From: Keith Packard <keithp@keithp.com>
Date: Sat, 18 Jul 2009 08:04:17 +0000 (-0700)
Subject: Drain serial port before changing speed
X-Git-Tag: 0.5~18
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=d3f76ce58b9c0ed2e5a9fe3bbc7fb9cb38247714;hp=d7c2d358ed8a1afc9f0ba2bd830b10f6b56dc7b1

Drain serial port before changing speed

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/ao_serial.c b/src/ao_serial.c
index 7bc11b97..4155e776 100644
--- a/src/ao_serial.c
+++ b/src/ao_serial.c
@@ -75,6 +75,13 @@ ao_serial_putchar(char c) __critical
 	ao_serial_tx1_start();
 }
 
+static void
+ao_serial_drain(void) __critical
+{
+	while (!ao_fifo_empty(ao_usart1_tx_fifo))
+		ao_sleep(&ao_usart1_tx_fifo);
+}
+
 static void
 send_serial(void)
 {
@@ -115,6 +122,9 @@ static const struct {
 void
 ao_serial_set_speed(uint8_t speed)
 {
+	ao_serial_drain();
+	if (speed > AO_SERIAL_SPEED_57600)
+		return;
 	U1BAUD = ao_serial_speeds[speed].baud;
 	U1GCR = ao_serial_speeds[speed].gcr;
 }