From: Peng Fan <peng.fan@nxp.com>
To: Cristian Marussi <cristian.marussi@arm.com>,
"Peng Fan (OSS)" <peng.fan@oss.nxp.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk+dt@kernel.org>,
Conor Dooley <conor+dt@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 0/2] firmware: arm_scmi: add notification completion channel
Date: Thu, 9 May 2024 03:38:42 +0000 [thread overview]
Message-ID: <DU0PR04MB941788789A3B0DF23995D28488E62@DU0PR04MB9417.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <ZjuwgLZ1Sh5jRBWn@pluto>
Hi Cristian,
> Subject: Re: [PATCH 0/2] firmware: arm_scmi: add notification completion
> channel
>
> On Tue, May 07, 2024 at 11:34:59PM +0800, Peng Fan (OSS) wrote:
> > Per spec:
>
> Hi Peng,
>
> thanks for doing this.
>
> > Completion interrupts This transport supports polling or interrupt
> > driven modes of communication. In interrupt mode, when the callee
> > completes processing a message, it raises an interrupt to the caller.
> > Hardware support for completion interrupts is optional.
> >
> > i.MX95 SCMI firmware is fully interrupt driven, so Platform expects
> > completion interrupt for Platform to Agent(P2A) notifictions.
> >
> > Add another optional mailbox channel for Agent to notify Platform that
> > notification message has been accepted
> >
> > After notification channel status become freed, Agent will use the new
> > mailbox channel to send completion interrupt to Platform.
> >
> > Add shmem_channel_intr_enabled to check channel flags.
>
> Glancing through the series I think the bindings and the code are quite good
> and sensible to achieve the addition of the optional P2A completion interrupt.
>
> Your current solution, though, addresses only the case of a mailbox controller
> providing unidirectional channels. (which I suppose is the one you are using
> on your platform)
Right. i.MX95 use unidirectional channels.
>
> We should take care to add such optional P2A completion interrupt support
> also for the case of mailboxes sporting bidirectional channels.
>
> For bidirectional channels we really have already the needed bindings...
> ...no changes there...you have just to also ring the doorbell on that same P2A
> if completion IRQs are requested.
>
> IOW, when the DT description is made by 2 mboxes + 2 shmem, means we
> have both A2P and P2A provided via bidirectional channels...we currently just
> use the P2A (RX) channel to receive notifs/dresp via rx_callback (so using only
> the platform_to_agent direction)...now we should also ring the P2A doorbell
> on the existing P2A channel if the FLAG_INTR_ENABLED is set to signal the
> completion interrupt on the other direction (agent_to_platform)
>
> Not sure if I have been clear or make it worst with my explanation :P
Thanks for detailed explanation, it is clear enough. I will update to support
bidirectional channel in V2.
Thanks,
Peng.
>
> Thanks,
> Cristian
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prev parent reply other threads:[~2024-05-09 3:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 15:34 [PATCH 0/2] firmware: arm_scmi: add notification completion channel Peng Fan (OSS)
2024-05-07 15:35 ` [PATCH 1/2] dt-bindings: firmware: arm,scmi: Support " Peng Fan (OSS)
2024-05-07 15:35 ` [PATCH 2/2] firmware: arm_scmi: mailbox: support P2A channel completion Peng Fan (OSS)
2024-05-08 17:04 ` [PATCH 0/2] firmware: arm_scmi: add notification completion channel Cristian Marussi
2024-05-09 3:38 ` Peng Fan [this message]
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