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Commit 373e882f authored by Soren Brinkmann's avatar Soren Brinkmann Committed by Greg Kroah-Hartman
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tty: xuartps: Refactor IRQ handling 



The system could deadlock handling RX IRQs when RX-related IRQ
conditions became true while the receiver was disabled. To avoid this,
enable/disable the RX/TX IRQs together with the receiver/transmitter.

Signed-off-by: default avatarSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 55861d11

drivers/tty/serial/xilinx_uartps.c

+11 −6
Original line number Diff line number Diff line
@@ -126,6 +126,10 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); 
#define CDNS_UART_IXR_RXEMPTY	0x00000002 /* RX FIFO empty interrupt. */

#define CDNS_UART_IXR_MASK	0x00001FFF /* Valid bit mask */



#define CDNS_UART_RX_IRQS	(CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | \

				 CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_RXTRIG | \

				 CDNS_UART_IXR_TOUT)



/* Goes in read_status_mask for break detection as the HW doesn't do it*/

#define CDNS_UART_IXR_BRK	0x80000000
@@ -272,6 +276,7 @@ static irqreturn_t cdns_uart_isr(int irq, void *dev_id) 
	 */

	isrstatus = readl(port->membase + CDNS_UART_ISR_OFFSET);



	if (isrstatus & CDNS_UART_RX_IRQS)

		cdns_uart_handle_rx(port, isrstatus);



	/* Dispatch an appropriate handler */
@@ -580,9 +585,12 @@ static void cdns_uart_stop_rx(struct uart_port *port) 
{

	unsigned int regval;



	/* Disable RX IRQs */

	writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR_OFFSET);



	/* Disable the receiver */

	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);

}
@@ -820,10 +828,7 @@ static int cdns_uart_startup(struct uart_port *port) 
	}



	/* Set the Interrupt Registers with desired interrupts */

	writel(CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_PARITY |

		CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN |

		CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT,

		port->membase + CDNS_UART_IER_OFFSET);

	writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER_OFFSET);



	return 0;

}