On Wed, Oct 9, 2019 at 3:18 AM Kuninori Morimoto kuninori.morimoto.gx@renesas.com wrote:

Hi Daniel

...

...

 * ex1)
 * CPU0 --- Codec0
 * CPU1 --- Codec1
 * CPU2 -----/
 * CPU3 --- Codec2
 *
 *    => 5 links = 2xCPU-Codec + 2xCPU-dummy + 1xdummy-Codec
 *    => 7 DAIs  = 4xCPU + 3xCodec
 *    => 1 ccnf  = 1xdummy-Codec

So, I don't understand exactly how did you get the formula for links. AFAICT there should be 3 x CPU-Codec + 1 x CPU-dummy.

CPU1/CPU2 and Codec1 are using DPCM. Thus, it is...

2xCPU-Codec: CPU0 - Codec0 CPU3 - Codec2

2xCPU-dummy: CPU1 - dummy CPU2 - dummy

1xdummy-Codec: dummy - Codec1

...

Also, I wonder how can i use simple-card to create just a backend link CPU-dummy + Codec :).

Is this supported?

Do you mean CPU-dummy + dummy-Codec ? But anyway, simple-card/audio-graph DPCM support is very limited. Unfortunately it doesn't have flexibility...

Yes, exactly. I need 1 DAI link with 1 FE + 1 BE for DSP / SOF usecase.

Thanks for your answer. See my comments inline

On Thu, Oct 10, 2019 at 2:37 AM Kuninori Morimoto kuninori.morimoto.gx@renesas.com wrote:

Hi Daniel

...

...

Do you mean CPU-dummy + dummy-Codec ? But anyway, simple-card/audio-graph DPCM support is very limited. Unfortunately it doesn't have flexibility...

Yes, exactly. I need 1 DAI link with 1 FE + 1 BE for DSP / SOF usecase.

simple-card support it if it needs convert-rate or convert-channels.

Yes, but this is needed for ASRC-like components. I don't think I can abuse this usage for my usecase.

Please check below

    static simple_for_each_link(xxx)
    {
            ...
            for_each_child_of_node(node, np) {
                    /*
                     * It is DPCM
                     * if it has many CPUs,
                     * or has convert-xxx property
                     */

(1) if (dpcm_selectable && (2) (num > 2 || (3) adata.convert_rate || adata.convert_channels)) ret = func_dpcm(priv, np, codec, li, is_top); ...

(1) : using simple-scu-audio-card (2) : 2 nodes or more (3) : has convert-xxx property

In fact I just need 1 BE DAI link. My use case is with SOF where the FE will be added by topology.

I think I can modify simple-card to do this. Just let me know if you see something obviously wrong on making the simple-card / simple-scu-card handling this case with creating just 1 BE DAI link.

Maybe add a property like "dpcm".

Hi Daniel

Thank you for your email

I think I can modify simple-card to do this. Just let me know if you see something obviously wrong on making the simple-card / simple-scu-card handling this case with creating just 1 BE DAI link.

Current DPCM support is used for "TDM-Split mode", "MIXer", "Sampling rate convert" for now.

But, of course I have no objection if you can add new feature.

simple-audio-card,dai-link@2 { cpu { sound-dai=<&cpu1>; } }

It looks FE, but is this for BE ?

Maybe add a property like "dpcm".

I think property "dpcm" is very ALSA-SoC naming, DT guy don't like it (?). "simple-xxx-card" (1) or new node (2) can be acceptable ? I'm not sure...

machine_drv { (1) compatible = "simple-xxx-card"; ...

simple-audio-card,dai-link@2 { (2) dpcm-fe { sound-dai=<&cpu1>; ...

Thank you for your help !! Best regards --- Kuninori Morimoto