console: Introduce console_start() and console_stop()

In the future we would like to stop unused consoles and
also add a reference counting to avoid imbalanced calls
to ->start() and ->stop() in some cases.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

common/console.c

@@ -172,13 +172,9 @@ static int console_setfile(int file, struct stdio_dev * dev)
 	case stdin:
 	case stdout:
 	case stderr:
-		/* Start new device */
-		if (dev->start) {
-			error = dev->start(dev);
-			/* If it's not started dont use it */
-			if (error < 0)
-				break;
-		}
+		error = console_start(file, dev);
+		if (error)
+			break;
 
 		/* Assign the new device (leaving the existing one started) */
 		stdio_devices[file] = dev;
@@ -389,6 +385,26 @@ static inline void console_doenv(int file, struct stdio_dev *dev)
 #endif
 #endif /* CONIFIG_IS_ENABLED(CONSOLE_MUX) */
 
+int console_start(int file, struct stdio_dev *sdev)
+{
+	int error;
+
+	/* Start new device */
+	if (sdev->start) {
+		error = sdev->start(sdev);
+		/* If it's not started don't use it */
+		if (error < 0)
+			return error;
+	}
+	return 0;
+}
+
+void console_stop(int file, struct stdio_dev *sdev)
+{
+	if (sdev->stop)
+		sdev->stop(sdev);
+}
+
 /** U-Boot INITIAL CONSOLE-NOT COMPATIBLE FUNCTIONS *************************/
 
 int serial_printf(const char *fmt, ...)

include/console.h

@@ -8,6 +8,7 @@
 #define __CONSOLE_H
 
 #include <stdbool.h>
+#include <stdio_dev.h>
 #include <linux/errno.h>
 
 extern char console_buffer[];
@@ -15,6 +16,8 @@ extern char console_buffer[];
 /* common/console.c */
 int console_init_f(void);	/* Before relocation; uses the serial  stuff */
 int console_init_r(void);	/* After  relocation; uses the console stuff */
+int console_start(int file, struct stdio_dev *sdev);	/* Start a console device */
+void console_stop(int file, struct stdio_dev *sdev);	/* Stop a console device */
 int console_assign(int file, const char *devname);	/* Assign the console */
 int ctrlc(void);
 int had_ctrlc(void);	/* have we had a Control-C since last clear? */