[PATCH 02/26] console: Add a way to output to serial only

[Simon Glass]

In the video drivers it is useful to print errors while debugging but
doing so risks an infinite loop as the debugging info itself may go
through the video drivers.

Add a new console function that prints information only to the serial
device, thus making it safe for use in debugging.

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

 common/console.c  | 28 ++++++++++++++++++++++------
 include/console.h | 13 +++++++++++++
 2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/common/console.c b/common/console.c
index 1deca3cb78..31f46470d2 100644
--- a/common/console.c
+++ b/common/console.c
@@ -229,18 +229,34 @@ static void console_putc(int file, const char c)
 	}
 }
 
-static void console_puts_noserial(int file, const char *s)
+/**
+ * console_puts_select() - Output a string to all console devices
+ *
+ * @file: File number to output to (e,g, stdout, see stdio.h)
+ * @serial_only: true to output only to serial, false to output to everything
+ *	else
+ * @s: String to output
+ */
+static void console_puts_select(int file, bool serial_only, const char *s)
 {
 	int i;
 	struct stdio_dev *dev;
 
 	for (i = 0; i < cd_count[file]; i++) {
+		bool is_serial;
+
 		dev = console_devices[file][i];
-		if (dev->puts != NULL && !console_dev_is_serial(dev))
+		is_serial = console_dev_is_serial(dev);
+		if (dev->puts && serial_only == is_serial)
 			dev->puts(dev, s);
 	}
 }
 
+void console_puts_select_stderr(bool serial_only, const char *s)
+{
+	console_puts_select(stderr, serial_only, s);
+}
+
 static void console_puts(int file, const char *s)
 {
 	int i;
@@ -275,9 +291,9 @@ static inline void console_putc(int file, const char c)
 	stdio_devices[file]->putc(stdio_devices[file], c);
 }
 
-static inline void console_puts_noserial(int file, const char *s)
+void console_puts_select(int file, bool serial_only, const char *s)
 {
-	if (!console_dev_is_serial(stdio_devices[file]))
+	if (serial_only == console_dev_is_serial(stdio_devices[file]))
 		stdio_devices[file]->puts(stdio_devices[file], s);
 }
 
@@ -489,7 +505,7 @@ static void print_pre_console_buffer(int flushpoint)
 		puts(buf_out);
 		break;
 	case PRE_CONSOLE_FLUSHPOINT2_EVERYTHING_BUT_SERIAL:
-		console_puts_noserial(stdout, buf_out);
+		console_puts_select(stdout, false, buf_out);
 		break;
 	}
 }
@@ -776,7 +792,7 @@ int console_announce_r(void)
 
 	display_options_get_banner(false, buf, sizeof(buf));
 
-	console_puts_noserial(stdout, buf);
+	console_puts_select(stdout, false, buf);
 #endif
 
 	return 0;
diff --git a/include/console.h b/include/console.h
index 74afe22b7e..4c6b8f2614 100644
--- a/include/console.h
+++ b/include/console.h
@@ -7,6 +7,8 @@
 #ifndef __CONSOLE_H
 #define __CONSOLE_H
 
+#include <stdbool.h>
+
 extern char console_buffer[];
 
 /* common/console.c */
@@ -72,6 +74,17 @@ int console_record_avail(void);
  */
 int console_announce_r(void);
 
+/**
+ * console_puts_select_stderr() - Output a string to selected console devices
+ *
+ * This writes to stderr only. It is useful for outputting errors
+ *
+ * @serial_only: true to output only to serial, false to output to everything
+ *	else
+ * @s: String to output
+ */
+void console_puts_select_stderr(bool serial_only, const char *s);
+
 /*
  * CONSOLE multiplexing.
  */
-- 
2.26.2.761.g0e0b3e54be-goog