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[PATCH LINUX v3 07/10] tty: xuartps: Acquire port lock for shutdown

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Shutting down the UART port can happen while console operations are in
progress. Holding the port lock serializes these operations and avoids
the UART HW to be disabled in the middle of console prints.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
 drivers/tty/serial/xilinx_uartps.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index ab3995d00973..f3ac69387b0a 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -826,6 +826,9 @@ static int cdns_uart_startup(struct uart_port *port)
 static void cdns_uart_shutdown(struct uart_port *port)
 {
 	int status;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
 
 	/* Disable interrupts */
 	status = readl(port->membase + CDNS_UART_IMR_OFFSET);
@@ -835,6 +838,9 @@ 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);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
 	free_irq(port->irq, port);
 }
 
-- 
2.6.3.3.g9bb996a

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Thread

[PATCH LINUX v3 00/10] tty: xuartps: Fix lock ups Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:00 +0100
  [PATCH LINUX v3 07/10] tty: xuartps: Acquire port lock for shutdown Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:00 +0100
  [PATCH LINUX v3 01/10] tty: xuartps: Beautify read-modify writes Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:10 +0100
  [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX is enabled Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:10 +0100
  [PATCH LINUX v3 03/10] tty: xuartps: Don't consider circular buffer when enabling transmitter Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:10 +0100
  [PATCH LINUX v3 04/10] tty: xuartps: Clear interrupt status register in shutdown Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:10 +0100
  [PATCH LINUX v3 05/10] tty: xuartps: Improve startup function Soren Brinkmann <soren.brinkmann@xilinx.com> - 2015-11-22 04:10 +0100

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