1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * PTP virtual clock driver
4 *
5 * Copyright 2021 NXP
6 */
7#include <linux/slab.h>
8#include <linux/hashtable.h>
9#include "ptp_private.h"
10
11#define PTP_VCLOCK_CC_SHIFT 31
12#define PTP_VCLOCK_CC_MULT (1 << PTP_VCLOCK_CC_SHIFT)
13#define PTP_VCLOCK_FADJ_SHIFT 9
14#define PTP_VCLOCK_FADJ_DENOMINATOR 15625ULL
15#define PTP_VCLOCK_REFRESH_INTERVAL (HZ * 2)
16
17/* protects vclock_hash addition/deletion */
18static DEFINE_SPINLOCK(vclock_hash_lock);
19
20static DEFINE_READ_MOSTLY_HASHTABLE(vclock_hash, 8);
21
22static void ptp_vclock_hash_add(struct ptp_vclock *vclock)
23{
24 spin_lock(lock: &vclock_hash_lock);
25
26 hlist_add_head_rcu(n: &vclock->vclock_hash_node,
27 h: &vclock_hash[vclock->clock->index % HASH_SIZE(vclock_hash)]);
28
29 spin_unlock(lock: &vclock_hash_lock);
30}
31
32static void ptp_vclock_hash_del(struct ptp_vclock *vclock)
33{
34 spin_lock(lock: &vclock_hash_lock);
35
36 hlist_del_init_rcu(n: &vclock->vclock_hash_node);
37
38 spin_unlock(lock: &vclock_hash_lock);
39
40 synchronize_rcu();
41}
42
43static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
44{
45 struct ptp_vclock *vclock = info_to_vclock(ptp);
46 s64 adj;
47
48 adj = (s64)scaled_ppm << PTP_VCLOCK_FADJ_SHIFT;
49 adj = div_s64(dividend: adj, PTP_VCLOCK_FADJ_DENOMINATOR);
50
51 if (mutex_lock_interruptible(&vclock->lock))
52 return -EINTR;
53 timecounter_read(tc: &vclock->tc);
54 vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;
55 mutex_unlock(lock: &vclock->lock);
56
57 return 0;
58}
59
60static int ptp_vclock_adjtime(struct ptp_clock_info *ptp, s64 delta)
61{
62 struct ptp_vclock *vclock = info_to_vclock(ptp);
63
64 if (mutex_lock_interruptible(&vclock->lock))
65 return -EINTR;
66 timecounter_adjtime(tc: &vclock->tc, delta);
67 mutex_unlock(lock: &vclock->lock);
68
69 return 0;
70}
71
72static int ptp_vclock_gettime(struct ptp_clock_info *ptp,
73 struct timespec64 *ts)
74{
75 struct ptp_vclock *vclock = info_to_vclock(ptp);
76 u64 ns;
77
78 if (mutex_lock_interruptible(&vclock->lock))
79 return -EINTR;
80 ns = timecounter_read(tc: &vclock->tc);
81 mutex_unlock(lock: &vclock->lock);
82 *ts = ns_to_timespec64(nsec: ns);
83
84 return 0;
85}
86
87static int ptp_vclock_gettimex(struct ptp_clock_info *ptp,
88 struct timespec64 *ts,
89 struct ptp_system_timestamp *sts)
90{
91 struct ptp_vclock *vclock = info_to_vclock(ptp);
92 struct ptp_clock *pptp = vclock->pclock;
93 struct timespec64 pts;
94 int err;
95 u64 ns;
96
97 err = pptp->info->getcyclesx64(pptp->info, &pts, sts);
98 if (err)
99 return err;
100
101 if (mutex_lock_interruptible(&vclock->lock))
102 return -EINTR;
103 ns = timecounter_cyc2time(tc: &vclock->tc, cycle_tstamp: timespec64_to_ns(ts: &pts));
104 mutex_unlock(lock: &vclock->lock);
105
106 *ts = ns_to_timespec64(nsec: ns);
107
108 return 0;
109}
110
111static int ptp_vclock_settime(struct ptp_clock_info *ptp,
112 const struct timespec64 *ts)
113{
114 struct ptp_vclock *vclock = info_to_vclock(ptp);
115 u64 ns = timespec64_to_ns(ts);
116
117 if (mutex_lock_interruptible(&vclock->lock))
118 return -EINTR;
119 timecounter_init(tc: &vclock->tc, cc: &vclock->cc, start_tstamp: ns);
120 mutex_unlock(lock: &vclock->lock);
121
122 return 0;
123}
124
125static int ptp_vclock_getcrosststamp(struct ptp_clock_info *ptp,
126 struct system_device_crosststamp *xtstamp)
127{
128 struct ptp_vclock *vclock = info_to_vclock(ptp);
129 struct ptp_clock *pptp = vclock->pclock;
130 int err;
131 u64 ns;
132
133 err = pptp->info->getcrosscycles(pptp->info, xtstamp);
134 if (err)
135 return err;
136
137 if (mutex_lock_interruptible(&vclock->lock))
138 return -EINTR;
139 ns = timecounter_cyc2time(tc: &vclock->tc, cycle_tstamp: ktime_to_ns(kt: xtstamp->device));
140 mutex_unlock(lock: &vclock->lock);
141
142 xtstamp->device = ns_to_ktime(ns);
143
144 return 0;
145}
146
147static long ptp_vclock_refresh(struct ptp_clock_info *ptp)
148{
149 struct ptp_vclock *vclock = info_to_vclock(ptp);
