From patchwork Tue Oct 11 03:41:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai-Heng Feng X-Patchwork-Id: 1688441 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=canonical.com header.i=@canonical.com header.a=rsa-sha256 header.s=20210705 header.b=f4i1wqyi; dkim-atps=neutral Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4MmhST5LMWz23jS for ; Tue, 11 Oct 2022 14:42:47 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1oi6A8-0005kx-Fl; Tue, 11 Oct 2022 03:42:36 +0000 Received: from smtp-relay-canonical-1.internal ([10.131.114.174] helo=smtp-relay-canonical-1.canonical.com) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1oi6A6-0005jr-6y for kernel-team@lists.ubuntu.com; Tue, 11 Oct 2022 03:42:34 +0000 Received: from localhost.localdomain (unknown [10.101.196.174]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 057EA42C01 for ; Tue, 11 Oct 2022 03:42:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1665459753; bh=U667MvvuM/lftrAtfhA9ExYpOekbkYH5OmIDgUxMmLI=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=f4i1wqyiSbe52jjZjnsdPf3LI3X2r7dJ381/Op3NvdWUM16OSvUXPaBKydr36Hfsl E5xIWWpT8afgQnTd+9kWnk7ccUCs+wIGEp+n+4Gu31CdrAA2sRRE1uVQlNuf/M9oRt HgnG4eoSpFqtf3HNr7oQCyvbMVGx4Xt+XNpcK8kXILZMVjDQeaXBrJ765kcxmx+usz G6Ro65qZDZR0uxhN0h+58Q/i0j7JpurReLr1bwKSGRO8I5txDUe3fc95ANqJRs+9PD 0bHHO2Zkh5UP22iItKMgjE5/fOSKK/s9GrpymEr0Yr09vccfTnwEkm1csozdo416qu EiQ9mbGx1U0Kw== From: Kai-Heng Feng To: kernel-team@lists.ubuntu.com Subject: [J/K] [PATCH 03/10] PCI/PTM: Separate configuration and enable Date: Tue, 11 Oct 2022 11:41:31 +0800 Message-Id: <20221011034139.731146-4-kai.heng.feng@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20221011034139.731146-1-kai.heng.feng@canonical.com> References: <20221011034139.731146-1-kai.heng.feng@canonical.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Bjorn Helgaas BugLink: https://bugs.launchpad.net/bugs/1988797 PTM configuration and enabling were previously mixed together: pci_ptm_init() collected granularity info and enabled PTM for Root Ports and Switch Upstream Ports; pci_enable_ptm() did the same for Endpoints. Move everything related to the PTM Capability register to pci_ptm_init() for all devices, and everything related to the PTM Control register to pci_enable_ptm(). Link: https://lore.kernel.org/r/20220909202505.314195-4-helgaas@kernel.org Tested-by: Rajvi Jingar Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg (cherry picked from commit 118b9dfdc18b68abf736a71330e3ad1f5af7e47e linux-next) Signed-off-by: Kai-Heng Feng --- drivers/pci/pcie/ptm.c | 104 +++++++++++++++++++---------------------- 1 file changed, 49 insertions(+), 55 deletions(-) diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c index 0df6cdfe38b40..ba1d50c965fa1 100644 --- a/drivers/pci/pcie/ptm.c +++ b/drivers/pci/pcie/ptm.c @@ -99,25 +99,19 @@ static struct pci_dev *pci_upstream_ptm(struct pci_dev *dev) return NULL; } +/* + * Find the PTM Capability (if present) and extract the information we need + * to use it. + */ void pci_ptm_init(struct pci_dev *dev) { u16 ptm; - u32 cap, ctrl; - u8 local_clock; + u32 cap; struct pci_dev *ups; if (!pci_is_pcie(dev)) return; - /* - * Enable PTM only on interior devices (root ports, switch ports, - * etc.) on the assumption that it causes no link traffic until an - * endpoint enables it. - */ - if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ENDPOINT || - pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)) - return; - ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); if (!ptm) return; @@ -126,76 +120,76 @@ void pci_ptm_init(struct pci_dev *dev) pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_PTM, sizeof(u16)); pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap); - local_clock = (cap & PCI_PTM_GRANULARITY_MASK) >> 8; + dev->ptm_granularity = (cap & PCI_PTM_GRANULARITY_MASK) >> 8; /* - * There's no point in enabling PTM unless it's enabled in the - * upstream device or this device can be a PTM Root itself. Per - * the spec recommendation (PCIe r3.1, sec 7.32.3), select the - * furthest upstream Time Source as the PTM Root. + * Per the spec recommendation (PCIe r6.0, sec 7.9.15.3), select the + * furthest upstream Time Source as the PTM Root. For Endpoints, + * "the Effective Granularity is the maximum Local Clock Granularity + * reported by the PTM Root and all intervening PTM Time Sources." */ ups = pci_upstream_ptm(dev); - if (ups && ups->ptm_enabled) { - ctrl = PCI_PTM_CTRL_ENABLE; + if (ups) { if (ups->ptm_granularity == 0) dev->ptm_granularity = 0; - else if (ups->ptm_granularity > local_clock) + else if (ups->ptm_granularity > dev->ptm_granularity) dev->ptm_granularity = ups->ptm_granularity; - } else { - if (cap & PCI_PTM_CAP_ROOT) { - ctrl = PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT; - dev->ptm_root = 1; - dev->ptm_granularity = local_clock; - } else - return; - } + } else if (cap & PCI_PTM_CAP_ROOT) { + dev->ptm_root = 1; + } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { - ctrl |= dev->ptm_granularity << 8; - pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl); - dev->ptm_enabled = 1; + /* + * Per sec 7.9.15.3, this should be the Local Clock + * Granularity of the associated Time Source. But it + * doesn't say how to find that Time Source. + */ + dev->ptm_granularity = 0; + } - pci_ptm_info(dev); + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM) + pci_enable_ptm(dev, NULL); } +/** + * pci_enable_ptm() - Enable Precision Time Measurement + * @dev: PCI device + * @granularity: pointer to return granularity + * + * Enable Precision Time Measurement for @dev. If successful and + * @granularity is non-NULL, return the Effective Granularity. + * + * Return: zero if successful, or -EINVAL if @dev lacks a PTM Capability or + * is not a PTM Root and lacks an upstream path of PTM-enabled devices. + */ int pci_enable_ptm(struct pci_dev *dev, u8 *granularity) { - u16 ptm; - u32 cap, ctrl; + u16 ptm = dev->ptm_cap; struct pci_dev *ups; + u32 ctrl; - if (!pci_is_pcie(dev)) - return -EINVAL; - - ptm = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); if (!ptm) return -EINVAL; - dev->ptm_cap = ptm; - pci_read_config_dword(dev, ptm + PCI_PTM_CAP, &cap); - if (!(cap & PCI_PTM_CAP_REQ)) - return -EINVAL; - /* - * For a PCIe Endpoint, PTM is only useful if the endpoint can - * issue PTM requests to upstream devices that have PTM enabled. - * - * For Root Complex Integrated Endpoints, there is no upstream - * device, so there must be some implementation-specific way to - * associate the endpoint with a time source. + * A device uses local PTM Messages to request time information + * from a PTM Root that's farther upstream. Every device along the + * path must support PTM and have it enabled so it can handle the + * messages. Therefore, if this device is not a PTM Root, the + * upstream link partner must have PTM enabled before we can enable + * PTM. */ - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ENDPOINT) { + if (!dev->ptm_root) { ups = pci_upstream_ptm(dev); if (!ups || !ups->ptm_enabled) return -EINVAL; - - dev->ptm_granularity = ups->ptm_granularity; - } else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { - dev->ptm_granularity = 0; - } else - return -EINVAL; + } ctrl = PCI_PTM_CTRL_ENABLE; ctrl |= dev->ptm_granularity << 8; + if (dev->ptm_root) + ctrl |= PCI_PTM_CTRL_ROOT; + pci_write_config_dword(dev, ptm + PCI_PTM_CTRL, ctrl); dev->ptm_enabled = 1;