From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sat, 6 Oct 2012 08:04:03 +0000 (+0100)
Subject: SERIAL: omap: don't read back LCR/MCR/EFR
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1fe8aa8803536b8030375525a07a152ba8f15363;p=linux.git

SERIAL: omap: don't read back LCR/MCR/EFR

There's really no reason to read back these registers while setting
the termios modes, provided we keep our cached copies up to date.
Remove these readbacks.

This has the benefit that we know that the EFR_ECB and MCR_TCRTLR
bits will always be clear, so we don't need to keep masking these
bits throughout the code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 4888bd1ab3225..6d588e20c648b 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -912,8 +912,11 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 		/* Enable AUTORTS and AUTOCTS */
 		up->efr |= UART_EFR_CTS | UART_EFR_RTS;
 
+		/* Ensure MCR RTS is asserted */
+		up->mcr |= UART_MCR_RTS;
+
 		/* Disable access to TCR/TLR */
-		serial_out(up, UART_MCR, up->mcr | UART_MCR_RTS);
+		serial_out(up, UART_MCR, up->mcr);
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 		serial_out(up, UART_EFR, up->efr);
 		serial_out(up, UART_LCR, cval);
@@ -928,10 +931,8 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	/* Software Flow Control Configuration */
 	if (up->port.flags & UPF_SOFT_FLOW) {
-		up->lcr = serial_in(up, UART_LCR);
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
-		up->efr = serial_in(up, UART_EFR);
-		serial_out(up, UART_EFR, up->efr & ~UART_EFR_ECB);
+		serial_out(up, UART_EFR, up->efr);
 
 		serial_out(up, UART_XON1, termios->c_cc[VSTART]);
 		serial_out(up, UART_XOFF1, termios->c_cc[VSTOP]);
@@ -958,8 +959,6 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 		serial_out(up, UART_EFR, up->efr | UART_EFR_ECB);
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
 
-		up->mcr = serial_in(up, UART_MCR);
-
 		/*
 		 * IXANY Flag:
 		 * Enable any character to restart output.
@@ -975,7 +974,7 @@ serial_omap_set_termios(struct uart_port *port, struct ktermios *termios,
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 		serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_TRIG);
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
-		serial_out(up, UART_MCR, up->mcr & ~UART_MCR_TCRTLR);
+		serial_out(up, UART_MCR, up->mcr);
 		serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 		serial_out(up, UART_EFR, up->efr);
 		serial_out(up, UART_LCR, up->lcr);