[PATCH 1/2] ASoC: qcom: audioreach: use a 32-bit container for S24_LE PCM

[Marc Herrero via B4 Relay]

From: Marc Herrero <marcht@xxxxxxxxx>

SNDRV_PCM_FORMAT_S24_LE carries 24 valid bits in a 32-bit container, but
audioreach_shmem_set_media_format() and audioreach_pcm_set_media_format()
set bits_per_sample = bit_width = 24 in PARAM_ID_MEDIA_FORMAT and
PARAM_ID_PCM_OUTPUT_FORMAT_CFG, which tells the DSP that the samples are
packed 3-byte words.

q6apm-dai advertises S24_LE, so with a topology that allows it on a
playback front end the DSP walks the buffer with the wrong stride. On
QCS6490 (Radxa Dragon Q6A) this crashes the ADSP audio_process:

  PDM: service 'audio_process' crash: 'EX:audio_process:0x2:...'
  q6apm-lpass-dais ...: Failed to start APM port 113
  remoteproc remoteproc0: crash detected in adsp: type fatal error

Use the container size (32) for 24-bit data and keep bit_width = 24,
alignment = PCM_LSB_ALIGNED and q_factor = 23. With this change S24_LE
playback works on the headphone path (codec DMA RX -> LPASS RX macro ->
WCD9385), tested with the back end at S16_LE, S24_LE and S32_LE and at
48, 96 and 192 kHz.

The DSP then reads each 32-bit word as Q23, so S24_LE samples must be
sign-extended into the top byte, as alsa-lib's conversions do.

Fixes: 25ab80db6b13 ("ASoC: qdsp6: audioreach: add module configuration command helpers")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Marc Herrero <marcht@xxxxxxxxx>
---
 sound/soc/qcom/qdsp6/audioreach.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/qcom/qdsp6/audioreach.c b/sound/soc/qcom/qdsp6/audioreach.c
index d2dc5d37bccf..937506edf34a 100644
--- a/sound/soc/qcom/qdsp6/audioreach.c
+++ b/sound/soc/qcom/qdsp6/audioreach.c
@@ -1216,7 +1216,7 @@ static int audioreach_pcm_set_media_format(struct q6apm_graph *graph,
 	media_cfg->interleaved = module->interleave_type;
 	media_cfg->num_channels = mcfg->num_channels;
 	media_cfg->q_factor = mcfg->bit_width - 1;
-	media_cfg->bits_per_sample = mcfg->bit_width;
+	media_cfg->bits_per_sample = mcfg->bit_width == 24 ? 32 : mcfg->bit_width;
 	/* Convert the physical mapping to a logical mapping of the channels */
 	for (i = 0, j = 0; i < AR_PCM_MAX_NUM_CHANNEL && j < mcfg->num_channels; i++) {
 		if (!mcfg->channel_map[i])
@@ -1308,7 +1308,7 @@ static int audioreach_shmem_set_media_format(struct q6apm_graph *graph,
 		cfg->sample_rate = mcfg->sample_rate;
 		cfg->bit_width = mcfg->bit_width;
 		cfg->alignment = PCM_LSB_ALIGNED;
-		cfg->bits_per_sample = mcfg->bit_width;
+		cfg->bits_per_sample = mcfg->bit_width == 24 ? 32 : mcfg->bit_width;
 		cfg->q_factor = mcfg->bit_width - 1;
 		cfg->endianness = PCM_LITTLE_ENDIAN;
 		cfg->num_channels = mcfg->num_channels;

-- 
2.53.0