I have been wondering why DPCM needs special flag (= dpcm_playback/capture) to use it. Below is the history why it was added to ASoC.

(A) In beginning, there was no dpcm_xxx flag on ASoC. It checks channels_min for DPCM, same as current non-DPCM. Let's name it as "validation check" here.

if (rtd->dai_link->dynamic || rtd->dai_link->no_pcm) { if (cpu_dai->driver->playback.channels_min) playback = 1; if (cpu_dai->driver->capture.channels_min) capture = 1;

(B) commit 1e9de42f4324 ("ASoC: dpcm: Explicitly set BE DAI link supported stream directions") force to use dpcm_xxx flag on DPCM. According to this commit log, this is because "Some BE dummy DAI doesn't set channels_min for playback/capture". But we don't know which DAI is it, and not know why it can't/don't have channels_min. Let's name it as "no_chan_DAI" here. According to the code and git-log, it is used as DCPM-BE and is CPU DAI. I think the correct solution was set channels_min on "no_chan_DAI" side, not update ASoC framework side. But everything is under smoke today.

if (rtd->dai_link->dynamic || rtd->dai_link->no_pcm) { playback = rtd->dai_link->dpcm_playback; capture = rtd->dai_link->dpcm_capture;

(C) commit 9b5db059366a ("ASoC: soc-pcm: dpcm: Only allow playback/capture if supported") checks channels_min (= validation check) again. Because DPCM availability was handled by dpcm_xxx flag at that time, but some Sound Card set it even though it wasn't available. Clearly there's a contradiction here. I think correct solution was update Sound Card side instead of ASoC framework. Sound Card side will be updated to handle this issue later (commit 25612477d20b ("ASoC: soc-dai: set dai_link dpcm_ flags with a helper"))

if (rtd->dai_link->dynamic || rtd->dai_link->no_pcm) { ... playback = rtd->dai_link->dpcm_playback && snd_soc_dai_stream_valid(cpu_dai, ...); capture = rtd->dai_link->dpcm_capture && snd_soc_dai_stream_valid(cpu_dai, ...);

This (C) patch should have broken "no_chan_DAI" which doesn't have channels_min, but there was no such report during this 4 years. Possibilities case are as follows - No one is using "no_chan_DAI" - "no_chan_DAI" is no longer exist : was removed ? - "no_chan_DAI" is no longer exist : has channels_min ?

Because of these history, this dpcm_xxx is unneeded flag today. But because we have been used it for 10 years since (B), it may have been used differently. For example some DAI available both playback/capture, but it set dpcm_playback flag only, in this case dpcm_xxx flag is used as availability limitation. We can use playback_only flag instead in this case, but it is very difficult to find such DAI today.

Let's add grace time to remove dpcm_playback/capture flag.

This patch don't use dpcm_xxx flag anymore, and indicates warning to use xxx_only flag if both playback/capture were available but using only one of dpcm_xxx flag, and not using xxx_only flag.

Link: https://lore.kernel.org/r/87edaym2cg.wl-kuninori.morimoto.gx@renesas.com Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com Tested-by: Jerome Brunet jbrunet@baylibre.com --- include/sound/soc.h | 1 + sound/soc/soc-pcm.c | 65 ++++++++++++++++++++++++++------------------- 2 files changed, 38 insertions(+), 28 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h index e844f6afc5b5..81ef380b2e06 100644 --- a/include/sound/soc.h +++ b/include/sound/soc.h @@ -815,6 +815,7 @@ struct snd_soc_dai_link { /* This DAI link can route to other DAI links at runtime (Frontend)*/ unsigned int dynamic:1;

+ /* REMOVE ME */ /* DPCM capture and Playback support */ unsigned int dpcm_capture:1; unsigned int dpcm_playback:1; diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c index f79abcf36105..f4a012e633b3 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -2745,6 +2745,7 @@ static int soc_get_playback_capture(struct snd_soc_pcm_runtime *rtd, { struct snd_soc_dai_link *dai_link = rtd->dai_link; struct snd_soc_dai *cpu_dai; + struct snd_soc_dai_link_ch_map *ch_maps; int has_playback = 0; int has_capture = 0; int i; @@ -2755,43 +2756,51 @@ static int soc_get_playback_capture(struct snd_soc_pcm_runtime *rtd, }

if (dai_link->dynamic || dai_link->no_pcm) { - int stream;

- if (dai_link->dpcm_playback) { - stream = SNDRV_PCM_STREAM_PLAYBACK; + for_each_rtd_ch_maps(rtd, i, ch_maps) { + cpu_dai = snd_soc_rtd_to_cpu(rtd, ch_maps->cpu);

