From 9afd561acabe5059ff16d163a176e2350269aba5 Mon Sep 17 00:00:00 2001
From: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Date: Wed, 16 Jul 2008 21:52:46 +0100
Subject: [PATCH] Subject: [PATCH 2/2] atmel_serial: Implement flush_buffer()
hook
Avoid dumping garbage to the serial port when the tty is flushed. This
tends to happen when rebooting from a serial console.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/serial/atmel_serial.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 6aeef22bd203..c17fcd6085f3 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -955,6 +955,20 @@ static void atmel_shutdown(struct uart_port *port)
atmel_close_hook(port);
}
+/*
+ * Flush any TX data submitted for DMA. Called when the TX circular
+ * buffer is reset.
+ */
+static void atmel_flush_buffer(struct uart_port *port)
+{
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+ if (atmel_use_dma_tx(port)) {
+ UART_PUT_TCR(port, 0);
+ atmel_port->pdc_tx.ofs = 0;
+ }
+}
+
/*
* Power / Clock management.
*/
@@ -1189,6 +1203,7 @@ static struct uart_ops atmel_pops = {
.break_ctl = atmel_break_ctl,
.startup = atmel_startup,
.shutdown = atmel_shutdown,
+ .flush_buffer = atmel_flush_buffer,
.set_termios = atmel_set_termios,
.type = atmel_type,
.release_port = atmel_release_port,