linux/drivers/pci/pcie/ptm.c

// SPDX-License-Identifier: GPL-2.0
/*
 * PCI Express Precision Time Measurement
 * Copyright (c) 2016, Intel Corporation.
 */

#include <linux/bitfield.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include "../pci.h"

/*
 * If the next upstream device supports PTM, return it; otherwise return
 * NULL.  PTM Messages are local, so both link partners must support it.
 */
static struct pci_dev *pci_upstream_ptm(struct pci_dev *dev)
{ … }

/*
 * Find the PTM Capability (if present) and extract the information we need
 * to use it.
 */
void pci_ptm_init(struct pci_dev *dev)
{ … }

void pci_save_ptm_state(struct pci_dev *dev)
{ … }

void pci_restore_ptm_state(struct pci_dev *dev)
{ … }

/* Enable PTM in the Control register if possible */
static int __pci_enable_ptm(struct pci_dev *dev)
{ … }

/**
 * 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)
{ … }
EXPORT_SYMBOL(…);

static void __pci_disable_ptm(struct pci_dev *dev)
{ … }

/**
 * pci_disable_ptm() - Disable Precision Time Measurement
 * @dev: PCI device
 *
 * Disable Precision Time Measurement for @dev.
 */
void pci_disable_ptm(struct pci_dev *dev)
{ … }
EXPORT_SYMBOL(…);

/*
 * Disable PTM, but preserve dev->ptm_enabled so we silently re-enable it on
 * resume if necessary.
 */
void pci_suspend_ptm(struct pci_dev *dev)
{ … }

/* If PTM was enabled before suspend, re-enable it when resuming */
void pci_resume_ptm(struct pci_dev *dev)
{ … }

bool pcie_ptm_enabled(struct pci_dev *dev)
{ … }
EXPORT_SYMBOL(…);