exynos: Add debug UART support for Samsung S5P serial

Add a debug UART implementation for this serial driver. It does not set up
pinmux automatically - this must be done before calling debug_uart_init().

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/serial/Kconfig

@@ -53,6 +53,13 @@ config DEBUG_EFI_CONSOLE
 	  U-Boot when running on top of EFI (Extensive Firmware Interface).
 	  This is a type of BIOS used by PCs.
 
+config DEBUG_UART_S5P
+	bool "Samsung S5P"
+	help
+	  Select this to enable a debug UART using the serial_s5p driver. You
+	  will need to provide parameters to make this work. The driver will
+	  be available until the real driver-model serial is running.
+
 endchoice
 
 config DEBUG_UART_BASE

drivers/serial/serial_s5p.c

@@ -200,3 +200,28 @@ U_BOOT_DRIVER(serial_s5p) = {
 	.ops	= &s5p_serial_ops,
 	.flags = DM_FLAG_PRE_RELOC,
 };
+
+#ifdef CONFIG_DEBUG_UART_S5P
+
+#include <debug_uart.h>
+
+void debug_uart_init(void)
+{
+	struct s5p_uart *uart = (struct s5p_uart *)CONFIG_DEBUG_UART_BASE;
+
+	s5p_serial_init(uart);
+	s5p_serial_baud(uart, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+	struct s5p_uart *uart = (struct s5p_uart *)CONFIG_DEBUG_UART_BASE;
+
+	while (readl(&uart->ufstat) & TX_FIFO_FULL);
+
+	writeb(ch, &uart->utxh);
+}
+
+DEBUG_UART_FUNCS
+
+#endif