From patchwork Tue Oct 16 03:01:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Masahiro Yamada X-Patchwork-Id: 148903 Delivered-To: patch@linaro.org Received: by 2002:a2e:8595:0:0:0:0:0 with SMTP id b21-v6csp4543404lji; Mon, 15 Oct 2018 20:02:42 -0700 (PDT) X-Google-Smtp-Source: ACcGV60nDMbF1PgJWQpTHenjwU1dW0XsOvhrxsw4GhSVP6EuaWBPs80m6XpOXoVie/FUmxDjNOmN X-Received: by 2002:a17:902:6843:: with SMTP id f3-v6mr19628715pln.64.1539658961861; Mon, 15 Oct 2018 20:02:41 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1539658961; cv=none; d=google.com; s=arc-20160816; b=CmfX/qYMAqr/8Xq7uRj74k3O6qtp58zjsr4pQ5Hx2aX0IjB0OOiqewNTzQaYAc9nkK 3mpDhaIDMDmnN3/S5xpibpsw4UAhk1OyJTG7KHeaTV4h6rwBGo+dSy/y7SKip0qEc3a9 S3ndUoJkoND9tRAUMsvxWPKw7crhcOV8+ibBp+fVcon6DFs8wulftC+9U2uf431HTFln 8FkNLfCBMNRVti15Id0kJFxG8BcGaWyw5D6At++DRrtHLYY5pM8lptnLb08UxuiSudnX hemx0cOk4EZxqtTKxTSSW9Hk2jfHhV/BHwxrBPOuJyR+vuJtb6AGqohQIuvZ8WuSLrYo TTwg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:dkim-filter; bh=8mve5wKKHLT57E+Sp7ZGGe3P0Plrd/MS1fwKPvtPSt8=; b=llxvlwhKdd9gWOwf3GKoit3ReTrxPNSLjOEiTCxTZktTYDK/A3Yb7r/Qf1wy8YJEBa vb0amIggSYwNrzf5DWJ8B2VwW9dLT7Wy+5ibPXa/CEKJjHIWztppPilLevEx7ql8CpGd BvmN4i0KTfdeFkutzWLgxZt1XBUpOT+8OCJ5ELLMQ4pnmLYzOMLghFalht2STMBLB35m LRuaRkWyhcKBHS1DV7sB7ASKpdZ9qKTICUUc8MjOvmBd38pBJ2uPpNDdl7jCklX1A5Xk IQ3Mz5jD5YxTNQRaCaBuxvqrttT9paGmJFMXnkJc6PCAqFrUai8Fq+SsIEMQc6yOtvcz ywgA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=LTjHPHS2; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id m21-v6si13154888pgh.167.2018.10.15.20.02.41; Mon, 15 Oct 2018 20:02:41 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@nifty.com header.s=dec2015msa header.b=LTjHPHS2; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727434AbeJPKuq (ORCPT + 32 others); Tue, 16 Oct 2018 06:50:46 -0400 Received: from conuserg-12.nifty.com ([210.131.2.79]:45986 "EHLO conuserg-12.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726987AbeJPKuq (ORCPT ); Tue, 16 Oct 2018 06:50:46 -0400 Received: from pug.e01.socionext.com (p14092-ipngnfx01kyoto.kyoto.ocn.ne.jp [153.142.97.92]) (authenticated) by conuserg-12.nifty.com with ESMTP id w9G31q7E017707; Tue, 16 Oct 2018 12:01:53 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-12.nifty.com w9G31q7E017707 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1539658913; bh=8mve5wKKHLT57E+Sp7ZGGe3P0Plrd/MS1fwKPvtPSt8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LTjHPHS2jUAIvbnoEx2x8kABx7XncEYbGUAOSlKcjGjbxYlC7+hSSbuPsGYZAVFaj dsCEglEGxJ5JhAErLe8S1GE0CrKGgUX30kcfs9Nfp/6K3YNVltTBomCJ9Rvwn028rd X8hnZ/WiKodJSUjrT4aCFl/RlcRrr1obzFTQ9nseYFcdQr3CeGLgvZBNQPwX6Cu7XM xM4VTN4vmwtOW5tNy8F0ksR21EMIm6HiNZMaZyjYL1uWCHEekrhr1AQcHXdqS3Mavs nXFG6iq1BgETiRjB2/XKpmfJ2WEvfDmjRT8v2QQQ7E6BYJheMBB8hzWqBGokk0HxDJ orLyuaR2T1YAA== X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: Wolfram Sang , linux-i2c@vger.kernel.org Cc: Masahiro Yamada , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] i2c: uniphier-f: make driver robust against concurrency Date: Tue, 16 Oct 2018 12:01:47 +0900 Message-Id: <1539658909-26691-2-git-send-email-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1539658909-26691-1-git-send-email-yamada.masahiro@socionext.com> References: <1539658909-26691-1-git-send-email-yamada.masahiro@socionext.