From patchwork Wed Aug 2 17:18:24 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 9877255 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 2FE6B60360 for ; Wed, 2 Aug 2017 17:19:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 15F352873F for ; Wed, 2 Aug 2017 17:19:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0AD3D28753; Wed, 2 Aug 2017 17:19:09 +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 B2C852873F for ; Wed, 2 Aug 2017 17:19:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752195AbdHBRSt (ORCPT ); Wed, 2 Aug 2017 13:18:49 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:35818 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751948AbdHBRSf (ORCPT ); Wed, 2 Aug 2017 13:18:35 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 1976A6085F; Wed, 2 Aug 2017 17:18:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1501694315; bh=IGjLaC5QVr1I4K9AmY0wskf0zyaD2UGLiX40vdlA6LI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LchSsXh/Gm+rGRsIdVISjpyhheNHcj7TxeZxaFWBCBrqZi4xW6T9uh3CJqiq2p5oj sjpRqotGbbfoIdvMhPrXFQ+l2drtrAKNNHvUtgh/OwOGnDSIjdnzFnVBk0ISFcyz1Q 0S6q8E6jI8uPoS6e/+KoTTNqWnkdyw6kGggkxbsU= 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 CA5EB607E2; Wed, 2 Aug 2017 17:18:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1501694314; bh=IGjLaC5QVr1I4K9AmY0wskf0zyaD2UGLiX40vdlA6LI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HPmkA2X6B9hogbWimZKNnxFRQ58zU5+5XiMzREPbw6UCmG4+tjQQl3NoU7S/A/sRC Vjb9bE2PHMeaBd3jHlM84EzviHWT3txD7ejectUAHy7+K+aJe5r0sBs6BqSNSCTiG2 TrANeu7EtCFL6tWjHswif0Tvpj3MxuUzfXc5Lbw0= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org CA5EB607E2 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 , Bjorn Helgaas , linux-kernel@vger.kernel.org Subject: [PATCH V6 2/2] PCI: handle CRS returned by device after FLR Date: Wed, 2 Aug 2017 13:18:24 -0400 Message-Id: <1501694304-16554-2-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1501694304-16554-1-git-send-email-okaya@codeaurora.org> References: <1501694304-16554-1-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 | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2ed604a..01b28ac 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3813,30 +3813,40 @@ 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 300ms 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 sleep = 1000, total = 0; u32 id; + bool ret; if (dev->is_virtfn) { msleep(100); return; } + /* don't touch the HW before waiting 100ms */ + msleep(100); + do { - msleep(100); - pci_read_config_dword(dev, PCI_COMMAND, &id); - } while (i++ < 10 && id == ~0); - - if (id == ~0) - 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); + ret = pci_bus_read_dev_vendor_id(dev->bus, dev->devfn, &id, + sleep); + if (ret) + break; + total += sleep; + sleep *= 2; + } while (total < 60000 && !ret); + + if (!ret) + dev_warn(&dev->dev, "Failed to return from FLR after %ds\n", + total); + else if (total) + dev_info(&dev->dev, "Required additional %ds to return from FLR\n", + total); } /**