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=unavailable 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 54101C38A24 for ; Thu, 7 May 2020 14:29:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 276C0208D6 for ; Thu, 7 May 2020 14:29:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588861758; bh=mKuQExT/XtGq4HcwCYsGAbbI38P9Ix+FvVyT7xS0ZcU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dg0/LMPWs90h1BbUOdtwZotF8FdEGALi7ozOOJ4aB2Sd2WeaT91jWbGavL+GWoHtT V+FCSb/bcpS6xU59d4xG5yVwVkwPpkB5iUFnd6QTk1e6LYettqiZH5XJTCUE2nQblW iMY0/eupzj7RR/5GV6A6B3gFciKX2Lzq1fWqryqA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728500AbgEGO3R (ORCPT ); Thu, 7 May 2020 10:29:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:56552 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728466AbgEGO3M (ORCPT ); Thu, 7 May 2020 10:29:12 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 7929E20A8B; Thu, 7 May 2020 14:29:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588861751; bh=mKuQExT/XtGq4HcwCYsGAbbI38P9Ix+FvVyT7xS0ZcU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VszrsqY7GJ0p9HcCzdvI5xI/OIMdMMv6/HWpq/JKxdP9cwBWaSXP8LBlFBtYm9CkK O7CQnzna3jH5GaIwCke8Tx2dMLNKe7Z9swKeRUM3Z17r/dt82LK4mwacU++RODkF2I MuzMwrH9Nw7S1au6+dr466gzX9LVYjgG77puT5cY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: ryan_chen , Benjamin Herrenschmidt , Wolfram Sang , Sasha Levin , linux-i2c@vger.kernel.org, openbmc@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org Subject: [PATCH AUTOSEL 5.4 32/35] i2c: aspeed: Avoid i2c interrupt status clear race condition. Date: Thu, 7 May 2020 10:28:26 -0400 Message-Id: <20200507142830.26239-32-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200507142830.26239-1-sashal@kernel.org> References: <20200507142830.26239-1-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: ryan_chen [ Upstream commit c926c87b8e36dcc0ea5c2a0a0227ed4f32d0516a ] In AST2600 there have a slow peripheral bus between CPU and i2c controller. Therefore GIC i2c interrupt status clear have delay timing, when CPU issue write clear i2c controller interrupt status. To avoid this issue, the driver need have read after write clear at i2c ISR. Fixes: f327c686d3ba ("i2c: aspeed: added driver for Aspeed I2C") Signed-off-by: ryan_chen Acked-by: Benjamin Herrenschmidt [wsa: added Fixes tag] Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-aspeed.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 7b098ff5f5dd3..dad6e432de89f 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -603,6 +603,7 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id) /* Ack all interrupts except for Rx done */ writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE, bus->base + ASPEED_I2C_INTR_STS_REG); + readl(bus->base + ASPEED_I2C_INTR_STS_REG); irq_remaining = irq_received; #if IS_ENABLED(CONFIG_I2C_SLAVE) @@ -645,9 +646,11 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id) irq_received, irq_handled); /* Ack Rx done */ - if (irq_received & ASPEED_I2CD_INTR_RX_DONE) + if (irq_received & ASPEED_I2CD_INTR_RX_DONE) { writel(ASPEED_I2CD_INTR_RX_DONE, bus->base + ASPEED_I2C_INTR_STS_REG); + readl(bus->base + ASPEED_I2C_INTR_STS_REG); + } spin_unlock(&bus->lock); return irq_remaining ? IRQ_NONE : IRQ_HANDLED; } -- 2.20.1