Re: [RFC PATCH 1/2] soundwire: add support for static port mapping
From: Pierre-Louis Bossart
Date: Thu Jan 21 2021 - 13:03:53 EST
On 1/21/21 9:41 AM, Srinivas Kandagatla wrote:
On 21/01/2021 14:56, Pierre-Louis Bossart wrote:
Port allocations are something like this:
RX: (Simple)
Port 1 -> HPH L/R
Port 2 -> CLASS H Amp
Port 3 -> COMP
Port 4 -> DSD.
TX: (This get bit more complicated)
Port 1: PCM
Port 2: ADC 1 & 2
Port 3: ADC 3 & 4
Port 4: DMIC-0, DMIC-1, DIMC-2 , DMIC-3 and MBHC
Port 5: DMIC-4, DMIC-5, DMIC-6 and DMIC-7
We handle the port allocation dynamically based on mixer and dapm
widgets in my code! Also channel allocations are different for each
function!
Sorry, I am not following here. What is dynamic here and use-case
dependent? And is this a mapping on the master or the codec sides that
you want to modify?
[SLAVE]-------[MASTER]
NA-------------Port 1: PCM
Port 1---------Port 2: ADC 1 & 2
Port 2---------Port 3: ADC 3 & 4
Port 3---------Port 4: DMIC-0, DMIC-1, DIMC-2 , DMIC-3 and MBHC
Port 4---------Port 5: DMIC-4, DMIC-5, DMIC-6 and DMIC-7
Mapping is still static however Number of ports selection and channel
mask will be dynamic here.
Example: for Headset MIC usecase we will be using Slv Port1, Slv Port3
along with Mstr Port2 and Master Port4
Similarly for usecases like Digital MIC or other Analog MICs.
Sorry, I must be thick here, but in my experience the choice of Digital
or analog mics is a hardware design level not a use-case one. Using ADC
1 & 2 at the same time as DMICs is very surprising to me. You'd have
different sensitivities/performance, not sure how you would combine the
results.
I also don't see how a headset mic can both use Analog and digital,
unless we have a different definition of what a 'headset' is.
Does this help and can you align on what Intel started with?
Firstly, This is where the issue comes, if we go with the
suggested(dai->id) solution, we would end up with a long list of
dai-links with different combinations of both inputs/output
connections and usecases. Again we have to deal with limited DSP
resources too!
Secondly, The check [1] in stream.c will not allow more than one
master port config to be added to master runtime. Ex: RX Port 1, 2, 3
is used for Headset Playback.
I am confused here, we do have examples in existing codec drivers
where we use multiple ports for a single stream, e.g. for IV feedback
we use 2 ports.
Is this on multi_link? which is why it might be working for you.
no, this is done at the codec driver level, which has no notion of
multi-link. we pass a port_config as a array of 2.
Currently we have below check in sdw_stream_add_master().
if (!bus->multi_link && stream->m_rt_count > 0) {
dev_err(bus->dev, "Multilink not supported, link %d\n", bus->link_id);
ret = -EINVAL;
goto unlock;
}
If we have single master(like my case) and dai-links which have more
then one port will be calling sdw_stream_add_master() for each port,
so m_rt_count above check will fail for the second call!
if you use multiple ports in a given master for the same stream, you
should have the m_rt_count == 1. That's a feature, not a bug.
A port is not a stream... You cannot call sdw_stream_add_master() for
each port, that's not what the concept was. You allocate ONE master_rt
per master, and that master_rt deals with one or more ports - your choice.
A 'stream' is an abstract data transport which can be split across
multiple masters/sales and for each master/slave use multiple ports.
When calling sdw_stream_add_master/slave, you need to provide a
port_config/num_ports to state which ports will be used on that
master/slave when using the stream. That's how we e.g. deal with 4ch
streams that are handled by two ports on each side.
To up-level a bit, the notion of 'stream' is actually very very similar
to the notion of dailink. And in fact, the 'stream' is actually created
for Intel in the dailink .startup callback, so I am quite in the dark on
what you are trying to accomplish.