ASoC: fsl: fsl_qmc_audio: Reset audio data pointers on TRIGGER_START event

On SNDRV_PCM_TRIGGER_START event, audio data pointers are not reset.

This leads to wrong data buffer usage when multiple TRIGGER_START are
received and ends to incorrect buffer usage between the user-space and
the driver. Indeed, the driver can read data that are not already set by
the user-space or the user-space and the driver are writing and reading
the same area.

Fix that resetting data pointers on each SNDRV_PCM_TRIGGER_START events.

Fixes: 075c712 ("ASoC: fsl: Add support for QMC audio")
Cc: stable@vger.kernel.org
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Link: https://patch.msgid.link/20250410091643.535627-1-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: hcodina

sound/soc/fsl/fsl_qmc_audio.c

@@ -250,6 +250,9 @@ static int qmc_audio_pcm_trigger(struct snd_soc_component *component,
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		bitmap_zero(prtd->chans_pending, 64);
+		prtd->buffer_ended = 0;
+		prtd->ch_dma_addr_current = prtd->ch_dma_addr_start;
+
 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 			for (i = 0; i < prtd->channels; i++)
 				prtd->qmc_dai->chans[i].prtd_tx = prtd;