linux/drivers/thunderbolt/path.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt driver - path/tunnel functionality
 *
 * Copyright (c) 2014 Andreas Noever <[email protected]>
 * Copyright (C) 2019, Intel Corporation
 */

#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/ktime.h>

#include "tb.h"

static void tb_dump_hop(const struct tb_path_hop *hop, const struct tb_regs_hop *regs)
{ … }

static struct tb_port *tb_path_find_dst_port(struct tb_port *src, int src_hopid,
					     int dst_hopid)
{ … }

static int tb_path_find_src_hopid(struct tb_port *src,
	const struct tb_port *dst, int dst_hopid)
{ … }

/**
 * tb_path_discover() - Discover a path
 * @src: First input port of a path
 * @src_hopid: Starting HopID of a path (%-1 if don't care)
 * @dst: Expected destination port of the path (%NULL if don't care)
 * @dst_hopid: HopID to the @dst (%-1 if don't care)
 * @last: Last port is filled here if not %NULL
 * @name: Name of the path
 * @alloc_hopid: Allocate HopIDs for the ports
 *
 * Follows a path starting from @src and @src_hopid to the last output
 * port of the path. Allocates HopIDs for the visited ports (if
 * @alloc_hopid is true). Call tb_path_free() to release the path and
 * allocated HopIDs when the path is not needed anymore.
 *
 * Note function discovers also incomplete paths so caller should check
 * that the @dst port is the expected one. If it is not, the path can be
 * cleaned up by calling tb_path_deactivate() before tb_path_free().
 *
 * Return: Discovered path on success, %NULL in case of failure
 */
struct tb_path *tb_path_discover(struct tb_port *src, int src_hopid,
				 struct tb_port *dst, int dst_hopid,
				 struct tb_port **last, const char *name,
				 bool alloc_hopid)
{ … }

/**
 * tb_path_alloc() - allocate a thunderbolt path between two ports
 * @tb: Domain pointer
 * @src: Source port of the path
 * @src_hopid: HopID used for the first ingress port in the path
 * @dst: Destination port of the path
 * @dst_hopid: HopID used for the last egress port in the path
 * @link_nr: Preferred link if there are dual links on the path
 * @name: Name of the path
 *
 * Creates path between two ports starting with given @src_hopid. Reserves
 * HopIDs for each port (they can be different from @src_hopid depending on
 * how many HopIDs each port already have reserved). If there are dual
 * links on the path, prioritizes using @link_nr but takes into account
 * that the lanes may be bonded.
 *
 * Return: Returns a tb_path on success or NULL on failure.
 */
struct tb_path *tb_path_alloc(struct tb *tb, struct tb_port *src, int src_hopid,
			      struct tb_port *dst, int dst_hopid, int link_nr,
			      const char *name)
{ … }

/**
 * tb_path_free() - free a path
 * @path: Path to free
 *
 * Frees a path. The path does not need to be deactivated.
 */
void tb_path_free(struct tb_path *path)
{ … }

static void __tb_path_deallocate_nfc(struct tb_path *path, int first_hop)
{ … }

static int __tb_path_deactivate_hop(struct tb_port *port, int hop_index,
				    bool clear_fc)
{ … }

/**
 * tb_path_deactivate_hop() - Deactivate one path in path config space
 * @port: Lane or protocol adapter
 * @hop_index: HopID of the path to be cleared
 *
 * This deactivates or clears a single path config space entry at
 * @hop_index. Returns %0 in success and negative errno otherwise.
 */
int tb_path_deactivate_hop(struct tb_port *port, int hop_index)
{ … }

static void __tb_path_deactivate_hops(struct tb_path *path, int first_hop)
{ … }

void tb_path_deactivate(struct tb_path *path)
{ … }

/**
 * tb_path_activate() - activate a path
 * @path: Path to activate
 *
 * Activate a path starting with the last hop and iterating backwards. The
 * caller must fill path->hops before calling tb_path_activate().
 *
 * Return: Returns 0 on success or an error code on failure.
 */
int tb_path_activate(struct tb_path *path)
{ … }

/**
 * tb_path_is_invalid() - check whether any ports on the path are invalid
 * @path: Path to check
 *
 * Return: Returns true if the path is invalid, false otherwise.
 */
bool tb_path_is_invalid(struct tb_path *path)
{ … }

/**
 * tb_path_port_on_path() - Does the path go through certain port
 * @path: Path to check
 * @port: Switch to check
 *
 * Goes over all hops on path and checks if @port is any of them.
 * Direction does not matter.
 */
bool tb_path_port_on_path(const struct tb_path *path, const struct tb_port *port)
{ … }