Re: [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX is enabled
From: Peter Hurley <hidden>
Date: 2015-12-05 17:43:20
Also in:
linux-arm-kernel, lkml
On 11/21/2015 09:59 PM, Soren Brinkmann wrote:
Ignore RX-related interrupts if RX is not enabled.
This doesn't look like a safe approach; fast-forward a couple of years and some is trying to add some feature but can't figure out why no data is arriving... What is this trying to solve? Regards, Peter Hurley
quoted hunk ↗ jump to hunk
Signed-off-by: Soren Brinkmann <redacted> --- drivers/tty/serial/xilinx_uartps.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index db9e23eaf300..3a1e508926c1 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c@@ -161,6 +161,7 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); * @pclk: APB clock * @baud: Current baud rate * @clk_rate_change_nb: Notifier block for clock changes + * @flags: Driver flags */ struct cdns_uart { struct uart_port *port;@@ -168,7 +169,11 @@ struct cdns_uart { struct clk *pclk; unsigned int baud; struct notifier_block clk_rate_change_nb; + u32 flags; }; + +#define CDNS_FLAG_RX_ENABLED BIT(0) + #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ clk_rate_change_nb);@@ -262,6 +267,7 @@ static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus) static irqreturn_t cdns_uart_isr(int irq, void *dev_id) { struct uart_port *port = (struct uart_port *)dev_id; + struct cdns_uart *cdns_uart = port->private_data; unsigned long flags; unsigned int isrstatus, numbytes;@@ -272,7 +278,8 @@ 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 (cdns_uart->flags & CDNS_FLAG_RX_ENABLED) + cdns_uart_handle_rx(port, isrstatus); /* Dispatch an appropriate handler */ if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY) {@@ -579,11 +586,13 @@ static void cdns_uart_stop_tx(struct uart_port *port) static void cdns_uart_stop_rx(struct uart_port *port) { unsigned int regval; + struct cdns_uart *cdns_uart = port->private_data; 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); + cdns_uart->flags &= ~CDNS_FLAG_RX_ENABLED; } /**@@ -764,6 +773,7 @@ static int cdns_uart_startup(struct uart_port *port) { unsigned long flags; unsigned int retval = 0, status = 0; + struct cdns_uart *cdns_uart = port->private_data; retval = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, (void *)port);@@ -790,6 +800,7 @@ static int cdns_uart_startup(struct uart_port *port) status &= CDNS_UART_CR_RX_DIS; status |= CDNS_UART_CR_RX_EN; writel(status, port->membase + CDNS_UART_CR_OFFSET); + cdns_uart->flags |= CDNS_FLAG_RX_ENABLED; /* Set the Mode Register with normal mode,8 data bits,1 stop bit, * no parity.@@ -833,6 +844,7 @@ static void cdns_uart_shutdown(struct uart_port *port) { int status; unsigned long flags; + struct cdns_uart *cdns_uart = port->private_data; spin_lock_irqsave(&port->lock, flags);@@ -844,6 +856,7 @@ 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); + cdns_uart->flags &= ~CDNS_FLAG_RX_ENABLED; spin_unlock_irqrestore(&port->lock, flags);