drivers/ptp/ptp_vclock.c

   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
  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
  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
  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         s64 adj;
  47
  48         adj = (s64)scaled_ppm << PTP_VCLOCK_FADJ_SHIFT;
  49         adj = div_s64(adj, PTP_VCLOCK_FADJ_DENOMINATOR);
  50
  51         if (mutex_lock_interruptible(&vclock->lock))
  52                 return -EINTR;
  53         timecounter_read(&vclock->tc);
  54         vclock->cc.mult = PTP_VCLOCK_CC_MULT + adj;
  55         mutex_unlock(&vclock->lock);
  56
  57         return 0;
  58 }
  59
  60 static 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(&vclock->tc, delta);
  67         mutex_unlock(&vclock->lock);
  68
  69         return 0;
  70 }
  71
  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         u64 ns;
  77
  78         if (mutex_lock_interruptible(&vclock->lock))
  79                 return -EINTR;
  80         ns = timecounter_read(&vclock->tc);
  81         mutex_unlock(&vclock->lock);
  82         *ts = ns_to_timespec64(ns);
  83
  84         return 0;
  85 }
  86
  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         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(&vclock->tc, timespec64_to_ns(&pts));
 104         mutex_unlock(&vclock->lock);
 105
 106         *ts = ns_to_timespec64(ns);
 107
 108         return 0;
 109 }
 110
 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
 117         if (mutex_lock_interruptible(&vclock->lock))
 118                 return -EINTR;
 119         timecounter_init(&vclock->tc, &vclock->cc, ns);
 120         mutex_unlock(&vclock->lock);
 121
 122         return 0;
 123 }
 124
 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         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(&vclock->tc, ktime_to_ns(xtstamp->device));
 140         mutex_unlock(&vclock->lock);
 141
 142         xtstamp->device = ns_to_ktime(ns);
 143
 144         return 0;
 145 }
 146
 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
 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
 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         mutex_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
 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)
 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
 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         u64 ns;
 273         u64 vclock_ns = 0;
 274
 275         ns = ktime_to_ns(*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(&vclock->tc, ns);
 286                 mutex_unlock(&vclock->lock);
 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