[alsa-devel] [PATCH v3 01/25] dt-bindings: soc: qcom: Add bindings for APR bus

[Srinivas Kandagatla]

On 22/02/18 10:03, Srinivas Kandagatla wrote:
>>> Also the versions of each service are independent to each other.
>>
>> Not sure I follow the last statement. Meaning firmware updates change
>> the services?
> Sorry for not being clear, so the services like AFE, ASM, ADM have 
> different version numbers for a given SoC/firmware.
> 
> Not 100% sure if firmware updates would change the service version 
> number, even if it does, it can be queried dynamically on new B family 
> SoCs, and on older A Family SoCs I have not seen the firmware updates in 
> last 4 years.
> 
>> I don't see any versioning of services here.
> 
> Yes, Plan is that it will be part of the compatible string in cases 
> where version query is not supported on older QCOM A family SoCs.
> On B Family SoCs we can query the version dynamically.
> 
>>
>>>
>>>>>
>>>>> apr {
>>>>>           compatible = "qcom,apr-v2";
>>>>>           qcom,smd-channels = "apr_audio_svc";
>>>>>           qcom,apr-dest-domain-id = <APR_DOMAIN_ADSP>;
>>>>>
>>>>>           apr-services {
>>>>>                   q6core {
>>>>>                           qcom,apr-svc-name = "CORE";
>>>>>                           qcom,apr-svc-id = <APR_SVC_ADSP_CORE>;
>>>>>                           compatible = "qcom,q6core";
>>>>>                   };
>>>>>
>>>>>                   q6afe: q6afe {
>>>>>                           compatible = "qcom,q6afe";
>>>>>                           qcom,apr-svc-name = "AFE";
>>>>>                           qcom,apr-svc-id = <APR_SVC_AFE>;
>>>>>                           #sound-dai-cells = <1>;
>>>>>                   };
>>>>>
>>>>>                   q6asm: q6asm {
>>>>>                           compatible = "qcom,q6asm";
>>>>>                           qcom,apr-svc-name = "ASM";
>>>>>                           qcom,apr-svc-id = <APR_SVC_ASM>;
>>>>>                           #sound-dai-cells = <1>;
>>>>>                   };
>>>>>
>>>>>                   q6adm: q6adm {, "external-sleep"
>>>>>                           compatible = "qcom,q6adm";
>>>>>                           qcom,apr-svc-name = "ADM";
>>>>>                           qcom,apr-svc-id = <APR_SVC_ADM>;
>>>>>                           #sound-dai-cells = <0>;
>>>>>                   };
>>>>
>>>>
>>>> All these DAI nodes could be a single node and the cell value be the
>>>> svc-id?
>>>
> So we will have 2 cell values, one representing the apr service and 
> other the dai.
> 
>>> No, DAI's here are both backends and frontends, and some of the services
>>> like core, USM are not DAI's
>>>
>>> Are you also saying that we should have a single driver entity for 
>>> all these
>>> services?
>>
>> DT nodes do not equate driver entities. A driver can instantiate other 
>> drivers.
>>
>> Am I saying a single DT node for this? Yes, perhaps.
> Yes, I will give that a go.

I did try your suggestion of making audio services into a single node 
and it ended up more messy and non scalable.

Mainly because q6afe node has more than one interface type of backend 
dais (child nodes).

Each of this backend dai may need board specific setting ex: MI2S case 
where board could wire up specific tx and rx lines from 4 possible lines 
for that board. Also other type of dais also have some interface 
specific properties.

MI2S example:
apr {
	...
	q6afe: q6afe {
		compatible = "qcom,q6afe";
		qcom,apr-svc-name = "AFE";
		qcom,apr-svc-id = <APR_SVC_AFE>;
		pinctrl-0 = <&ext_sec_tlmm_lines_act>;
		pinctrl-names = "default";
		#sound-dai-cells = <1>;

                 mi2s_prim_rx_dai at 34{
			reg = <34>;
			rx-lines = <0>;
			...
		};

		mi2s_prim_tx_dai at 35{
			reg = <35>;
			tx-lines = <1 2>
			...
		};
	     	...
	};
};

Here is block diagram to give a quick overview of the components


   +---------+          +---------+         +---------+
   |  q6asm  |          |q6routing|         | q6afe   |
   |  fedai  | <------> |  mixers | <-----> | bedai   |
   +---------+          +---------+         +---------+
       ^                     ^                   ^
       |                     |                   |
       |  +------------------+----------------+  |
       |  |                  |                |  |
       v  v                  v                v  v
   +---------+          +---------+         +---------+
   |   q6ASM |          |  q6ADM  |         |   q6AFE |
   +---------+          +---------+         +---------+
       ^                     ^                   ^          ^
       |                     |                   | CPU Side |
------+---------------------+-------------------+--------
       |                     |                   |
       |APR                  |APR                |APR
       |                     |                   |
       |  +------------------+----------------+  |
       |  |                  |                |  |
+-----+--+-----------------------------------+--+-------
       |  |                  |                |  | QDSP Side |
       v  v                  v                v  v           v
  +---------+          +---------+         +---------+
  |   ASM   | <------> |   ADM   | <-----> |   AFE   |
  +---------+          +---------+         +---------+
                                                ^
                                                |
                            +-------------------+
                            |
---------------------------+--------------------------
                            |            Audio I/O |
                            v                      v
     +--------------------------------------------------+
     |                Audio devices                     |
     | CODEC | HDMI-TX | PCM  | SLIMBUS | I2S |MI2S |...|
     |                                                  |
     +--------------------------------------------------+

thanks,
srini