Re: [PATCH v3 1/6] dt-bindings: remoteproc: k3-r5f: Add Jacinto LPM memory region

[Richard GENOUD <richard.genoud@bootlin.com>]

Le 16/07/2026 à 21:48, Rob Herring (Arm) a écrit :
> 
> On Fri, 03 Jul 2026 16:37:12 +0200, Richard Genoud (TI) wrote:
>> Declare a carveout memory region to store LPM metadata on Jacinto
>> devices.
>>
>> For Jacinto devices, this memory region is needed for saving ATF context
>> and the certificate information of ATF and OPTEE and DM image. This LPM
>> metadata area is firewalled to be accessed only by TIFS.
>>
>> U-Boot R5 SPL/TIFS will use this area to save and restore:
>> - ATF context
>> - ATF certificate information
>> - OPTEE certificate information
>> - DM image (which has been copied in memory at boot time by U-Boot
>> R5-SPL)
>>
>> At resume, U-Boot R5 SPL is executed and detects that the board is
>> resuming (with a flag set in the PMIC), then it:
>> - brings out of retention the DDR
>> - retrieves the LPM memory region from DTS
>> - authenticates certificates from LPM memory region and applies firewalls
>> - asks TIFS to restore TFA and its own minimal context
>> - starts TFA on remote proc
>> - loads back DM image from memory and jumps to DM
>>
>> https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/pm/lpm.html#lpm-msg-lpm-save-addr
>>
>> NB: This memory region is not part of DM memory (which is not retained
>> at suspend)
>>
>> Signed-off-by: Richard Genoud (TI) <richard.genoud@bootlin.com>
>> ---
>>   .../bindings/remoteproc/ti,k3-r5f-rproc.yaml   | 18 +++++++++++++++---
>>   1 file changed, 15 insertions(+), 3 deletions(-)
>>
> 
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
> 
> Seems like sashiko raises a legit issue, but that's a kernel issue and
> not my problem if your board crashes.
Thanks for raising this.

Indeed, Sashiko is right.
Using no-map; doesn't prevent from direct mapping through 
devm_ioremap_resource_wc().

Nishanth: Would it be acceptable for Sitara if we skip 
devm_ioremap_resource_wc() for lpm-metadata?
Or should we use a different name for Jacinto, like
firewalled-lpm-metadata?

Regards,
Richard

> 
> Rob