From patchwork Fri Nov 1 23:56:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuppuswamy Sathyanarayanan X-Patchwork-Id: 11223935 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 8FABE913 for ; Fri, 1 Nov 2019 23:59:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F7E820881 for ; Fri, 1 Nov 2019 23:59:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727838AbfKAX7P (ORCPT ); Fri, 1 Nov 2019 19:59:15 -0400 Received: from mga04.intel.com ([192.55.52.120]:63645 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727269AbfKAX7P (ORCPT ); Fri, 1 Nov 2019 19:59:15 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Nov 2019 16:59:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,257,1569308400"; d="scan'208";a="199469573" Received: from skuppusw-desk.jf.intel.com ([10.54.74.33]) by fmsmga008.fm.intel.com with ESMTP; 01 Nov 2019 16:59:15 -0700 From: sathyanarayanan.kuppuswamy@linux.intel.com To: bhelgaas@google.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, ashok.raj@intel.com, keith.busch@intel.com, sathyanarayanan.kuppuswamy@linux.intel.com Subject: [PATCH v10 2/8] PCI/DPC: Allow dpc_probe() even if firmware first mode is enabled Date: Fri, 1 Nov 2019 16:56:50 -0700 Message-Id: X-Mailer: git-send-email 2.21.0 In-Reply-To: References: MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Kuppuswamy Sathyanarayanan As per ACPI specification v6.3, sec 5.6.6, Error Disconnect Recover (EDR) notification used by firmware to let OS know about the DPC event and permit OS to perform error recovery when processing the EDR notification. Also, as per PCI firmware specification r3.2 Downstream Port Containment Related Enhancements ECN, sec 4.5.1, table 4-6, if DPC is controlled by firmware (firmware first mode), it's responsible for initializing Downstream Port Containment Extended Capability Structures per firmware policy. And, OS is permitted to read or write DPC Control and Status registers of a port while processing an Error Disconnect Recover (EDR) notification from firmware on that port. Currently, if firmware controls DPC (firmware first mode), OS will not create/enumerate DPC PCIe port services. But, if OS supports EDR feature, then as mentioned in above spec references, it should permit enumeration of DPC driver and also support handling ACPI EDR notification. So as first step, allow dpc_probe() to continue even if firmware first mode is enabled. Also add appropriate checks to ensure device registers are not modified outside EDR notification window in firmware first mode. This is a preparatory patch for adding EDR support. Signed-off-by: Kuppuswamy Sathyanarayanan Acked-by: Keith Busch --- drivers/pci/pcie/dpc.c | 65 +++++++++++++++++++++++++++++++++--------- 1 file changed, 52 insertions(+), 13 deletions(-) diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c index a32ec3487a8d..c3e0b05efa4b 100644 --- a/drivers/pci/pcie/dpc.c +++ b/drivers/pci/pcie/dpc.c @@ -69,6 +69,14 @@ void pci_save_dpc_state(struct pci_dev *dev) if (!dpc) return; + /* + * If DPC is controlled by firmware then save/restore tasks are also + * controller by firmware. So skip rest of the function if DPC is + * controlled by firmware. + */ + if (pcie_aer_get_firmware_first(dev)) + return; + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC); if (!save_state) return; @@ -90,6 +98,14 @@ void pci_restore_dpc_state(struct pci_dev *dev) if (!dpc) return; + /* + * If DPC is controlled by firmware then save/restore tasks are also + * controller by firmware. So skip rest of the function if DPC is + * controlled by firmware. + */ + if (pcie_aer_get_firmware_first(dev)) + return; + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_DPC); if (!save_state) return; @@ -291,9 +307,6 @@ static int dpc_probe(struct pcie_device *dev) int status; u16 ctl, cap; - if (pcie_aer_get_firmware_first(pdev)) - return -ENOTSUPP; - dpc = devm_kzalloc(device, sizeof(*dpc), GFP_KERNEL); if (!dpc) return -ENOMEM; @@ -302,13 +315,32 @@ static int dpc_probe(struct pcie_device *dev) dpc->dev = dev; set_service_data(dev, dpc); - status = devm_request_threaded_irq(device, dev->irq, dpc_irq, - dpc_handler, IRQF_SHARED, - "pcie-dpc", dpc); - if (status) { - pci_warn(pdev, "request IRQ%d failed: %d\n", dev->irq, - status); - return status; + /* + * As per PCIe spec r5.0, implementation note titled "Determination + * of DPC Control", to avoid conflicts over whether platform + * firmware or the operating system have control of DPC, it is + * recommended that platform firmware and operating systems always link + * the control of DPC to the control of Advanced Error Reporting. + * + * So use AER FF mode check API pcie_aer_get_firmware_first() to decide + * whether DPC is controlled by software or firmware. + * + * If DPC is handled in firmware and ACPI support is not enabled + * in OS, skip probe and return error. + */ + if (pcie_aer_get_firmware_first(pdev) && !IS_ENABLED(CONFIG_ACPI)) + return -ENODEV; + + /* Register interrupt handler only if OS controls DPC */ + if (!pcie_aer_get_firmware_first(pdev)) { + status = devm_request_threaded_irq(device, dev->irq, dpc_irq, + dpc_handler, IRQF_SHARED, + "pcie-dpc", dpc); + if (status) { + pci_warn(pdev, "request IRQ%d failed: %d\n", dev->irq, + status); + return status; + } } pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap); @@ -323,9 +355,12 @@ static int dpc_probe(struct pcie_device *dev) dpc->rp_log_size = 0; } } - - ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN; - pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl); + if (!pcie_aer_get_firmware_first(pdev)) { + ctl = (ctl & 0xfff4) | + (PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN); + pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, + ctl); + } pci_info(pdev, "error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n", cap & PCI_EXP_DPC_IRQ, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT), @@ -343,6 +378,10 @@ static void dpc_remove(struct pcie_device *dev) struct pci_dev *pdev = dev->port; u16 ctl; + /* Skip updating DPC registers if DPC is controlled by firmware */ + if (pcie_aer_get_firmware_first(pdev)) + return; + pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl); ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN); pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);