ASoC: SOF: Introduce fragment elapsed notification API

This patch prepares the introduction of the compress API with SOF.

After each fragment is accepted by the DSP we need to inform
the userspace applications that they can send the next fragment.
This is done via snd_compr_fragment_elapsed.

Similar with the PCM case, in order to avoid sending an IPC before
the previous IPC is handled we need to schedule a delayed work to
call snd_compr_fragment_elapsed().

See snd_sof_pcm_period_elapsed.

To sum up this patch offers the following API to SOF code:
	* snd_sof_compr_init_elapsed_work
	* snd_sof_compr_fragment_elapsed

Note that implementation for compressed function is in a new file
selected via CONFIG_SND_SOC_SOF_COMPRESS invisible config option.
This option is automatically selected for platforms that support
the compress interface. For now only i.MX8 platforms support this.

For symmetry we introduce snd_sof_pcm_init_elapsed_work to setup
the work struct for PCM case.

Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Signed-off-by: Bud Liviu-Alexandru <budliviu@gmail.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Paul Olaru <paul.olaru@oss.nxp.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20211004152147.1268978-5-daniel.baluta@oss.nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/Kconfig

@@ -46,6 +46,10 @@ config SND_SOC_SOF_OF
 	  required to enable i.MX8 devices.
 	  Say Y if you need this option. If unsure select "N".
 
+config SND_SOC_SOF_COMPRESS
+	tristate
+	select SND_SOC_COMPRESS
+
 config SND_SOC_SOF_DEBUG_PROBES
 	bool "SOF enable data probing"
 	select SND_SOC_COMPRESS

sound/soc/sof/Makefile

@@ -4,6 +4,7 @@ snd-sof-objs := core.o ops.o loader.o ipc.o pcm.o pm.o debug.o topology.o\
 		control.o trace.o utils.o sof-audio.o stream-ipc.o
 
 snd-sof-$(CONFIG_SND_SOC_SOF_DEBUG_PROBES) += sof-probes.o
+snd-sof-$(CONFIG_SND_SOC_SOF_COMPRESS) += compress.o
 
 snd-sof-pci-objs := sof-pci-dev.o
 snd-sof-acpi-objs := sof-acpi-dev.o

sound/soc/sof/compress.c

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// Copyright 2021 NXP
+//
+// Author: Daniel Baluta <daniel.baluta@nxp.com>
+
+#include <sound/soc.h>
+#include <sound/sof.h>
+#include <sound/compress_driver.h>
+#include "sof-audio.h"
+#include "sof-priv.h"
+
+static void snd_sof_compr_fragment_elapsed_work(struct work_struct *work)
+{
+	struct snd_sof_pcm_stream *sps =
+		container_of(work, struct snd_sof_pcm_stream,
+			     period_elapsed_work);
+
+	snd_compr_fragment_elapsed(sps->cstream);
+}
+
+void snd_sof_compr_init_elapsed_work(struct work_struct *work)
+{
+	INIT_WORK(work, snd_sof_compr_fragment_elapsed_work);
+}
+
+/*
+ * sof compr fragment elapse, this could be called in irq thread context
+ */
+void snd_sof_compr_fragment_elapsed(struct snd_compr_stream *cstream)
+{
+	struct snd_soc_component *component;
+	struct snd_soc_pcm_runtime *rtd;
+	struct snd_sof_pcm *spcm;
+
+	if (!cstream)
+		return;
+
+	rtd = cstream->private_data;
+	component = snd_soc_rtdcom_lookup(rtd, SOF_AUDIO_PCM_DRV_NAME);
+
+	spcm = snd_sof_find_spcm_dai(component, rtd);
+	if (!spcm) {
+		dev_err(component->dev,
+			"fragment elapsed called for unknown stream!\n");
+		return;
+	}
+
+	/* use the same workqueue-based solution as for PCM, cf. snd_sof_pcm_elapsed */
+	schedule_work(&spcm->stream[cstream->direction].period_elapsed_work);
+}

sound/soc/sof/imx/Kconfig

@@ -38,6 +38,7 @@ config SND_SOC_SOF_IMX8
 	tristate
 	select SND_SOC_SOF_IMX_COMMON
 	select SND_SOC_SOF_XTENSA
+	select SND_SOC_SOF_COMPRESS
 	help
 	  This option is not user-selectable but automagically handled by
 	  'select' statements at a higher level.
@@ -54,6 +55,7 @@ config SND_SOC_SOF_IMX8M
 	tristate
 	select SND_SOC_SOF_IMX_COMMON
 	select SND_SOC_SOF_XTENSA
+	select SND_SOC_SOF_COMPRESS
 	help
 	  This option is not user-selectable but automagically handled by
 	  'select' statements at a higher level.

