sunxi: add support for V3s DRAM controller

Allwinner V3s features a DRAM controller like the on in H3, but with a
DDR2 DRAM.

Add support for it.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>

arch/arm/mach-sunxi/Kconfig

@@ -225,11 +225,13 @@ config SUNXI_DRAM_DDR2
 
 choice
 	prompt "DRAM Type and Timing"
-	default SUNXI_DRAM_DDR3_1333
+	default SUNXI_DRAM_DDR3_1333 if !MACH_SUN8I_V3S
+	default SUNXI_DRAM_DDR2_V3S if MACH_SUN8I_V3S
 
 config SUNXI_DRAM_DDR3_1333
 	bool "DDR3 1333"
 	select SUNXI_DRAM_DDR3
+	depends on !MACH_SUN8I_V3S
 	---help---
 	This option is the original only supported memory type, which suits
 	many H3/H5/A64 boards available now.
@@ -237,6 +239,7 @@ config SUNXI_DRAM_DDR3_1333
 config SUNXI_DRAM_DDR2_V3S
 	bool "DDR2 found in V3s chip"
 	select SUNXI_DRAM_DDR2
+	depends on MACH_SUN8I_V3S
 	---help---
 	This option is only for the DDR2 memory chip which is co-packaged in
 	Allwinner V3s SoC.

arch/arm/mach-sunxi/dram_sunxi_dw.c

@@ -723,6 +723,9 @@ unsigned long sunxi_dram_init(void)
 	uint16_t socid = SOCID_R40;
 	/* Currently we cannot support R40 with dual rank memory */
 	para.dual_rank = 0;
+#elif defined(CONFIG_MACH_SUN8I_V3S)
+	/* TODO: set delays and mbus priority for V3s */
+	uint16_t socid = SOCID_H3;
 #elif defined(CONFIG_MACH_SUN50I)
 	uint16_t socid = SOCID_A64;
 #elif defined(CONFIG_MACH_SUN50I_H5)