linux-kernel - [PATCH v2 1/2] serial: 8250_early: do not save and restore IER in write callback

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Date:	Sat, 24 Oct 2015 13:17:44 +0900
From:	Masahiro Yamada <yamada.masahiro@...ionext.com>
To:	linux-serial@...r.kernel.org
Cc:	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Vineet Gupta <Vineet.Gupta1@...opsys.com>,
	Kevin Cernekee <cernekee@...il.com>,
	Jiri Slaby <jslaby@...e.com>, Rob Herring <robh@...nel.org>,
	Peter Hurley <peter@...leysoftware.com>,
	linux-kernel@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH v2 1/2] serial: 8250_early: do not save and restore IER in write callback

The IER has already been masked in early_serial8250_setup(), there is
no reason to save and restore it every time early_serial8250_write()
is called.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 drivers/tty/serial/8250/8250_early.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index 7aff3d8..559b681 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -99,20 +99,8 @@ static void __init early_serial8250_write(struct console *console,
 {
 	struct earlycon_device *device = console->data;
 	struct uart_port *port = &device->port;
-	unsigned int ier;
-
-	/* Save the IER and disable interrupts preserving the UUE bit */
-	ier = serial8250_early_in(port, UART_IER);
-	if (ier)
-		serial8250_early_out(port, UART_IER, ier & UART_IER_UUE);
 
 	uart_console_write(port, s, count, serial_putc);
-
-	/* Wait for transmitter to become empty and restore the IER */
-	wait_for_xmitr(port);
-
-	if (ier)
-		serial8250_early_out(port, UART_IER, ier);
 }
 
 static void __init init_port(struct earlycon_device *device)
-- 
1.9.1

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