From da7fa058a36cd8d4ebd42001fa72a40c0aefd6e3 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Mon, 24 Oct 2016 17:00:30 +0900 Subject: [PATCH] serial: 8250_uniphier: avoid locking for FCR register write The hardware book says, the FCR is combined with a register called CHAR (it will trigger interrupt when a specific character is received). At first, I used lock/read/modify/write/unlock dance for the FCR to not affect the upper bits, but the CHAR is actually never used. It should not hurt to always clear the CHAR and to handle the FCR as a normal case. It can save the costly locking. Signed-off-by: Masahiro Yamada Suggested-by: Denys Vlasenko Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_uniphier.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c index 92e7bb7b3f83..746680ebf90c 100644 --- a/drivers/tty/serial/8250/8250_uniphier.c +++ b/drivers/tty/serial/8250/8250_uniphier.c @@ -101,7 +101,7 @@ static unsigned int uniphier_serial_in(struct uart_port *p, int offset) static void uniphier_serial_out(struct uart_port *p, int offset, int value) { unsigned int valshift = 0; - bool normal = false; + bool normal = true; switch (offset) { case UART_FCR: @@ -114,9 +114,9 @@ static void uniphier_serial_out(struct uart_port *p, int offset, int value) /* fall through */ case UART_MCR: offset = UNIPHIER_UART_LCR_MCR; + normal = false; break; default: - normal = true; offset <<= UNIPHIER_UART_REGSHIFT; break; } -- 2.39.5