Originally, normal dai link fixup callback is overwritten by sof fixup
callback on mtk_sof_card_late_probe and it relies on the mapping defined
on struct sof_conn_stream.

It's not flexible. When a new hardware connection is adopted, user needs
to update struct sof_conn_stream defined in machine driver which is used
to specify the mapping relationship of normal BE and SOF BE.

In the patch, mtk_sof_check_tplg_be_dai_link_fixup() is introduced for
all normal BEs. In mtk_sof_late_probe, back up normal BE fixup if it
exists and then overwrite be_hw_params_fixup by the new callback.

There are two cases for FE and BE connection.

case 1:
SOF FE -> normal BE
       -> SOF_BE

case 2:
normal FE -> normal BE

In the new fixup callback, it tries to find SOF_BE which connects to the
same FE, and then reuses the fixup of SOF_BE. If no SOF_BE exists,
it must be case 2, so rollback to the original fixup if it exists.

As a result, the predefined relation is not needed anymore. Hardware
connection can be controlled by the mixer control for AFE interconn.
Then, DPCM finds the BE mapping at runtime.

Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
---
 .../soc/mediatek/common/mtk-dsp-sof-common.c  | 113 +++++++++++++++---
 .../soc/mediatek/common/mtk-dsp-sof-common.h  |   8 ++
 2 files changed, 106 insertions(+), 15 deletions(-)

diff --git a/sound/soc/mediatek/common/mtk-dsp-sof-common.c b/sound/soc/mediatek/common/mtk-dsp-sof-common.c
index 6fef16306f74..f3894010f656 100644
--- a/sound/soc/mediatek/common/mtk-dsp-sof-common.c
+++ b/sound/soc/mediatek/common/mtk-dsp-sof-common.c
@@ -54,6 +54,8 @@ int mtk_sof_card_probe(struct snd_soc_card *card)
 {
 	int i;
 	struct snd_soc_dai_link *dai_link;
+	struct mtk_soc_card_data *soc_card_data = snd_soc_card_get_drvdata(card);
+	struct mtk_sof_priv *sof_priv = soc_card_data->sof_priv;
 
 	/* Set stream_name to help sof bind widgets */
 	for_each_card_prelinks(card, i, dai_link) {
@@ -61,10 +63,81 @@ int mtk_sof_card_probe(struct snd_soc_card *card)
 			dai_link->stream_name = dai_link->name;
 	}
 
+	INIT_LIST_HEAD(&sof_priv->dai_link_list);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(mtk_sof_card_probe);
 
+static struct snd_soc_pcm_runtime *mtk_sof_find_tplg_be(struct snd_soc_pcm_runtime *rtd)
+{
+	struct snd_soc_card *card = rtd->card;
+	struct mtk_soc_card_data *soc_card_data = snd_soc_card_get_drvdata(card);
+	struct mtk_sof_priv *sof_priv = soc_card_data->sof_priv;
+	struct snd_soc_pcm_runtime *fe;
+	struct snd_soc_pcm_runtime *be;
+	struct snd_soc_dpcm *dpcm;
+	int i, stream;
+
+	for_each_pcm_streams(stream) {
+		fe = NULL;
+		for_each_dpcm_fe(rtd, stream, dpcm) {
+			fe = dpcm->fe;
+			if (fe)
+				break;
+		}
+
+		if (!fe)
+			continue;
+
+		for_each_dpcm_be(fe, stream, dpcm) {
+			be = dpcm->be;
+			if (be == rtd)
+				continue;
+
+			for (i = 0; i < sof_priv->num_streams; i++) {
+				const struct sof_conn_stream *conn = &sof_priv->conn_streams[i];
+
+				if (!strcmp(be->dai_link->name, conn->sof_link))
+					return be;
+			}
+		}
+	}
+
+	return NULL;
+}
+
+/* fixup the BE DAI link to match any values from topology */
+static int mtk_sof_check_tplg_be_dai_link_fixup(struct snd_soc_pcm_runtime *rtd,
+						struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_card *card = rtd->card;
+	struct mtk_soc_card_data *soc_card_data = snd_soc_card_get_drvdata(card);
+	struct mtk_sof_priv *sof_priv = soc_card_data->sof_priv;
+	struct snd_soc_pcm_runtime *sof_be;
+	struct mtk_dai_link *dai_link;
+	int ret = 0;
+
+	sof_be = mtk_sof_find_tplg_be(rtd);
+	if (sof_be) {
+		if (sof_priv->sof_dai_link_fixup)
+			ret = sof_priv->sof_dai_link_fixup(rtd, params);
+		else if (sof_be->dai_link->be_hw_params_fixup)
+			ret = sof_be->dai_link->be_hw_params_fixup(sof_be, params);
+	} else {
+		list_for_each_entry(dai_link, &sof_priv->dai_link_list, list) {
+			if (strcmp(dai_link->name, rtd->dai_link->name) == 0) {
+				if (dai_link->be_hw_params_fixup)
+					ret = dai_link->be_hw_params_fixup(rtd, params);
+
+				break;
+			}
+		}
+	}
+
+	return ret;
+}
+
 int mtk_sof_card_late_probe(struct snd_soc_card *card)
 {
 	struct snd_soc_pcm_runtime *rtd;
@@ -72,6 +145,8 @@ int mtk_sof_card_late_probe(struct snd_soc_card *card)
 	struct mtk_soc_card_data *soc_card_data =
 		snd_soc_card_get_drvdata(card);
 	struct mtk_sof_priv *sof_priv = soc_card_data->sof_priv;
+	struct snd_soc_dai_link *dai_link;
+	struct mtk_dai_link *mtk_dai_link;
 	int i;
 
