Re: [PATCH 2/6] dt-bindings: arm: keystone: ti,sci: Add ti,tda54-sci-pdm compatible

[Krzysztof Kozlowski <krzk@kernel.org>]

On 02/10/2026 11:30, Padhi, Beleswar wrote:
> 
> On 10/2/2026 12:01 PM, Krzysztof Kozlowski wrote:
>> On Thu, Oct 01, 2026 at 01:11:27AM +0530, Beleswar Padhi wrote:
>>> The previous TI K2G and K3 architectures were tightly coupled systems in
>>> terms of Safety and Security. All the TI-SCI messages from HLOS (Linux)
>>> were sent to a single sec proxy thread terminating at the core running
>>> Safety service (DM). In K2G systems, DM handled both Safety & Security
>>> requests by itself. Whereas in K3 systems, DM serviced the Safety
>>> requests itself, and forwarded the Security requests to core running
>>> Security service (TIFS) on the HLOS's behalf. This posed various
>>> limitations:
>>>     a. Increased latency: An extra forwarding hop through DM adds latency
>>>        in requests and responses.
>>>     b. Freedom From Interference (FFI) concerns: Having Safety service
>>>        proxy Security's requests (& vice versa) undermines the isolation
>>>        and FFI of the system.
>>>     c. Potential Deadlock Scenario: Forwarding messages between Safety
>>>        and Security cores can result in a deadlock if there are circular
>>>        dependencies.
>>>
>>> To eliminate all the above limitations, the TI TDA54 class of SoCs
>>> introduce an architectural change: Isolation of Security and Safety
>>> services. To realize this enhanced isolation in hardware, two
>>> independent sec proxy threads are now provided for HLOS to communicate
>>> separately with the Security and Safety cores respectively. And the
>>> TI-SCI message forwarding has been eliminated in Software. The System
>>> Firmware ABI5.0 version necessitates this improved isolation and FFI
>>> change.
>> I don't get at all how above description helps to understand this patch
>> and this new compatible, except that this is not compatible with old
>> variants.
> 
> 
> You just answered your own question.
> 
>>   So 30 lines of text instead of 3?
> 
> 
> The existing system controllers have been compatible in all TI SoCs
> for over 10+ years since Keystone generations. Using 30 lines of
> text to explain "why" the new system controller is not compatible
> with old variants is worth it.

If you decide to spam us with a lot of description, including marketing
crap ("To realize this enhanced isolation in hardware", "this improved
isolation") instead of writing concise and precise messages, accept the
outcome of maintainers choosing to allocate their time in "improved way".

Best regards,
Krzysztof