From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA0ABFA372C for ; Fri, 8 Nov 2019 19:09:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A10C520673 for ; Fri, 8 Nov 2019 19:09:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573240169; bh=8qsdJ47uQfrB7A5Ki3q409/MXPdNkeR+L2SHHSL7maA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PyktFq5SUKrUeAp8Nqjq08PZ+L9fMUlMG0jWzXl0it5OP/zOi8aw7tkWOAiGIiY3e V7V7DfxAc5+AHny8KXvTrm7sJf5Wo7L741dRSl8HtfY6UUEKzZsa9ZmoapgfFvAIwD DNfEtj128SgxVDzQ1xXxT481AzVDY0sxfseXAI1c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390852AbfKHTJ2 (ORCPT ); Fri, 8 Nov 2019 14:09:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:41050 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391792AbfKHTJY (ORCPT ); Fri, 8 Nov 2019 14:09:24 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 947CA20673; Fri, 8 Nov 2019 19:09:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573240163; bh=8qsdJ47uQfrB7A5Ki3q409/MXPdNkeR+L2SHHSL7maA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i9+RQI+2o5cwuIuafAkfcbO3RrnUQGGCbb/tPfFCO13c84GDB+8KHe09ifFM01B5o YB+JznuX+/bdV9yTvQQNdO1bnjZlZhkwKwQ9LjQFVgcFdXJotAb/5ns01gfjamSpUX l/cm5LrFH2zt+tF+F//nP/Q9BSa6n7aExYzeDrbg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Fabrice Gasnier , Pierre-Yves MORDRET , Wolfram Sang , Sasha Levin Subject: [PATCH 5.3 073/140] i2c: stm32f7: fix a race in slave mode with arbitration loss irq Date: Fri, 8 Nov 2019 19:50:01 +0100 Message-Id: <20191108174909.738013388@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191108174900.189064908@linuxfoundation.org> References: <20191108174900.189064908@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Fabrice Gasnier [ Upstream commit 6d6b0d0d5afc8c4c84b08261260ba11dfa5206f2 ] When in slave mode, an arbitration loss (ARLO) may be detected before the slave had a chance to detect the stop condition (STOPF in ISR). This is seen when two master + slave adapters switch their roles. It provokes the i2c bus to be stuck, busy as SCL line is stretched. - the I2C_SLAVE_STOP event is never generated due to STOPF flag is set but don't generate an irq (race with ARLO irq, STOPIE is masked). STOPF flag remains set until next master xfer (e.g. when STOPIE irq get unmasked). In this case, completion is generated too early: immediately upon new transfer request (then it doesn't send all data). - Some data get stuck in TXDR register. As a consequence, the controller stretches the SCL line: the bus gets busy until a future master transfer triggers the bus busy / recovery mechanism (this can take time... and may never happen at all) So choice is to let the STOPF being detected by the slave isr handler, to properly handle this stop condition. E.g. don't mask IRQs in error handler, when the slave is running. Fixes: 60d609f30de2 ("i2c: i2c-stm32f7: Add slave support") Signed-off-by: Fabrice Gasnier Reviewed-by: Pierre-Yves MORDRET Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-stm32f7.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c index 0af9219e45f79..82705deef7bff 100644 --- a/drivers/i2c/busses/i2c-stm32f7.c +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -1503,7 +1503,7 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) void __iomem *base = i2c_dev->base; struct device *dev = i2c_dev->dev; struct stm32_i2c_dma *dma = i2c_dev->dma; - u32 mask, status; + u32 status; status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR); @@ -1528,12 +1528,15 @@ static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data) f7_msg->result = -EINVAL; } - /* Disable interrupts */ - if (stm32f7_i2c_is_slave_registered(i2c_dev)) - mask = STM32F7_I2C_XFER_IRQ_MASK; - else - mask = STM32F7_I2C_ALL_IRQ_MASK; - stm32f7_i2c_disable_irq(i2c_dev, mask); + if (!i2c_dev->slave_running) { + u32 mask; + /* Disable interrupts */ + if (stm32f7_i2c_is_slave_registered(i2c_dev)) + mask = STM32F7_I2C_XFER_IRQ_MASK; + else + mask = STM32F7_I2C_ALL_IRQ_MASK; + stm32f7_i2c_disable_irq(i2c_dev, mask); + } /* Disable dma */ if (i2c_dev->use_dma) { -- 2.20.1