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is unlikely to happen, but it is possible for a CPU to enter the interrupt handler just after wait_for_completion_timeout() has expired. If this happens, the hardware is accessed from multiple contexts concurrently. Disable the IRQ after wait_for_completion_timeout(), and do nothing from the handler when the IRQ is disabled. Fixes: 6a62974b667f ("i2c: uniphier_f: add UniPhier FIFO-builtin I2C driver") Signed-off-by: Masahiro Yamada --- drivers/i2c/busses/i2c-uniphier-f.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) -- 2.7.4 diff --git a/drivers/i2c/busses/i2c-uniphier-f.c b/drivers/i2c/busses/i2c-uniphier-f.c index a403e85..200dfd1 100644 --- a/drivers/i2c/busses/i2c-uniphier-f.c +++ b/drivers/i2c/busses/i2c-uniphier-f.c @@ -98,6 +98,7 @@ struct uniphier_fi2c_priv { unsigned int flags; unsigned int busy_cnt; unsigned int clk_cycle; + spinlock_t lock; /* IRQ synchronization */ }; static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv, @@ -162,7 +163,10 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id) struct uniphier_fi2c_priv *priv = dev_id; u32 irq_status; + spin_lock(&priv->lock); + irq_status = readl(priv->membase + UNIPHIER_FI2C_INT); + irq_status &= priv->enabled_irqs; dev_dbg(&priv->adap.dev, "interrupt: enabled_irqs=%04x, irq_status=%04x\n", @@ -230,6 +234,8 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id) goto handled; } + spin_unlock(&priv->lock); + return IRQ_NONE; data_done: @@ -246,6 +252,8 @@ static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id) handled: uniphier_fi2c_clear_irqs(priv); + spin_unlock(&priv->lock); + return IRQ_HANDLED; } @@ -311,7 +319,7 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap, { struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap); bool is_read = msg->flags & I2C_M_RD; - unsigned long time_left; + unsigned long time_left, flags; dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n", is_read ? "receive" : "transmit", msg->addr, msg->len, stop); @@ -342,6 +350,12 @@ static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap, priv->membase + UNIPHIER_FI2C_CR); time_left = wait_for_completion_timeout(&priv->comp, adap->timeout); + + spin_lock_irqsave(&priv->lock, flags); + priv->enabled_irqs = 0; + uniphier_fi2c_set_irqs(priv); + spin_unlock_irqrestore(&priv->lock, flags); + if (!time_left) { dev_err(&adap->dev, "transaction timeout.\n"); uniphier_fi2c_recover(priv); @@ -529,6 +543,7 @@ static int uniphier_fi2c_probe(struct platform_device *pdev) priv->clk_cycle = clk_rate / bus_speed; init_completion(&priv->comp); + spin_lock_init(&priv->lock); priv->adap.owner = THIS_MODULE; priv->adap.algo = &uniphier_fi2c_algo; priv->adap.dev.parent = dev;