sound/soc/sof/ipc.c

@@ -539,8 +539,10 @@ static void ipc_period_elapsed(struct snd_sof_dev *sdev, u32 msg_id)
 
 	memcpy(&stream->posn, &posn, sizeof(posn));
 
-	/* only inform ALSA for period_wakeup mode */
-	if (!stream->substream->runtime->no_period_wakeup)
+	if (spcm->pcm.compress)
+		snd_sof_compr_fragment_elapsed(stream->cstream);
+	else if (!stream->substream->runtime->no_period_wakeup)
+		/* only inform ALSA for period_wakeup mode */
 		snd_sof_pcm_period_elapsed(stream->substream);
 }
 

sound/soc/sof/pcm.c

@@ -57,7 +57,7 @@ static int sof_pcm_dsp_params(struct snd_sof_pcm *spcm, struct snd_pcm_substream
 /*
  * sof pcm period elapse work
  */
-void snd_sof_pcm_period_elapsed_work(struct work_struct *work)
+static void snd_sof_pcm_period_elapsed_work(struct work_struct *work)
 {
 	struct snd_sof_pcm_stream *sps =
 		container_of(work, struct snd_sof_pcm_stream,
@@ -66,6 +66,11 @@ void snd_sof_pcm_period_elapsed_work(struct work_struct *work)
 	snd_pcm_period_elapsed(sps->substream);
 }
 
+void snd_sof_pcm_init_elapsed_work(struct work_struct *work)
+{
+	 INIT_WORK(work, snd_sof_pcm_period_elapsed_work);
+}
+
 /*
  * sof pcm period elapse, this could be called at irq thread context.
  */

sound/soc/sof/sof-audio.h

@@ -36,6 +36,7 @@ struct snd_sof_pcm_stream {
 	struct snd_dma_buffer page_table;
 	struct sof_ipc_stream_posn posn;
 	struct snd_pcm_substream *substream;
+	struct snd_compr_stream *cstream;
 	struct work_struct period_elapsed_work;
 	struct snd_soc_dapm_widget_list *list; /* list of connected DAPM widgets */
 	bool d0i3_compatible; /* DSP can be in D0I3 when this pcm is opened */
@@ -231,7 +232,15 @@ struct snd_sof_pcm *snd_sof_find_spcm_pcm_id(struct snd_soc_component *scomp,
 const struct sof_ipc_pipe_new *snd_sof_pipeline_find(struct snd_sof_dev *sdev,
 						     int pipeline_id);
 void snd_sof_pcm_period_elapsed(struct snd_pcm_substream *substream);
-void snd_sof_pcm_period_elapsed_work(struct work_struct *work);
+void snd_sof_pcm_init_elapsed_work(struct work_struct *work);
+
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_COMPRESS)
+void snd_sof_compr_fragment_elapsed(struct snd_compr_stream *cstream);
+void snd_sof_compr_init_elapsed_work(struct work_struct *work);
+#else
+static inline void snd_sof_compr_fragment_elapsed(struct snd_compr_stream *cstream) { }
+static inline void snd_sof_compr_init_elapsed_work(struct work_struct *work) { }
+#endif
 
 /*
  * Mixer IPC

sound/soc/sof/topology.c

@@ -2587,8 +2587,10 @@ static int sof_dai_load(struct snd_soc_component *scomp, int index,
 
 	for_each_pcm_streams(stream) {
 		spcm->stream[stream].comp_id = COMP_ID_UNASSIGNED;
-		INIT_WORK(&spcm->stream[stream].period_elapsed_work,
-			  snd_sof_pcm_period_elapsed_work);
+		if (pcm->compress)
+			snd_sof_compr_init_elapsed_work(&spcm->stream[stream].period_elapsed_work);
+		else
+			snd_sof_pcm_init_elapsed_work(&spcm->stream[stream].period_elapsed_work);
 	}
 
 	spcm->pcm = *pcm;