[v6,1/3] PCI: Add Precision Time Measurement (PTM) support

Message ID	20160613190534.12503.18923.stgit@bhelgaas-glaptop2.roam.corp.google.com (mailing list archive)
State	New, archived
Delegated to:	Bjorn Helgaas
Headers	show Return-Path: <linux-pci-owner@kernel.org> Subject: [PATCH v6 1/3] PCI: Add Precision Time Measurement (PTM) support To: Jonathan Yong <jonathan.yong@intel.com> From: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org, intel-wired-lan@lists.osuosl.org, Jeff Kirsher <jeffrey.t.kirsher@intel.com>, linux-kernel@vger.kernel.org Date: Mon, 13 Jun 2016 14:05:34 -0500 Message-ID: <20160613190534.12503.18923.stgit@bhelgaas-glaptop2.roam.corp.google.com> In-Reply-To: <20160613185945.12503.32760.stgit@bhelgaas-glaptop2.roam.corp.google.com> References: <20160613185945.12503.32760.stgit@bhelgaas-glaptop2.roam.corp.google.com> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index a814bbb..faed7b7 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -321,6 +321,12 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev, void pci_enable_acs(struct pci_dev *dev); +#ifdef CONFIG_PCIE_PTM +void pci_ptm_init(struct pci_dev *dev); +#else +static inline void pci_ptm_init(struct pci_dev *dev) { } +#endif + struct pci_dev_reset_methods { u16 vendor; u16 device; diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index 22ca641..52c0c0f5 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -95,3 +95,15 @@ config PCIE_DPC To compile this driver as a module, choose M here: the module will be called pcie-dpc. + +config PCIE_PTM + bool "PCIe Precision Time Measurement support" + default y + depends on PCIEPORTBUS + help + This enables PCI Express Precision Time Measurement (PTM) + support. If you have devices that support PTM, it will be + enabled automatically. + + This is only useful if you have devices that support PTM, but it + is safe to enable even if you don't. diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile index b24525b..36e35ea 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -16,3 +16,4 @@ obj-$(CONFIG_PCIEAER) += aer/ obj-$(CONFIG_PCIE_PME) += pme.o obj-$(CONFIG_PCIE_DPC) += pcie-dpc.o +obj-$(CONFIG_PCIE_PTM) += ptm.o diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c new file mode 100644 index 0000000..5c8479b --- /dev/null +++ b/drivers/pci/pcie/ptm.c @@ -0,0 +1,70 @@ +/* + * PCI Express Precision Time Measurement + * Copyright (c) 2016, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/pci.h> +#include "../pci.h" + +static void pci_ptm_info(struct pci_dev *dev) +{ + dev_info(&dev->dev, "PTM enabled%s\n", dev->ptm_root ? " (root)" : ""); +} + +void pci_ptm_init(struct pci_dev *dev) +{ + int pos; + struct pci_dev *ups; + u32 cap, ctrl; + + if (!pci_is_pcie(dev)) + return; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_PTM); + if (!pos) + return; + + /* + * Enable PTM only on upstream 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; + + pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap); + + /* + * 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. + */ + ups = pci_upstream_bridge(dev); + if (ups && ups->ptm_enabled) { + ctrl = PCI_PTM_CTRL_ENABLE; + } else { + if (cap & PCI_PTM_CAP_ROOT) { + ctrl = PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT; + dev->ptm_root = 1; + } else + return; + } + + pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl); + dev->ptm_enabled = 1; + + pci_ptm_info(dev); +} diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8e3ef72..4b5c099 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1658,6 +1658,9 @@ static void pci_init_capabilities(struct pci_dev *dev) pci_enable_acs(dev); pci_cleanup_aer_error_status_regs(dev); + + /* Precision Time Measurement */ + pci_ptm_init(dev); } /* diff --git a/include/linux/pci.h b/include/linux/pci.h index b67e4df..09e6c18 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -361,6 +361,11 @@ struct pci_dev { int rom_attr_enabled; /* has display of the rom attribute been enabled? */ struct bin_attribute *res_attr[DEVICE_COUNT_RESOURCE]; /* sysfs file for resources */ struct bin_attribute *res_attr_wc[DEVICE_COUNT_RESOURCE]; /* sysfs file for WC mapping of resources */ + +#ifdef CONFIG_PCIE_PTM + unsigned int ptm_root:1; + unsigned int ptm_enabled:1; +#endif #ifdef CONFIG_PCI_MSI const struct attribute_group **msi_irq_groups; #endif diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index 4040951..926fff4 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -671,7 +671,8 @@ #define PCI_EXT_CAP_ID_PMUX 0x1A /* Protocol Multiplexing */ #define PCI_EXT_CAP_ID_PASID 0x1B /* Process Address Space ID */ #define PCI_EXT_CAP_ID_DPC 0x1D /* Downstream Port Containment */ -#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_DPC +#define PCI_EXT_CAP_ID_PTM 0x1F /* Precision Time Measurement */ +#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_PTM #define PCI_EXT_CAP_DSN_SIZEOF 12 #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40 @@ -964,4 +965,11 @@ #define PCI_EXP_DPC_SOURCE_ID 10 /* DPC Source Identifier */ +/* Precision Time Measurement */ +#define PCI_PTM_CAP 0x04 /* PTM Capability */ +#define PCI_PTM_CAP_ROOT 0x00000004 /* Root capable */ +#define PCI_PTM_CTRL 0x08 /* PTM Control */ +#define PCI_PTM_CTRL_ENABLE 0x00000001 /* PTM enable */ +#define PCI_PTM_CTRL_ROOT 0x00000002 /* Root select */ + #endif /* LINUX_PCI_REGS_H */

[v6,1/3] PCI: Add Precision Time Measurement (PTM) support

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