ARM: zynq: Fix debug uart initialization

The commit 0dba45864b2a ("arm: Init the debug UART") calls
debug_uart_init() from crt0.S but it won't work because SOC is not
configured yet. That's why create board_debug_uart_init() which calls
ps7_init() earlier before the first access to UART.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/18e67e02a0c7190839a1ef3a11f3fd6babcf34cc.1645104518.git.michal.simek@xilinx.com
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ae5002c..c5b21cd 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1157,6 +1157,7 @@
 	select CLK
 	select CLK_ZYNQ
 	select CPU_V7A
+	select DEBUG_UART_BOARD_INIT if SPL && DEBUG_UART
 	select DM
 	select DM_ETH if NET
 	select DM_MMC if MMC
diff --git a/arch/arm/mach-zynq/spl.c b/arch/arm/mach-zynq/spl.c
index b1a5184..fea1c9b 100644
--- a/arch/arm/mach-zynq/spl.c
+++ b/arch/arm/mach-zynq/spl.c
@@ -16,17 +16,20 @@
 #include <asm/arch/sys_proto.h>
 #include <asm/arch/ps7_init_gpl.h>
 
+#if defined(CONFIG_DEBUG_UART_BOARD_INIT)
+void board_debug_uart_init(void)
+{
+	ps7_init();
+}
+#endif
+
 void board_init_f(ulong dummy)
 {
+#if !defined(CONFIG_DEBUG_UART_BOARD_INIT)
 	ps7_init();
+#endif
 
 	arch_cpu_init();
-
-#ifdef CONFIG_DEBUG_UART
-	/* Uart debug for sure */
-	debug_uart_init();
-	puts("Debug uart enabled\n"); /* or printch() */
-#endif
 }
 
 #ifdef CONFIG_SPL_BOARD_INIT
diff --git a/board/xilinx/zynq/board.c b/board/xilinx/zynq/board.c
index 1111ad6..26ef048 100644
--- a/board/xilinx/zynq/board.c
+++ b/board/xilinx/zynq/board.c
@@ -25,6 +25,13 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_DEBUG_UART_BOARD_INIT)
+void board_debug_uart_init(void)
+{
+	/* Add initialization sequence if UART is not configured */
+}
+#endif
+
 int board_init(void)
 {
 	if (IS_ENABLED(CONFIG_SPL_BUILD))