zephyr: Use emul_dma for Virtual DAI on i.MX8MP

Add emul_dma configuration to enable Virtual DAI with memory-to-memory
DMA for software-based audio pipelines on i.MX8MP.

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

Author: SurajSonawane2415

app/boards/imx8mp_evk_mimx8ml8_adsp.overlay

@@ -12,6 +12,10 @@
 	};
 };
 
+&emul_dma {
+	status = "okay";
+};
+
 &sdma3 {
 	status = "okay";
 };

src/audio/dai-zephyr.c

@@ -496,8 +496,12 @@ __cold int dai_common_new(struct dai_data *dd, struct comp_dev *dev,
 	dd->ipc_config = *dai_cfg;
 
 	/* request GP LP DMA with shared access privilege */
+#if CONFIG_DAI_VIRTUAL
+	dir = SOF_DMA_DIR_MEM_TO_MEM;
+#else
 	dir = dai_cfg->direction == SOF_IPC_STREAM_PLAYBACK ?
 		SOF_DMA_DIR_MEM_TO_DEV : SOF_DMA_DIR_DEV_TO_MEM;
+#endif
 
 	dd->dma = sof_dma_get(dir, dd->dai->dma_caps, dd->dai->dma_dev, SOF_DMA_ACCESS_SHARED);
 	if (!dd->dma) {

zephyr/include/sof/lib/dma.h

@@ -99,6 +99,7 @@ struct comp_dev;
 #define SOF_DMA_DEV_HS		BIT(13) /**< connectable to ACP HS I2S */
 #define SOF_DMA_DEV_MICFIL	BIT(14) /**< connectable to MICFIL fifo */
 #define SOF_DMA_DEV_SW		BIT(15) /**< connectable to ACP SW */
+#define SOF_DMA_DEV_DAI_VIRTUAL	BIT(16) /**< connectable to Virtual DAI */
 
 /* DMA access privilege flag */
 #define SOF_DMA_ACCESS_EXCLUSIVE	1

zephyr/lib/dma.c

@@ -151,6 +151,17 @@ SHARED_DATA struct sof_dma dma[] = {
 },
 #endif
 #if defined(CONFIG_SOC_MIMX8ML8_ADSP)
+#if CONFIG_DAI_VIRTUAL
+{
+	.plat_data = {
+		.dir = SOF_DMA_DIR_MEM_TO_MEM,
+		.devs = SOF_DMA_DEV_DAI_VIRTUAL,
+		.channels = 32,
+		.period_count = 2,
+	},
+	.z_dev = DEVICE_DT_GET(DT_NODELABEL(emul_dma)),
+},
+#endif /* CONFIG_DAI_VIRTUAL */
 {
 	.plat_data = {
 		.dir = SOF_DMA_DIR_MEM_TO_DEV | SOF_DMA_DIR_DEV_TO_MEM,