150 struct timespec64 ts;
151
152 ptp_vclock_gettime(ptp: &vclock->info, ts: &ts);
153
154 return PTP_VCLOCK_REFRESH_INTERVAL;
155}
156
157static const struct ptp_clock_info ptp_vclock_info = {
158 .owner = THIS_MODULE,
159 .name = "ptp virtual clock",
160 .max_adj = 500000000,
161 .adjfine = ptp_vclock_adjfine,
162 .adjtime = ptp_vclock_adjtime,
163 .settime64 = ptp_vclock_settime,
164 .do_aux_work = ptp_vclock_refresh,
165};
166
167static u64 ptp_vclock_read(const struct cyclecounter *cc)
168{
169 struct ptp_vclock *vclock = cc_to_vclock(cc);
170 struct ptp_clock *ptp = vclock->pclock;
171 struct timespec64 ts = {};
172
173 ptp->info->getcycles64(ptp->info, &ts);
174
175 return timespec64_to_ns(ts: &ts);
176}
177
178static const struct cyclecounter ptp_vclock_cc = {
179 .read = ptp_vclock_read,
180 .mask = CYCLECOUNTER_MASK(32),
181 .mult = PTP_VCLOCK_CC_MULT,
182 .shift = PTP_VCLOCK_CC_SHIFT,
183};
184
185struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
186{
187 struct ptp_vclock *vclock;
188
189 vclock = kzalloc(size: sizeof(*vclock), GFP_KERNEL);
190 if (!vclock)
191 return NULL;
192
193 vclock->pclock = pclock;
194 vclock->info = ptp_vclock_info;
195 if (pclock->info->getcyclesx64)
196 vclock->info.gettimex64 = ptp_vclock_gettimex;
197 else
198 vclock->info.gettime64 = ptp_vclock_gettime;
199 if (pclock->info->getcrosscycles)
200 vclock->info.getcrosststamp = ptp_vclock_getcrosststamp;
201 vclock->cc = ptp_vclock_cc;
202
203 snprintf(buf: vclock->info.name, PTP_CLOCK_NAME_LEN, fmt: "ptp%d_virt",
204 pclock->index);
205
206 INIT_HLIST_NODE(h: &vclock->vclock_hash_node);
207
208 mutex_init(&vclock->lock);
209
210 vclock->clock = ptp_clock_register(info: &vclock->info, parent: &pclock->dev);
211 if (IS_ERR_OR_NULL(ptr: vclock->clock)) {
212 kfree(objp: vclock);
213 return NULL;
214 }
215
216 timecounter_init(tc: &vclock->tc, cc: &vclock->cc, start_tstamp: 0);
217 ptp_schedule_worker(ptp: vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);
218
219 ptp_vclock_hash_add(vclock);
220
221 return vclock;
222}
223
224void ptp_vclock_unregister(struct ptp_vclock *vclock)
225{
226 ptp_vclock_hash_del(vclock);
227
228 ptp_clock_unregister(ptp: vclock->clock);
229 kfree(objp: vclock);
230}
231
232#if IS_BUILTIN(CONFIG_PTP_1588_CLOCK)
233int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
234{
235 char name[PTP_CLOCK_NAME_LEN] = "";
236 struct ptp_clock *ptp;
237 struct device *dev;
238 int num = 0;
239
240 if (pclock_index < 0)
241 return num;
242
243 snprintf(buf: name, PTP_CLOCK_NAME_LEN, fmt: "ptp%d", pclock_index);
244 dev = class_find_device_by_name(class: &ptp_class, name);
245 if (!dev)
246 return num;
247
248 ptp = dev_get_drvdata(dev);
249
250 if (mutex_lock_interruptible(&ptp->n_vclocks_mux)) {
251 put_device(dev);
252 return num;
253 }
254
255 *vclock_index = kzalloc(size: sizeof(int) * ptp->n_vclocks, GFP_KERNEL);
256 if (!(*vclock_index))
257 goto out;
258
259 memcpy(*vclock_index, ptp->vclock_index, sizeof(int) * ptp->n_vclocks);
260 num = ptp->n_vclocks;
261out:
262 mutex_unlock(lock: &ptp->n_vclocks_mux);
263 put_device(dev);
264 return num;
265}
266EXPORT_SYMBOL(ptp_get_vclocks_index);
267
268ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index)
269{
270 unsigned int hash = vclock_index % HASH_SIZE(vclock_hash);
271 struct ptp_vclock *vclock;
272 u64 ns;
273 u64 vclock_ns = 0;
274
275 ns = ktime_to_ns(kt: *hwtstamp);
276
277 rcu_read_lock();
278
279 hlist_for_each_entry_rcu(vclock, &vclock_hash[hash], vclock_hash_node) {
280 if (vclock->clock->index != vclock_index)
281 continue;
282
283 if (mutex_lock_interruptible(&vclock->lock))
284 break;
285 vclock_ns = timecounter_cyc2time(tc: &vclock->tc, cycle_tstamp: ns);
286 mutex_unlock(lock: &vclock->lock);
287 break;
288 }
289
290 rcu_read_unlock();
291
292 return ns_to_ktime(ns: vclock_ns);
293}
294EXPORT_SYMBOL(ptp_convert_timestamp);
295#endif
296

source code of linux/drivers/ptp/ptp_vclock.c