From patchwork Mon Sep 28 04:06:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Zhao, Haifeng" X-Patchwork-Id: 11802777 X-Patchwork-Delegate: bhelgaas@google.com 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 2446E618 for ; Mon, 28 Sep 2020 04:08:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1387F23998 for ; Mon, 28 Sep 2020 04:08:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726477AbgI1EI2 (ORCPT ); Mon, 28 Sep 2020 00:08:28 -0400 Received: from mga18.intel.com ([134.134.136.126]:30276 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725290AbgI1EI1 (ORCPT ); Mon, 28 Sep 2020 00:08:27 -0400 IronPort-SDR: wRDBwBBX99j+Q1ERbJr4dfJVh7hgGG8pAQ4wTuvxdp37xjImcXJ6lhZSjeaZiKnhgRvdF1FXKO 5bvT6vj/DAsA== X-IronPort-AV: E=McAfee;i="6000,8403,9757"; a="149710883" X-IronPort-AV: E=Sophos;i="5.77,312,1596524400"; d="scan'208";a="149710883" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Sep 2020 21:08:27 -0700 IronPort-SDR: /dR6Zsvn4ZqhrX64qoZxy7osbDuMI+x74QV0Z51ZhpO1VMycux+C5qZyKDYh07MBjK8qiQL6VG HGp4ICIdAAog== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,312,1596524400"; d="scan'208";a="311628137" Received: from shskylake.sh.intel.com ([10.239.48.137]) by orsmga006.jf.intel.com with ESMTP; 27 Sep 2020 21:08:24 -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 V5] PCI: define a function to check and wait till port finish DPC handling Date: Mon, 28 Sep 2020 00:06:47 -0400 Message-Id: <20200928040651.24937-2-haifeng.zhao@intel.com> X-Mailer: git-send-email 2.18.4 In-Reply-To: <20200928040651.24937-1-haifeng.zhao@intel.com> References: <20200928040651.24937-1-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 --- changes: V2：align ICS code name to public doc. V3: no change. V4: response to Christoph's (Christoph Hellwig ) tip, move pci_wait_port_outdpc() to DPC driver and its declaration to pci.h. V5: fix building issue reported by lkp@intel.com with some config. drivers/pci/pci.h | 2 ++ drivers/pci/pcie/dpc.c | 27 +++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index fa12f7cbc1a0..8fdb0d823d5a 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -455,10 +455,12 @@ void pci_restore_dpc_state(struct pci_dev *dev); void pci_dpc_init(struct pci_dev *pdev); void dpc_process_error(struct pci_dev *pdev); pci_ers_result_t dpc_reset_link(struct pci_dev *pdev); +bool pci_wait_port_outdpc(struct pci_dev *pdev); #else static inline void pci_save_dpc_state(struct pci_dev *dev) {} static inline void pci_restore_dpc_state(struct pci_dev *dev) {} static inline void pci_dpc_init(struct pci_dev *pdev) {} +static inline bool pci_wait_port_outdpc(struct pci_dev *pdev) { return false; } #endif #ifdef CONFIG_PCI_ATS diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index daa9a4153776..2e0e091ce923 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -71,6 +71,33 @@ void pci_restore_dpc_state(struct pci_dev *dev) pci_write_config_word(dev, dev->dpc_cap + PCI_EXP_DPC_CTL, *cap); } +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; +} + static int dpc_wait_rp_inactive(struct pci_dev *pdev) { unsigned long timeout = jiffies + HZ;