm/boot/dts/stm32f769-disco.dts  | 21 +++++++++++++++++++++
>>   arch/arm/boot/dts/stm32h743i-disco.dts | 21 +++++++++++++++++++++
>>   arch/arm/boot/dts/stm32h743i-eval.dts  | 21 +++++++++++++++++++++
>>   arch/arm/configs/stm32_defconfig       |  2 --
>>   arch/arm/mach-stm32/Kconfig            |  3 +++
>>   6 files changed, 87 insertions(+), 2 deletions(-)
>>
>