[PATCH v2 3/7] tty: xuartps: Refactor read-modify-writes

Soren Brinkmann
2014-03-10T21:40:06Z

A lot of read-modify-write sequences used a one-line statement which
nests a readl() within a writel(). Convert this into code sequences that
make the three steps more obvious.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
drivers/tty/serial/xilinx_uartps.c | 52 ++++++++++++++++++--------------------
1 file changed, 24 insertions(+), 28 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index b00060052316..a4bd6242e72d 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -437,9 +437,9 @@ static int xuartps_clk_notifier_cb(struct notifier_block *nb,
spin_lock_irqsave(&xuartps->port->lock, flags);

/* Disable the TX and RX to set baud rate */
- xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
- (XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS),
- XUARTPS_CR_OFFSET);
+ ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
+ ctrl_reg |= XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

spin_unlock_irqrestore(&xuartps->port->lock, flags);

@@ -464,9 +464,9 @@ static int xuartps_clk_notifier_cb(struct notifier_block *nb,
spin_lock_irqsave(&xuartps->port->lock, flags);

/* Set TX/RX Reset */
- xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
- (XUARTPS_CR_TXRST | XUARTPS_CR_RXRST),
- XUARTPS_CR_OFFSET);
+ ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
+ ctrl_reg |= XUARTPS_CR_TXRST | XUARTPS_CR_RXRST;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

while (xuartps_readl(XUARTPS_CR_OFFSET) &
(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST))
@@ -479,10 +479,9 @@ static int xuartps_clk_notifier_cb(struct notifier_block *nb,
*/
xuartps_writel(rx_timeout, XUARTPS_RXTOUT_OFFSET);
ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
- xuartps_writel(
- (ctrl_reg & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS)) |
- (XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN),
- XUARTPS_CR_OFFSET);
+ ctrl_reg &= ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS);
+ ctrl_reg |= XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

spin_unlock_irqrestore(&xuartps->port->lock, flags);

@@ -631,9 +630,9 @@ static void xuartps_set_termios(struct uart_port *port,
}

/* Disable the TX and RX to set baud rate */
- xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
- (XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS),
- XUARTPS_CR_OFFSET);
+ ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
+ ctrl_reg |= XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

/*
* Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk
@@ -651,20 +650,18 @@ static void xuartps_set_termios(struct uart_port *port,
uart_update_timeout(port, termios->c_cflag, baud);

/* Set TX/RX Reset */
- xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
- (XUARTPS_CR_TXRST | XUARTPS_CR_RXRST),
- XUARTPS_CR_OFFSET);
-
ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
+ ctrl_reg |= XUARTPS_CR_TXRST | XUARTPS_CR_RXRST;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

/*
* Clear the RX disable and TX disable bits and then set the TX enable
* bit and RX enable bit to enable the transmitter and receiver.
*/
- xuartps_writel(
- (ctrl_reg & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS))
- | (XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN),
- XUARTPS_CR_OFFSET);
+ ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
+ ctrl_reg &= ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS);
+ ctrl_reg |= XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

xuartps_writel(rx_timeout, XUARTPS_RXTOUT_OFFSET);

@@ -1245,9 +1242,9 @@ static int xuartps_resume(struct device *device)
spin_lock_irqsave(&port->lock, flags);

/* Set TX/RX Reset */
- xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
- (XUARTPS_CR_TXRST | XUARTPS_CR_RXRST),
- XUARTPS_CR_OFFSET);
+ ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
+ ctrl_reg |= XUARTPS_CR_TXRST | XUARTPS_CR_RXRST;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);
while (xuartps_readl(XUARTPS_CR_OFFSET) &
(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST))
cpu_relax();
@@ -1256,10 +1253,9 @@ static int xuartps_resume(struct device *device)
xuartps_writel(rx_timeout, XUARTPS_RXTOUT_OFFSET);
/* Enable Tx/Rx */
ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
- xuartps_writel(
- (ctrl_reg & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS)) |
- (XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN),
- XUARTPS_CR_OFFSET);
+ ctrl_reg &= ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS);
+ ctrl_reg |= XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN;
+ xuartps_writel(ctrl_reg, XUARTPS_CR_OFFSET);

spin_unlock_irqrestore(&port->lock, flags);
} else {
--
1.9.0.1.g4196000