ARM: vf610: add UART choice for low-level debug

Add choice for low-level debug UART. Similar to i.MX6, there is a
numeric configuration, valid choices are 0 to 3.
Note that the kernel assumes that the boot loader initialized clock
properly.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/Kconfig.debug

@@ -942,6 +942,15 @@ config DEBUG_IMX_UART_PORT
 	  Choose UART port on which kernel low-level debug messages
 	  should be output.
 
+config DEBUG_VF_UART_PORT
+	int "Vybrid Debug UART Port Selection" if DEBUG_VF_UART
+	default 1
+	range 0 3
+	depends on SOC_VF610
+	help
+	  Choose UART port on which kernel low-level debug messages
+	  should be output.
+
 config DEBUG_TEGRA_UART
 	bool
 	depends on ARCH_TEGRA

arch/arm/include/debug/vf.S

@@ -7,9 +7,20 @@
  *
  */
 
+#define VF_UART0_BASE_ADDR	0x40027000
+#define VF_UART1_BASE_ADDR	0x40028000
+#define VF_UART2_BASE_ADDR	0x40029000
+#define VF_UART3_BASE_ADDR	0x4002a000
+#define VF_UART_BASE_ADDR(n)	VF_UART##n##_BASE_ADDR
+#define VF_UART_BASE(n)		VF_UART_BASE_ADDR(n)
+#define VF_UART_PHYSICAL_BASE	VF_UART_BASE(CONFIG_DEBUG_VF_UART_PORT)
+
+#define VF_UART_VIRTUAL_BASE	0xfe000000
+
 	.macro	addruart, rp, rv, tmp
-	ldr	\rp, =0x40028000	@ physical
-	ldr	\rv, =0xfe028000	@ virtual
+	ldr	\rp, =VF_UART_PHYSICAL_BASE 	@ physical
+	and	\rv, \rp, #0xffffff		@ offset within 16MB section
+	add	\rv, \rv, #VF_UART_VIRTUAL_BASE
 	.endm
 
 	.macro	senduart, rd, rx