 	/* 1. find sof component */
@@ -86,25 +161,37 @@ int mtk_sof_card_late_probe(struct snd_soc_card *card)
 		return 0;
 	}
 
-	/* 2. add route path and fixup callback */
+	/* 2. overwrite all BE fixups, and backup the existing fixup */
+	for_each_card_prelinks(card, i, dai_link) {
+		if (dai_link->be_hw_params_fixup) {
+			mtk_dai_link = devm_kzalloc(card->dev,
+						    sizeof(*mtk_dai_link),
+						    GFP_KERNEL);
+			if (!mtk_dai_link)
+				return -ENOMEM;
+
+			mtk_dai_link->be_hw_params_fixup = dai_link->be_hw_params_fixup;
+			mtk_dai_link->name = dai_link->name;
+
+			list_add(&mtk_dai_link->list, &sof_priv->dai_link_list);
+		}
+
+		if (dai_link->no_pcm)
+			dai_link->be_hw_params_fixup = mtk_sof_check_tplg_be_dai_link_fixup;
+	}
+
+	/* 3. add route path and SOF_BE fixup callback */
 	for (i = 0; i < sof_priv->num_streams; i++) {
 		const struct sof_conn_stream *conn = &sof_priv->conn_streams[i];
 		struct snd_soc_pcm_runtime *sof_rtd = NULL;
-		struct snd_soc_pcm_runtime *normal_rtd = NULL;
 
 		for_each_card_rtds(card, rtd) {
 			if (!strcmp(rtd->dai_link->name, conn->sof_link)) {
 				sof_rtd = rtd;
-				continue;
-			}
-			if (!strcmp(rtd->dai_link->name, conn->normal_link)) {
-				normal_rtd = rtd;
-				continue;
-			}
-			if (normal_rtd && sof_rtd)
 				break;
+			}
 		}
-		if (normal_rtd && sof_rtd) {
+		if (sof_rtd) {
 			int j;
 			struct snd_soc_dai *cpu_dai;
 
@@ -131,13 +218,9 @@ int mtk_sof_card_late_probe(struct snd_soc_card *card)
 				}
 			}
 
+			/* overwrite SOF BE fixup */
 			sof_rtd->dai_link->be_hw_params_fixup =
 				sof_comp->driver->be_hw_params_fixup;
-			if (sof_priv->sof_dai_link_fixup)
-				normal_rtd->dai_link->be_hw_params_fixup =
-					sof_priv->sof_dai_link_fixup;
-			else
-				normal_rtd->dai_link->be_hw_params_fixup = mtk_sof_dai_link_fixup;
 		}
 	}
 
diff --git a/sound/soc/mediatek/common/mtk-dsp-sof-common.h b/sound/soc/mediatek/common/mtk-dsp-sof-common.h
index dd38c4a93574..4bc5e1c0c8ed 100644
--- a/sound/soc/mediatek/common/mtk-dsp-sof-common.h
+++ b/sound/soc/mediatek/common/mtk-dsp-sof-common.h
@@ -18,11 +18,19 @@ struct sof_conn_stream {
 	int stream_dir;
 };
 
+struct mtk_dai_link {
+	const char *name;
+	int (*be_hw_params_fixup)(struct snd_soc_pcm_runtime *rtd,
+				  struct snd_pcm_hw_params *params);
+	struct list_head list;
+};
+
 struct mtk_sof_priv {
 	const struct sof_conn_stream *conn_streams;
 	int num_streams;
 	int (*sof_dai_link_fixup)(struct snd_soc_pcm_runtime *rtd,
 				  struct snd_pcm_hw_params *params);
+	struct list_head dai_link_list;
 };
 
 int mtk_sof_dai_link_fixup(struct snd_soc_pcm_runtime *rtd,
-- 
2.18.0