ASoC: atmel: mchp-asrc: rework maxburst calculation

Rework the maxburst calculations so that all HW limitations are taken into
account. Also, snd_pcm_lib_period_bytes() can't be used at this time since
substream->runtime members are not initialized.

Fixes: 264353f ("ASoC: atmel: Add ASRC driver")
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
(cherry picked from linux-6.1-trunk/at91/sound)
Signed-off-by: Andrei Simion <andrei.simion@microchip.com>

Author: Codrin Ciubotariu

sound/soc/atmel/mchp-asrc.c

@@ -13,6 +13,7 @@
 #include <linux/io.h>
 #include <linux/lcm.h>
 #include <linux/list.h>
+#include <linux/minmax.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 
@@ -365,7 +366,6 @@ struct mchp_asrc_be_rtm {
 	struct mchp_asrc_be_trigger	*trig;	/* backpointer */
 	struct snd_pcm_hw_params	*hw_params;	// used by the links that are not BE
 	struct mchp_asrc_slot const	*slot;
-	int				maxburst;
 	struct list_head		list;
 };
 
@@ -388,6 +388,7 @@ struct mchp_asrc_pcm_priv {
 	struct xmit_ch				*tc;
 	struct mchp_asrc_be_rtm			rtm_fe;		/* used for FE --- BEs links */
 	int					refcount;
+	int					maxburst;
 	bool					is_hostless;
 };
 
@@ -405,18 +406,18 @@ struct mchp_asrc_dev {
 	int					rhr_opmode;
 };
 
-static inline int mchp_asrc_period_to_burst(int period_size)
+static inline int mchp_asrc_period_to_burst(int period_size, int sample_size)
 {
-	if (!(period_size % 16))
+	if (!(period_size % (sample_size * 16)))
 		return 16;
 
-	if (!(period_size % 8))
+	if (!(period_size % (sample_size * 8)))
 		return 8;
 
-	if (!(period_size % 4))
+	if (!(period_size % (sample_size * 4)))
 		return 4;
 
-	if (!(period_size % 2))
+	if (!(period_size % (sample_size * 2)))
 		return 2;
 
 	return 1;
@@ -700,7 +701,6 @@ static int mchp_asrc_bes_get(struct mchp_asrc_dev *priv, struct snd_pcm_substrea
 		struct snd_soc_pcm_runtime *be = dpcm->be;
 		struct snd_soc_dai *dai = asoc_rtd_to_cpu(be, 0);
 		struct snd_pcm_substream *substream_be;
-		int period_bytes;
 
 		if (dpcm->fe != rtd)
 			continue;
@@ -717,7 +717,6 @@ static int mchp_asrc_bes_get(struct mchp_asrc_dev *priv, struct snd_pcm_substrea
 			params_width(&be->dpcm[substream->stream].hw_params),
 			params_channels(&be->dpcm[substream->stream].hw_params));
 
-		period_bytes = snd_pcm_lib_period_bytes(substream_be);
 		for (i = 0; i < priv->trig_count; i++) {
 			struct mchp_asrc_be_trigger *trig_be = &priv->trig[i];
 			struct mchp_asrc_be_rtm *rtm_be;
@@ -731,8 +730,8 @@ static int mchp_asrc_bes_get(struct mchp_asrc_dev *priv, struct snd_pcm_substrea
 			rtm_be = trig_be->rtm[substream->stream];
 			if (set_trig)
 				rtm_be->trig = trig_be;
+
 			rtm_be->hw_params = &be->dpcm[substream->stream].hw_params;
-			rtm_be->maxburst = mchp_asrc_period_to_burst(period_bytes);
 
 			/* keep the order */
 			list_add_tail(&rtm_be->list, head);
@@ -989,11 +988,11 @@ static void mchp_asrc_tc_free(struct mchp_asrc_dev *priv, struct mchp_asrc_pcm_p
 			   MCHP_ASRC_CH_CONF_THROPMODE_MASK | MCHP_ASRC_CH_CONF_RHROPMODE_MASK, 0);
 }
 
-static void mchp_asrc_maxburst_limit(int thr_opmode, int rhr_opmode,
-				     int dsps_used, bool is_mono,
+/* apply HW DMA Chunk Size limitations */
+static void mchp_asrc_maxburst_limit(int thr_opmode, int rhr_opmode, bool is_mono,
 				     int *maxburst)
 {
-	if ((thr_opmode == 0 || rhr_opmode == 0 || dsps_used == 1) &&
+	if ((thr_opmode == 0 || rhr_opmode == 0) &&
 	    *maxburst > 4) {
 		if (is_mono)
 			*maxburst = 4;
@@ -1032,9 +1031,9 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 	int ratio_min;
 	struct list_head *list_head_bes;
 	int i;
-	int maxburst[MCHP_ASRC_NB_STEREO_CH]  = {0};
 	struct opmode_to_slot const *be_opm;
 	struct xmit_ch *tc;
+	bool is_mono = false;
 
 	dev_dbg(priv->dev, "%s() DAI %s id %d rate=%u format=%#x width=%u channels=%u\n",
 		__func__, dai->name, dai->id, fs, params ? params_format(params) : 0,
@@ -1092,11 +1091,8 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 		goto __cleanup_bes;
 
 	if (!pcm->is_hostless) {
-		int period_size = snd_pcm_lib_period_bytes(substream);
-
 		pcm->rtm_fe.hw_params = params;
 		pcm->rtm_fe.trig = NULL;
-		pcm->rtm_fe.maxburst = mchp_asrc_period_to_burst(period_size);
 
