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 */
18 static DEFINE_SPINLOCK(vclock_hash_lock);
19
20 static DEFINE_READ_MOSTLY_HASHTABLE(vclock_hash, 8);
21
ptp_vclock_hash_add(struct ptp_vclock * vclock)22 static void ptp_vclock_hash_add(struct ptp_vclock *vclock)
23 {
24 spin_lock(&vclock_hash_lock);
25
26 hlist_add_head_rcu(&vclock->vclock_hash_node,
27 &vclock_hash[vclock->clock->index % HASH_SIZE(vclock_hash)]);
28
29 spin_unlock(&vclock_hash_lock);
30 }
31
ptp_vclock_hash_del(struct ptp_vclock * vclock)32 static void ptp_vclock_hash_del(struct ptp_vclock *vclock)
33 {
34 spin_lock(&vclock_hash_lock);
35
36 hlist_del_init_rcu(&vclock->vclock_hash_node);
37
38 spin_unlock(&vclock_hash_lock);
39
40 synchronize_rcu();
41 }
42
ptp_vclock_adjfine(struct ptp_clock_info * ptp,long scaled_ppm)43 static int ptp_vclock_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
44 {
45 struct ptp_vclock *vclock = info_to_vclock(ptp);
46 unsigned long flags;
47 s64 adj;
48
49 adj = (s64)scaled_ppm << PTP_VCLOCK_FADJ_SHIFT;
50 adj = div_s64(adj, PTP_VCLOCK_FADJ_DENOMINATOR);
51
52 spin_lock_irqsave(&vclock->lock, flags);
53 timecounter_read(&vclock->tc);
54 vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;
55 spin_unlock_irqrestore(&vclock->lock, flags);
56
57 return 0;
58 }
59
ptp_vclock_adjtime(struct ptp_clock_info * ptp,s64 delta)60 static int ptp_vclock_adjtime(struct ptp_clock_info *ptp, s64 delta)
61 {
62 struct ptp_vclock *vclock = info_to_vclock(ptp);
63 unsigned long flags;
64
65 spin_lock_irqsave(&vclock->lock, flags);
66 timecounter_adjtime(&vclock->tc, delta);
67 spin_unlock_irqrestore(&vclock->lock, flags);
68
69 return 0;
70 }
71
ptp_vclock_gettime(struct ptp_clock_info * ptp,struct timespec64 * ts)72 static int ptp_vclock_gettime(struct ptp_clock_info *ptp,
73 struct timespec64 *ts)
74 {
75 struct ptp_vclock *vclock = info_to_vclock(ptp);
76 unsigned long flags;
77 u64 ns;
78
79 spin_lock_irqsave(&vclock->lock, flags);
80 ns = timecounter_read(&vclock->tc);
81 spin_unlock_irqrestore(&vclock->lock, flags);
82 *ts = ns_to_timespec64(ns);
83
84 return 0;
85 }
86
ptp_vclock_gettimex(struct ptp_clock_info * ptp,struct timespec64 * ts,struct ptp_system_timestamp * sts)87 static 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 unsigned long flags;
95 int err;
96 u64 ns;
97
98 err = pptp->info->getcyclesx64(pptp->info, &pts, sts);
99 if (err)
100 return err;
101
102 spin_lock_irqsave(&vclock->lock, flags);
103 ns = timecounter_cyc2time(&vclock->tc, timespec64_to_ns(&pts));
104 spin_unlock_irqrestore(&vclock->lock, flags);
105
106 *ts = ns_to_timespec64(ns);
107
108 return 0;
109 }
110
ptp_vclock_settime(struct ptp_clock_info * ptp,const struct timespec64 * ts)111 static 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 unsigned long flags;
117
118 spin_lock_irqsave(&vclock->lock, flags);
119 timecounter_init(&vclock->tc, &vclock->cc, ns);
120 spin_unlock_irqrestore(&vclock->lock, flags);
121
122 return 0;
123 }
124
ptp_vclock_getcrosststamp(struct ptp_clock_info * ptp,struct system_device_crosststamp * xtstamp)125 static 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 unsigned long flags;
131 int err;
132 u64 ns;
133
134 err = pptp->info->getcrosscycles(pptp->info, xtstamp);
135 if (err)
136 return err;
137
138 spin_lock_irqsave(&vclock->lock, flags);
139 ns = timecounter_cyc2time(&vclock->tc, ktime_to_ns(xtstamp->device));
140 spin_unlock_irqrestore(&vclock->lock, flags);
141
142 xtstamp->device = ns_to_ktime(ns);
143
144 return 0;
145 }
146
ptp_vclock_refresh(struct ptp_clock_info * ptp)147 static 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(&vclock->info, &ts);
153
154 return PTP_VCLOCK_REFRESH_INTERVAL;
155 }
156
157 static 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
ptp_vclock_read(const struct cyclecounter * cc)167 static 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);
176 }
177
178 static 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
ptp_vclock_register(struct ptp_clock * pclock)185 struct ptp_vclock *ptp_vclock_register(struct ptp_clock *pclock)
186 {
187 struct ptp_vclock *vclock;
188
189 vclock = kzalloc(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(vclock->info.name, PTP_CLOCK_NAME_LEN, "ptp%d_virt",
204 pclock->index);
205
206 INIT_HLIST_NODE(&vclock->vclock_hash_node);
207
208 spin_lock_init(&vclock->lock);
209
210 vclock->clock = ptp_clock_register(&vclock->info, &pclock->dev);
211 if (IS_ERR_OR_NULL(vclock->clock)) {
212 kfree(vclock);
213 return NULL;
214 }
215
216 timecounter_init(&vclock->tc, &vclock->cc, 0);
217 ptp_schedule_worker(vclock->clock, PTP_VCLOCK_REFRESH_INTERVAL);
218
219 ptp_vclock_hash_add(vclock);
220
221 return vclock;
222 }
223
ptp_vclock_unregister(struct ptp_vclock * vclock)224 void ptp_vclock_unregister(struct ptp_vclock *vclock)
225 {
226 ptp_vclock_hash_del(vclock);
227
228 ptp_clock_unregister(vclock->clock);
229 kfree(vclock);
230 }
231
232 #if IS_BUILTIN(CONFIG_PTP_1588_CLOCK)
ptp_get_vclocks_index(int pclock_index,int ** vclock_index)233 int 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(name, PTP_CLOCK_NAME_LEN, "ptp%d", pclock_index);
244 dev = class_find_device_by_name(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(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;
261 out:
262 mutex_unlock(&ptp->n_vclocks_mux);
263 put_device(dev);
264 return num;
265 }
266 EXPORT_SYMBOL(ptp_get_vclocks_index);
267
ptp_convert_timestamp(const ktime_t * hwtstamp,int vclock_index)268 ktime_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 unsigned long flags;
273 u64 ns;
274 u64 vclock_ns = 0;
275
276 ns = ktime_to_ns(*hwtstamp);
277
278 rcu_read_lock();
279
280 hlist_for_each_entry_rcu(vclock, &vclock_hash[hash], vclock_hash_node) {
281 if (vclock->clock->index != vclock_index)
282 continue;
283
284 spin_lock_irqsave(&vclock->lock, flags);
285 vclock_ns = timecounter_cyc2time(&vclock->tc, ns);
286 spin_unlock_irqrestore(&vclock->lock, flags);
287 break;
288 }
289
290 rcu_read_unlock();
291
292 return ns_to_ktime(vclock_ns);
293 }
294 EXPORT_SYMBOL(ptp_convert_timestamp);
295 #endif
296