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From: Jim Quinlan <james.quinlan@broadcom.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Cristian Marussi <cristian.marussi@arm.com>,
	open list <linux-kernel@vger.kernel.org>,
	"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
	<linux-arm-kernel@lists.infradead.org>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	etienne.carriere@linaro.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Souvik Chakravarty <souvik.chakravarty@arm.com>
Subject: Re: [PATCH v4 11/12] [RFC] firmware: arm_scmi: Add sync_cmds_atomic_replies transport flag
Date: Wed, 25 Aug 2021 13:17:47 -0400	[thread overview]
Message-ID: <CA+-6iNw-_VXcntU_UE8kTiPb8Sq28KkZG1__N7rE4ezo=VqQVQ@mail.gmail.com> (raw)
In-Reply-To: <7a2f972d-fdd0-d0f7-cac2-1989980ed872@gmail.com>

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On Wed, Aug 25, 2021 at 12:38 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
>
>
>
> On 8/24/2021 3:59 PM, Cristian Marussi wrote:
> > A flag is added to let the transport signal the core that its handling of
> > synchronous command messages implies that, after .send_message has returned
> > successfully, the requested command can be assumed to be fully and
> > completely executed on SCMI platform side so that any possible response
> > value is already immediately available to be retrieved by a .fetch_reponse:
> > in other words the polling phase can be skipped in such a case and the
> > response values accessed straight away.
> >
> > Note that all of the above applies only when polling mode of operation was
> > selected by the core: if instead a completion IRQ was found to be available
> > the normal response processing path based on completions will still be
> > followed.
>
> This might actually have to be settable on a per-message basis ideally
> since we may be transporting short lived SCMI messages for which the
> completion can be done at SMC time, and long lived SCMI messages (e.g.:
> involving a voltage change) for which we would prefer a completion
> interrupt. Jim, what do you think?
Even if the SCMI main driver could be configured this way in an
elegant manner, I'm not sure that there is a clean way of specifying
this  attribute on a per-message basis.  Certainly we could do this
with our own protocols, but  many of our "long lived" messages are the
Perf protocol's set_level command.  At any rate, let me give it some
thought.

Regards,
Jim
> --
> Florian

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  reply	other threads:[~2021-08-25 17:18 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 13:59 [PATCH v4 0/12] Introduce atomic support for SCMI transports Cristian Marussi
2021-08-24 13:59 ` [PATCH v4 01/12] firmware: arm_scmi: Perform earlier cinfo lookup call in do_xfer Cristian Marussi
2021-08-25 16:28   ` Florian Fainelli
2021-08-24 13:59 ` [PATCH v4 02/12] firmware: arm_scmi: Add configurable polling mode for transports Cristian Marussi
2021-08-25 16:29   ` Florian Fainelli
2021-08-24 13:59 ` [PATCH v4 03/12] firmware: arm_scmi: Add support for atomic transports Cristian Marussi
2021-08-25 16:18   ` Jim Quinlan
2021-08-25 17:50     ` Cristian Marussi
2021-08-24 13:59 ` [PATCH v4 04/12] include: trace: Add new scmi_xfer_response_wait event Cristian Marussi
2021-08-25 16:30   ` Florian Fainelli
2021-08-24 13:59 ` [PATCH v4 05/12] firmware: arm_scmi: Use new trace event scmi_xfer_response_wait Cristian Marussi
2021-08-25 16:31   ` Florian Fainelli
2021-08-25 17:52     ` Cristian Marussi
2021-08-24 13:59 ` [PATCH v4 06/12] firmware: arm_scmi: Add is_transport_atomic() handle method Cristian Marussi
2021-08-25 16:32   ` Florian Fainelli
2021-08-24 13:59 ` [PATCH v4 07/12] clk: scmi: Support atomic enable/disable API Cristian Marussi
2021-08-25 16:33   ` Florian Fainelli
2021-08-24 13:59 ` [PATCH v4 08/12] firmware: arm_scmi: Declare virtio transport .atomic_capable Cristian Marussi
2021-08-24 13:59 ` [PATCH v4 09/12] [RFC] firmware: arm_scmi: Make smc transport use common completions Cristian Marussi
2021-08-25 16:35   ` Florian Fainelli
2021-08-24 13:59 ` [PATCH v4 10/12] [RFC] firmware: arm_scmi: Make smc transport atomic Cristian Marussi
2021-08-24 13:59 ` [PATCH v4 11/12] [RFC] firmware: arm_scmi: Add sync_cmds_atomic_replies transport flag Cristian Marussi
2021-08-25 16:38   ` Florian Fainelli
2021-08-25 17:17     ` Jim Quinlan [this message]
2021-08-25 18:49       ` Cristian Marussi
2021-08-26 18:29         ` Jim Quinlan
2021-08-31  5:56           ` Cristian Marussi
2021-09-23 15:03           ` Cristian Marussi
2021-10-04 17:50             ` Jim Quinlan
2021-10-04 18:00               ` Cristian Marussi
2021-08-24 13:59 ` [PATCH v4 12/12] [RFC] firmware: arm_scmi: Make smc support atomic commands replies Cristian Marussi

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