linux-kernel - [PATCH v3 1/3] serial: 8250_early: do not save and restore IER in write callback

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Message-Id: <1446172745-5115-2-git-send-email-yamada.masahiro@socionext.com>
Date:	Fri, 30 Oct 2015 11:39:03 +0900
From:	Masahiro Yamada <yamada.masahiro@...ionext.com>
To:	linux-serial@...r.kernel.org
Cc:	Peter Hurley <peter@...leysoftware.com>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, Jiri Slaby <jslaby@...e.com>
Subject: [PATCH v3 1/3] 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 | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index 7aff3d8..23c322f 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -99,20 +99,11 @@ 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 transmitter to become empty */
 	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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