Re: [PATCH v3 0/7] arm64: dts: ti: k3-am62a7-sk: Split r5f memory region

["Markus Schneider-Pargmann" <msp@baylibre.com>]

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Hi Vignesh,

On Thu Apr 9, 2026 at 11:46 AM CEST, Vignesh Raghavendra wrote:
> Hi Markus
>
> On 08/04/26 20:33, Rob Herring wrote:
>> On Wed, Mar 18, 2026 at 10:14 AM Markus Schneider-Pargmann (TI)
>> <msp@baylibre.com> wrote:
>>>
>>> Hi,
>>>
>>> Split the firmware memory region in more specific parts so it is better
>>> described where which information is stored. Specifically the LPM metadata
>>> region is important as bootloader software like U-Boot has to know where
>>> that data is to be able to read that data and resume from RAM.
>>>
>>> IO+DDR is a deep sleep state in which a few pins are set to be sensitive
>>> for wakeup while the DDR is kept in self refresh. Everything else is
>>> powered off.
>>>
>>> The changes in this series were suggested as part of the IO+DDR u-boot series:
>>>   https://lore.kernel.org/r/814c211f-a9eb-4311-bb84-165b1a69755f@ti.com
>>>
>>> There are currently no real users of the memory-region that is split in
>>> this series. The size of the memory-region in total stays the same.
>>> The new layout is derived from the software running on the r5f
>>> processor:
>>>   https://github.com/TexasInstruments/mcupsdk-core-k3/blob/k3_main/examples/drivers/ipc/ipc_rpmsg_echo_linux/am62ax-sk/r5fss0-0_freertos/ti-arm-clang/linker.cmd#L172
>>>   https://github.com/TexasInstruments/mcupsdk-core-k3/blob/k3_main/source/drivers/device_manager/sciclient.h#L459
>>>
>>> Additionally the two important devicetree nodes for resuming from IO+DDR
>>> have the bootph-pre-ram flag added as this data needs to be read before
>>> the RAM is in use.
>>>
>>> Best
>>> Markus
>>>
>>> Signed-off-by: Markus Schneider-Pargmann (TI) <msp@baylibre.com>
>>> ---
>>> Changes in v3:
>>> - Squash the enforcement of the memory-region-names requirement in the
>>>   patch adding the memory-region-names, as suggested.
>>> - Link to v2: https://lore.kernel.org/r/20260312-topic-am62a-ioddr-dt-v6-19-v2-0-37cb7ceec658@baylibre.com
>>>
>>> Changes in v2:
>>> - Make memory-region-names required if memory-region is present
>>> - Fixup memory-region and memory-region-names conditions. Require either
>>>   2 or 6 regions for memory-region and memory-region-names
>>> - Reword and restructure the binding documentation for memory-region and
>>>   memory-region-names
>>> - Add memory-region-names to all uses of memory-region
>>> - Link to v1: https://lore.kernel.org/r/20260303-topic-am62a-ioddr-dt-v6-19-v1-0-12fe72bb40d2@baylibre.com
>>>
>>> ---
>>> Markus Schneider-Pargmann (TI) (7):
>>>       dt-bindings: remoteproc: k3-r5f: Split up memory regions
>>>       dt-bindings: remoteproc: k3-r5f: Add memory-region-names
>>>       arm64: dts: ti: k3: Use memory-region-names for r5f
>>>       arm64: dts: ti: k3-am62a7-sk: Split r5f memory region
>>>       arm64: dts: ti: k3-am62p5-sk: Split r5f memory region
>>>       arm64: dts: ti: k3-am62a7-sk: Add r5f nodes to pre-ram bootphase
>>>       arm64: dts: ti: k3-am62p5-sk: Add r5f nodes to pre-ram bootphase
>> 
>> TI folks, Please make sure these dts patches are picked up for 7.1.
>> There's now a crap load of warnings in next with the binding change:
>> 
>>      58 (ti,am62-r5fss): r5f@78000000: 'memory-region-names' is a
>> required property
>
> [...]
>
>> If they aren't applied, making  'memory-region-names' required needs
>> to be dropped from the binding.
>>
>
> This breaks DT backward compatibility. Why is memory-region-names now a
> required item and cannot be assumed as "dma" and "firmware" as default?
> Is that intentional (should have at least had a Fixes tag then if the
> original definition was wrong)?

Conor suggested to make the memory-region-names required for easier
distinction of the layouts:
  https://lore.kernel.org/all/20260303-payphone-pancake-b6068c545bc3@spud/

And a follow-up discussion here:
  https://lore.kernel.org/all/20260313-kettle-craftily-aa087e6b74db@spud/

Also I don't think it really breaks backward compatibility. I don't
think there is any user for it and the previous binding documentation
only refers to it as reserved regions.

Best
Markus


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