drivers/net/ethernet/ti/cpts.c

   1 /*
   2  * TI Common Platform Time Sync
   3  *
   4  * Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  */
  20 #include <linux/err.h>
  21 #include <linux/if.h>
  22 #include <linux/hrtimer.h>
  23 #include <linux/module.h>
  24 #include <linux/net_tstamp.h>
  25 #include <linux/ptp_classify.h>
  26 #include <linux/time.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/if_ether.h>
  30 #include <linux/if_vlan.h>
  31
  32 #include "cpts.h"
  33
  34 #define CPTS_SKB_TX_WORK_TIMEOUT 1 /* jiffies */
  35
  36 struct cpts_skb_cb_data {
  37         unsigned long tmo;
  38 };
  39
  40 #define cpts_read32(c, r)       readl_relaxed(&c->reg->r)
  41 #define cpts_write32(c, v, r)   writel_relaxed(v, &c->reg->r)
  42
  43 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
  44                       u16 ts_seqid, u8 ts_msgtype);
  45
  46 static int event_expired(struct cpts_event *event)
  47 {
  48         return time_after(jiffies, event->tmo);
  49 }
  50
  51 static int event_type(struct cpts_event *event)
  52 {
  53         return (event->high >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
  54 }
  55
  56 static int cpts_fifo_pop(struct cpts *cpts, u32 *high, u32 *low)
  57 {
  58         u32 r = cpts_read32(cpts, intstat_raw);
  59
  60         if (r & TS_PEND_RAW) {
  61                 *high = cpts_read32(cpts, event_high);
  62                 *low  = cpts_read32(cpts, event_low);
  63                 cpts_write32(cpts, EVENT_POP, event_pop);
  64                 return 0;
  65         }
  66         return -1;
  67 }
  68
  69 static int cpts_purge_events(struct cpts *cpts)
  70 {
  71         struct list_head *this, *next;
  72         struct cpts_event *event;
  73         int removed = 0;
  74
  75         list_for_each_safe(this, next, &cpts->events) {
  76                 event = list_entry(this, struct cpts_event, list);
  77                 if (event_expired(event)) {
  78                         list_del_init(&event->list);
  79                         list_add(&event->list, &cpts->pool);
  80                         ++removed;
  81                 }
  82         }
  83
  84         if (removed)
  85                 pr_debug("cpts: event pool cleaned up %d\n", removed);
  86         return removed ? 0 : -1;
  87 }
  88
  89 static bool cpts_match_tx_ts(struct cpts *cpts, struct cpts_event *event)
  90 {
  91         struct sk_buff *skb, *tmp;
  92         u16 seqid;
  93         u8 mtype;
  94         bool found = false;
  95
  96         mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
  97         seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
  98
  99         /* no need to grab txq.lock as access is always done under cpts->lock */
 100         skb_queue_walk_safe(&cpts->txq, skb, tmp) {
 101                 struct skb_shared_hwtstamps ssh;
 102                 unsigned int class = ptp_classify_raw(skb);
 103                 struct cpts_skb_cb_data *skb_cb =
 104                                         (struct cpts_skb_cb_data *)skb->cb;
 105
 106                 if (cpts_match(skb, class, seqid, mtype)) {
 107                         u64 ns = timecounter_cyc2time(&cpts->tc, event->low);
 108
 109                         memset(&ssh, 0, sizeof(ssh));
 110                         ssh.hwtstamp = ns_to_ktime(ns);
 111                         skb_tstamp_tx(skb, &ssh);
 112                         found = true;
 113                         __skb_unlink(skb, &cpts->txq);
 114                         dev_consume_skb_any(skb);
 115                         dev_dbg(cpts->dev, "match tx timestamp mtype %u seqid %04x\n",
 116                                 mtype, seqid);
 117                         break;
 118                 }
 119
 120                 if (time_after(jiffies, skb_cb->tmo)) {
 121                         /* timeout any expired skbs over 1s */
 122                         dev_dbg(cpts->dev, "expiring tx timestamp from txq\n");
 123                         __skb_unlink(skb, &cpts->txq);
 124                         dev_consume_skb_any(skb);
 125                 }
 126         }
 127
 128         return found;
 129 }
 130
 131 /*
 132  * Returns zero if matching event type was found.
