ram: rockchip: Add rv1126 ddr4 support

Add support for ddr4 on rv1126. Timing detection files are imported
from downstream Rockchip BSP u-boot. Allow selecting ddr4 ram with
define CONFIG_RAM_ROCKCHIP_DDR4.

Signed-off-by: Tim Lunn <tim@feathertop.org>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/ram/rockchip/sdram-rv1126-ddr4-detect-784.inc b/drivers/ram/rockchip/sdram-rv1126-ddr4-detect-784.inc
new file mode 100644
index 0000000..ef2e934
--- /dev/null
+++ b/drivers/ram/rockchip/sdram-rv1126-ddr4-detect-784.inc
@@ -0,0 +1,75 @@
+{
+	{
+		{
+			.rank = 0x1,
+			.col = 0xA,
+			.bk = 0x2,
+			.bw = 0x1,
+			.dbw = 0x0,
+			.row_3_4 = 0x0,
+			.cs0_row = 0x11,
+			.cs1_row = 0x0,
+			.cs0_high16bit_row = 0x11,
+			.cs1_high16bit_row = 0x0,
+			.ddrconfig = 0
+		},
+		{
+			{0x50160d14},
+			{0x0e020502},
+			{0x00000002},
+			{0x00001111},
+			{0x0000000c},
+			{0x0000033a},
+			0x000000ff
+		}
+	},
+	{
+		.ddr_freq = 784,	/* clock rate(MHz) */
+		.dramtype = DDR4,
+		.num_channels = 1,
+		.stride = 0,
+		.odt = 1
+	},
+	{
+		{
+			{0x00000000, 0x43041010},	/* MSTR */
+			{0x00000064, 0x005f008a},	/* RFSHTMG */
+			{0x000000d0, 0x000200c1},	/* INIT0 */
+			{0x000000d4, 0x004e0000},	/* INIT1 */
+			{0x000000d8, 0x00000100},	/* INIT2 */
+			{0x000000dc, 0x03140401},	/* INIT3 */
+			{0x000000e0, 0x00000000},	/* INIT4 */
+			{0x000000e4, 0x00110000},	/* INIT5 */
+			{0x000000e8, 0x00000420},	/* INIT6 */
+			{0x000000ec, 0x00000400},	/* INIT7 */
+			{0x000000f4, 0x000f011f},	/* RANKCTL */
+			{0x00000100, 0x0c0e1a0e},	/* DRAMTMG0 */
+			{0x00000104, 0x00030314},	/* DRAMTMG1 */
+			{0x00000108, 0x0506050b},	/* DRAMTMG2 */
+			{0x0000010c, 0x0040400c},	/* DRAMTMG3 */
+			{0x00000110, 0x06030307},	/* DRAMTMG4 */
+			{0x00000114, 0x04040302},	/* DRAMTMG5 */
+			{0x00000120, 0x06060b06},	/* DRAMTMG8 */
+			{0x00000124, 0x00020308},	/* DRAMTMG9 */
+			{0x00000180, 0x01000040},	/* ZQCTL0 */
+			{0x00000184, 0x00000000},	/* ZQCTL1 */
+			{0x00000190, 0x07040003},	/* DFITMG0 */
+			{0x00000198, 0x07000101},	/* DFILPCFG0 */
+			{0x000001a0, 0xc0400003},	/* DFIUPD0 */
+			{0x00000240, 0x0600060c},	/* ODTCFG */
+			{0x00000244, 0x00000201},	/* ODTMAP */
+			{0x00000250, 0x00001f00},	/* SCHED */
+			{0x00000490, 0x00000001},	/* PCTRL_0 */
+			{0xffffffff, 0xffffffff}
+		}
+	},
+	{
+		{
+			{0x00000004, 0x0000008c},	/* PHYREG01 */
+			{0x00000014, 0x0000000c},	/* PHYREG05 */
+			{0x00000018, 0x00000000},	/* PHYREG06 */
+			{0x0000001c, 0x00000009},	/* PHYREG07 */
+			{0xffffffff, 0xffffffff}
+		}
+	}
+},