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,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 0DF30C33CAF for ; Thu, 16 Jan 2020 17:17:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEC1A24693 for ; Thu, 16 Jan 2020 17:17:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579195072; bh=a5NXb3Y9E0fU3qlVRFz+TmR7Y8NUePy1259Ab0G/ik4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=JYlDO8qyrKo1SnEjCi11hca+pYZOtXhfwGOjL++x6Jzs4PmSyEZ+6IE/EHj/Y/pLR GDVCKXmmZFP0IXP9vUie3oNnOLbWOfqJ9NiUJMXq4T0pJBe2te0kldQ2DXH5jioi9n F6KX6gJSJs/QMixo0FCp7QiNYS8IMYMQPCQvvruc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391289AbgAPRRv (ORCPT ); Thu, 16 Jan 2020 12:17:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:43894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391287AbgAPRRv (ORCPT ); Thu, 16 Jan 2020 12:17:51 -0500 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 927902469D; Thu, 16 Jan 2020 17:17:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579195070; bh=a5NXb3Y9E0fU3qlVRFz+TmR7Y8NUePy1259Ab0G/ik4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uxZPe7VG9IiybWYh9/kexZybybAaPGU+Si/WBxdhRGfLqDgEV8ZbrendjrbibCwOv BOwk8lMz1idoGSMbELwnwjUkWCXLQgH93kKXDR/X2Mq5xOoMOr1AE4VTR2h4MBsO2o OkqWAZiCcMmhMa0LvP+6HEmcRLfyzCLGx2y9fJFo= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kelvin Cao , Wesley Sheng , Bjorn Helgaas , Logan Gunthorpe , Sasha Levin , linux-pci@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 023/371] switchtec: Remove immediate status check after submitting MRPC command Date: Thu, 16 Jan 2020 12:11:31 -0500 Message-Id: <20200116171719.16965-23-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116171719.16965-1-sashal@kernel.org> References: <20200116171719.16965-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Kelvin Cao [ Upstream commit 526180408b815aa7b96fd48bd23cdd33ef04e38e ] After submitting a Firmware Download MRPC command, Switchtec firmware will delay Management EP BAR MemRd TLP responses by more than 10ms. This is a firmware limitation. Delayed MemRd completions are a problem for systems with a low Completion Timeout (CTO). The current driver checks the MRPC status immediately after submitting an MRPC command, which results in a delayed MemRd completion that may cause a Completion Timeout. Remove the immediate status check and rely on the check after receiving an interrupt or timing out. This is only a software workaround to the READ issue and a proper fix of this should be done in firmware. Fixes: 080b47def5e5 ("MicroSemi Switchtec management interface driver") Signed-off-by: Kelvin Cao Signed-off-by: Wesley Sheng Signed-off-by: Bjorn Helgaas Reviewed-by: Logan Gunthorpe Signed-off-by: Sasha Levin --- drivers/pci/switch/switchtec.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 0941555b84a5..73dba2739849 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -399,10 +399,6 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev) stuser->data, stuser->data_len); iowrite32(stuser->cmd, &stdev->mmio_mrpc->cmd); - stuser->status = ioread32(&stdev->mmio_mrpc->status); - if (stuser->status != SWITCHTEC_MRPC_STATUS_INPROGRESS) - mrpc_complete_cmd(stdev); - schedule_delayed_work(&stdev->mrpc_timeout, msecs_to_jiffies(500)); } -- 2.20.1