[PATCH 9/9] tty: xuartps: Only handle RX IRQs when RX is enabled

From: Soren Brinkmann
Date: Tue Nov 03 2015 - 19:21:34 EST


Ignore RX-related interrupts if RX is not enabled.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
---
drivers/tty/serial/xilinx_uartps.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 149868cc003c..76a060a68934 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -161,6 +161,7 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
* @pclk: APB clock
* @baud: Current baud rate
* @clk_rate_change_nb: Notifier block for clock changes
+ * @flags: Driver flags
*/
struct cdns_uart {
struct uart_port *port;
@@ -168,7 +169,11 @@ struct cdns_uart {
struct clk *pclk;
unsigned int baud;
struct notifier_block clk_rate_change_nb;
+ u32 flags;
};
+
+#define CDNS_FLAG_RX_ENABLED BIT(0)
+
#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
clk_rate_change_nb);

@@ -262,6 +267,7 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
+ struct cdns_uart *cdns_uart = port->private_data;
unsigned long flags;
unsigned int isrstatus, numbytes;

@@ -272,7 +278,8 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
*/
isrstatus = readl(port->membase + CDNS_UART_ISR_OFFSET);

- cdns_uart_handle_rx(port, isrstatus);
+ if (cdns_uart->flags & CDNS_FLAG_RX_ENABLED)
+ cdns_uart_handle_rx(port, isrstatus);

/* Dispatch an appropriate handler */
if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {
@@ -576,11 +583,13 @@ static void cdns_uart_stop_tx(struct uart_port *port)
static void cdns_uart_stop_rx(struct uart_port *port)
{
unsigned int regval;
+ struct cdns_uart *cdns_uart = port->private_data;

regval = readl(port->membase + CDNS_UART_CR_OFFSET);
regval |= CDNS_UART_CR_RX_DIS;
/* Disable the receiver */
writel(regval, port->membase + CDNS_UART_CR_OFFSET);
+ cdns_uart->flags &= ~CDNS_FLAG_RX_ENABLED;
}

/**
@@ -761,6 +770,7 @@ static int cdns_uart_startup(struct uart_port *port)
{
unsigned long flags;
unsigned int retval = 0, status = 0;
+ struct cdns_uart *cdns_uart = port->private_data;

retval = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME,
(void *)port);
@@ -787,6 +797,7 @@ static int cdns_uart_startup(struct uart_port *port)
status &= CDNS_UART_CR_RX_DIS;
status |= CDNS_UART_CR_RX_EN;
writel(status, port->membase + CDNS_UART_CR_OFFSET);
+ cdns_uart->flags |= CDNS_FLAG_RX_ENABLED;

/* Set the Mode Register with normal mode,8 data bits,1 stop bit,
* no parity.
@@ -830,6 +841,7 @@ static void cdns_uart_shutdown(struct uart_port *port)
{
int status;
unsigned long flags;
+ struct cdns_uart *cdns_uart = port->private_data;

spin_lock_irqsave(&port->lock, flags);

@@ -841,6 +853,7 @@ static void cdns_uart_shutdown(struct uart_port *port)
/* Disable the TX and RX */
writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
port->membase + CDNS_UART_CR_OFFSET);
+ cdns_uart->flags &= ~CDNS_FLAG_RX_ENABLED;

spin_unlock_irqrestore(&port->lock, flags);

--
2.6.2.3.ga463a5b

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