1// SPDX-License-Identifier: GPL-2.0
2//
3// Support for generic time stamping devices on MII buses.
4// Copyright (C) 2018 Richard Cochran <richardcochran@gmail.com>
5//
6
7#include <linux/mii_timestamper.h>
8
9static LIST_HEAD(mii_timestamping_devices);
10static DEFINE_MUTEX(tstamping_devices_lock);
11
12struct mii_timestamping_desc {
13 struct list_head list;
14 struct mii_timestamping_ctrl *ctrl;
15 struct device *device;
16};
17
18/**
19 * register_mii_tstamp_controller() - registers an MII time stamping device.
20 *
21 * @device: The device to be registered.
22 * @ctrl: Pointer to device's control interface.
23 *
24 * Returns zero on success or non-zero on failure.
25 */
26int register_mii_tstamp_controller(struct device *device,
27 struct mii_timestamping_ctrl *ctrl)
28{
29 struct mii_timestamping_desc *desc;
30
31 desc = kzalloc(size: sizeof(*desc), GFP_KERNEL);
32 if (!desc)
33 return -ENOMEM;
34
35 INIT_LIST_HEAD(list: &desc->list);
36 desc->ctrl = ctrl;
37 desc->device = device;
38
39 mutex_lock(&tstamping_devices_lock);
40 list_add_tail(new: &mii_timestamping_devices, head: &desc->list);
41 mutex_unlock(lock: &tstamping_devices_lock);
42
43 return 0;
44}
45EXPORT_SYMBOL(register_mii_tstamp_controller);
46
47/**
48 * unregister_mii_tstamp_controller() - unregisters an MII time stamping device.
49 *
50 * @device: A device previously passed to register_mii_tstamp_controller().
51 */
52void unregister_mii_tstamp_controller(struct device *device)
53{
54 struct mii_timestamping_desc *desc;
55 struct list_head *this, *next;
56
57 mutex_lock(&tstamping_devices_lock);
58 list_for_each_safe(this, next, &mii_timestamping_devices) {
59 desc = list_entry(this, struct mii_timestamping_desc, list);
60 if (desc->device == device) {
61 list_del_init(entry: &desc->list);
62 kfree(objp: desc);
63 break;
64 }
65 }
66 mutex_unlock(lock: &tstamping_devices_lock);
67}
68EXPORT_SYMBOL(unregister_mii_tstamp_controller);
69
70/**
71 * register_mii_timestamper - Enables a given port of an MII time stamper.
72 *
73 * @node: The device tree node of the MII time stamp controller.
74 * @port: The index of the port to be enabled.
75 *
76 * Returns a valid interface on success or ERR_PTR otherwise.
77 */
78struct mii_timestamper *register_mii_timestamper(struct device_node *node,
79 unsigned int port)
80{
81 struct mii_timestamper *mii_ts = NULL;
82 struct mii_timestamping_desc *desc;
83 struct list_head *this;
84
85 mutex_lock(&tstamping_devices_lock);
86 list_for_each(this, &mii_timestamping_devices) {
87 desc = list_entry(this, struct mii_timestamping_desc, list);
88 if (desc->device->of_node == node) {
89 mii_ts = desc->ctrl->probe_channel(desc->device, port);
90 if (!IS_ERR(ptr: mii_ts)) {
91 mii_ts->device = desc->device;
92 get_device(dev: desc->device);
93 }
94 break;
95 }
96 }
97 mutex_unlock(lock: &tstamping_devices_lock);
98
99 return mii_ts ? mii_ts : ERR_PTR(error: -EPROBE_DEFER);
100}
101EXPORT_SYMBOL(register_mii_timestamper);
102
103/**
104 * unregister_mii_timestamper - Disables a given MII time stamper.
105 *
106 * @mii_ts: An interface obtained via register_mii_timestamper().
107 *
108 */
109void unregister_mii_timestamper(struct mii_timestamper *mii_ts)
110{
111 struct mii_timestamping_desc *desc;
112 struct list_head *this;
113
114 if (!mii_ts)
115 return;
116
117 /* mii_timestamper statically registered by the PHY driver won't use the
118 * register_mii_timestamper() and thus don't have ->device set. Don't
119 * try to unregister these.
120 */
121 if (!mii_ts->device)
122 return;
123
124 mutex_lock(&tstamping_devices_lock);
125 list_for_each(this, &mii_timestamping_devices) {
126 desc = list_entry(this, struct mii_timestamping_desc, list);
127 if (desc->device == mii_ts->device) {
128 desc->ctrl->release_channel(desc->device, mii_ts);
129 put_device(dev: desc->device);
130 break;
131 }
132 }
133 mutex_unlock(lock: &tstamping_devices_lock);
134}
135EXPORT_SYMBOL(unregister_mii_timestamper);
136

source code of linux/drivers/net/phy/mii_timestamper.c