[PATCH] serial: stm32: restrict _debug_uart_init() usage

[Patrice Chotard]

Since commit 948da7773e34 ("arm: Add new config option ARCH_VERY_EARLY_INIT")
debug_uart_init() is called respectively in crt0.S and crt0_64.S.
That means that _debug_uart_init() is called for all STM32MP platforms
even for those which doesn't support SPL_BUILD.

So restrict _debug_uart_init() execution for platforms which can have
SPL_BUILD enabled (STM32MP1 platform only).

It's more needed to call debug_uart_init() in stm32mp1/cpu.c.

Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
---

 arch/arm/mach-stm32mp/stm32mp1/cpu.c |  2 --
 drivers/serial/serial_stm32.c        | 18 ++++++++++++------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mach-stm32mp/stm32mp1/cpu.c b/arch/arm/mach-stm32mp/stm32mp1/cpu.c
index cb1b84c9af9..bc410128479 100644
--- a/arch/arm/mach-stm32mp/stm32mp1/cpu.c
+++ b/arch/arm/mach-stm32mp/stm32mp1/cpu.c
@@ -138,8 +138,6 @@ int mach_cpu_init(void)
 	if (IS_ENABLED(CONFIG_CMD_STM32PROG_SERIAL) &&
 	    (boot_mode & TAMP_BOOT_DEVICE_MASK) == BOOT_SERIAL_UART)
 		gd->flags |= GD_FLG_SILENT | GD_FLG_DISABLE_CONSOLE;
-	else if (IS_ENABLED(CONFIG_DEBUG_UART) && IS_ENABLED(CONFIG_XPL_BUILD))
-		debug_uart_init();
 
 	return 0;
 }
diff --git a/drivers/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index 1ee58142b3f..1675a9cb9d1 100644
--- a/drivers/serial/serial_stm32.c
+++ b/drivers/serial/serial_stm32.c
@@ -299,13 +299,19 @@ static inline struct stm32_uart_info *_debug_uart_info(void)
 
 static inline void _debug_uart_init(void)
 {
-	void __iomem *base = (void __iomem *)CONFIG_VAL(DEBUG_UART_BASE);
-	struct stm32_uart_info *uart_info = _debug_uart_info();
+	void __maybe_unused __iomem *base = (void __iomem *)CONFIG_VAL(DEBUG_UART_BASE);
+	struct stm32_uart_info *uart_info __maybe_unused = _debug_uart_info();
 
-	_stm32_serial_init(base, uart_info);
-	_stm32_serial_setbrg(base, uart_info,
-			     CONFIG_DEBUG_UART_CLOCK,
-			     CONFIG_BAUDRATE);
+	/*
+	 * debug_uart_init() is only usable when SPL_BUILD is enabled
+	 * (STM32MP1 case only)
+	 */
+	if (IS_ENABLED(CONFIG_DEBUG_UART) && IS_ENABLED(CONFIG_SPL_BUILD)) {
+		_stm32_serial_init(base, uart_info);
+		_stm32_serial_setbrg(base, uart_info,
+				     CONFIG_DEBUG_UART_CLOCK,
+				     CONFIG_BAUDRATE);
+	}
 }
 
 static inline void _debug_uart_putc(int c)
-- 
2.25.1