[PATCH for 7.0 v2 2/2] ASoC: SOF: Intel: hda: modify period size constraints for ACE4

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

From: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Intel ACE4 based products set more strict constraints on HDA BDLE start
address and length alignment. Add a constraint to align period size to
128 bytes.

The commit removes the "minimum as per HDA spec" comment. This comment
was misleading as spec actually does allow a 2 byte BDLE length, and
more importantly, period size also directly impacts how the BDLE start
addresses are aligned, so it is not sufficient just to consider allowed
buffer length.

Fixes: d3df422f66e8 ("ASoC: SOF: Intel: add initial support for NVL-S")
Reported-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
---
 sound/soc/sof/intel/hda-pcm.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sof/intel/hda-pcm.c b/sound/soc/sof/intel/hda-pcm.c
index da6c1e7263cd..16a364072821 100644
--- a/sound/soc/sof/intel/hda-pcm.c
+++ b/sound/soc/sof/intel/hda-pcm.c
@@ -219,6 +219,7 @@ EXPORT_SYMBOL_NS(hda_dsp_pcm_pointer, "SND_SOC_SOF_INTEL_HDA_COMMON");
 int hda_dsp_pcm_open(struct snd_sof_dev *sdev,
 		     struct snd_pcm_substream *substream)
 {
+	const struct sof_intel_dsp_desc *chip_info = get_chip_info(sdev->pdata);
 	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_soc_component *scomp = sdev->component;
@@ -268,8 +269,17 @@ int hda_dsp_pcm_open(struct snd_sof_dev *sdev,
 		return -ENODEV;
 	}
 
-	/* minimum as per HDA spec */
-	snd_pcm_hw_constraint_step(substream->runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);
+	/*
+	 * Set period size constraint to ensure BDLE buffer length and
+	 * start address alignment requirements are met. Align to 128
+	 * bytes for newer Intel platforms, with older ones using 4 byte alignment.
+	 */
+	if (chip_info->hw_ip_version >= SOF_INTEL_ACE_4_0)
+		snd_pcm_hw_constraint_step(substream->runtime, 0,
+					   SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 128);
+	else
+		snd_pcm_hw_constraint_step(substream->runtime, 0,
+					   SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);
 
 	/* avoid circular buffer wrap in middle of period */
 	snd_pcm_hw_constraint_integer(substream->runtime,
-- 
2.53.0