Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756242Ab3HAQtR (ORCPT ); Thu, 1 Aug 2013 12:49:17 -0400 Received: from us01smtp3.synopsys.com ([198.182.44.81]:59417 "EHLO hermes.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754046Ab3HAQtP (ORCPT ); Thu, 1 Aug 2013 12:49:15 -0400 From: Vineet Gupta To: CC: Mischa Jonker , Vineet Gupta , Greg Kroah-Hartman , Jiri Slaby , Subject: [PATCH 1/2] serial/arc-uart: Handle Rx Error Interrupts w/o any data Date: Thu, 1 Aug 2013 21:49:19 -0700 Message-ID: <1375418960-21491-1-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 1.8.1.2 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.9.21.33] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2877 Lines: 91 Currently, Rx error handling only triggers if there is some Rx data. Fix that by checking for error - before the data handling. Reported-by: Mischa Jonker Tested-by: Mischa Jonker Signed-off-by: Vineet Gupta Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- drivers/tty/serial/arc_uart.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c index 22f280a..10f981b 100644 --- a/drivers/tty/serial/arc_uart.c +++ b/drivers/tty/serial/arc_uart.c @@ -209,9 +209,9 @@ static void arc_serial_start_tx(struct uart_port *port) arc_serial_tx_chars(uart); } -static void arc_serial_rx_chars(struct arc_uart_port *uart) +static void arc_serial_rx_chars(struct arc_uart_port *uart, unsigned int status) { - unsigned int status, ch, flg = 0; + unsigned int ch, flg = 0; /* * UART has 4 deep RX-FIFO. Driver's recongnition of this fact @@ -222,11 +222,11 @@ static void arc_serial_rx_chars(struct arc_uart_port *uart) * before RX-EMPTY=0, implies some sort of buffering going on in the * controller, which is indeed the Rx-FIFO. */ - while (!((status = UART_GET_STATUS(uart)) & RXEMPTY)) { - - ch = UART_GET_DATA(uart); - uart->port.icount.rx++; - + do { + /* + * This could be an Rx Intr for err (no data), + * so check err and clear that Intr first + */ if (unlikely(status & (RXOERR | RXFERR))) { if (status & RXOERR) { uart->port.icount.overrun++; @@ -242,6 +242,12 @@ static void arc_serial_rx_chars(struct arc_uart_port *uart) } else flg = TTY_NORMAL; + if (status & RXEMPTY) + continue; + + ch = UART_GET_DATA(uart); + uart->port.icount.rx++; + if (unlikely(uart_handle_sysrq_char(&uart->port, ch))) goto done; @@ -249,7 +255,7 @@ static void arc_serial_rx_chars(struct arc_uart_port *uart) done: tty_flip_buffer_push(&uart->port.state->port); - } + } while (!((status = UART_GET_STATUS(uart)) & RXEMPTY)); } /* @@ -292,11 +298,11 @@ static irqreturn_t arc_serial_isr(int irq, void *dev_id) * notifications from the UART Controller. * To demultiplex between the two, we check the relevant bits */ - if ((status & RXIENB) && !(status & RXEMPTY)) { + if (status & RXIENB) { /* already in ISR, no need of xx_irqsave */ spin_lock(&uart->port.lock); - arc_serial_rx_chars(uart); + arc_serial_rx_chars(uart, status); spin_unlock(&uart->port.lock); } -- 1.8.1.2 -- 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/