Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753772AbbLERnU (ORCPT ); Sat, 5 Dec 2015 12:43:20 -0500 Received: from mail-ig0-f172.google.com ([209.85.213.172]:33202 "EHLO mail-ig0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbbLERnR (ORCPT ); Sat, 5 Dec 2015 12:43:17 -0500 Subject: Re: [PATCH LINUX v3 09/10] tty: xuartps: Only handle RX IRQs when RX is enabled To: Soren Brinkmann , Greg Kroah-Hartman , Jiri Slaby References: <1448161172-19717-1-git-send-email-soren.brinkmann@xilinx.com> <1448161172-19717-10-git-send-email-soren.brinkmann@xilinx.com> Cc: Michal Simek , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org From: Peter Hurley Message-ID: <56632231.6000000@hurleysoftware.com> Date: Sat, 5 Dec 2015 12:43:13 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <1448161172-19717-10-git-send-email-soren.brinkmann@xilinx.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3925 Lines: 112 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 > Signed-off-by: Soren Brinkmann > --- > 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); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/