From patchwork Wed Aug 2 03:44:13 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 9875901 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 911C86037D for ; Wed, 2 Aug 2017 03:44:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7F23821BED for ; Wed, 2 Aug 2017 03:44:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 74440286E4; Wed, 2 Aug 2017 03:44:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F29BC21BED for ; Wed, 2 Aug 2017 03:44:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751837AbdHBDoW (ORCPT ); Tue, 1 Aug 2017 23:44:22 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:45614 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751729AbdHBDoU (ORCPT ); Tue, 1 Aug 2017 23:44:20 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 1C1E5607C8; Wed, 2 Aug 2017 03:44:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1501645460; bh=ladQ/QcQrsOb5/zzGaWmw+l8LPyALp6vnmWdIKEigxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iXbpUwz7UAp+c11Zi8nwMYkk1FZxX2dlqRGTAfvFaO3JCR0AkYGpd4TaSvGGsE/38 Bzhxp3/GADHPOejVsi2YvAbEUr+TM28Be5C17E0CknmPI/XFG9cjfRz204eFln05jw gT7R6cKjPIxmBBRId9XF/Dc2IWbUPmyzVzR0cMT0= Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 09B0860794; Wed, 2 Aug 2017 03:44:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1501645459; bh=ladQ/QcQrsOb5/zzGaWmw+l8LPyALp6vnmWdIKEigxQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qgv7Xysgl66v5WvSPpsFfC6SwDzxDlCOefZ7E1mzU40455J1UHu0CnHWSYvzbltS/ 8aOkE2TAfG8bjIVh/r2ognON1y/Qd7HtZW+Xp3aVQdwcm8M8fuxOe/e1d8bZ19LmT5 Gq26hsEXHNKpWR2V3p33FOOv3XIWKCKSNRLnzKcc= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 09B0860794 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org From: Sinan Kaya To: linux-pci@vger.kernel.org, timur@codeaurora.org, alex.williamson@redhat.com Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , linux-kernel@vger.kernel.org Subject: [PATCH V5 2/2] PCI: handle CRS returned by device after FLR Date: Tue, 1 Aug 2017 23:44:13 -0400 Message-Id: <1501645453-22842-2-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1501645453-22842-1-git-send-email-okaya@codeaurora.org> References: <1501645453-22842-1-git-send-email-okaya@codeaurora.org> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP An endpoint is allowed to issue Configuration Request Retry Status (CRS) following a Function Level Reset (FLR) request to indicate that it is not ready to accept new requests. CRS is defined in PCIe r3.1, sec 2.3.1. Request Handling Rules and CRS usage in FLR context is mentioned in PCIe r3.1, sec 6.6.2. Function-Level Reset. Adding a vendor ID read if this is a physical function before attempting to read any other registers on the endpoint. A CRS indication will only be given if the address to be read is vendor ID register. pci_bus_read_dev_vendor_id() knows how to deal with CRS returned values. If pci_bus_read_dev_vendor_id() fails, it prints a user visible warning after provided 1 second timeout is reached. pci_flr_wait() will keep calling this function 60 times to allow up to 60 seconds to be consistent with the rest of the kernel CRS timeout handling. Signed-off-by: Sinan Kaya --- drivers/pci/pci.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2ed604a..25c7a83 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3813,14 +3813,16 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev) /* * We should only need to wait 100ms after FLR for virtual functions. - * Wait for up to 1000ms for config space to return something other than -1. - * Intel IGD requires this when an LCD panel is attached. We read the 2nd - * dword because VFs don't implement the 1st dword. + * Wait for up to 60s for config space to return something other than -1. + * Intel IGD requires 1s when an LCD panel is attached. We use + * pci_bus_read_dev_vendor_id() for reading the vendor ID as it handles + * CRS gracefully. */ static void pci_flr_wait(struct pci_dev *dev) { int i = 0; u32 id; + bool ret; if (dev->is_virtfn) { msleep(100); @@ -3828,15 +3830,15 @@ static void pci_flr_wait(struct pci_dev *dev) } do { - msleep(100); - pci_read_config_dword(dev, PCI_COMMAND, &id); - } while (i++ < 10 && id == ~0); + ret = pci_bus_read_dev_vendor_id(dev->bus, dev->devfn, &id, + 1000); + } while (i++ < 60 && !ret); - if (id == ~0) + if (!ret) dev_warn(&dev->dev, "Failed to return from FLR\n"); else if (i > 1) - dev_info(&dev->dev, "Required additional %dms to return from FLR\n", - (i - 1) * 100); + dev_info(&dev->dev, "Required additional %ds to return from FLR\n", + (i - 1)); } /**