[PATCH 1/2] ASoC: SOF: Intel: pci-tgl: unblock S5 entry if DMA stop has failed"

[Kai Vehmanen]

If system shutdown has not been completed cleanly, it is possible the
DMA stream shutdown has not been done, or was not clean.

If this is the case, Intel TGL/ADL HDA platforms may fail to shutdown
cleanly due to pending HDA DMA transactions. To avoid this, detect this
scenario in the shutdown callback, and perform an additional controller
reset. This has been tested to unblock S5 entry if this condition is
hit.

Co-developed-by: Archana Patni <archana.patni at intel.com>
Signed-off-by: Archana Patni <archana.patni at intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi at linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
---
 sound/soc/sof/intel/hda-dsp.c | 72 +++++++++++++++++++++++++++++++++++
 sound/soc/sof/intel/hda.h     |  1 +
 sound/soc/sof/intel/tgl.c     |  2 +-
 3 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sof/intel/hda-dsp.c b/sound/soc/sof/intel/hda-dsp.c
index 5fa29df54b42..b4eacae8564c 100644
--- a/sound/soc/sof/intel/hda-dsp.c
+++ b/sound/soc/sof/intel/hda-dsp.c
@@ -878,6 +878,78 @@ int hda_dsp_suspend(struct snd_sof_dev *sdev, u32 target_state)
 	return snd_sof_dsp_set_power_state(sdev, &target_dsp_state);
 }
 
+static unsigned int hda_dsp_check_for_dma_streams(struct snd_sof_dev *sdev)
+{
+	struct hdac_bus *bus = sof_to_bus(sdev);
+	struct hdac_stream *s;
+	unsigned int active_streams = 0;
+	int sd_offset;
+	u32 val;
+
+	list_for_each_entry(s, &bus->stream_list, list) {
+		sd_offset = SOF_STREAM_SD_OFFSET(s);
+		val = snd_sof_dsp_read(sdev, HDA_DSP_HDA_BAR,
+				       sd_offset);
+		if (val & SOF_HDA_SD_CTL_DMA_START)
+			active_streams |= BIT(s->index);
+	}
+
+	return active_streams;
+}
+
+static int hda_dsp_s5_quirk(struct snd_sof_dev *sdev)
+{
+	int ret;
+
+	/*
+	 * Do not assume a certain timing between the prior
+	 * suspend flow, and running of this quirk function.
+	 * This is needed if the controller was just put
+	 * to reset before calling this function.
+	 */
+	usleep_range(500, 1000);
+
+	/*
+	 * Take controller out of reset to flush DMA
+	 * transactions.
+	 */
+	ret = hda_dsp_ctrl_link_reset(sdev, false);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(500, 1000);
+
+	/* Restore state for shutdown, back to reset */
+	ret = hda_dsp_ctrl_link_reset(sdev, true);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+int hda_dsp_shutdown_dma_flush(struct snd_sof_dev *sdev)
+{
+	unsigned int active_streams;
+	int ret, ret2;
+
+	/* check if DMA cleanup has been successful */
+	active_streams = hda_dsp_check_for_dma_streams(sdev);
+
+	sdev->system_suspend_target = SOF_SUSPEND_S3;
+	ret = snd_sof_suspend(sdev->dev);
+
+	if (active_streams) {
+		dev_warn(sdev->dev,
+			 "There were active DSP streams (%#x) at shutdown, trying to recover\n",
+			 active_streams);
+		ret2 = hda_dsp_s5_quirk(sdev);
+		if (ret2 < 0)
+			dev_err(sdev->dev, "shutdown recovery failed (%d)\n", ret2);
+	}
+
+	return ret;
+}
+
 int hda_dsp_shutdown(struct snd_sof_dev *sdev)
 {
 	sdev->system_suspend_target = SOF_SUSPEND_S3;
diff --git a/sound/soc/sof/intel/hda.h b/sound/soc/sof/intel/hda.h
index 022ce80968dd..caccaf8fba9c 100644
--- a/sound/soc/sof/intel/hda.h
+++ b/sound/soc/sof/intel/hda.h
@@ -592,6 +592,7 @@ int hda_dsp_resume(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_suspend(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_resume(struct snd_sof_dev *sdev);
 int hda_dsp_runtime_idle(struct snd_sof_dev *sdev);
+int hda_dsp_shutdown_dma_flush(struct snd_sof_dev *sdev);
 int hda_dsp_shutdown(struct snd_sof_dev *sdev);
 int hda_dsp_set_hw_params_upon_resume(struct snd_sof_dev *sdev);
 void hda_dsp_dump(struct snd_sof_dev *sdev, u32 flags);
diff --git a/sound/soc/sof/intel/tgl.c b/sound/soc/sof/intel/tgl.c
index 30f2f49ee149..58ac3a46e6a7 100644
--- a/sound/soc/sof/intel/tgl.c
+++ b/sound/soc/sof/intel/tgl.c
@@ -60,7 +60,7 @@ int sof_tgl_ops_init(struct snd_sof_dev *sdev)
 	memcpy(&sof_tgl_ops, &sof_hda_common_ops, sizeof(struct snd_sof_dsp_ops));
 
 	/* probe/remove/shutdown */
-	sof_tgl_ops.shutdown	= hda_dsp_shutdown;
+	sof_tgl_ops.shutdown	= hda_dsp_shutdown_dma_flush;
 
 	if (sdev->pdata->ipc_type == SOF_IPC) {
 		/* doorbell */
-- 
2.38.1