summaryrefslogtreecommitdiffstats
path: root/drivers/ptp/ptp_vclock.c
blob: 1c0ed4805c0aac7017258165582ead085427a712 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PTP virtual clock driver
 *
 * Copyright 2021 NXP
 */
#include <linux/slab.h>
#include <linux/hashtable.h>
#include "ptp_private.h"

#define PTP_VCLOCK_CC_SHIFT		31
#define PTP_VCLOCK_CC_MULT		(1 << PTP_VCLOCK_CC_SHIFT)
#define PTP_VCLOCK_FADJ_SHIFT		9
#define PTP_VCLOCK_FADJ_DENOMINATOR	15625ULL
#define PTP_VCLOCK_REFRESH_INTERVAL	(HZ * 2)

/* protects vclock_hash addition/deletion */
static DEFINE_SPINLOCK(vclock_hash_lock);

static DEFINE_READ_MOSTLY_HASHTABLE(vclock_hash, 8);

static void ptp_vclock_hash_add(struct ptp_vclock *vclock)
{
	spin_lock(&vclock_hash_lock);

	hlist_add_head_rcu(&vclock->vclock_hash_node,
			   &vclock_hash[vclock->clock->index % HASH_SIZE(vclock_hash)]);

	spin_unlock(&vclock_hash_lock);
}

static void ptp_vclock_hash_del(struct ptp_vclock *vclock)
{
	spin_lock(&vclock_hash_lock);

	hlist_del_init_rcu(&vclock->vclock_hash_node);

	spin_unlock(&vclock_hash_lock);

	synchronize_rcu();
}

static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	unsigned long flags;
	s64 adj;

	adj = (s64)scaled_ppm << PTP_VCLOCK_FADJ_SHIFT;
	adj = div_s64(adj, PTP_VCLOCK_FADJ_DENOMINATOR);

	spin_lock_irqsave(&vclock->lock, flags);
	timecounter_read(&vclock->tc);
	vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;
	spin_unlock_irqrestore(&vclock->lock, flags);

	return 0;
}

static int ptp_vclock_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	unsigned long flags;

	spin_lock_irqsave(&vclock->lock, flags);
	timecounter_adjtime(&vclock->tc, delta);
	spin_unlock_irqrestore(&vclock->lock, flags);

	return 0;
}

static int ptp_vclock_gettime(struct ptp_clock_info *ptp,
			      struct timespec64 *ts)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	unsigned long flags;
	u64 ns;

	spin_lock_irqsave(&vclock->lock, flags);
	ns = timecounter_read(&vclock->tc);
	spin_unlock_irqrestore(&vclock->lock, flags);
	*ts = ns_to_timespec64(ns);

	return 0;
}

static int ptp_vclock_gettimex(struct ptp_clock_info *ptp,
			       struct timespec64 *ts,
			       struct ptp_system_timestamp *sts)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	struct ptp_clock *pptp = vclock->pclock;
	struct timespec64 pts;
	unsigned long flags;
	int err;
	u64 ns;

	err = pptp->info->getcyclesx64(pptp->info, &pts, sts);
	if (err)
		return err;

	spin_lock_irqsave(&vclock->lock, flags);
	ns = timecounter_cyc2time(&vclock->tc, timespec64_to_ns(&pts));
	spin_unlock_irqrestore(&vclock->lock, flags);

	*ts = ns_to_timespec64(ns);

	return 0;
}

static int ptp_vclock_settime(struct ptp_clock_info *ptp,
			      const struct timespec64 *ts)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	u64 ns = timespec64_to_ns(ts);
	unsigned long flags;

	spin_lock_irqsave(&vclock->lock, flags);
	timecounter_init(&vclock->tc, &vclock->cc, ns);
	spin_unlock_irqrestore(&vclock->lock, flags);

	return 0;
}

static int ptp_vclock_getcrosststamp(struct ptp_clock_info *ptp,
				     struct system_device_crosststamp *xtstamp)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	struct ptp_clock *pptp = vclock->pclock;
	unsigned long flags;
	int err;
	u64 ns;

	err = pptp->info->getcrosscycles(pptp->info, xtstamp);
	if (err)
		return err;

	spin_lock_irqsave(&vclock->lock, flags);
	ns = timecounter_cyc2time(&vclock->tc, ktime_to_ns(xtstamp->device));
	spin_unlock_irqrestore(&vclock->lock, flags);

	xtstamp->device = ns_to_ktime(ns);

	return 0;
}

static long ptp_vclock_refresh(struct ptp_clock_info *ptp)
{
	struct ptp_vclock *vclock = info_to_vclock(ptp);
	struct timespec64 ts;

	ptp_vclock_gettime(&vclock->info, &ts);

