ARM: zynq: Allow UART1 to be used as DEBUG_LL console.

The main UART on the Xilinx ZC702 board is UART1, located at address
e0001000.  Add a Kconfig option to select this device as the low-level
debugging port.  This allows the really early boot printouts to reach
the USB serial adaptor on this board.

For consistency's sake, add a choice entry for UART0 even though it is
the the default if UART1 is not selected.

Signed-off-by: Nick Bowler <nbowler@elliptictech.com>
Tested-by: Josh Cartwright <josh.cartwright@ni.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/Kconfig.debug

@@ -132,6 +132,23 @@ choice
 		  their output to UART1 serial port on DaVinci TNETV107X
 		  devices.
 
+	config DEBUG_ZYNQ_UART0
+		bool "Kernel low-level debugging on Xilinx Zynq using UART0"
+		depends on ARCH_ZYNQ
+		help
+		  Say Y here if you want the debug print routines to direct
+		  their output to UART0 on the Zynq platform.
+
+	config DEBUG_ZYNQ_UART1
+		bool "Kernel low-level debugging on Xilinx Zynq using UART1"
+		depends on ARCH_ZYNQ
+		help
+		  Say Y here if you want the debug print routines to direct
+		  their output to UART1 on the Zynq platform.
+
+		  If you have a ZC702 board and want early boot messages to
+		  appear on the USB serial adaptor, select this option.
+
 	config DEBUG_DC21285_PORT
 		bool "Kernel low-level debugging messages via footbridge serial port"
 		depends on FOOTBRIDGE

arch/arm/mach-zynq/common.c

@@ -85,9 +85,9 @@ static struct map_desc io_desc[] __initdata = {
 
 #ifdef CONFIG_DEBUG_LL
 	{
-		.virtual	= UART0_VIRT,
-		.pfn		= __phys_to_pfn(UART0_PHYS),
-		.length		= UART0_SIZE,
+		.virtual	= LL_UART_VADDR,
+		.pfn		= __phys_to_pfn(LL_UART_PADDR),
+		.length		= UART_SIZE,
 		.type		= MT_DEVICE,
 	},
 #endif

arch/arm/mach-zynq/include/mach/zynq_soc.h

@@ -25,8 +25,9 @@
  * address that is known to work.
  */
 #define UART0_PHYS		0xE0000000
-#define UART0_SIZE		SZ_4K
-#define UART0_VIRT		0xF0001000
+#define UART1_PHYS		0xE0001000
+#define UART_SIZE		SZ_4K
+#define UART_VIRT		0xF0001000
 
 #define TTC0_PHYS		0xF8001000
 #define TTC0_SIZE		SZ_4K
@@ -36,12 +37,17 @@
 #define SCU_PERIPH_SIZE		SZ_8K
 #define SCU_PERIPH_VIRT		(TTC0_VIRT - SCU_PERIPH_SIZE)
 
+#if IS_ENABLED(CONFIG_DEBUG_ZYNQ_UART1)
+# define LL_UART_PADDR		UART1_PHYS
+#else
+# define LL_UART_PADDR		UART0_PHYS
+#endif
+
+#define LL_UART_VADDR		UART_VIRT
+
 /* The following are intended for the devices that are mapped early */
 
 #define TTC0_BASE			IOMEM(TTC0_VIRT)
 #define SCU_PERIPH_BASE			IOMEM(SCU_PERIPH_VIRT)
 
-#define LL_UART_PADDR	UART0_PHYS
-#define LL_UART_VADDR	UART0_VIRT
-
 #endif