Re: [PATCH v18 4/7] firmware: arm_rmm: Add support for SRO

[Suzuki K Poulose]

On 14/09/2026 07:22, Suzuki K Poulose wrote:
> Hi Gavin
>
> Thank you for the review, I will address most of them. Responses inline.
>
> On 14/09/2026 06:04, Gavin Shan wrote:
> > On 9/12/26 6:36 PM, Suzuki K Poulose wrote:
> > > RMM v2.0 introduces the concept of "Stateful RMI Operations" (SRO). This
> > > means that an SMC can return with an operation still in progress. The
> > > host is expected to continue the operation until it reaches a conclusion
> > > (either success or failure). During this process the RMM can request
> > > additional memory ('donate') or hand memory back to the host
> > > ('reclaim'). The host can request an in progress operation is cancelled,
> > > but still continue the operation until it has completed (otherwise the
> > > incomplete operation may cause future RMM operations to fail).
> > >
> > > The SRO is tracked using a struct rmi_sro_state object which keeps track
> > > of any memory which has been allocated but not yet consumed by the RMM
> > > or reclaimed from the RMM. This allows the memory to be reused in a
> > > future request within the same operation. It will also permit an
> > > operation to be done in a context where memory allocation may be
> > > difficult (e.g. atomic context) with the option to abort the operation
> > > and retry the memory allocation outside of the atomic context. The
> > > memory stored in the struct rmi_sro_state object can then be reused on
> > > the subsequent attempt.
> > >
> > > Wrappers for SRO RMI commands are also provided here because they depend
> > > on the rmi_sro_execute() implementation added by this patch.
> > > Delegate/undelegate handles are also added here because they now use the
> > > SRO/stateful command infrastructure and are also used for the memory
> > > DONATE/RECLAIM flows.
> > >
> > > Signed-off-by: Steven Price <steven.price@xxxxxxx>
> > > Co-Developed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>
>
>
> > > ---
> > >   drivers/firmware/arm_rmm/rmi.c | 586 +++++++++++++++++++++++++++++++++
> > >   include/linux/arm-rmi-cmds.h   |  41 +++
> > >   2 files changed, 627 insertions(+)
> > >
> > > diff --git a/drivers/firmware/arm_rmm/rmi.c b/drivers/firmware/ 
> > > arm_rmm/rmi.c
> > > index 5b0e342ce3d58..4f9898ece7547 100644
> > > --- a/drivers/firmware/arm_rmm/rmi.c
> > > +++ b/drivers/firmware/arm_rmm/rmi.c
>
> > I would drop rmi_granule_range_{delegate, undelegate}() by combining 
> > their logics to
> > their only callers rmi_{delegate, undelegate}_range(). More details 
> > are provided for
> > rmi_{delegate, undelegate}_range() in the below.
>
> Ack

I have moved them closer, but kept the logic separate, since this is not
a simple RMI call.

Cheers
Suzuki