From patchwork Wed Sep 7 08:52:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Fitzgerald X-Patchwork-Id: 603840 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 alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BD9E0C38145 for ; Wed, 7 Sep 2022 08:55:33 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 15FB3161F; Wed, 7 Sep 2022 10:54:42 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 15FB3161F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1662540932; bh=UTBaGbiL322WIgSxdFPNTmtt+LWiX5RGqmSBpbJavs8=; h=From:To:Subject:Date:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=gvO0l+kYL6No/1EcUlRJ59piootGtnIa3JeQo8Zy2RKZFjaKm3RDuG2A9HVi4xY/X 8wYdcvpNLjjeFS16afjizYx1QsGS/QJ7acO2Y6Tc+8fXTAUuEdytiOrar91VF9Vs9C eKouyrXaK0vm9l6mFx6AJS+0b+uo3Y0k43DhCCW0= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 2C706F80553; Wed, 7 Sep 2022 10:53:25 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 2AB2DF80536; Wed, 7 Sep 2022 10:53:21 +0200 (CEST) Received: from mx0b-001ae601.pphosted.com (mx0a-001ae601.pphosted.com [67.231.149.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 9E717F804CA for ; Wed, 7 Sep 2022 10:53:08 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 9E717F804CA Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key) header.d=cirrus.com header.i=@cirrus.com header.b="fWIjgIIS" Received: from pps.filterd (m0077473.ppops.net [127.0.0.1]) by mx0a-001ae601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 2876sQ69005118; Wed, 7 Sep 2022 03:53:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cirrus.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=PODMain02222019; bh=t+rkmWKhbw2VsiGIx98OXne4OR4T75WeNsHgfR4luRs=; b=fWIjgIIS2SlZ0v+x8Y9cZQlhmav8waPc+7EQ11zbQHcv2jxTRt0yoASp0oln4bJt9d/y HBoEeMxv2VmZNPuN+bo+V9dJ1YaSxt1WMBnHm3gXad8ENN+HWtuGSK1rH/HPOm1Lzz0E ZzsGds005Y0dT+5ovsh5X8HcO/2nS+TdOZG5cxkMkgX0i4QmDSo3hdxgiuHoOkWXWr7s 4zQME3PTVjooKB6fPGExHVlIFoEKinI2S+WfOo3Kr3AgEtCXAiUwdmSpl5T6I+Q4Dals 4l5WC72330CDZKWmZCseAaI7QAetQ/5gY78blj4yvM6KQa1FQ7XGVDoluYljAry9wGhZ NQ== Received: from ediex02.ad.cirrus.com ([84.19.233.68]) by mx0a-001ae601.pphosted.com (PPS) with ESMTPS id 3jc4b2dcum-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 07 Sep 2022 03:53:07 -0500 Received: from ediex01.ad.cirrus.com (198.61.84.80) by ediex02.ad.cirrus.com (198.61.84.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.12; Wed, 7 Sep 2022 03:53:05 -0500 Received: from ediswmail.ad.cirrus.com (198.61.86.93) by ediex01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server id 15.2.1118.12 via Frontend Transport; Wed, 7 Sep 2022 03:53:05 -0500 Received: from debianA11184.ad.cirrus.com (unknown [198.61.65.149]) by ediswmail.ad.cirrus.com (Postfix) with ESMTP id AC3937C; Wed, 7 Sep 2022 08:53:04 +0000 (UTC) From: Richard Fitzgerald To: , , , Subject: [PATCH v2 4/5] soundwire: cadence: Fix lost ATTACHED interrupts when enumerating Date: Wed, 7 Sep 2022 09:52:58 +0100 Message-ID: <20220907085259.3602-5-rf@opensource.cirrus.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220907085259.3602-1-rf@opensource.cirrus.com> References: <20220907085259.3602-1-rf@opensource.cirrus.com> MIME-Version: 1.0 X-Proofpoint-GUID: 7da_1ldsMNPl-OTEaDdYfpFUHjAgr7Ee X-Proofpoint-ORIG-GUID: 7da_1ldsMNPl-OTEaDdYfpFUHjAgr7Ee X-Proofpoint-Spam-Reason: safe Cc: patches@opensource.cirrus.com, alsa-devel@alsa-project.org, Richard Fitzgerald , linux-kernel@vger.kernel.