From mboxrd@z Thu Jan 1 00:00:00 1970 From: Soren Brinkmann Subject: [PATCH LINUX 2/6] tty: xuartps: Refactor IRQ handling Date: Mon, 11 Jan 2016 17:41:37 -0800 Message-ID: <1452562901-17848-3-git-send-email-soren.brinkmann@xilinx.com> References: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> Sender: linux-kernel-owner@vger.kernel.org To: Greg Kroah-Hartman , Jiri Slaby Cc: Michal Simek , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Peter Hurley , Soren Brinkmann List-Id: linux-serial@vger.kernel.org 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: Soren Brinkmann --- drivers/tty/serial/xilinx_uartps.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 5da1c51e9e40..a0039cbcf812 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -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 @@ -272,7 +276,8 @@ 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 (isrstatus & CDNS_UART_RX_IRQS) + cdns_uart_handle_rx(port, isrstatus); /* Dispatch an appropriate handler */ if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) { @@ -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; } -- 2.7.0.3.g497ea1e