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>

3 files changed, 31 insertions, 8 deletions

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index b0f3857b3a4c..7754d51f2b19 100644
--- a/arch/arm/Kconfig.debug
+++ b/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
diff --git a/arch/arm/mach-zynq/common.c b/arch/arm/mach-zynq/common.c
index 6f058258b491..f0eef848c0d0 100644
--- a/arch/arm/mach-zynq/common.c
+++ b/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
diff --git a/arch/arm/mach-zynq/include/mach/zynq_soc.h b/arch/arm/mach-zynq/include/mach/zynq_soc.h
index 1b8bf0ecbcb0..5ebbd8e6eeee 100644
--- a/arch/arm/mach-zynq/include/mach/zynq_soc.h
+++ b/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