[U-Boot] [PATCH] altera_jtag_uart: bypass when no jtag connection

[Thomas Chou]

This patch adds an option to bypass output waiting when there
is no jtag connection. This allows the jtag uart work similar
to a serial uart, ie, boot even without connection.

This option is enabled with,
#define CONFIG_ALTERA_JTAG_UART_BYPASS

Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
---
 drivers/serial/altera_jtag_uart.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/serial/altera_jtag_uart.c b/drivers/serial/altera_jtag_uart.c
index 9eccaa0..54d481b 100644
--- a/drivers/serial/altera_jtag_uart.c
+++ b/drivers/serial/altera_jtag_uart.c
@@ -38,8 +38,16 @@ int serial_init( void ) { return(0);}
 
 void serial_putc (char c)
 {
-	while (NIOS_JTAG_WSPACE ( readl (&jtag->control)) == 0)
-		WATCHDOG_RESET ();
+	while (1) {
+		unsigned st = readl(&jtag->control);
+		if (NIOS_JTAG_WSPACE(st))
+			break;
+#ifdef CONFIG_ALTERA_JTAG_UART_BYPASS
+		if (!(st & NIOS_JTAG_AC)) /* no connection */
+			return;
+#endif
+		WATCHDOG_RESET();
+	}
 	writel (&jtag->data, (unsigned char)c);
 }
 
-- 
1.6.6.1