Instead of disabling the IRQ, use the spin lock to serialize accesses to
the HW. This protects the driver from interference of non-IRQ callbacks
with each other and makes the driver more consistent in its
serialization method.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
---
drivers/tty/serial/xilinx_uartps.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 50d4082d2354..dc1987f3dc0a 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -947,10 +947,9 @@ static int cdns_uart_poll_get_char(struct uart_port *port)
{
u32 imr;
int c;
+ unsigned long flags;
- /* Disable all interrupts */
- imr = readl(port->membase + CDNS_UART_IMR_OFFSET);
- writel(imr, port->membase + CDNS_UART_IDR_OFFSET);
+ spin_lock_irqsave(&port->lock, flags);
/* Check if FIFO is empty */
if (readl(port->membase + CDNS_UART_SR_OFFSET) & CDNS_UART_SR_RXEMPTY)
@@ -959,8 +958,7 @@ static int cdns_uart_poll_get_char(struct uart_port *port)
c = (unsigned char) readl(
port->membase + CDNS_UART_FIFO_OFFSET);
- /* Enable interrupts */
- writel(imr, port->membase + CDNS_UART_IER_OFFSET);
+ spin_unlock_irqrestore(&port->lock, flags);
return c;
}
@@ -968,10 +966,9 @@ static int cdns_uart_poll_get_char(struct uart_port *port)
static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c)
{
u32 imr;
+ unsigned long flags;
- /* Disable all interrupts */
- imr = readl(port->membase + CDNS_UART_IMR_OFFSET);
- writel(imr, port->membase + CDNS_UART_IDR_OFFSET);
+ spin_lock_irqsave(&port->lock, flags);
/* Wait until FIFO is empty */
while (!(readl(port->membase + CDNS_UART_SR_OFFSET) &
@@ -986,8 +983,7 @@ static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c)
CDNS_UART_SR_TXEMPTY))
cpu_relax();
- /* Enable interrupts */
- writel(imr, port->membase + CDNS_UART_IER_OFFSET);
+ spin_unlock_irqrestore(&port->lock, flags);
return;
}
--
2.6.2.3.ga463a5b
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