 		/* keep the order */
 		if (is_playback)
@@ -1166,12 +1162,17 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 		struct mchp_asrc_slot const *slot_be = rtm_be->slot;
 		int chan_be = params_channels(rtm_be->hw_params);
 		u32 idx = trig_be ? trig_be->idx : 0;
+		int physical_width = params_physical_width(rtm_be->hw_params) / 8;
+		int period_bytes = params_period_size(rtm_be->hw_params) *
+			params_channels(rtm_be->hw_params) * physical_width;
+		int maxburst = mchp_asrc_period_to_burst(period_bytes, physical_width);
 
 		/* treat odd streams, set only last DSP as mono */
 		if (chan_be % 2) {
 			dsp = slot_be->first_dsp + slot_be->dsp_count - 1;
 			ch_conf |= MCHP_ASRC_CH_CONF_MONO(dsp);
 			ch_conf_mask |= MCHP_ASRC_CH_CONF_MONO(dsp);
+			is_mono = true;
 		}
 
 		for (dsp = slot_be->first_dsp;
@@ -1190,23 +1191,32 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 		if (max_sr < params_rate(rtm_be->hw_params))
 			max_sr = params_rate(rtm_be->hw_params);
 
-		maxburst[slot_be->slot_id] = rtm_be->maxburst;
+		if (pcm->maxburst)
+			pcm->maxburst = min(pcm->maxburst, maxburst);
+		else
+			pcm->maxburst = maxburst;
 
-		mchp_asrc_maxburst_limit(priv->thr_opmode, priv->rhr_opmode, slot_be->dsp_count,
-					 chan_be % 2, &maxburst[slot_be->slot_id]);
+		dev_dbg(priv->dev, "%s: period bytes %d, width %d -> maxburst %d\n",
+			trig_be ? trig_be->phandle->np->full_name : dai->name,
+			period_bytes, physical_width, maxburst);
 	}
 
 	list_for_each_entry(rtm_be, &pcm->list_head_out, list) {
 		struct mchp_asrc_be_trigger *trig_be = rtm_be->trig;
 		struct mchp_asrc_slot const *slot_be = rtm_be->slot;
 		int chan_be = params_channels(rtm_be->hw_params);
+		int physical_width = params_physical_width(rtm_be->hw_params) / 8;
+		int period_bytes = params_period_size(rtm_be->hw_params) *
+			params_channels(rtm_be->hw_params) * physical_width;
+		int maxburst = mchp_asrc_period_to_burst(period_bytes, physical_width);
 		u32 idx = trig_be ? trig_be->idx : 0;
 
 		/* treat odd streams, set only last DSP as mono */
 		if (chan_be % 2) {
 			dsp = slot_be->first_dsp + slot_be->dsp_count - 1;
 			ch_conf |= MCHP_ASRC_CH_CONF_MONO(dsp);
 			ch_conf_mask |= MCHP_ASRC_CH_CONF_MONO(dsp);
+			is_mono = true;
 		}
 
 		for (dsp = slot_be->first_dsp;
@@ -1225,15 +1235,19 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 		if (max_sr < params_rate(rtm_be->hw_params))
 			max_sr = params_rate(rtm_be->hw_params);
 
-		if (!maxburst[slot_be->slot_id] ||
-		    maxburst[slot_be->slot_id] > rtm_be->maxburst)
-			maxburst[slot_be->slot_id] = rtm_be->maxburst;
+		if (pcm->maxburst)
+			pcm->maxburst = min(pcm->maxburst, maxburst);
+		else
+			pcm->maxburst = maxburst;
 
-		mchp_asrc_maxburst_limit(priv->thr_opmode, priv->rhr_opmode,
-					 slot_be->dsp_count, chan_be % 2,
-					 &maxburst[slot_be->slot_id]);
+		dev_dbg(priv->dev, "%s: period bytes %d, width %d -> maxburst %d\n",
+			trig_be ? trig_be->phandle->np->full_name : dai->name,
+			period_bytes, physical_width, maxburst);
 	}
 
+	mchp_asrc_maxburst_limit(priv->thr_opmode, priv->rhr_opmode, is_mono, &pcm->maxburst);
+	dev_dbg(priv->dev, "maxburst value to be used by all DSPs: %d\n", pcm->maxburst);
+
 	/* set DMAengine data for each IN/OUT AIF */
 	INIT_LIST_HEAD(&dma->dma_in_list);
 	list_for_each_entry(rtm_be, &pcm->list_head_in, list) {
@@ -1255,7 +1269,7 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 			ret = -ENOMEM;
 			goto __cleanup_dma_bes;
 		}
-		dma_data_be->maxburst = maxburst[slot_be->slot_id];
+		dma_data_be->maxburst = pcm->maxburst;
 
 		/* keep the order of the BEs */
 		list_add_tail(&dma_be->list, &dma->dma_in_list);
@@ -1287,13 +1301,13 @@ static int mchp_asrc_hw_params(struct snd_pcm_substream *substream,
 			ret = -ENOMEM;
 			goto __cleanup_dma_bes;
 		}
-		dma_data_be->maxburst = maxburst[slot_be->slot_id];
+		dma_data_be->maxburst = pcm->maxburst;
 
 		 /* needed only once, since the same DPSs are used for IN and OUT AIFs */
 		for (dsp = slot_be->first_dsp; dsp < slot_be->first_dsp + slot_be->dsp_count;
 		     dsp++) {
 			ch_conf |= mchp_asrc_burst_to_chunk(dsp,
-							    maxburst[slot_be->slot_id]);
+							    pcm->maxburst);
 			ch_conf_mask |= MCHP_ASRC_CH_CONF_CHUNK_MASK(dsp);
 		}