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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A3D8C433F5 for ; Tue, 19 Oct 2021 14:39:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20CEB6113B for ; Tue, 19 Oct 2021 14:39:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229963AbhJSOlf (ORCPT ); Tue, 19 Oct 2021 10:41:35 -0400 Received: from mga01.intel.com ([192.55.52.88]:57346 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229641AbhJSOle (ORCPT ); Tue, 19 Oct 2021 10:41:34 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10142"; a="252001992" X-IronPort-AV: E=Sophos;i="5.87,164,1631602800"; d="scan'208";a="252001992" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Oct 2021 07:17:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.87,164,1631602800"; d="scan'208";a="661823740" Received: from mylly.fi.intel.com (HELO mylly.fi.intel.com.) ([10.237.72.56]) by orsmga005.jf.intel.com with ESMTP; 19 Oct 2021 07:17:04 -0700 From: Jarkko Nikula To: linux-i2c@vger.kernel.org Cc: Jean Delvare , Wolfram Sang , Andy Shevchenko , Jarkko Nikula , ck+kernelbugzilla@bl4ckb0x.de, stephane.poignant@protonmail.com Subject: [PATCH] i2c: i801: Fix interrupt storm from SMB_ALERT signal Date: Tue, 19 Oct 2021 17:17:00 +0300 Message-Id: <20211019141700.764413-1-jarkko.nikula@linux.intel.com> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Currently interrupt storm will occur from i2-i801 after first transaction if SMB_ALERT signal is enabled and ever asserted, even before the driver is loaded and does not recover because that interrupt is not acknowledged. This fix aims to fix it by two ways: - Add acknowledging for the SMB_ALERT interrupt status - Disable the SMB_ALERT interrupt on platforms where possible since the driver currently does not make use for it Acknowledging resets the SMB_ALERT interrupt status on all platforms and also should help to avoid interrupt storm on older platforms where the SMB_ALERT interrupt disabling is not available. For simplicity this fix reuses the host notify feature for disabling and restoring original register value. Link: https://bugzilla.kernel.org/show_bug.cgi?id=177311 Reported-by: ck+kernelbugzilla@bl4ckb0x.de Reported-by: stephane.poignant@protonmail.com Signed-off-by: Jarkko Nikula --- Hi Conrad and Stephane. This patch is otherwise the same than the one I had in bugzilla but this adds also acknowledging for the SMB_ALERT interrupt. There is short time window during driver load and unload where interrupt storm will still occur if signal was asserted. Also interrupt disabling is possible only on ICH3 and later so interrupt acknowledging should also help those old platforms. --- drivers/i2c/busses/i2c-i801.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 115660dce722..e95de4ce6b64 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -190,6 +190,7 @@ #define SMBSLVSTS_HST_NTFY_STS BIT(0) /* Host Notify Command register bits */ +#define SMBSLVCMD_SMBALERT_DISABLE BIT(2) #define SMBSLVCMD_HST_NTFY_INTREN BIT(0) #define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \ @@ -642,9 +643,11 @@ static irqreturn_t i801_isr(int irq, void *dev_id) * Clear irq sources and report transaction result. * ->status must be cleared before the next transaction is started. */ - status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS; - if (status) { + status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS | SMBHSTSTS_SMBALERT_STS; + if (status) outb_p(status, SMBHSTSTS(priv)); + status &= ~SMBHSTSTS_SMBALERT_STS; + if (status) { priv->status = status; complete(&priv->done); } @@ -972,9 +975,9 @@ static void i801_enable_host_notify(struct i2c_adapter *adapter) if (!(priv->features & FEATURE_HOST_NOTIFY)) return; - if (!(SMBSLVCMD_HST_NTFY_INTREN & priv->original_slvcmd)) - outb_p(SMBSLVCMD_HST_NTFY_INTREN | priv->original_slvcmd, - SMBSLVCMD(priv)); + /* Enable host notify interrupt and disable SMB_ALERT signal */ + outb_p(SMBSLVCMD_HST_NTFY_INTREN | SMBSLVCMD_SMBALERT_DISABLE | + priv->original_slvcmd, SMBSLVCMD(priv)); /* clear Host Notify bit to allow a new notification */ outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv)); -- 2.33.0