[PATCH 5/5] ASoC: SOF: Intel: hda-dai: improve SSP DAI handling for dynamic pipelines

[Pierre-Louis Bossart]

In order to keep the widget use_count balanced, make sure the DAI
widgets are allocated once in hw_params and released in hw_free. A
'setup' status flag is used to deal with cases where the .hw_params
callback is invoked multiple times, and likewise with cases where
hw_free is invoked without hw_params being called first (which can
happen if the FE hw_params fails).

In addition, this patch frees the widgets in the suspend transition,
and reallocates them in the .prepare callback. The 'setup' flag helps
in this case differentiate between resume (setup needed) and
xruns (setup not needed).

This balanced operation was not needed previously but will be required
when SOF dynamic pipelines are enabled.

Co-developed-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Reviewed-by: Bard Liao <bard.liao at intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski at linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi at linux.intel.com>
---
 sound/soc/sof/intel/hda-dai.c | 82 ++++++++++++++++++++++++++++++++++-
 1 file changed, 80 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sof/intel/hda-dai.c b/sound/soc/sof/intel/hda-dai.c
index 59d6750c6a20..dfd2df0b1bc3 100644
--- a/sound/soc/sof/intel/hda-dai.c
+++ b/sound/soc/sof/intel/hda-dai.c
@@ -440,6 +440,11 @@ static const struct snd_soc_dai_ops hda_link_dai_ops = {
 
 #endif
 
+/* only one flag used so far to harden hw_params/hw_free/trigger/prepare */
+struct ssp_dai_dma_data {
+	bool setup;
+};
+
 static int ssp_dai_setup_or_free(struct snd_pcm_substream *substream, struct snd_soc_dai *dai,
 				 bool setup)
 {
@@ -469,22 +474,95 @@ static int ssp_dai_setup_or_free(struct snd_pcm_substream *substream, struct snd
 	return hda_ctrl_dai_widget_free(w);
 }
 
+static int ssp_dai_startup(struct snd_pcm_substream *substream,
+			   struct snd_soc_dai *dai)
+{
+	struct ssp_dai_dma_data *dma_data;
+
+	dma_data = kzalloc(sizeof(*dma_data), GFP_KERNEL);
+	if (!dma_data)
+		return -ENOMEM;
+
+	snd_soc_dai_set_dma_data(dai, substream, dma_data);
+
+	return 0;
+}
+
+static int ssp_dai_setup(struct snd_pcm_substream *substream,
+			 struct snd_soc_dai *dai,
+			 bool setup)
+{
+	struct ssp_dai_dma_data *dma_data;
+	int ret = 0;
+
+	dma_data = snd_soc_dai_get_dma_data(dai, substream);
+	if (!dma_data) {
+		dev_err(dai->dev, "%s: failed to get dma_data\n", __func__);
+		return -EIO;
+	}
+
+	if (dma_data->setup != setup) {
+		ret = ssp_dai_setup_or_free(substream, dai, setup);
+		if (!ret)
+			dma_data->setup = setup;
+	}
+	return ret;
+}
+
 static int ssp_dai_hw_params(struct snd_pcm_substream *substream,
 			     struct snd_pcm_hw_params *params,
 			     struct snd_soc_dai *dai)
 {
-	return ssp_dai_setup_or_free(substream, dai, true);
+	/* params are ignored for now */
+	return ssp_dai_setup(substream, dai, true);
+}
+
+static int ssp_dai_prepare(struct snd_pcm_substream *substream,
+			   struct snd_soc_dai *dai)
+{
+	/*
+	 * the SSP will only be reconfigured during resume operations and
+	 * not in case of xruns
+	 */
+	return ssp_dai_setup(substream, dai, true);
+}
+
+static int ssp_dai_trigger(struct snd_pcm_substream *substream,
+			   int cmd, struct snd_soc_dai *dai)
+{
+	if (cmd != SNDRV_PCM_TRIGGER_SUSPEND)
+		return 0;
+
+	return ssp_dai_setup(substream, dai, false);
 }
 
 static int ssp_dai_hw_free(struct snd_pcm_substream *substream,
 			   struct snd_soc_dai *dai)
 {
-	return ssp_dai_setup_or_free(substream, dai, false);
+	return ssp_dai_setup(substream, dai, false);
+}
+
+static void ssp_dai_shutdown(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *dai)
+{
+	struct ssp_dai_dma_data *dma_data;
+
+	dma_data = snd_soc_dai_get_dma_data(dai, substream);
+	if (!dma_data) {
+		dev_err(dai->dev, "%s: failed to get dma_data\n", __func__);
+		return;
+	}
+	snd_soc_dai_set_dma_data(dai, substream, NULL);
+	kfree(dma_data);
 }
 
 static const struct snd_soc_dai_ops ssp_dai_ops = {
+	.startup = ssp_dai_startup,
 	.hw_params = ssp_dai_hw_params,
+	.prepare = ssp_dai_prepare,
+	.trigger = ssp_dai_trigger,
 	.hw_free = ssp_dai_hw_free,
+	.shutdown = ssp_dai_shutdown,
 };
 
 /*
-- 
2.25.1