	return PTP_VCLOCK_REFRESH_INTERVAL;
}

static const struct ptp_clock_info ptp_vclock_info = {
	.owner		= THIS_MODULE,
	.name		= "ptp virtual clock",
	.max_adj	= 500000000,
	.adjfine	= ptp_vclock_adjfine,
	.adjtime	= ptp_vclock_adjtime,
	.settime64	= ptp_vclock_settime,
	.do_aux_work	= ptp_vclock_refresh,
};

static u64 ptp_vclock_read(const struct cyclecounter *cc)
{
	struct ptp_vclock *vclock = cc_to_vclock(cc);
	struct ptp_clock *ptp = vclock->pclock;
	struct timespec64 ts = {};

	ptp->info->getcycles64(ptp->info, &ts);

	return timespec64_to_ns(&ts);
}

static const struct cyclecounter ptp_vclock_cc = {
	.read	= ptp_vclock_read,
	.mask	= CYCLECOUNTER_MASK(32),
	.mult	= PTP_VCLOCK_CC_MULT,
	.shift	= PTP_VCLOCK_CC_SHIFT,
};

struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
{
	struct ptp_vclock *vclock;

	vclock = kzalloc(sizeof(*vclock), GFP_KERNEL);
	if (!vclock)
		return NULL;

	vclock->pclock = pclock;
	vclock->info = ptp_vclock_info;
	if (pclock->info->getcyclesx64)
		vclock->info.gettimex64 = ptp_vclock_gettimex;
	else
		vclock->info.gettime64 = ptp_vclock_gettime;
	if (pclock->info->getcrosscycles)
		vclock->info.getcrosststamp = ptp_vclock_getcrosststamp;
	vclock->cc = ptp_vclock_cc;

	snprintf(vclock->info.name, PTP_CLOCK_NAME_LEN, "ptp%d_virt",
		 pclock->index);

	INIT_HLIST_NODE(&vclock->vclock_hash_node);

	spin_lock_init(&vclock->lock);

	vclock->clock = ptp_clock_register(&vclock->info, &pclock->dev);
	if (IS_ERR_OR_NULL(vclock->clock)) {
		kfree(vclock);
		return NULL;
	}

	timecounter_init(&vclock->tc, &vclock->cc, 0);
	ptp_schedule_worker(vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);

	ptp_vclock_hash_add(vclock);

	return vclock;
}

void ptp_vclock_unregister(struct ptp_vclock *vclock)
{
	ptp_vclock_hash_del(vclock);

	ptp_clock_unregister(vclock->clock);
	kfree(vclock);
}

#if IS_BUILTIN(CONFIG_PTP_1588_CLOCK)
int ptp_get_vclocks_index(int pclock_index, int **vclock_index)
{
	char name[PTP_CLOCK_NAME_LEN] = "";
	struct ptp_clock *ptp;
	struct device *dev;
	int num = 0;

	if (pclock_index < 0)
		return num;

	snprintf(name, PTP_CLOCK_NAME_LEN, "ptp%d", pclock_index);
	dev = class_find_device_by_name(ptp_class, name);
	if (!dev)
		return num;

	ptp = dev_get_drvdata(dev);

	if (mutex_lock_interruptible(&ptp->n_vclocks_mux)) {
		put_device(dev);
		return num;
	}

	*vclock_index = kzalloc(sizeof(int) * ptp->n_vclocks, GFP_KERNEL);
	if (!(*vclock_index))
		goto out;

	memcpy(*vclock_index, ptp->vclock_index, sizeof(int) * ptp->n_vclocks);
	num = ptp->n_vclocks;
out:
	mutex_unlock(&ptp->n_vclocks_mux);
	put_device(dev);
	return num;
}
EXPORT_SYMBOL(ptp_get_vclocks_index);

ktime_t ptp_convert_timestamp(const ktime_t *hwtstamp, int vclock_index)
{
	unsigned int hash = vclock_index % HASH_SIZE(vclock_hash);
	struct ptp_vclock *vclock;
	unsigned long flags;
	u64 ns;
	u64 vclock_ns = 0;

	ns = ktime_to_ns(*hwtstamp);

	rcu_read_lock();

	hlist_for_each_entry_rcu(vclock, &vclock_hash[hash], vclock_hash_node) {
		if (vclock->clock->index != vclock_index)
			continue;

		spin_lock_irqsave(&vclock->lock, flags);
		vclock_ns = timecounter_cyc2time(&vclock->tc, ns);
		spin_unlock_irqrestore(&vclock->lock, flags);
		break;
	}

	rcu_read_unlock();

	return ns_to_ktime(vclock_ns);
}
EXPORT_SYMBOL(ptp_convert_timestamp);
#endif