linux-kernel - Re: [PATCH V4 3/5] mailbox: imx: add imx mu support

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Message-ID: <20180710141940.oed3kwhbplnykl36@pengutronix.de>
Date:   Tue, 10 Jul 2018 16:19:40 +0200
From:   Sascha Hauer <s.hauer@...gutronix.de>
To:     Dong Aisheng <aisheng.dong@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, dongas86@...il.com,
        Jassi Brar <jassisinghbrar@...il.com>,
        linux-kernel@...r.kernel.org,
        Oleksij Rempel <o.rempel@...gutronix.de>, linux-imx@....com,
        kernel@...gutronix.de, fabio.estevam@....com, shawnguo@...nel.org
Subject: Re: [PATCH V4 3/5] mailbox: imx: add imx mu support

Hi,

On Sun, Jul 08, 2018 at 10:56:55PM +0800, Dong Aisheng wrote:
> This is used for i.MX multi core communication.
> e.g. A core to SCU firmware(M core) on MX8.
> 
> Tx is using polling mode while Rx is interrupt driven and
> schedule a hrtimer to receive remain words if have more than
> 4 words.

You told us that using interrupts is not possible due to miserable
performance, we then provided you a way with which you could poll.  Why
are you using interrupts now?

We also suggested a way how the SCU mode could be integrated into the
generic MU support driver Oleksij posted and now you send a driver which
uses the same name as Oleksijs driver, but it only and exclusively works
in SCU mode. This doesn't bring us forward.

We suggested a binding that allows coexisting of the SCU mode and the
generic mode of the MU by putting the mode information into the second
mbox-cell. Why don't you use this?

I don't think it's necessary to rewrite Oleksijs driver, instead it
should rather be extended with the code I already provided as an
example. With that we could make both of us happy since we can both
have a suitable driver and even share most of the MU code.

Regards,
Sascha

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