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Subject[PATCH 5.3 051/344] ASoC: SOF: reset DMA state in prepare
Date
From: Kai Vehmanen <kai.vehmanen@linux.intel.com>

[ Upstream commit 04c8027764bc82a325d3abc6f39a6a4642a937cb ]

When application goes through SUSPEND/STOP->PREPARE->START
cycle, we should always reprogram the SOF device to start
DMA from a known state so that hw_ptr/appl_ptrs remain valid.
This is expected by ALSA core as it resets the buffer
state as part of prepare (see snd_pcm_do_prepare()).

Fix the issue by forcing reconfiguration of the FW with
STREAM_PCM_PARAMS in prepare(). Use combined logic to handle
prepare and the existing flow to reprogram hw-params after
system suspend.

Without the fix, first call to pcm pointer() will return
an invalid hw_ptr and application may immediately observe XRUN
status, unless "start_threshold" SW parameter is set to maximum
value by the application.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190722141402.7194-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/soc/sof/pcm.c | 27 +++++++++++++++------------
sound/soc/sof/pm.c | 2 +-
sound/soc/sof/sof-priv.h | 2 +-
3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/sound/soc/sof/pcm.c b/sound/soc/sof/pcm.c
index 334e9d59b1baf..3b8955e755b24 100644
--- a/sound/soc/sof/pcm.c
+++ b/sound/soc/sof/pcm.c
@@ -208,12 +208,11 @@ static int sof_pcm_hw_params(struct snd_pcm_substream *substream,
if (ret < 0)
return ret;

+ spcm->prepared[substream->stream] = true;
+
/* save pcm hw_params */
memcpy(&spcm->params[substream->stream], params, sizeof(*params));

- /* clear hw_params_upon_resume flag */
- spcm->hw_params_upon_resume[substream->stream] = 0;
-
return ret;
}

@@ -236,6 +235,9 @@ static int sof_pcm_hw_free(struct snd_pcm_substream *substream)
if (!spcm)
return -EINVAL;

+ if (!spcm->prepared[substream->stream])
+ return 0;
+
dev_dbg(sdev->dev, "pcm: free stream %d dir %d\n", spcm->pcm.pcm_id,
substream->stream);

@@ -258,6 +260,8 @@ static int sof_pcm_hw_free(struct snd_pcm_substream *substream)
if (ret < 0)
dev_err(sdev->dev, "error: platform hw free failed\n");

+ spcm->prepared[substream->stream] = false;
+
return ret;
}

@@ -278,11 +282,7 @@ static int sof_pcm_prepare(struct snd_pcm_substream *substream)
if (!spcm)
return -EINVAL;

- /*
- * check if hw_params needs to be set-up again.
- * This is only needed when resuming from system sleep.
- */
- if (!spcm->hw_params_upon_resume[substream->stream])
+ if (spcm->prepared[substream->stream])
return 0;

dev_dbg(sdev->dev, "pcm: prepare stream %d dir %d\n", spcm->pcm.pcm_id,
@@ -311,6 +311,7 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
struct snd_sof_pcm *spcm;
struct sof_ipc_stream stream;
struct sof_ipc_reply reply;
+ bool reset_hw_params = false;
int ret;

/* nothing to do for BE */
@@ -351,6 +352,7 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_STOP:
stream.hdr.cmd |= SOF_IPC_STREAM_TRIG_STOP;
+ reset_hw_params = true;
break;
default:
dev_err(sdev->dev, "error: unhandled trigger cmd %d\n", cmd);
@@ -363,17 +365,17 @@ static int sof_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
ret = sof_ipc_tx_message(sdev->ipc, stream.hdr.cmd, &stream,
sizeof(stream), &reply, sizeof(reply));

- if (ret < 0 || cmd != SNDRV_PCM_TRIGGER_SUSPEND)
+ if (ret < 0 || !reset_hw_params)
return ret;

/*
- * The hw_free op is usually called when the pcm stream is closed.
- * Since the stream is not closed during suspend, the DSP needs to be
- * notified explicitly to free pcm to prevent errors upon resume.
+ * In case of stream is stopped, DSP must be reprogrammed upon
+ * restart, so free PCM here.
*/
stream.hdr.size = sizeof(stream);
stream.hdr.cmd = SOF_IPC_GLB_STREAM_MSG | SOF_IPC_STREAM_PCM_FREE;
stream.comp_id = spcm->stream[substream->stream].comp_id;
+ spcm->prepared[substream->stream] = false;

/* send IPC to the DSP */
return sof_ipc_tx_message(sdev->ipc, stream.hdr.cmd, &stream,
@@ -481,6 +483,7 @@ static int sof_pcm_open(struct snd_pcm_substream *substream)
spcm->stream[substream->stream].posn.host_posn = 0;
spcm->stream[substream->stream].posn.dai_posn = 0;
spcm->stream[substream->stream].substream = substream;
+ spcm->prepared[substream->stream] = false;

ret = snd_sof_pcm_platform_open(sdev, substream);
if (ret < 0)
diff --git a/sound/soc/sof/pm.c b/sound/soc/sof/pm.c
index 278abfd10490d..48c6d78d72e2e 100644
--- a/sound/soc/sof/pm.c
+++ b/sound/soc/sof/pm.c
@@ -233,7 +233,7 @@ static int sof_set_hw_params_upon_resume(struct snd_sof_dev *sdev)

state = substream->runtime->status->state;
if (state == SNDRV_PCM_STATE_SUSPENDED)
- spcm->hw_params_upon_resume[dir] = 1;
+ spcm->prepared[dir] = false;
}
}

diff --git a/sound/soc/sof/sof-priv.h b/sound/soc/sof/sof-priv.h
index b8c0b2a226845..fa5cb7d2a6602 100644
--- a/sound/soc/sof/sof-priv.h
+++ b/sound/soc/sof/sof-priv.h
@@ -297,7 +297,7 @@ struct snd_sof_pcm {
struct snd_sof_pcm_stream stream[2];
struct list_head list; /* list in sdev pcm list */
struct snd_pcm_hw_params params[2];
- int hw_params_upon_resume[2]; /* set up hw_params upon resume */
+ bool prepared[2]; /* PCM_PARAMS set successfully */
};

/* ALSA SOF Kcontrol device */
--
2.20.1


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