- for_each_rtd_cpu_dais(rtd, i, cpu_dai) { - if (snd_soc_dai_stream_valid(cpu_dai, stream)) { - has_playback = 1; - break; - } - } - if (!has_playback) { - dev_err(rtd->card->dev, - "No CPU DAIs support playback for stream %s\n", - dai_link->stream_name); - return -EINVAL; - } + if (snd_soc_dai_stream_valid(cpu_dai, SNDRV_PCM_STREAM_PLAYBACK)) + has_playback = 1; + + if (snd_soc_dai_stream_valid(cpu_dai, SNDRV_PCM_STREAM_CAPTURE)) + has_capture = 1; } - if (dai_link->dpcm_capture) { - stream = SNDRV_PCM_STREAM_CAPTURE;

- for_each_rtd_cpu_dais(rtd, i, cpu_dai) { - if (snd_soc_dai_stream_valid(cpu_dai, stream)) { - has_capture = 1; - break; - } + /* + * REMOVE ME + * + * dpcm_xxx flag will be removed soon, Indicates warning if dpcm_xxx flag was used + * as availability limitation + */ + if (has_playback && has_capture) { + if ( dai_link->dpcm_playback && + !dai_link->dpcm_capture && + !dai_link->playback_only) { + dev_warn(rtd->card->dev, + "both playback/capture are available," + " but not using playback_only flag (%s)\n", + dai_link->stream_name); + dev_warn(rtd->card->dev, + "dpcm_playback/capture are no longer needed," + " please use playback/capture_only instead\n"); + has_capture = 0; }

- if (!has_capture) { - dev_err(rtd->card->dev, - "No CPU DAIs support capture for stream %s\n", - dai_link->stream_name); - return -EINVAL; + if (!dai_link->dpcm_playback && + dai_link->dpcm_capture && + !dai_link->capture_only) { + dev_warn(rtd->card->dev, + "both playback/capture are available," + " but not using capture_only flag (%s)\n", + dai_link->stream_name); + dev_warn(rtd->card->dev, + "dpcm_playback/capture are no longer needed," + " please use playback/capture_only instead\n"); + has_playback = 0; } } } else { - struct snd_soc_dai_link_ch_map *ch_maps; struct snd_soc_dai *codec_dai;

/* Adapt stream for codec2codec links */

From: Jerome Brunet jbrunet@baylibre.com

dpcm_playback/capture flags are being deprecated in ASoC. Use playback/capture_only flags instead

Suggested-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com Signed-off-by: Jerome Brunet jbrunet@baylibre.com Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com --- sound/soc/meson/axg-card.c | 10 +++++----- sound/soc/meson/meson-card-utils.c | 4 ++-- 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/sound/soc/meson/axg-card.c b/sound/soc/meson/axg-card.c index 09aa36e94c85..646ab87afac2 100644 --- a/sound/soc/meson/axg-card.c +++ b/sound/soc/meson/axg-card.c @@ -132,7 +132,7 @@ static int axg_card_add_tdm_loopback(struct snd_soc_card *card, lb->stream_name = lb->name; lb->cpus->of_node = pad->cpus->of_node; lb->cpus->dai_name = "TDM Loopback"; - lb->dpcm_capture = 1; + lb->capture_only = 1; lb->no_pcm = 1; lb->ops = &axg_card_tdm_be_ops; lb->init = axg_card_tdm_dai_lb_init; @@ -176,7 +176,7 @@ static int axg_card_parse_cpu_tdm_slots(struct snd_soc_card *card,

/* Disable playback is the interface has no tx slots */ if (!tx) - link->dpcm_playback = 0; + link->capture_only = 1;

for (i = 0, rx = 0; i < AXG_TDM_NUM_LANES; i++) { snprintf(propname, 32, "dai-tdm-slot-rx-mask-%d", i); @@ -186,9 +186,9 @@ static int axg_card_parse_cpu_tdm_slots(struct snd_soc_card *card,

/* Disable capture is the interface has no rx slots */ if (!rx) - link->dpcm_capture = 0; + link->playback_only = 1;

- /* ... but the interface should at least have one of them */ + /* ... but the interface should at least have one direction */ if (!tx && !rx) { dev_err(card->dev, "tdm link has no cpu slots\n"); return -EINVAL; @@ -275,7 +275,7 @@ static int axg_card_parse_tdm(struct snd_soc_card *card, return ret;

/* Add loopback if the pad dai has playback */ - if (link->dpcm_playback) { + if (!link->capture_only) { ret = axg_card_add_tdm_loopback(card, index); if (ret) return ret; diff --git a/sound/soc/meson/meson-card-utils.c b/sound/soc/meson/meson-card-utils.c index ed6c7e2f609c..1a4ef124e4e2 100644 --- a/sound/soc/meson/meson-card-utils.c +++ b/sound/soc/meson/meson-card-utils.c @@ -186,9 +186,9 @@ int meson_card_set_fe_link(struct snd_soc_card *card, link->dpcm_merged_rate = 1;

if (is_playback) - link->dpcm_playback = 1; + link->playback_only = 1; else - link->dpcm_capture = 1; + link->capture_only = 1;

return meson_card_set_link_name(card, link, node, "fe"); }