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" The correct way to handle interrupts is to clear the bits we are about to handle _before_ handling them. Thus if the condition then re-asserts during the handling we won't lose it. This patch changes cdns_update_slave_status_work() to do this. The previous code cleared the interrupts after handling them. The problem with this is that when handling enumeration of devices the ATTACH statuses can be accidentally cleared and so some or all of the devices never complete their enumeration. Thus we can have a situation like this: - one or more devices are reverting to ID #0 - accumulated status bits indicate some devices attached and some on ID #0. (Remember: status bits are sticky until they are handled) - Because of device on #0 sdw_handle_slave_status() programs the device ID and exits without handling the other status, expecting to get an ATTACHED from this reprogrammed device. - The device immediately starts reporting ATTACHED in PINGs, which will assert its CDNS_MCP_SLAVE_INTSTAT_ATTACHED bit. - cdns_update_slave_status_work() clears INTSTAT0/1. If the initial status had CDNS_MCP_SLAVE_INTSTAT_ATTACHED bit set it will be cleared. - The ATTACHED change for the device has now been lost. - cdns_update_slave_status_work() clears CDNS_MCP_INT_SLAVE_MASK so if the new ATTACHED state had set it, it will be cleared without ever having been handled. Unless there is some other state change from another device to cause a new interrupt, the ATTACHED state of the reprogrammed device will never cause an interrupt so its enumeration will not be completed. Signed-off-by: Richard Fitzgerald --- drivers/soundwire/cadence_master.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c index 245191d22ccd..3acd7b89c940 100644 --- a/drivers/soundwire/cadence_master.c +++ b/drivers/soundwire/cadence_master.c @@ -954,9 +954,22 @@ static void cdns_update_slave_status_work(struct work_struct *work) u32 device0_status; int retry_count = 0; + /* + * Clear main interrupt first so we don't lose any assertions + * the happen during this function. + */ + cdns_writel(cdns, CDNS_MCP_INTSTAT, CDNS_MCP_INT_SLAVE_MASK); + slave0 = cdns_readl(cdns, CDNS_MCP_SLAVE_INTSTAT0); slave1 = cdns_readl(cdns, CDNS_MCP_SLAVE_INTSTAT1); + /* + * Clear the bits before handling so we don't lose any + * bits that re-assert. + */ + cdns_writel(cdns, CDNS_MCP_SLAVE_INTSTAT0, slave0); + cdns_writel(cdns, CDNS_MCP_SLAVE_INTSTAT1, slave1); + /* combine the two status */ slave_intstat = ((u64)slave1 << 32) | slave0; @@ -964,8 +977,6 @@ static void cdns_update_slave_status_work(struct work_struct *work) update_status: cdns_update_slave_status(cdns, slave_intstat); - cdns_writel(cdns, CDNS_MCP_SLAVE_INTSTAT0, slave0); - cdns_writel(cdns, CDNS_MCP_SLAVE_INTSTAT1, slave1); /* * When there is more than one peripheral per link, it's @@ -1001,8 +1012,7 @@ static void cdns_update_slave_status_work(struct work_struct *work) } } - /* clear and unmask Slave interrupt now */ - cdns_writel(cdns, CDNS_MCP_INTSTAT, CDNS_MCP_INT_SLAVE_MASK); + /* unmask Slave interrupt now */ cdns_updatel(cdns, CDNS_MCP_INTMASK, CDNS_MCP_INT_SLAVE_MASK, CDNS_MCP_INT_SLAVE_MASK);