Hi Rob On Thu, Mar 11, 2021 at 5:12 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > On Wed, Mar 10, 2021 at 6:33 AM Shengjiu Wang <shengjiu.wang@xxxxxxxxx> wrote: > > > > Hi Rob > > > > On Wed, Mar 10, 2021 at 10:49 AM Rob Herring <robh@xxxxxxxxxx> wrote: > > > > > > On Mon, Mar 08, 2021 at 09:22:27PM +0800, Shengjiu Wang wrote: > > > > fsl_rpmsg cpu dai driver is driver for rpmsg audio, which is mainly used > > > > > > Bindings describe h/w blocks, not drivers. > > > > I will modify the descriptions. but here it is a virtual device. the > > mapping in real h/w is cortex M core, Cortex M core controls the SAI, > > DMA interface. What we see from Linux side is a audio service > > through rpmsg channel. > > It's describing the h/w from the view of the OS. It's not important > that it's a Cortex-M, but how you interface to it whether that's > shared registers, mailbox, etc. And it's what resources the block uses > that the OS controls. ok. > > > > > for getting the user's configuration from device tree and configure the > > > > clocks which is used by Cortex-M core. So in this document define the > > > > needed property. > > > > > > > > Signed-off-by: Shengjiu Wang <shengjiu.wang@xxxxxxx> > > > > --- > > > > .../devicetree/bindings/sound/fsl,rpmsg.yaml | 118 ++++++++++++++++++ > > > > 1 file changed, 118 insertions(+) > > > > create mode 100644 Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml > > > > > > > > diff --git a/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml > > > > new file mode 100644 > > > > index 000000000000..5731c1fbc0a6 > > > > --- /dev/null > > > > +++ b/Documentation/devicetree/bindings/sound/fsl,rpmsg.yaml > > > > @@ -0,0 +1,118 @@ > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > +%YAML 1.2 > > > > +--- > > > > +$id: http://devicetree.org/schemas/sound/fsl,rpmsg.yaml# > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > + > > > > +title: NXP Audio RPMSG CPU DAI Controller > > > > + > > > > +maintainers: > > > > + - Shengjiu Wang <shengjiu.wang@xxxxxxx> > > > > + > > > > +description: | > > > > + fsl_rpmsg cpu dai driver is virtual driver for rpmsg audio, which doesn't > > > > + touch hardware. It is mainly used for getting the user's configuration > > > > + from device tree and configure the clocks which is used by Cortex-M core. > > > > + So in this document define the needed property. > > > > + > > > > +properties: > > > > + compatible: > > > > + enum: > > > > + - fsl,imx7ulp-rpmsg > > > > + - fsl,imx8mn-rpmsg > > > > + - fsl,imx8mm-rpmsg > > > > + - fsl,imx8mp-rpmsg > > > > + > > > > + model: > > > > + $ref: /schemas/types.yaml#/definitions/string > > > > + description: User specified audio sound card name > > > > + > > > > + clocks: > > > > + items: > > > > + - description: Peripheral clock for register access > > > > + - description: Master clock > > > > + - description: DMA clock for DMA register access > > > > + - description: Parent clock for multiple of 8kHz sample rates > > > > + - description: Parent clock for multiple of 11kHz sample rates > > > > + minItems: 5 > > > > > > If this doesn't touch hardware, what are these clocks for? > > > > When the cortex-M core support audio service, these clock > > needed prepared & enabled by ALSA driver. > > > > > > > > You don't need 'minItems' unless it's less than the number of 'items'. > > > > Ok, I will remove this minItems. > > > > > > > > > + > > > > + clock-names: > > > > + items: > > > > + - const: ipg > > > > + - const: mclk > > > > + - const: dma > > > > + - const: pll8k > > > > + - const: pll11k > > > > + minItems: 5 > > > > + > > > > + power-domains: > > > > + maxItems: 1 > > > > + > > > > + fsl,audioindex: > > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > > > + enum: [0, 1] > > > > + default: 0 > > > > + description: Instance index for sound card in > > > > + M core side, which share one rpmsg > > > > + channel. > > > > > > We don't do indexes in DT. What's this numbering tied to? > > > > I will remove it. it is not necessary > > > > > > > > > + > > > > + fsl,version: > > > > > > version of what? > > > > > > This seems odd at best. > > > > > > > I will remove it. it is not necessary > > > > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > > > + enum: [1, 2] > > > > > > You're going to update this with every new firmware version? > > > > > > > + default: 2 > > > > + description: The version of M core image, which is > > > > + to make driver compatible with different image. > > > > + > > > > + fsl,buffer-size: > > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > > > + description: pre allocate dma buffer size > > > > > > How can you have DMA, this doesn't touch h/w? > > > > The DMA is handled by M core image for sound playback > > and capture. we need to allocated buffer in Linux side. > > here just make the buffer size to be configurable. > > Do we set audio buffer sizes for other audio devices in DT? If not, > why is this special? If so, why is it not common. No. I will move it to driver. > > > > > + fsl,enable-lpa: > > > > + $ref: /schemas/types.yaml#/definitions/flag > > > > + description: enable low power audio path. > > > > + > > > > + fsl,rpmsg-out: > > > > + $ref: /schemas/types.yaml#/definitions/flag > > > > + description: | > > > > + This is a boolean property. If present, the transmitting function > > > > + will be enabled. > > > > + > > > > + fsl,rpmsg-in: > > > > + $ref: /schemas/types.yaml#/definitions/flag > > > > + description: | > > > > + This is a boolean property. If present, the receiving function > > > > + will be enabled. > > > > + > > > > + fsl,codec-type: > > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > > > + enum: [0, 1, 2] > > > > + default: 0 > > > > + description: Sometimes the codec is registered by > > > > + driver not by the device tree, this items > > > > + can be used to distinguish codecs. > > > > > > How does one decide what value to use? > > > > I will add more description: > > 0: dummy codec > > 1: WM8960 codec > > 2: AK4497 codec > > I assume the last 2 cases have nodes in DT (pointed to by > 'audio-codec'), so this is redundant. Ok, will remove it. > > > > > + > > > > + audio-codec: > > > > + $ref: /schemas/types.yaml#/definitions/phandle > > > > + description: The phandle of the audio codec > > > > > > The codec is controlled from the Linux side? > > > > yes. > > > > > > > > > + > > > > + memory-region: > > > > + $ref: /schemas/types.yaml#/definitions/phandle > > > > + description: phandle to the reserved memory nodes > > > > + > > > > +required: > > > > + - compatible > > > > + - fsl,audioindex > > > > + - fsl,version > > > > + - fsl,buffer-size > > > > + > > > > +additionalProperties: false > > > > + > > > > +examples: > > > > + - | > > > > + rpmsg_audio: rpmsg_audio { > > > > + compatible = "fsl,imx8mn-rpmsg"; > > > > + fsl,audioindex = <0> ; > > > > + fsl,version = <2>; > > > > + fsl,buffer-size = <0x6000000>; > > > > + fsl,enable-lpa; > > > > > > How does this work? Don't you need somewhere to put the 'rpmsg' data? > > > > The rpmsg data is not handled in this "rpmsg_audio" device, it is just to > > prepare the resource for rpmsg audio function, the clock, the memory > > the power... > > > > The rpmsg data is handled in imx-pcm-rpmsg.c and imx-audio-rpmsg.c > > These devices is registered by imx remoteproc driver. > > Then what is 'memory-region' for? You need that, a mailbox, or ??? > somewhere in DT. > The M core can't access all the DDR memory space on some platform, so use 'memory-region' reserve a specific memory for dma buffer which M core can access. best regards wang shengjiu
