On Thu, Jun 21, 2018 at 05:11:33PM +0000, A.s. Dong wrote: > Hi Sascha, > > > -----Original Message----- > > From: Sascha Hauer [mailto:s.hauer@xxxxxxxxxxxxxx] > > Sent: Thursday, June 21, 2018 3:47 PM > > To: Rob Herring <robh@xxxxxxxxxx> > > Cc: A.s. Dong <aisheng.dong@xxxxxxx>; linux-arm- > > kernel@xxxxxxxxxxxxxxxxxxx; dongas86@xxxxxxxxx; kernel@xxxxxxxxxxxxxx; > > shawnguo@xxxxxxxxxx; Fabio Estevam <fabio.estevam@xxxxxxx>; dl-linux- > > imx <linux-imx@xxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx>; > > devicetree@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH V2 2/4] dt-bindings: arm: fsl: add mu binding doc > > > > On Wed, Jun 20, 2018 at 01:43:10PM -0600, Rob Herring wrote: > > > On Sun, Jun 17, 2018 at 08:49:47PM +0800, Dong Aisheng wrote: > > > > The Messaging Unit module enables two processors within the SoC to > > > > communicate and coordinate by passing messages (e.g. data, status > > > > and control) through the MU interface. > > > > > > > > Cc: Shawn Guo <shawnguo@xxxxxxxxxx> > > > > Cc: Sascha Hauer <kernel@xxxxxxxxxxxxxx> > > > > Cc: Fabio Estevam <fabio.estevam@xxxxxxx> > > > > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > > > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > > > Cc: devicetree@xxxxxxxxxxxxxxx > > > > Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx> > > > > --- > > > > v1->v2: > > > > * typo fixes > > > > * remove status property > > > > * remove imx6&7 compatible string which may be added later for > > > > the generic mailbox binding > > > > > > > > Note: Because MU used by SCU is not implemented as a mailbox driver, > > > > Instead, they're provided in library calls to gain higher performance. > > > > > > Using a binding doesn't mean you have to use an OS's subsystem. > > > > > > What needs higher performance? What's the performance difference? > > Why > > > can't the mailbox framework be improved? > > > > From what I see the performance is improved by polling the interrupt > > registers rather than using interrupts. > > I see no reason though why this can't be implemented with the mailbox > > framework as is. > > > > I thought you've agreed to not write generic MU(mailbox) driver for SCU. > https://www.spinics.net/lists/arm-kernel/msg650217.html > But seems it's still not quite certain... My suggestion was that we change the compatible of the MU unit to something that the SCU driver matches. But since we do not do that and instead use a fsl,imx8qxp-mu compatible for the MU we have to come up with a MU driver that handles both the SCU case and the regular usecase. Otherwise we'll end up with a generic driver attaching to the device you are using under the hoods. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
