From patchwork Wed Apr 17 09:03:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= X-Patchwork-Id: 13633050 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CDF77C4345F for ; Wed, 17 Apr 2024 09:05:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=lLPmQ2UcuT+56/K3CIUyp1sc7sbADuUpFQ0VGuTbF/M=; b=v++Wb32X5zejqn rT9hUoeGmfsIgfA6m4e/T55Q1wHIkyF7iMVqjRdUJiu8HB39eOkcUEUrnsMGN9M9dyaXx40w0ys+4 cv9R7gEFj5G70a7cYQ6Ju79j9GyshWd3iGP7CQkT0kTREPyoBg2cOjekUIjzuVxFIVmOFZDHYKNb5 UKYrX5gVWyk43+4Y0ijMHfYOdVt9BHGFlVdT8U8rM+YfCRzJpA/jgcXXyf7PCIuDaVQkZdxcTIiHf bgMUkLgt9C+FzFRlpgaorleS7UbnHwYS8xQ+UO+9BG0kdGdi8ztgjkBMt889DtiTdTlRn3PNJmLqV 7mZ1P7iGZimPud3Jif+A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rx1Dh-0000000FKKR-0xZt; Wed, 17 Apr 2024 09:04:45 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rx1DV-0000000FKIH-3LGl for linux-arm-kernel@lists.infradead.org; Wed, 17 Apr 2024 09:04:37 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rx1DD-0004om-PA; Wed, 17 Apr 2024 11:04:15 +0200 Received: from [2a0a:edc0:0:900:1d::77] (helo=ptz.office.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rx1DB-00ClGH-Va; Wed, 17 Apr 2024 11:04:13 +0200 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1rx1DB-002hM0-2s; Wed, 17 Apr 2024 11:04:13 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Greg Kroah-Hartman , Jiri Slaby , Maxime Coquelin Cc: Andy Shevchenko , kernel@pengutronix.de, Alexandre Torgue , Valentin Caron , Lino Sanfilippo , Thomas Gleixner , Erwan Le Ray , Peter Hurley , Vladimir Zapolskiy , linux-serial@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org Subject: [PATCH 1/2] serial: stm32: Return IRQ_NONE in the ISR if no handling happend Date: Wed, 17 Apr 2024 11:03:27 +0200 Message-ID: <5f92603d0dfd8a5b8014b2b10a902d91e0bb881f.1713344161.git.u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2801; i=u.kleine-koenig@pengutronix.de; h=from:subject:message-id; bh=jz6AwetzGMEFARbI09ryhM79Cpp+5tcl5jRCkdSNET4=; b=owEBbQGS/pANAwAKAY+A+1h9Ev5OAcsmYgBmH5BgGqqxohanUIs9ldgC3LKg8mUkUOW5enTWc nNTWDud12aJATMEAAEKAB0WIQQ/gaxpOnoeWYmt/tOPgPtYfRL+TgUCZh+QYAAKCRCPgPtYfRL+ Tn61B/wLkA8sd9+OtnXiV7D2HuC8Y3rIY+yd3AqI83nlYd01ePT6tnPUuatJgNSOV1d5bvjLaJm Ww7/8w3VW765fy5wfteHQLWausCQyAutmj+F6PnsX/OwEPLE4g4nxolcav8z+bREIaOtvDzyxy7 a/pNV+1rHNPJdvh/WU7yxwYahJbXPp/8CE1ULP4jU1fSzERqTXO9Ezig1qg5F1j4DDjhP4XxX57 ZBQ6Vr0E385ebYDSFYLSHM95N1xNfBpWjXb3Rs575gZMYo/3U+2F8eiw0j4QvXFfEHIOaAOBqGy pNB5jT61gSQrg8z709OwewOeRD9EqDtj7zvOHIteSZzbR+9u X-Developer-Key: i=u.kleine-koenig@pengutronix.de; a=openpgp; fpr=0D2511F322BFAB1C1580266BE2DCDD9132669BD6 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-arm-kernel@lists.infradead.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240417_020433_856945_1C2B041A X-CRM114-Status: GOOD ( 15.38 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org If there is a stuck irq that the handler doesn't address, returning IRQ_HANDLED unconditionally makes it impossible for the irq core to detect the problem and disable the irq. So only return IRQ_HANDLED if an event was handled. A stuck irq is still problematic, but with this change at least it only makes the UART nonfunctional instead of occupying the (usually only) CPU by 100% and so stall the whole machine. Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König --- drivers/tty/serial/stm32-usart.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 8c66abcfe6ca..2bea1d7c9858 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -849,6 +849,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; u32 sr; unsigned int size; + irqreturn_t ret = IRQ_NONE; sr = readl_relaxed(port->membase + ofs->isr); @@ -857,11 +858,14 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) (sr & USART_SR_TC)) { stm32_usart_tc_interrupt_disable(port); stm32_usart_rs485_rts_disable(port); + ret = IRQ_HANDLED; } - if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) + if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) { writel_relaxed(USART_ICR_RTOCF, port->membase + ofs->icr); + ret = IRQ_HANDLED; + } if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) { /* Clear wake up flag and disable wake up interrupt */ @@ -870,6 +874,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) pm_wakeup_event(tport->tty->dev, 0); + ret = IRQ_HANDLED; } /* @@ -884,6 +889,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; } } @@ -891,6 +897,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) uart_port_lock(port); stm32_usart_transmit_chars(port); uart_port_unlock(port); + ret = IRQ_HANDLED; } /* Receiver timeout irq for DMA RX */ @@ -900,9 +907,10 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; } - return IRQ_HANDLED; + return ret; } static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)