linux-kernel - Re: [PATCH v4 02/12] firmware: arm_scmi: Add configurable polling mode for transports

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Date:   Wed, 25 Aug 2021 18:29:31 +0200
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Cristian Marussi <cristian.marussi@....com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     sudeep.holla@....com, james.quinlan@...adcom.com,
        Jonathan.Cameron@...wei.com, etienne.carriere@...aro.org,
        vincent.guittot@...aro.org, souvik.chakravarty@....com
Subject: Re: [PATCH v4 02/12] firmware: arm_scmi: Add configurable polling
 mode for transports



On 8/24/2021 3:59 PM, Cristian Marussi wrote:
> SCMI communications along TX channels can optionally be provided of a
> completion interrupt; when such interrupt is not available, command
> transactions should rely on polling, where the SCMI core takes care to
> repeatedly evaluate the transport-specific .poll_done() function to
> determine if and when a request was fully completed or timed out.
> 
> Such mechanism is already present and working on a single transfer base:
> SCMI protocols can indeed enable hdr.poll_completion on specific commands
> ahead of each transfer and cause that transaction to be handled with
> polling.
> 
> Introduce a couple of flags to be able to enforce such polling behaviour
> globally at will:
> 
>   - scmi_desc.force_polling: to statically switch the whole transport to
>     polling mode.
> 
>   - scmi_chan_info.no_completion_irq: to switch a single channel dynamically
>     to polling mode if at runtime is determined that no completion interrupt
>     was available for such channel.
> 
> Signed-off-by: Cristian Marussi <cristian.marussi@....com>

Reviewed-by: Florian Fainelli <f.fainelli@...il.com>
-- 
Florian