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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2018-03-02 11:07:27 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-09 10:21:01 -0800
commit81ca8e8286c48df22eb798879d99aabac663b5f1 (patch)
treeb53787d6ac61b186bcbfe7a70199d9997ef11e2b /drivers/tty
parent76821e222c189b81d553b855ee7054340607eb46 (diff)
downloadlinux-81ca8e8286c48df22eb798879d99aabac663b5f1.tar.bz2
serial: imx: Also enable the aging timer in PIO mode
This allows to increase the RX waterlevel which allows to delay the RRDY irq. The desired effect is that less irqs are needed to handle characters and so reduce irq count of the system. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/imx.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 3c1bfe8742a4..e1f00d5aced9 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -418,6 +418,7 @@ static void imx_start_rx(struct uart_port *port)
ucr1 |= UCR1_RXDMAEN | UCR1_ATDMAEN;
} else {
ucr1 |= UCR1_RRDYEN;
+ ucr2 |= UCR2_ATEN;
}
/* Write UCR2 first as it includes RXEN */
@@ -472,6 +473,7 @@ static void imx_stop_rx(struct uart_port *port)
ucr1 &= ~(UCR1_RXDMAEN | UCR1_ATDMAEN);
} else {
ucr1 &= ~UCR1_RRDYEN;
+ ucr2 &= ~UCR2_ATEN;
}
imx_uart_writel(sport, ucr1, UCR1);
@@ -1393,6 +1395,10 @@ static int imx_startup(struct uart_port *port)
ucr1 = imx_uart_readl(sport, UCR1);
ucr1 |= UCR1_RRDYEN;
imx_uart_writel(sport, ucr1, UCR1);
+
+ ucr2 = imx_uart_readl(sport, UCR2);
+ ucr2 |= UCR2_ATEN;
+ imx_uart_writel(sport, ucr2, UCR2);
}
spin_unlock_irqrestore(&sport->port.lock, flags);
@@ -1424,7 +1430,7 @@ static void imx_shutdown(struct uart_port *port)
spin_lock_irqsave(&sport->port.lock, flags);
ucr2 = imx_uart_readl(sport, UCR2);
- ucr2 &= ~UCR2_TXEN;
+ ucr2 &= ~(UCR2_TXEN | UCR2_ATEN);
imx_uart_writel(sport, ucr2, UCR2);
spin_unlock_irqrestore(&sport->port.lock, flags);
@@ -1613,13 +1619,14 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
imx_uart_writel(sport,
old_ucr1 & ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN),
UCR1);
+ old_ucr2 = imx_uart_readl(sport, UCR2);
+ imx_uart_writel(sport, old_ucr2 & ~UCR2_ATEN, UCR2);
while (!(imx_uart_readl(sport, USR2) & USR2_TXDC))
barrier();
/* then, disable everything */
- old_ucr2 = imx_uart_readl(sport, UCR2);
- imx_uart_writel(sport, old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN), UCR2);
+ imx_uart_writel(sport, old_ucr2 & ~(UCR2_TXEN | UCR2_RXEN | UCR2_ATEN), UCR2);
old_ucr2 &= (UCR2_TXEN | UCR2_RXEN | UCR2_ATEN);
/* custom-baudrate handling */
@@ -1750,12 +1757,14 @@ static int imx_poll_init(struct uart_port *port)
ucr1 &= ~(UCR1_TXMPTYEN | UCR1_RTSDEN | UCR1_RRDYEN);
ucr2 |= UCR2_RXEN;
+ ucr2 &= ~UCR2_ATEN;
imx_uart_writel(sport, ucr1, UCR1);
imx_uart_writel(sport, ucr2, UCR2);
/* now enable irqs */
imx_uart_writel(sport, ucr1 | UCR1_RRDYEN, UCR1);
+ imx_uart_writel(sport, ucr2 | UCR2_ATEN, UCR2);
spin_unlock_irqrestore(&sport->port.lock, flags);