[PATCH LINUX v4 10/13] tty: xuartps: Refactor IRQ handling
From: Soren Brinkmann <hidden>
Date: 2015-12-06 04:40:32
Also in:
linux-serial, lkml
Subsystem:
the rest, tty layer and serial drivers · Maintainers:
Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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 <redacted> --- drivers/tty/serial/xilinx_uartps.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 3780d1cf207e..1229bb3a275e 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
@@ -169,6 +173,7 @@ struct cdns_uart { unsigned int baud; struct notifier_block clk_rate_change_nb; }; + #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ clk_rate_change_nb);
@@ -272,7 +277,8 @@ 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 +586,12 @@ 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); }
@@ -810,10 +819,7 @@ static int cdns_uart_startup(struct uart_port *port) port->membase + CDNS_UART_ISR_OFFSET); /* 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); spin_unlock_irqrestore(&port->lock, flags);
--
2.6.3.3.g9bb996a