From patchwork Thu Nov 19 00:18:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "David E. Box" X-Patchwork-Id: 11918759 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72469C6379D for ; Thu, 19 Nov 2020 00:17:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21800246BB for ; Thu, 19 Nov 2020 00:17:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726739AbgKSARk (ORCPT ); Wed, 18 Nov 2020 19:17:40 -0500 Received: from mga03.intel.com ([134.134.136.65]:23260 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725947AbgKSARk (ORCPT ); Wed, 18 Nov 2020 19:17:40 -0500 IronPort-SDR: rOM0dF1zMSKYTdaDmRXQxGKVFJR9jrljXRmtan0rIOqDNvJGZ2CtpHzXzRq3uNjdodnbgSLPGm UfC7A4T5B/Kg== X-IronPort-AV: E=McAfee;i="6000,8403,9809"; a="171305805" X-IronPort-AV: E=Sophos;i="5.77,488,1596524400"; d="scan'208";a="171305805" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2020 16:17:38 -0800 IronPort-SDR: WkNLjActaftn3S33vHtSNX+0spN//6sH8osv7Nk+VHGbETzOlKxQuwItZMRQlvkKSM56Y2bKU2 0UQedZQ8Covg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,488,1596524400"; d="scan'208";a="532952519" Received: from linux.intel.com ([10.54.29.200]) by fmsmga006.fm.intel.com with ESMTP; 18 Nov 2020 16:17:35 -0800 Received: from debox1-desk2.jf.intel.com (debox1-desk2.jf.intel.com [10.54.75.16]) by linux.intel.com (Postfix) with ESMTP id BDE67580689; Wed, 18 Nov 2020 16:17:35 -0800 (PST) From: "David E. Box" To: bhelgaas@google.com, rafael@kernel.org, len.brown@intel.com Cc: "David E. Box" , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] PCI: Add save/restore of Precision Time Measurement capability Date: Wed, 18 Nov 2020 16:18:21 -0800 Message-Id: <20201119001822.31617-1-david.e.box@linux.intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The PCI subsystem does not currently save and restore the configuration space for the Precision Time Measurement (PTM) PCIe extended capability leading to the feature returning disabled on S3 resume. This has been observed on Intel Coffee Lake desktops. Add save/restore of the PTM control register. This saves the PTM Enable, Root Select, and Effective Granularity bits. Suggested-by: Rafael J. Wysocki Signed-off-by: David E. Box --- drivers/pci/pci.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e578d34095e9..6fd4ae910a88 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1539,6 +1539,44 @@ static void pci_restore_ltr_state(struct pci_dev *dev) pci_write_config_word(dev, ltr + PCI_LTR_MAX_NOSNOOP_LAT, *cap++); } +static void pci_save_ptm_state(struct pci_dev *dev) +{ + int ptm; + struct pci_cap_saved_state *save_state; + u16 *cap; + + if (!pci_is_pcie(dev)) + return; + + ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); + if (!ptm) + return; + + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM); + if (!save_state) { + pci_err(dev, "no suspend buffer for PTM\n"); + return; + } + + cap = (u16 *)&save_state->cap.data[0]; + pci_read_config_word(dev, ptm + PCI_PTM_CTRL, cap); +} + +static void pci_restore_ptm_state(struct pci_dev *dev) +{ + struct pci_cap_saved_state *save_state; + int ptm; + u16 *cap; + + save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_PTM); + ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); + if (!save_state || !ptm) + return; + + cap = (u16 *)&save_state->cap.data[0]; + pci_write_config_word(dev, ptm + PCI_PTM_CTRL, *cap); +} + /** * pci_save_state - save the PCI configuration space of a device before * suspending @@ -1566,6 +1604,7 @@ int pci_save_state(struct pci_dev *dev) pci_save_ltr_state(dev); pci_save_dpc_state(dev); pci_save_aer_state(dev); + pci_save_ptm_state(dev); return pci_save_vc_state(dev); } EXPORT_SYMBOL(pci_save_state); @@ -1677,6 +1716,7 @@ void pci_restore_state(struct pci_dev *dev) pci_restore_vc_state(dev); pci_restore_rebar_state(dev); pci_restore_dpc_state(dev); + pci_restore_ptm_state(dev); pci_aer_clear_status(dev); pci_restore_aer_state(dev); @@ -3332,6 +3372,10 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev) if (error) pci_err(dev, "unable to allocate suspend buffer for LTR\n"); + error = pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u16)); + if (error) + pci_err(dev, "unable to allocate suspend buffer for PTM\n"); + pci_allocate_vc_save_buffers(dev); }