ALSA: Support nonatomic dmaengine PCMs

*** possible v6.11 conflict: _snd_dmaengine_pcm_close

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>

Author: povik

sound/core/pcm_dmaengine.c

@@ -22,6 +22,8 @@
 struct dmaengine_pcm_runtime_data {
 	struct dma_chan *dma_chan;
 	dma_cookie_t cookie;
+	struct work_struct complete_wq; /* for nonatomic PCM */
+	struct snd_pcm_substream *substream;
 
 	unsigned int pos;
 };
@@ -145,6 +147,21 @@ static void dmaengine_pcm_dma_complete(void *arg)
 	snd_pcm_period_elapsed(substream);
 }
 
+static void dmaengine_pcm_dma_complete_nonatomic(struct work_struct *wq)
+{
+	struct dmaengine_pcm_runtime_data *prtd = \
+				container_of(wq, struct dmaengine_pcm_runtime_data, complete_wq);
+	struct snd_pcm_substream *substream = prtd->substream;
+	dmaengine_pcm_dma_complete(substream);
+}
+
+static void dmaengine_pcm_dma_complete_nonatomic_callback(void *arg)
+{
+	struct snd_pcm_substream *substream = arg;
+	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
+	schedule_work(&prtd->complete_wq);
+}
+
 static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
 {
 	struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
@@ -167,7 +184,11 @@ static int dmaengine_pcm_prepare_and_submit(struct snd_pcm_substream *substream)
 	if (!desc)
 		return -ENOMEM;
 
-	desc->callback = dmaengine_pcm_dma_complete;
+	if (substream->pcm->nonatomic)
+		desc->callback = dmaengine_pcm_dma_complete_nonatomic_callback;
+	else
+		desc->callback = dmaengine_pcm_dma_complete;
+
 	desc->callback_param = substream;
 	prtd->cookie = dmaengine_submit(desc);
 
@@ -320,6 +341,10 @@ int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
 	if (!prtd)
 		return -ENOMEM;
 
+	if (substream->pcm->nonatomic)
+		INIT_WORK(&prtd->complete_wq, dmaengine_pcm_dma_complete_nonatomic);
+
+	prtd->substream = substream;
 	prtd->dma_chan = chan;
 
 	substream->runtime->private_data = prtd;
@@ -380,6 +405,8 @@ static void __snd_dmaengine_pcm_close(struct snd_pcm_substream *substream,
 	 */
 	dmaengine_terminate_async(prtd->dma_chan);
 	dmaengine_synchronize(prtd->dma_chan);
+	if (substream->pcm->nonatomic)
+		flush_work(&prtd->complete_wq);
 	if (release_channel)
 		dma_release_channel(prtd->dma_chan);
 	kfree(prtd);