[PATCH] firmware: scmi: Drop mmu_set_region_dcache_behaviour() misuse

[Marek Vasut]

On 10/28/25 3:37 PM, Marek Vasut wrote:
> On 10/28/25 9:25 AM, Peng Fan wrote:
> 
> Hello Peng,
> 
>>> Subject: [PATCH] firmware: scmi: Drop
>>> mmu_set_region_dcache_behaviour() misuse
>>>
>>> MMU region cache behavior configuration for SCMI/SMT mailboxes is
>>> platform specific. Even on ARM systems, the mailbox memory may not
>>> even be located in any cacheable MMU region and may instead reside
>>> in some SRAM. Remove this non-generic cache behavior configuration
>>> code from generic code path.
>>>
>>> It is unlikely that any platform is affected by this change if it did
>>> configure its MMU regions correctly on start up. Platforms which might
>>> be affected are i.MX94/95 and STM32MP.
>>>
>>
>> If the memory is mapped before running SCMI stuff, it is ok.
>> But if memory is dynamic mapped at run time, there might be issue.
> 
> I wonder ... should ARM/ARM64 define CONFIG_HAVE_ARCH_IOREMAP and 
> implement actual ioremap() function which changes these cacheable 
> properties accordingly ?
> 
>> I saw TI platforms has some changes to use dynamic mappings,
>> I have not read the details, TBH.
> 
> Can we put the TI people on CC here ?

+CC Anshul

-- 
Best regards,
Marek Vasut