dai: Add support for Virtual DAI on i.MX8MP

Introduce a new DAI type, SOF_DAI_VIRTUAL, to enable rapid prototyping,
software loopback, and testing without requiring physical DAI hardware.

Define the IPC config structure for the virtual DAI and update the
Zephyr DAI mapping logic to recognize and configure this backend.
Enable virtual DAI for i.MX8MP to support software-based audio pipelines.

Signed-off-by: Suraj Sonawane <surajsonawane0215@gmail.com>

Author: SurajSonawane2415

app/boards/imx8mp_evk_mimx8ml8_adsp.overlay

@@ -27,3 +27,7 @@
 &micfil {
 	status = "okay";
 };
+
+&virtual_dai14 {
+	status = "okay";
+};

src/audio/dai-zephyr.c

@@ -194,6 +194,10 @@ __cold int dai_set_config(struct dai *dai, struct ipc_config_dai *common_config,
 		cfg.type = DAI_IMX_MICFIL;
 		cfg_params = &sof_cfg->micfil;
 		break;
+	case SOF_DAI_VIRTUAL:
+		cfg.type = DAI_VIRTUAL;
+		cfg_params = &sof_cfg->virtual_dai;
+		break;
 	default:
 		return -EINVAL;
 	}

src/include/ipc/dai.h

@@ -94,9 +94,31 @@ enum sof_ipc_dai_type {
 	SOF_DAI_AMD_SP_VIRTUAL,		/**<Amd SP VIRTUAL */
 	SOF_DAI_AMD_HS_VIRTUAL,		/**<Amd HS VIRTUAL */
 	SOF_DAI_IMX_MICFIL,		/**< i.MX MICFIL */
-	SOF_DAI_AMD_SW_AUDIO		/**<Amd SW AUDIO */
+	SOF_DAI_AMD_SW_AUDIO,		/**<Amd SW AUDIO */
+	SOF_DAI_VIRTUAL,		/**< Virtual DAI for testing/debugging*/
 };
 
+/* Virtual DAI Configuration Request - SOF_IPC_DAI_VIRTUAL_CONFIG */
+struct sof_ipc_dai_virtual_params {
+	uint32_t reserved0;
+
+	/* MCLK */
+	uint16_t reserved1;
+	uint16_t mclk_id;
+	uint32_t mclk_direction;
+
+	uint32_t mclk_rate; /* MCLK frequency in Hz */
+	uint32_t fsync_rate;
+	uint32_t bclk_rate;
+
+	/* TDM */
+	uint32_t tdm_slots;
+	uint32_t rx_slots;
+	uint32_t tx_slots;
+	uint16_t tdm_slot_width;
+	uint16_t reserved2;	/* alignment */
+} __attribute__((packed, aligned(4)));
+
 /* general purpose DAI configuration */
 struct sof_ipc_dai_config {
 	struct sof_ipc_cmd_hdr hdr;
@@ -126,6 +148,7 @@ struct sof_ipc_dai_config {
 		struct sof_ipc_dai_afe_params afe;
 		struct sof_ipc_dai_micfil_params micfil;
 		struct sof_ipc_dai_acp_sdw_params acpsdw;
+		struct sof_ipc_dai_virtual_params virtual_dai;
 	};
 } __attribute__((packed, aligned(4)));
 

src/ipc/ipc3/dai.c

@@ -63,6 +63,9 @@ int dai_config_dma_channel(struct dai_data *dd, struct comp_dev *dev, const void
 	case SOF_DAI_IMX_ESAI:
 		handshake = dai_get_handshake(dd->dai, dai->direction,
 					      dd->stream_id);
+	case SOF_DAI_VIRTUAL:
+		handshake = dai_get_handshake(dd->dai, dai->direction,
+					      dd->stream_id);
 /* TODO: remove this when transition to native drivers is complete on all NXP platforms */
 #ifndef CONFIG_ZEPHYR_NATIVE_DRIVERS
 		channel = EDMA_HS_GET_CHAN(handshake);
@@ -171,6 +174,7 @@ int ipc_dai_data_config(struct dai_data *dd, struct comp_dev *dev)
 	case SOF_DAI_IMX_MICFIL:
 	case SOF_DAI_IMX_SAI:
 	case SOF_DAI_IMX_ESAI:
+	case SOF_DAI_VIRTUAL:
 		dd->config.burst_elems = dai_get_fifo_depth(dd->dai, dai->direction);
 		break;
 	case SOF_DAI_AMD_BT:

src/lib/dai.c

@@ -185,6 +185,9 @@ const struct device *zephyr_dev[] = {
 #if CONFIG_DAI_NXP_MICFIL
 	DT_FOREACH_STATUS_OKAY(nxp_dai_micfil, GET_DEVICE_LIST)
 #endif
+#if CONFIG_DAI_VIRTUAL
+	DT_FOREACH_STATUS_OKAY(virtual_dai, GET_DEVICE_LIST)
+#endif
 };
 
 /* convert sof_ipc_dai_type to Zephyr dai_type */
@@ -218,6 +221,8 @@ static int sof_dai_type_to_zephyr(uint32_t type)
 	case SOF_DAI_AMD_HS_VIRTUAL:
 	case SOF_DAI_AMD_SW_AUDIO:
 		return -ENOTSUP;
+	case SOF_DAI_VIRTUAL:
+		return DAI_VIRTUAL;
 	default:
 		return -EINVAL;
 	}