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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 4A372CA9EC5 for ; Wed, 30 Oct 2019 15:55:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1775121906 for ; Wed, 30 Oct 2019 15:55:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572450947; bh=ajrQFUpHfoZrFxmZ57IP0Y32djqaiWekFynq+8+EYS8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lAjH3oGIhdh92Ba/PBUc1yS2D6fwzxM+3AJkx26Q08mVDidprQTyS7bMOpWOc3vPt 6nPMAgTRHgXEuyr7vSmI1lBbiR6VJ9wUNF8TBNSbVNPguhKt13vqjJSU40MwQzXtVV Y3qCLMR4vdGY3zUAAXWWPXBXg25dHAz3QqsPjIlg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728661AbfJ3Pzp (ORCPT ); Wed, 30 Oct 2019 11:55:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:57288 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728645AbfJ3Pzm (ORCPT ); Wed, 30 Oct 2019 11:55:42 -0400 Received: from sasha-vm.mshome.net (100.50.158.77.rev.sfr.net [77.158.50.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C07A92173E; Wed, 30 Oct 2019 15:55:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572450941; bh=ajrQFUpHfoZrFxmZ57IP0Y32djqaiWekFynq+8+EYS8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xikIvcNKjV59W4m+PWW+O/Crf4wBCAQfMtc9qb894kpXhEThH9iruisqhzMH4/wjn mJmz2w3r3ypuBP5Nm2gIH+8ar+OzOaLu9lAl2y2LFordD4d9JvZCpfc9GpoRUEWiZF Wh3HJLdo1U05VnPn/5ok1u35IVixU0PftjOpNTZc= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Fabrice Gasnier , Pierre-Yves MORDRET , Wolfram Sang , Sasha Levin , linux-i2c@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 33/38] i2c: stm32f7: fix a race in slave mode with arbitration loss irq Date: Wed, 30 Oct 2019 11:54:01 -0400 Message-Id: <20191030155406.10109-33-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191030155406.10109-1-sashal@kernel.org> References: <20191030155406.10109-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 48521bc8a4d23..362b23505f214 100644 --- a/drivers/i2c/busses/i2c-stm32f7.c +++ b/drivers/i2c/busses/i2c-stm32f7.c @@ -1488,7 +1488,7 @@ 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); @@ -1513,12 +1513,15 @@ 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