dmaengine: imx-sdma: support dual fifo for DEV_TO_DEV

SSI and SPDIF are dual fifo interface, when support ASRC P2P
with SSI and SPDIF, the src fifo or dst fifo number can be
two.

The p2p watermark level bit 13 and 14 are designed for
these use case. This patch is to complete this function
in driver.
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Signed-off-by: Joy Zou <joy.zou@nxp.com>
Acked-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20240329-sdma_upstream-v4-3-daeb3067dea7@nxp.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/imx-sdma.c

@@ -138,7 +138,11 @@
  *						0: Source on AIPS
  *	12		Destination Bit(DP)	1: Destination on SPBA
  *						0: Destination on AIPS
- *	13-15		---------		MUST BE 0
+ *	13		Source FIFO		1: Source is dual FIFO
+ *						0: Source is single FIFO
+ *	14		Destination FIFO	1: Destination is dual FIFO
+ *						0: Destination is single FIFO
+ *	15		---------		MUST BE 0
  *	16-23		Higher WML		HWML
  *	24-27		N			Total number of samples after
  *						which Pad adding/Swallowing
@@ -169,6 +173,8 @@
 #define SDMA_WATERMARK_LEVEL_SPDIF	BIT(10)
 #define SDMA_WATERMARK_LEVEL_SP		BIT(11)
 #define SDMA_WATERMARK_LEVEL_DP		BIT(12)
+#define SDMA_WATERMARK_LEVEL_SD		BIT(13)
+#define SDMA_WATERMARK_LEVEL_DD		BIT(14)
 #define SDMA_WATERMARK_LEVEL_HWML	(0xFF << 16)
 #define SDMA_WATERMARK_LEVEL_LWE	BIT(28)
 #define SDMA_WATERMARK_LEVEL_HWE	BIT(29)
@@ -1258,6 +1264,16 @@ static void sdma_set_watermarklevel_for_p2p(struct sdma_channel *sdmac)
 		sdmac->watermark_level |= SDMA_WATERMARK_LEVEL_DP;
 
 	sdmac->watermark_level |= SDMA_WATERMARK_LEVEL_CONT;
+
+	/*
+	 * Limitation: The p2p script support dual fifos in maximum,
+	 * So when fifo number is larger than 1, force enable dual
+	 * fifos.
+	 */
+	if (sdmac->n_fifos_src > 1)
+		sdmac->watermark_level |= SDMA_WATERMARK_LEVEL_SD;
+	if (sdmac->n_fifos_dst > 1)
+		sdmac->watermark_level |= SDMA_WATERMARK_LEVEL_DD;
 }
 
 static void sdma_set_watermarklevel_for_sais(struct sdma_channel *sdmac)