Re: scmi sensor

Re: scmi sensor

[Sudeep Holla]

On Mon, Oct 14, 2019 at 06:26:57AM +0000, Sujeet Kumar Baranwal wrote:
> Hi Sudeep,
>
> In order to use scmi sensor TRIP_POINT_NOTIFY part, the protocol only
> specifies trip points to be configured, and it doesn't have any handler
> associated that shall be invoked upon those points being violated on agent.
> After registering the trip points for a sensor, how does the linux scmi
> sensor driver ever comes to know any violations reported by SCP?!

The notification part is not yet implemented. It's yet another work
in progress feature.

>
> In the scmi_rx_callback() in ISR context, I only see complete(xfer->done)
> which would only let a blocked thread know it could proceed but that means
> some application needs to be initiated and permanently stalled, listening
> to this event?
>

Yes we need to set up Rx channel, buffers and then handle the event.
Rx channel support was added in v5.4, I have posted patch for setting up
buffers[1] but didn't merge without the user. I am still debating on how
to add notification APIs from SCMI for it's users.

> My requirement is that some how I register a call back in linux's scmi senor
> protocol that would be called when trip values are violated and it shall be
> initiated by platform to the agent. It doesn't appear to be a possibility
> looking at the current implementation and msg ids of scmi sensor protocol.
> Am I missing something?
>

As I mentioned earlier all these are WIP. Without platform to test, I am
not actively developing these. I can share patches when it's in good shape.

--
Regards,
Sudeep

[1] https://lore.kernel.org/lkml/20190708154730.16643-6-sudeep.holla@arm.com/

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RE: [EXT] Re: scmi sensor

[Sujeet Kumar Baranwal]

Thanks for your kind response.
Appreciate it.

Regards
Sujeet
-----Original Message-----
From: Sudeep Holla <sudeep.holla@arm.com> 
Sent: Monday, October 14, 2019 10:09 AM
To: Sujeet Kumar Baranwal <sbaranwal@marvell.com>
Cc: linux-arm-kernel@lists.infradead.org; Sudeep Holla <sudeep.holla@arm.com>
Subject: [EXT] Re: scmi sensor

External Email

----------------------------------------------------------------------
On Mon, Oct 14, 2019 at 06:26:57AM +0000, Sujeet Kumar Baranwal wrote:

> Hi Sudeep,

>

> In order to use scmi sensor TRIP_POINT_NOTIFY part, the protocol only

> specifies trip points to be configured, and it doesn't have any handler

> associated that shall be invoked upon those points being violated on agent.

> After registering the trip points for a sensor, how does the linux scmi

> sensor driver ever comes to know any violations reported by SCP?!



The notification part is not yet implemented. It's yet another work

in progress feature.



>

> In the scmi_rx_callback() in ISR context, I only see complete(xfer->done)

> which would only let a blocked thread know it could proceed but that means

> some application needs to be initiated and permanently stalled, listening

> to this event?

>



Yes we need to set up Rx channel, buffers and then handle the event.

Rx channel support was added in v5.4, I have posted patch for setting up

buffers[1] but didn't merge without the user. I am still debating on how

to add notification APIs from SCMI for it's users.



> My requirement is that some how I register a call back in linux's scmi senor

> protocol that would be called when trip values are violated and it shall be

> initiated by platform to the agent. It doesn't appear to be a possibility

> looking at the current implementation and msg ids of scmi sensor protocol.

> Am I missing something?

>



As I mentioned earlier all these are WIP. Without platform to test, I am

not actively developing these. I can share patches when it's in good shape.



--

Regards,

Sudeep



[1] https://urldefense.proofpoint.com/v2/url?u=https-3A__lore.kernel.org_lkml_20190708154730.16643-2D6-2Dsudeep.holla-40arm.com_&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=Hm1-XVU8b25YycWEs8mdXj-gi8TNI3X8J_X-2d6NuSA&m=3lG5ngBf9psdnYka42PZCdTc2VAJTACpUl2Q9B0Ncwk&s=aO8GKsDB1VVNuIyzJtZPPSglRWrlYoNa3W1jhhnOYLw&e= 


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