From patchwork Sun Sep 27 05:28:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11801773 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 587646CB for ; Sun, 27 Sep 2020 05:30:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49C35239E5 for ; Sun, 27 Sep 2020 05:30:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730283AbgI0FaT (ORCPT ); Sun, 27 Sep 2020 01:30:19 -0400 Received: from mga07.intel.com ([134.134.136.100]:23634 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726478AbgI0FaT (ORCPT ); Sun, 27 Sep 2020 01:30:19 -0400 IronPort-SDR: iXRjaFxMCts+zb+4vi/rfN5RdHhcXNE5ZRIDhYaZsvS0FYdeu4t4ZtJ+pHsCXM2KVHP7xE1rBz 4iVNBIba/DJg== X-IronPort-AV: E=McAfee;i="6000,8403,9756"; a="225993130" X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="225993130" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Sep 2020 22:30:18 -0700 IronPort-SDR: lwe9O8A/DcJFUChqzqo4COzMhjKnNj8pXL5qeArEGt4BbghcEeHLRf7jAXVfvDS7Einalw6MWK T2nkTDWvgufA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,308,1596524400"; d="scan'208";a="323909336" Received: from shskylake.sh.intel.com ([10.239.48.137]) by orsmga002.jf.intel.com with ESMTP; 26 Sep 2020 22:30:15 -0700 From: Ethan Zhao To: bhelgaas@google.com, oohall@gmail.com, ruscur@russell.cc, lukas@wunner.de, andriy.shevchenko@linux.intel.com, stuart.w.hayes@gmail.com, mr.nuke.me@gmail.com, mika.westerberg@linux.intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, pei.p.jia@intel.com, ashok.raj@linux.intel.com, sathyanarayanan.kuppuswamy@intel.com, Ethan Zhao Subject: [PATCH 1/5 V3] PCI: define a function to check and wait till port finish DPC handling Date: Sun, 27 Sep 2020 01:28:37 -0400 Message-Id: <20200927052841.12629-2-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200927052841.12629-1-haifeng.zhao@intel.com> References: <20200927052841.12629-1-haifeng.zhao@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Once root port DPC capability is enabled and triggered, at the beginning of DPC is triggered, the DPC status bits are set by hardware and then sends DPC/DLLSC/PDC interrupts to OS DPC and pciehp drivers, it will take the port and software DPC interrupt handler 10ms to 50ms (test data on ICS(Ice Lake SP platform, see https://en.wikichip.org/wiki/intel/microarchitectures/ice_lake_(server) & stable 5.9-rc6) to complete the DPC containment procedure till the DPC status is cleared at the end of the DPC interrupt handler. We use this function to check if the root port is in DPC handling status and wait till the hardware and software completed the procedure. Signed-off-by: Ethan Zhao Tested-by: Wen Jin Tested-by: Shanshan Zhang Reviewed-by: Andy Shevchenko --- changes: V2：align ICS code name to public doc. V3: no change. include/linux/pci.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/include/linux/pci.h b/include/linux/pci.h index 835530605c0d..5beb76c6ae26 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -38,6 +38,7 @@ #include #include #include +#include #include #include @@ -2427,4 +2428,34 @@ void pci_uevent_ers(struct pci_dev *pdev, enum pci_ers_result err_type); WARN_ONCE(condition, "%s %s: " fmt, \ dev_driver_string(&(pdev)->dev), pci_name(pdev), ##arg) +#ifdef CONFIG_PCIE_DPC +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev) +{ + u16 cap = pdev->dpc_cap, status; + u16 loop = 0; + + if (!cap) { + pci_WARN_ONCE(pdev, !cap, "No DPC capability initiated\n"); + return false; + } + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status); + pci_dbg(pdev, "DPC status %x, cap %x\n", status, cap); + while (status & PCI_EXP_DPC_STATUS_TRIGGER && loop < 100) { + msleep(10); + loop++; + pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status); + } + if (!(status & PCI_EXP_DPC_STATUS_TRIGGER)) { + pci_dbg(pdev, "Out of DPC %x, cost %d ms\n", status, loop*10); + return true; + } + pci_dbg(pdev, "Timeout to wait port out of DPC status\n"); + return false; +} +#else +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev) +{ + return true; +} +#endif #endif /* LINUX_PCI_H */