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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id u12sm927912pfm.165.2020.02.10.09.18.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Feb 2020 09:18:29 -0800 (PST) From: Mathieu Poirier To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: [stable 4.19][PATCH 1/3] serial: uartps: Add a timeout to the tx empty wait Date: Mon, 10 Feb 2020 10:18:25 -0700 Message-Id: <20200210171827.29693-2-mathieu.poirier@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200210171827.29693-1-mathieu.poirier@linaro.org> References: <20200210171827.29693-1-mathieu.poirier@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Shubhrajyoti Datta commit 277375b864e8147975b064b513f491e2a910e66a upstream In case the cable is not connected then the target gets into an infinite wait for tx empty. Add a timeout to the tx empty wait. Reported-by: Jean-Francois Dagenais Signed-off-by: Shubhrajyoti Datta Signed-off-by: Greg Kroah-Hartman Cc: stable # 4.19 Signed-off-by: Mathieu Poirier --- drivers/tty/serial/xilinx_uartps.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 66d49d511885..7cbee19ea93d 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -26,6 +26,7 @@ #include #include #include +#include #define CDNS_UART_TTY_NAME "ttyPS" #define CDNS_UART_NAME "xuartps" @@ -34,6 +35,7 @@ #define CDNS_UART_NR_PORTS 2 #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ #define CDNS_UART_REGISTER_SPACE 0x1000 +#define TX_TIMEOUT 500000 /* Rx Trigger level */ static int rx_trigger_level = 56; @@ -681,16 +683,20 @@ static void cdns_uart_set_termios(struct uart_port *port, unsigned int cval = 0; unsigned int baud, minbaud, maxbaud; unsigned long flags; - unsigned int ctrl_reg, mode_reg; + unsigned int ctrl_reg, mode_reg, val; + int err; spin_lock_irqsave(&port->lock, flags); /* Wait for the transmit FIFO to empty before making changes */ if (!(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_TX_DIS)) { - while (!(readl(port->membase + CDNS_UART_SR) & - CDNS_UART_SR_TXEMPTY)) { - cpu_relax(); + err = readl_poll_timeout(port->membase + CDNS_UART_SR, + val, (val & CDNS_UART_SR_TXEMPTY), + 1000, TX_TIMEOUT); + if (err) { + dev_err(port->dev, "timed out waiting for tx empty"); + return; } } -- 2.20.1