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Sun, 6 Dec 2015 04:39:52 +0000 Received: from unknown-38-66.xilinx.com ([149.199.38.66] helo=xsj-pvapsmtp01) by xsj-pvapsmtpgw01 with esmtp (Exim 4.63) (envelope-from ) id 1a5R71-0001wg-Fy; Sat, 05 Dec 2015 20:39:51 -0800 Received: from [127.0.0.1] (helo=localhost) by xsj-pvapsmtp01 with smtp (Exim 4.63) (envelope-from ) id 1a5R71-0006eP-Ar; Sat, 05 Dec 2015 20:39:51 -0800 Received: from xsj-pvapsmtp01 (xsj-pvapsmtp01.xilinx.com [149.199.38.66]) by xsj-smtp-dlp1.xlnx.xilinx.com (8.13.8/8.13.1) with ESMTP id tB64dgEH015379; Sat, 5 Dec 2015 20:39:42 -0800 Received: from [172.19.74.49] (helo=localhost) by xsj-pvapsmtp01 with esmtp (Exim 4.63) (envelope-from ) id 1a5R6s-0006di-6n; Sat, 05 Dec 2015 20:39:42 -0800 From: Soren Brinkmann To: Greg Kroah-Hartman , Jiri Slaby Subject: [PATCH LINUX v4 10/13] tty: xuartps: Refactor IRQ handling Date: Sat, 5 Dec 2015 20:39:26 -0800 Message-ID: <1449376769-13369-11-git-send-email-soren.brinkmann@xilinx.com> X-Mailer: git-send-email 2.6.3.3.g9bb996a In-Reply-To: <1449376769-13369-1-git-send-email-soren.brinkmann@xilinx.com> References: <1449376769-13369-1-git-send-email-soren.brinkmann@xilinx.com> X-RCIS-Action: ALLOW X-TM-AS-Product-Ver: IMSS-7.1.0.1224-8.0.0.1202-21982.006 X-TM-AS-User-Approved-Sender: Yes;Yes X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:149.199.60.83; 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SRVR:CY1NAM02HT042; BCL:0; PCL:0; RULEID:; SRVR:CY1NAM02HT042; X-Forefront-PRVS: 0782EC617F X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Dec 2015 04:39:52.0646 (UTC) X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c; Ip=[149.199.60.83]; Helo=[xsj-pvapsmtpgw01] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1NAM02HT042 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20151205_204015_386299_38ED14A5 X-CRM114-Status: GOOD ( 12.08 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Moritz Fischer , Peter Hurley , Michal Simek , linux-kernel@vger.kernel.org, Soren Brinkmann , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 --- 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);