ARM: tegra: add core Tegra186 support

This adds the bare minimum code to support Tegra186, with UART and eMMC
working.

The empty gpio.h is required because <asm/gpio.h> includes it. A future
cleanup round may be able to solve this for all Tegra generations at once.

mach-tegra/Makefile is adjusted not to compile anything for Tegra186, but
instead to defer everything to mach-tegra/tegra186/Makefile. This allows
the SoC code to pick-and-choose which of the C files in the "common"
mach-tegra/ directory to compile in based on the SoC's needs. Most of the
code is not valid for Tegra186, and this approach removes the need for
mach-tegra/Makefile to contain many SoC-specific ifdefs. This approach
may be applied to all other Tegra SoCs in a future cleanup round.

board186.c is introduced to replace board.c and board2.c. These files
currently contain a slew of SoC- and board-specific code that is not
valid for Tegra186. This approach avoids adding yet more ifdefs to those
files. A future cleanup round may refactor most of board*.c into board-/
SoC-specific functions files thus allowing the top-level functions like
board_init_early_f to be shared again.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/dts/tegra186.dtsi b/arch/arm/dts/tegra186.dtsi
new file mode 100644
index 0000000..18b6a26
--- /dev/null
+++ b/arch/arm/dts/tegra186.dtsi
@@ -0,0 +1,56 @@
+#include "skeleton.dtsi"
+#include <dt-bindings/gpio/tegra-gpio.h>
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+/ {
+	compatible = "nvidia,tegra186";
+	#address-cells = <2>;
+	#size-cells = <2>;
+
+	gpio@2200000 {
+		compatible = "nvidia,tegra186-gpio";
+		reg-names = "security", "gpio";
+		reg =
+			<0x0 0x2200000 0x0 0x10000>,
+			<0x0 0x2210000 0x0 0x10000>;
+		interrupts =
+			<GIC_SPI 47 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 50 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 53 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 59 IRQ_TYPE_LEVEL_HIGH>,
+			<GIC_SPI 180 IRQ_TYPE_LEVEL_HIGH>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		interrupt-controller;
+		#interrupt-cells = <2>;
+	};
+
+	uarta: serial@3100000 {
+		compatible = "nvidia,tegra186-uart", "nvidia,tegra20-uart";
+		reg = <0x0 0x03100000 0x0 0x10000>;
+		reg-shift = <2>;
+		status = "disabled";
+	};
+
+	sdhci@3460000 {
+		compatible = "nvidia,tegra186-sdhci";
+		reg = <0x0 0x03460000 0x0 0x200>;
+		interrupts = <GIC_SPI 31 0x04>;
+		status = "disabled";
+	};
+
+	gpio@c2f0000 {
+		compatible = "nvidia,tegra186-gpio-aon";
+		reg-names = "security", "gpio";
+		reg =
+			<0x0 0xc2f0000 0x0 0x1000>,
+			<0x0 0xc2f1000 0x0 0x1000>;
+		interrupts =
+			<GIC_SPI 60 IRQ_TYPE_LEVEL_HIGH>;
+		gpio-controller;
+		#gpio-cells = <2>;
+		interrupt-controller;
+		#interrupt-cells = <2>;
+	};
+};