dmaengine: rcar-dmac: Add support for R-Car S4-8

Add support for R-Car S4-8. We can reuse R-Car V3U code so that
renames variable names as "gen4".

Note that some registers of R-Car V3U do not exist on R-Car S4-8,
but none of them are used by the driver for now.

Signed-off-by: Yoshihiro Shimoda <[e-mail]>
Reviewed-by: Ulrich Hecht <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/sh/rcar-dmac.c

···
 #define RCAR_DMAOR_PRI_ROUND_ROBIN	(3 << 8)
 #define RCAR_DMAOR_AE			(1 << 2)
 #define RCAR_DMAOR_DME			(1 << 0)
-#define RCAR_DMACHCLR			0x0080	/* Not on R-Car V3U */
+#define RCAR_DMACHCLR			0x0080	/* Not on R-Car Gen4 */
 #define RCAR_DMADPSEC			0x00a0
 
 #define RCAR_DMASAR			0x0000
···
 #define RCAR_DMAFIXDAR			0x0014
 #define RCAR_DMAFIXDPBASE		0x0060
 
-/* For R-Car V3U */
-#define RCAR_V3U_DMACHCLR		0x0100
+/* For R-Car Gen4 */
+#define RCAR_GEN4_DMACHCLR		0x0100
 
 /* Hardcode the MEMCPY transfer size to 4 bytes. */
 #define RCAR_DMAC_MEMCPY_XFER_SIZE	4
···
 				 struct rcar_dmac_chan *chan)
 {
 	if (dmac->chan_base)
-		rcar_dmac_chan_write(chan, RCAR_V3U_DMACHCLR, 1);
+		rcar_dmac_chan_write(chan, RCAR_GEN4_DMACHCLR, 1);
 	else
 		rcar_dmac_write(dmac, RCAR_DMACHCLR, BIT(chan->index));
 }
···
 
 	if (dmac->chan_base) {
 		for_each_rcar_dmac_chan(i, dmac, chan)
-			rcar_dmac_chan_write(chan, RCAR_V3U_DMACHCLR, 1);
+			rcar_dmac_chan_write(chan, RCAR_GEN4_DMACHCLR, 1);
 	} else {
 		rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
 	}
···
 	.chan_offset_stride	= 0x80,
 };
 
-static const struct rcar_dmac_of_data rcar_v3u_dmac_data = {
+static const struct rcar_dmac_of_data rcar_gen4_dmac_data = {
 	.chan_offset_base	= 0x0,
 	.chan_offset_stride	= 0x1000,
 };
···
 		.compatible = "renesas,rcar-dmac",
 		.data = &rcar_dmac_data,
 	}, {
+		.compatible = "renesas,rcar-gen4-dmac",
+		.data = &rcar_gen4_dmac_data,
+	}, {
 		.compatible = "renesas,dmac-r8a779a0",
-		.data = &rcar_v3u_dmac_data,
+		.data = &rcar_gen4_dmac_data,
 	},
 	{ /* Sentinel */ }
 };