Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754516AbaFEFAN (ORCPT ); Thu, 5 Jun 2014 01:00:13 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43894 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752497AbaFEEUh (ORCPT ); Thu, 5 Jun 2014 00:20:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wenkai Du , Mika Westerberg , Wolfram Sang Subject: [PATCH 3.4 073/214] i2c: designware: Mask all interrupts during i2c controller enable Date: Wed, 4 Jun 2014 21:17:16 -0700 Message-Id: <20140605041649.358346980@linuxfoundation.org> X-Mailer: git-send-email 2.0.0 In-Reply-To: <20140605041639.638675216@linuxfoundation.org> References: <20140605041639.638675216@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Du, Wenkai" commit 47bb27e78867997040a228328f2a631c3c7f2c82 upstream. There have been "i2c_designware 80860F41:00: controller timed out" errors on a number of Baytrail platforms. The issue is caused by incorrect value in Interrupt Mask Register (DW_IC_INTR_MASK) when i2c core is being enabled. This causes call to __i2c_dw_enable() to immediately start the transfer which leads to timeout. There are 3 failure modes observed: 1. Failure in S0 to S3 resume path The default value after reset for DW_IC_INTR_MASK is 0x8ff. When we start the first transaction after resuming from system sleep, TX_EMPTY interrupt is already unmasked because of the hardware default. 2. Failure in normal operational path This failure happens rarely and is hard to reproduce. Debug trace showed that DW_IC_INTR_MASK had value of 0x254 when failure occurred, which meant TX_EMPTY was unmasked. 3. Failure in S3 to S0 suspend path This failure also happens rarely and is hard to reproduce. Adding debug trace that read DW_IC_INTR_MASK made this failure not reproducible. But from ISR call trace we could conclude TX_EMPTY was unmasked when problem occurred. The patch masks all interrupts before the controller is enabled to resolve the faulty DW_IC_INTR_MASK conditions. Signed-off-by: Wenkai Du Acked-by: Mika Westerberg [wsa: improved the comment and removed typo in commit msg] Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-designware-core.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -346,6 +346,9 @@ static void i2c_dw_xfer_init(struct dw_i ic_con &= ~DW_IC_CON_10BITADDR_MASTER; dw_writel(dev, ic_con, DW_IC_CON); + /* enforce disabled interrupts (due to HW issues) */ + i2c_dw_disable_int(dev); + /* Enable the adapter */ dw_writel(dev, 1, DW_IC_ENABLE); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/