stm32mp: fix compilation issue with DEBUG_UART

Fix the compilation issue when CONFIG_DEBUG_UART is activated

 drivers/serial/serial_stm32.o: in function `debug_uart_init':
 drivers/serial/serial_stm32.c:291: undefined reference to \
    `board_debug_uart_init'

The board_debug_uart_init is needed for SPL boot, called in
cpu.c::mach_cpu_init(); it is defined in board/st/stm32mp1/spl.c.

But with the removal #ifdefs patch, the function debug_uart_init() is
always compiled even if not present in the final U-Boot image.

This patch adds a file to provided this function when DEBUG_UART and SPL
are activated.

Fixes: c8b2eef52b6c ("stm32mp15: tidy up #ifdefs in cpu.c")
Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/board/st/stm32mp1/debug_uart.c b/board/st/stm32mp1/debug_uart.c
new file mode 100644
index 00000000000..24e3f9f2201
--- /dev/null
+++ b/board/st/stm32mp1/debug_uart.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause
+/*
+ * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
+ */
+
+#include <config.h>
+#include <debug_uart.h>
+#include <asm/io.h>
+#include <asm/arch/stm32.h>
+#include <linux/bitops.h>
+
+#define RCC_MP_APB1ENSETR (STM32_RCC_BASE + 0x0A00)
+#define RCC_MP_AHB4ENSETR (STM32_RCC_BASE + 0x0A28)
+
+#define GPIOG_BASE 0x50008000
+
+void board_debug_uart_init(void)
+{
+	if (CONFIG_DEBUG_UART_BASE == STM32_UART4_BASE) {
+		/* UART4 clock enable */
+		setbits_le32(RCC_MP_APB1ENSETR, BIT(16));
+
+		/* GPIOG clock enable */
+		writel(BIT(6), RCC_MP_AHB4ENSETR);
+		/* GPIO configuration for ST boards: Uart4 TX = G11 */
+		writel(0xffbfffff, GPIOG_BASE + 0x00);
+		writel(0x00006000, GPIOG_BASE + 0x24);
+	}
+}