On Thu, Jun 21, 2018 at 03:38:30AM +0000, A.s. Dong wrote: > Hi Rob, > > > -----Original Message----- > > From: Rob Herring [mailto:robh@xxxxxxxxxx] > > Sent: Thursday, June 21, 2018 3:45 AM > > To: A.s. Dong <aisheng.dong@xxxxxxx> > > Cc: 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 3/4] dt-bindings: arm: fsl: add scu binding doc > > > > On Sun, Jun 17, 2018 at 08:49:48PM +0800, Dong Aisheng wrote: > > > The System Controller Firmware (SCFW) is a low-level system function > > > which runs on a dedicated Cortex-M core to provide power, clock, and > > > resource management. It exists on some i.MX8 processors. e.g. i.MX8QM > > > (QM, QP), and i.MX8QX (QXP, DX). > > > > > > 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: > > > * remove status > > > * changed to mu1 > > > --- > > > .../devicetree/bindings/arm/freescale/fsl,scu.txt | 38 > > > ++++++++++++++++++++++ > > > 1 file changed, 38 insertions(+) > > > create mode 100644 > > > Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > > > > > > diff --git > > > a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > > > b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > > > new file mode 100644 > > > index 0000000..9b7c9fe > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt > > > @@ -0,0 +1,38 @@ > > > +NXP i.MX System Controller Firmware (SCFW) > > > +-------------------------------------------------------------------- > > > + > > > +The System Controller Firmware (SCFW) is a low-level system function > > > +which runs on a dedicated Cortex-M core to provide power, clock, and > > > +resource management. It exists on some i.MX8 processors. e.g. i.MX8QM > > > +(QM, QP), and i.MX8QX (QXP, DX). > > > + > > > +The AP communicates with the SC using a multi-ported MU module found > > > +in the LSIO subsystem. The current definition of this MU module > > > +provides > > > +5 remote AP connections to the SC to support up to 5 execution > > > +environments (TZ, HV, standard Linux, etc.). The SC side of this MU > > > +module interfaces with the LSIO DSC IP bus. The SC firmware will > > > +communicate with this MU using the MSI bus. > > > + > > > +System Controller Device Node: > > > +============================= > > > + > > > +Required properties: > > > +------------------- > > > +- compatible: should be "fsl,imx8qxp-scu" or "fsl,imx8qm-scu" > > > +- fsl,mu: a phandle to the Message Unit used by SCU. Should be > > > + one of LSIO MU0~M4 for imx8qxp and imx8qm. Users need > > > + to make sure not use the one which is conflict with > > > + other execution environments. e.g. ATF. > > > > Use the mailbox binding even if you don't use the mailbox subsystem. > > > > Looks reasonable. Will change it. > > BTW as I said before, the current mailbox binding fixed #mbox-cells to be > at least 1 which is not suitable for i.MX SCU MU as it has only one physical > channel. Why is that not suitable? If we use #mbox-cells = 1 we can encode the channel into the second cell. Furthermore, the SCU mode which uses all channels in a funny way could be another channel id the mu driver could use to distinguish the different channel/modes. i.e. #define MU_CHANNEL_0 0 #define MU_CHANNEL_1 1 #define MU_CHANNEL_2 2 #define MU_CHANNEL_3 3 #define MU_CHANNEL_SCU 4 scu { compatible = "fsl,imx8qxp-scu"; fsl,mu = <&lsio_mu1 MU_CHANNEL_SCU>; }; This would also allow to the MU-SCU-mode driver to coexist with the regular MU driver for which Oleksij posted a driver. 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
