From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933471AbcALBmP (ORCPT ); Mon, 11 Jan 2016 20:42:15 -0500 Received: from mail-cys01nam02on0050.outbound.protection.outlook.com ([104.47.37.50]:43447 "EHLO NAM02-CY1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761810AbcALBmB (ORCPT ); Mon, 11 Jan 2016 20:42:01 -0500 Authentication-Results: spf=pass (sender IP is 149.199.60.100) smtp.mailfrom=xilinx.com; hurleysoftware.com; dkim=none (message not signed) header.d=none;hurleysoftware.com; dmarc=bestguesspass action=none header.from=xilinx.com; From: Soren Brinkmann To: Greg Kroah-Hartman , Jiri Slaby CC: Michal Simek , , , , "Peter Hurley" , Soren Brinkmann Subject: [PATCH LINUX 2/6] tty: xuartps: Refactor IRQ handling Date: Mon, 11 Jan 2016 17:41:37 -0800 Message-ID: <1452562901-17848-3-git-send-email-soren.brinkmann@xilinx.com> X-Mailer: git-send-email 2.7.0.3.g497ea1e In-Reply-To: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> References: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> X-RCIS-Action: ALLOW X-TM-AS-Product-Ver: IMSS-7.1.0.1224-8.0.0.1202-22058.006 X-TM-AS-User-Approved-Sender: Yes;Yes X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:149.199.60.100;CTRY:US;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10009020)(6009001)(2980300002)(438002)(189002)(199003)(63266004)(92566002)(106466001)(2906002)(5001770100001)(36386004)(5003940100001)(50226001)(48376002)(1220700001)(4001430100002)(76506005)(81156007)(50466002)(229853001)(50986999)(57986006)(77096005)(586003)(1096002)(36756003)(19580405001)(5001960100002)(11100500001)(19580395003)(4326007)(189998001)(87936001)(47776003)(33646002)(2950100001)(5008740100001)(107886002)(6806005)(86362001)(76176999)(107986001)(217873001)(5001870100001);DIR:OUT;SFP:1101;SCL:1;SRVR:BL2NAM02HT187;H:xsj-pvapsmtpgw02;FPR:;SPF:Pass;PTR:xapps1.xilinx.com,unknown-60-100.xilinx.com;MX:1;A:1;LANG:en; MIME-Version: 1.0 Content-Type: text/plain X-MS-Office365-Filtering-Correlation-Id: 5fbbfa13-2610-42d5-2418-08d31af18f1c X-Exchange-Antispam-Report-Test: UriScan:;BCL:0;PCL:0;RULEID:(8251501002);SRVR:BL2NAM02HT187;UriScan:(192813158149592); X-Microsoft-Antispam-PRVS: <0b6ccc6585714631ae99d5a9235cdd1a@BL2NAM02HT187.eop-nam02.prod.protection.outlook.com> X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(5005006)(8121501046)(13018025)(520078)(13015025)(13017025)(10201501046)(3002001);SRVR:BL2NAM02HT187;BCL:0;PCL:0;RULEID:;SRVR:BL2NAM02HT187; X-Forefront-PRVS: 081904387B X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Jan 2016 01:41:57.7895 (UTC) X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.60.100];Helo=[xsj-pvapsmtpgw02] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL2NAM02HT187 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 5da1c51e9e40..a0039cbcf812 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 @@ -272,7 +276,8 @@ 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 +585,12 @@ 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); } @@ -820,10 +828,7 @@ static int cdns_uart_startup(struct uart_port *port) } /* 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); return 0; } -- 2.7.0.3.g497ea1e From mboxrd@z Thu Jan 1 00:00:00 1970 From: Soren Brinkmann Subject: [PATCH LINUX 2/6] tty: xuartps: Refactor IRQ handling Date: Mon, 11 Jan 2016 17:41:37 -0800 Message-ID: <1452562901-17848-3-git-send-email-soren.brinkmann@xilinx.com> References: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> Sender: linux-kernel-owner@vger.kernel.org To: Greg Kroah-Hartman , Jiri Slaby Cc: Michal Simek , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Peter Hurley , Soren Brinkmann List-Id: linux-serial@vger.kernel.org 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 | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 5da1c51e9e40..a0039cbcf812 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 @@ -272,7 +276,8 @@ 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 +585,12 @@ 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); } @@ -820,10 +828,7 @@ static int cdns_uart_startup(struct uart_port *port) } /* 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); return 0; } -- 2.7.0.3.g497ea1e From mboxrd@z Thu Jan 1 00:00:00 1970 From: soren.brinkmann@xilinx.com (Soren Brinkmann) Date: Mon, 11 Jan 2016 17:41:37 -0800 Subject: [PATCH LINUX 2/6] tty: xuartps: Refactor IRQ handling In-Reply-To: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> References: <1452562901-17848-1-git-send-email-soren.brinkmann@xilinx.com> Message-ID: <1452562901-17848-3-git-send-email-soren.brinkmann@xilinx.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 5da1c51e9e40..a0039cbcf812 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 @@ -272,7 +276,8 @@ 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 +585,12 @@ 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); } @@ -820,10 +828,7 @@ static int cdns_uart_startup(struct uart_port *port) } /* 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); return 0; } -- 2.7.0.3.g497ea1e