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 9D03CC54E4B for ; Thu, 7 May 2020 14:28:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DFD924953 for ; Thu, 7 May 2020 14:28:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588861701; bh=wWICHhShsjiNXg4Lrs8fFbE9djX+UgP3NHhA9p/iUbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZL7HOE/CxKRifxzP5Ni/Onq975lpz+21jW6lYNRy5KKJmPqaK88Rct0wY40EnfpGr rBrMay35VS9OK1xDyjrvBiIfM1ivA75IWoWdC2UHRaMkVCfXb1V04YNl9SUtPK51Vi gPoDkqInYzxvXP138KTsUIV0poSY5OgavA1o0W7s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728066AbgEGO2U (ORCPT ); Thu, 7 May 2020 10:28:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:54872 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728058AbgEGO2U (ORCPT ); Thu, 7 May 2020 10:28:20 -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 3EA892145D; Thu, 7 May 2020 14:28:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588861699; bh=wWICHhShsjiNXg4Lrs8fFbE9djX+UgP3NHhA9p/iUbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kAFbJKmw+kx+SNyLvkjCxoHkV2wHauOSygLJr1OgrBo5HjYYy4NCTm5u2V4kCsDzC iNq/4mXiwNFGWwHpkJAxF7QlYzucofEk6rH2gqcUoOIrrvAXciP1M9FOBhyc7ZUP41 g+4WwDXXuohA19NGyLQHOHKFbe8lfXBN0xjpJTA4= 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 5.6 41/50] i2c: aspeed: Avoid i2c interrupt status clear race condition. Date: Thu, 7 May 2020 10:27:17 -0400 Message-Id: <20200507142726.25751-41-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200507142726.25751-1-sashal@kernel.org> References: <20200507142726.25751-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@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 a7be6f24450bd..538dfc4110f85 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