ASoC: q6apm-dai: make use of q6apm_get_hw_pointer

JIRA: https://issues.redhat.com/browse/RHEL-80657

commit a93dad6
Author: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Date: Fri Mar 14 17:47:58 2025 +0000

    ASoC: q6apm-dai: make use of q6apm_get_hw_pointer

    With the existing code, the buffer position is only reset in pointer
    callback, which leaves the possiblity of it going over the size of
    buffer size and reporting incorrect position to userspace.

    Without this patch, its possible to see errors like:
    snd-x1e80100 sound: invalid position: pcmC0D0p:0, pos = 12288, buffer size = 12288, period size = 1536
    snd-x1e80100 sound: invalid position: pcmC0D0p:0, pos = 12288, buffer size = 12288, period size = 1536

    Fixes: 9b4fe0f ("ASoC: qdsp6: audioreach: add q6apm-dai support")
    Cc: stable@vger.kernel.org
    Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
    Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
    Tested-by: Johan Hovold <johan+linaro@kernel.org>
    Link: https://patch.msgid.link/20250314174800.10142-4-srinivas.kandagatla@linaro.org
    Signed-off-by: Mark Brown <broonie@kernel.org>

Signed-off-by: Jaroslav Kysela <jkysela@redhat.com>

Author: jkysela-rh

sound/soc/qcom/qdsp6/q6apm-dai.c

@@ -64,7 +64,6 @@ struct q6apm_dai_rtd {
 	phys_addr_t phys;
 	unsigned int pcm_size;
 	unsigned int pcm_count;
-	unsigned int pos;       /* Buffer position */
 	unsigned int periods;
 	unsigned int bytes_sent;
 	unsigned int bytes_received;
@@ -124,23 +123,16 @@ static void event_handler(uint32_t opcode, uint32_t token, void *payload, void *
 {
 	struct q6apm_dai_rtd *prtd = priv;
 	struct snd_pcm_substream *substream = prtd->substream;
-	unsigned long flags;
 
 	switch (opcode) {
 	case APM_CLIENT_EVENT_CMD_EOS_DONE:
 		prtd->state = Q6APM_STREAM_STOPPED;
 		break;
 	case APM_CLIENT_EVENT_DATA_WRITE_DONE:
-		spin_lock_irqsave(&prtd->lock, flags);
-		prtd->pos += prtd->pcm_count;
-		spin_unlock_irqrestore(&prtd->lock, flags);
 		snd_pcm_period_elapsed(substream);
 
 		break;
 	case APM_CLIENT_EVENT_DATA_READ_DONE:
-		spin_lock_irqsave(&prtd->lock, flags);
-		prtd->pos += prtd->pcm_count;
-		spin_unlock_irqrestore(&prtd->lock, flags);
 		snd_pcm_period_elapsed(substream);
 		if (prtd->state == Q6APM_STREAM_RUNNING)
 			q6apm_read(prtd->graph);
@@ -247,7 +239,6 @@ static int q6apm_dai_prepare(struct snd_soc_component *component,
 	}
 
 	prtd->pcm_count = snd_pcm_lib_period_bytes(substream);
-	prtd->pos = 0;
 	/* rate and channels are sent to audio driver */
 	ret = q6apm_graph_media_format_shmem(prtd->graph, &cfg);
 	if (ret < 0) {
@@ -446,16 +437,12 @@ static snd_pcm_uframes_t q6apm_dai_pointer(struct snd_soc_component *component,
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct q6apm_dai_rtd *prtd = runtime->private_data;
 	snd_pcm_uframes_t ptr;
-	unsigned long flags;
 
-	spin_lock_irqsave(&prtd->lock, flags);
-	if (prtd->pos == prtd->pcm_size)
-		prtd->pos = 0;
-
-	ptr =  bytes_to_frames(runtime, prtd->pos);
-	spin_unlock_irqrestore(&prtd->lock, flags);
+	ptr = q6apm_get_hw_pointer(prtd->graph, substream->stream) * runtime->period_size;
+	if (ptr)
+		return ptr - 1;
 
-	return ptr;
+	return 0;
 }
 
 static int q6apm_dai_hw_params(struct snd_soc_component *component,
@@ -670,8 +657,6 @@ static int q6apm_dai_compr_set_params(struct snd_soc_component *component,
 	prtd->pcm_size = runtime->fragments * runtime->fragment_size;
 	prtd->bits_per_sample = 16;
 
-	prtd->pos = 0;
-
 	if (prtd->next_track != true) {
 		memcpy(&prtd->codec, codec, sizeof(*codec));