net: Make the netconsole buffer size configurable

Allow a board to configure a larger buffer for netconsole, but leave
the default.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>

doc/README.NetConsole

@@ -6,6 +6,8 @@ serial and network input/output devices by adjusting the 'stdin' and
 set either of these variables to "nc". Input and output can be
 switched independently.
 
+CONFIG_NETCONSOLE_BUFFER_SIZE - Override the default buffer size
+
 We use an environment variable 'ncip' to set the IP address and the
 port of the destination. The format is <ip_addr>:<port>. If <port> is
 omitted, the value of 6666 is used. If the env var doesn't exist, the

drivers/net/netconsole.c

@@ -28,7 +28,11 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-static char input_buffer[512];
+#ifndef CONFIG_NETCONSOLE_BUFFER_SIZE
+#define CONFIG_NETCONSOLE_BUFFER_SIZE 512
+#endif
+
+static char input_buffer[CONFIG_NETCONSOLE_BUFFER_SIZE];
 static int input_size; /* char count in input buffer */
 static int input_offset; /* offset to valid chars in input buffer */
 static int input_recursion;
@@ -214,7 +218,7 @@ static void nc_puts(const char *s)
 
 	len = strlen(s);
 	while (len) {
-		int send_len = min(len, 512);
+		int send_len = min(len, sizeof(input_buffer));
 		nc_send_packet(s, send_len);
 		len -= send_len;
 		s += send_len;