[PATCH v2 4/6] serial: Implement serial_flush() function for console flush() fallback

["Pali Rohár" <pali@kernel.org>]

Like in all other console functions, implement also serial_flush() function
as a fallback int console flush() function.

Flush support is available only when config option CONSOLE_FLUSH_SUPPORT is
enabled. So when it is disabled then provides just empty static inline
function serial_flush().

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 common/console.c               |  3 +++
 common/stdio.c                 | 10 ++++++++++
 drivers/serial/serial-uclass.c | 10 ++++++++++
 include/serial.h               |  5 +++++
 4 files changed, 28 insertions(+)

diff --git a/common/console.c b/common/console.c
index 42415e34d16f..72ed7cd3b3b4 100644
--- a/common/console.c
+++ b/common/console.c
@@ -790,6 +790,9 @@ void flush(void)
 	if (gd->flags & GD_FLG_DEVINIT) {
 		/* Send to the standard output */
 		fflush(stdout);
+	} else {
+		/* Send directly to the handler */
+		serial_flush();
 	}
 }
 #endif
diff --git a/common/stdio.c b/common/stdio.c
index 92161a0df87d..b49a02f16f46 100644
--- a/common/stdio.c
+++ b/common/stdio.c
@@ -87,6 +87,13 @@ static void stdio_serial_puts(struct stdio_dev *dev, const char *s)
 	serial_puts(s);
 }
 
+#ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
+static void stdio_serial_flush(struct stdio_dev *dev)
+{
+	serial_flush();
+}
+#endif
+
 static int stdio_serial_getc(struct stdio_dev *dev)
 {
 	return serial_getc();
@@ -112,6 +119,9 @@ static void drv_system_init (void)
 	dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;
 	dev.putc = stdio_serial_putc;
 	dev.puts = stdio_serial_puts;
+#ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
+	dev.flush = stdio_serial_flush;
+#endif
 	dev.getc = stdio_serial_getc;
 	dev.tstc = stdio_serial_tstc;
 	stdio_register (&dev);
diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 71ea88e31c9f..4e32270d4660 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -327,6 +327,16 @@ void serial_puts(const char *str)
 		_serial_puts(gd->cur_serial_dev, str);
 }
 
+#ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
+void serial_flush(void)
+{
+	if (!gd->cur_serial_dev)
+		return;
+
+	_serial_flush(gd->cur_serial_dev);
+}
+#endif
+
 int serial_getc(void)
 {
 	if (!gd->cur_serial_dev)
diff --git a/include/serial.h b/include/serial.h
index e6051e0a7faf..4e951f0c5f52 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -386,6 +386,11 @@ void serial_setbrg(void);
 void serial_putc(const char ch);
 void serial_putc_raw(const char ch);
 void serial_puts(const char *str);
+#ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
+void serial_flush(void);
+#else
+static inline void serial_flush(void) {}
+#endif
 int serial_getc(void);
 int serial_tstc(void);
 
-- 
2.20.1