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Date:   Mon, 12 Aug 2019 15:19:45 +0200
From:   Shawn Guo <shawnguo@kernel.org>
To:     Daniel Baluta <daniel.baluta@nxp.com>
Cc:     s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com,
        linux-imx@nxp.com, aisheng.dong@nxp.com, anson.huang@nxp.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        gregkh@linuxfoundation.org, tglx@linutronix.de,
        o.rempel@pengutronix.de
Subject: Re: [PATCH v4] firmware: imx: Add DSP IPC protocol interface
Message-ID: <20190812131944.GE27041@X250>
References: <20190801095636.22944-1-daniel.baluta@nxp.com>
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On Thu, Aug 01, 2019 at 12:56:36PM +0300, Daniel Baluta wrote:
> Some of i.MX8 processors (e.g i.MX8QM, i.MX8QXP) contain
> the Tensilica HiFi4 DSP for advanced pre- and post-audio
> processing.
> 
> The communication between Host CPU and DSP firmware is
> taking place using a shared memory area for message passing
> and a dedicated Messaging Unit for notifications.
> 
> DSP IPC protocol offers a doorbell interface using
> imx-mailbox API.
> 
> We use 4 MU channels (2 x TXDB, 2 x RXDB) to implement a
> request-reply protocol.
> 
> Connection 0 (txdb0, rxdb0):
>         - Host writes messasge to shared memory [SHMEM]
> 	- Host sends a request [MU]
> 	- DSP handles request [SHMEM]
> 	- DSP sends reply [MU]
> 
> Connection 1 (txdb1, rxdb1):
> 	- DSP writes a message to shared memory [SHMEM]
> 	- DSP sends a request [MU]
> 	- Host handles request [SHMEM]
> 	- Host sends reply [MU]
> 
> The protocol interface will be used by a Host client to
> communicate with the DSP. First client will be the i.MX8
> part from Sound Open Firmware infrastructure.
> 
> The protocol offers the following interface:
> 
> On Tx:
>    - imx_dsp_ring_doorbell, will be called to notify the DSP
>    that it needs to handle a request.
> 
> On Rx:
>    - clients need to provide two callbacks:
> 	.handle_reply
> 	.handle_request
>   - the callbacks will be used by the protocol on
>     notification arrival from DSP.
> 
> Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>

Applied, thanks.