[PATCH 04/17] ASoC: SOF: Intel: hda: Implement get_stream_position (Linear Link Position)

[Peter Ujfalusi <peter.ujfalusi@linux.intel.com>]

When the Linear Link Position is not available in firmware SRAM window we
use the host accessible position registers to read it.
The address of the PPLCLLPL/U registers depend on the number of streams
(playback+capture).
At probe time the pplc_addr is calculated for each stream and we can use
it to read the LLP without the need of address re-calculation.

Set the get_stream_position callback in sof_hda_common_ops for all
platforms:
The callback is used for IPC4 delay calculations only but the register is
a generic HDA register, not tied to any specific IPC version.

Cc: stable@vger.kernel.org # 6.8
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 sound/soc/sof/intel/hda-common-ops.c |  2 ++
 sound/soc/sof/intel/hda-stream.c     | 32 ++++++++++++++++++++++++++++
 sound/soc/sof/intel/hda.h            |  3 +++
 3 files changed, 37 insertions(+)

diff --git a/sound/soc/sof/intel/hda-common-ops.c b/sound/soc/sof/intel/hda-common-ops.c
index 2b385cddc385..80a69599a8c3 100644
--- a/sound/soc/sof/intel/hda-common-ops.c
+++ b/sound/soc/sof/intel/hda-common-ops.c
@@ -57,6 +57,8 @@ struct snd_sof_dsp_ops sof_hda_common_ops = {
 	.pcm_pointer	= hda_dsp_pcm_pointer,
 	.pcm_ack	= hda_dsp_pcm_ack,
 
+	.get_stream_position = hda_dsp_get_stream_llp,
+
 	/* firmware loading */
 	.load_firmware = snd_sof_load_firmware_raw,
 
diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index b387b1a69d7e..48ea187f7230 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -1063,3 +1063,35 @@ snd_pcm_uframes_t hda_dsp_stream_get_position(struct hdac_stream *hstream,
 
 	return pos;
 }
+
+/**
+ * hda_dsp_get_stream_llp - Retrieve the LLP (Linear Link Position) of the stream
+ * @sdev: SOF device
+ * @component: ASoC component
+ * @substream: PCM substream
+ *
+ * Returns the raw Linear Link Position value
+ */
+u64 hda_dsp_get_stream_llp(struct snd_sof_dev *sdev,
+			   struct snd_soc_component *component,
+			   struct snd_pcm_substream *substream)
+{
+	struct hdac_stream *hstream = substream->runtime->private_data;
+	struct hdac_ext_stream *hext_stream = stream_to_hdac_ext_stream(hstream);
+	u32 llp_l, llp_u;
+
+	/*
+	 * The pplc_addr have been calculated during probe in
+	 * hda_dsp_stream_init():
+	 * pplc_addr = sdev->bar[HDA_DSP_PP_BAR] +
+	 *	       SOF_HDA_PPLC_BASE +
+	 *	       SOF_HDA_PPLC_MULTI * total_stream +
+	 *	       SOF_HDA_PPLC_INTERVAL * stream_index
+	 *
+	 * Use this pre-calculated address to avoid repeated re-calculation.
+	 */
+	llp_l = readl(hext_stream->pplc_addr + AZX_REG_PPLCLLPL);
+	llp_u = readl(hext_stream->pplc_addr + AZX_REG_PPLCLLPU);
+
+	return ((u64)llp_u << 32) | llp_l;
+}
diff --git a/sound/soc/sof/intel/hda.h b/sound/soc/sof/intel/hda.h
index b36eb7c78913..9d26cad785fe 100644
--- a/sound/soc/sof/intel/hda.h
+++ b/sound/soc/sof/intel/hda.h
@@ -662,6 +662,9 @@ bool hda_dsp_check_stream_irq(struct snd_sof_dev *sdev);
 
 snd_pcm_uframes_t hda_dsp_stream_get_position(struct hdac_stream *hstream,
 					      int direction, bool can_sleep);
+u64 hda_dsp_get_stream_llp(struct snd_sof_dev *sdev,
+			   struct snd_soc_component *component,
+			   struct snd_pcm_substream *substream);
 
 struct hdac_ext_stream *
 	hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction, u32 flags);
-- 
2.44.0