libpayload console: Add check for already existing driver

Add support to check if the driver for console_out or console_in is already
present in the list. If console_init is called twice, then the driver might get
added twice leading to a loop.

BUG=None
BRANCH=None
TEST=With console_init in libpayload and depthcharge both, there are no console
loops seen anymore

Change-Id: I9103230dfe88added28c51bff33ea4fa1ab034c1
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 6931236ba2cfa71849973fe41cc340b7d70656ad
Original-Change-Id: If9a927318b850ec59619d92b1da4dddd0aa09cd1
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/214072
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/8739
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/payloads/libpayload/libc/console.c b/payloads/libpayload/libc/console.c
index 827da792b9..7717daf5d1 100644
--- a/payloads/libpayload/libc/console.c
+++ b/payloads/libpayload/libc/console.c
@@ -35,15 +35,47 @@ struct console_output_driver *console_out;
 struct console_input_driver *console_in;
 static console_input_type last_getchar_input_type;
 
+static int output_driver_exists(struct console_output_driver *out)
+{
+	struct console_output_driver *head = console_out;
+
+	while (head) {
+		if (head == out)
+			return 1;
+		head = head->next;
+	}
+
+	return 0;
+}
+
+static int input_driver_exists(struct console_input_driver *in)
+{
+	struct console_input_driver *head = console_in;
+
+	while (head) {
+		if (head == in)
+			return 1;
+		head = head->next;
+	}
+
+	return 0;
+}
+
 void console_add_output_driver(struct console_output_driver *out)
 {
 	die_if(!out->putchar && !out->write, "Need at least one output func\n");
+	/* Check if this driver was already added to the console list */
+	if (output_driver_exists(out))
+		return;
 	out->next = console_out;
 	console_out = out;
 }
 
 void console_add_input_driver(struct console_input_driver *in)
 {
+	/* Check if this driver was already added to the console list */
+	if (input_driver_exists(in))
+		return;
 	in->next = console_in;
 	console_in = in;
 }