 133  */
 134 static int cpts_fifo_read(struct cpts *cpts, int match)
 135 {
 136         int i, type = -1;
 137         u32 hi, lo;
 138         struct cpts_event *event;
 139
 140         for (i = 0; i < CPTS_FIFO_DEPTH; i++) {
 141                 if (cpts_fifo_pop(cpts, &hi, &lo))
 142                         break;
 143
 144                 if (list_empty(&cpts->pool) && cpts_purge_events(cpts)) {
 145                         pr_err("cpts: event pool empty\n");
 146                         return -1;
 147                 }
 148
 149                 event = list_first_entry(&cpts->pool, struct cpts_event, list);
 150                 event->tmo = jiffies + 2;
 151                 event->high = hi;
 152                 event->low = lo;
 153                 type = event_type(event);
 154                 switch (type) {
 155                 case CPTS_EV_TX:
 156                         if (cpts_match_tx_ts(cpts, event)) {
 157                                 /* if the new event matches an existing skb,
 158                                  * then don't queue it
 159                                  */
 160                                 break;
 161                         }
 162                         /* fall through */
 163                 case CPTS_EV_PUSH:
 164                 case CPTS_EV_RX:
 165                         list_del_init(&event->list);
 166                         list_add_tail(&event->list, &cpts->events);
 167                         break;
 168                 case CPTS_EV_ROLL:
 169                 case CPTS_EV_HALF:
 170                 case CPTS_EV_HW:
 171                         break;
 172                 default:
 173                         pr_err("cpts: unknown event type\n");
 174                         break;
 175                 }
 176                 if (type == match)
 177                         break;
 178         }
 179         return type == match ? 0 : -1;
 180 }
 181
 182 static u64 cpts_systim_read(const struct cyclecounter *cc)
 183 {
 184         u64 val = 0;
 185         struct cpts_event *event;
 186         struct list_head *this, *next;
 187         struct cpts *cpts = container_of(cc, struct cpts, cc);
 188
 189         cpts_write32(cpts, TS_PUSH, ts_push);
 190         if (cpts_fifo_read(cpts, CPTS_EV_PUSH))
 191                 pr_err("cpts: unable to obtain a time stamp\n");
 192
 193         list_for_each_safe(this, next, &cpts->events) {
 194                 event = list_entry(this, struct cpts_event, list);
 195                 if (event_type(event) == CPTS_EV_PUSH) {
 196                         list_del_init(&event->list);
 197                         list_add(&event->list, &cpts->pool);
 198                         val = event->low;
 199                         break;
 200                 }
 201         }
 202
 203         return val;
 204 }
 205
 206 /* PTP clock operations */
 207
 208 static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 209 {
 210         u64 adj;
 211         u32 diff, mult;
 212         int neg_adj = 0;
 213         unsigned long flags;
 214         struct cpts *cpts = container_of(ptp, struct cpts, info);
 215
 216         if (ppb < 0) {
 217                 neg_adj = 1;
 218                 ppb = -ppb;
 219         }
 220         mult = cpts->cc_mult;
 221         adj = mult;
 222         adj *= ppb;
 223         diff = div_u64(adj, 1000000000ULL);
 224
 225         spin_lock_irqsave(&cpts->lock, flags);
 226
 227         timecounter_read(&cpts->tc);
 228
 229         cpts->cc.mult = neg_adj ? mult - diff : mult + diff;
 230
 231         spin_unlock_irqrestore(&cpts->lock, flags);
 232
 233         return 0;
 234 }
 235
 236 static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 237 {
 238         unsigned long flags;
 239         struct cpts *cpts = container_of(ptp, struct cpts, info);
 240
 241         spin_lock_irqsave(&cpts->lock, flags);
 242         timecounter_adjtime(&cpts->tc, delta);
 243         spin_unlock_irqrestore(&cpts->lock, flags);
 244
 245         return 0;
 246 }
 247
 248 static int cpts_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 249 {
 250         u64 ns;
 251         unsigned long flags;
 252         struct cpts *cpts = container_of(ptp, struct cpts, info);
 253
 254         spin_lock_irqsave(&cpts->lock, flags);
 255         ns = timecounter_read(&cpts->tc);
 256         spin_unlock_irqrestore(&cpts->lock, flags);
 257
 258         *ts = ns_to_timespec64(ns);
 259
 260         return 0;
 261 }
 262
 263 static int cpts_ptp_settime(struct ptp_clock_info *ptp,
 264                             const struct timespec64 *ts)
 265 {
 266         u64 ns;
 267         unsigned long flags;
 268         struct cpts *cpts = container_of(ptp, struct cpts, info);
 269
 270         ns = timespec64_to_ns(ts);
 271
 272         spin_lock_irqsave(&cpts->lock, flags);
 273         timecounter_init(&cpts->tc, &cpts->cc, ns);
 274         spin_unlock_irqrestore(&cpts->lock, flags);
 275
 276         return 0;
 277 }
 278
 279 static int cpts_ptp_enable(struct ptp_clock_info *ptp,
 280                            struct ptp_clock_request *rq, int on)
 281 {
 282         return -EOPNOTSUPP;
 283 }
 284
 285 static long cpts_overflow_check(struct ptp_clock_info *ptp)
 286 {
 287         struct cpts *cpts = container_of(ptp, struct cpts, info);
 288         unsigned long delay = cpts->ov_check_period;
 289         struct timespec64 ts;
 290         unsigned long flags;
 291
 292         spin_lock_irqsave(&cpts->lock, flags);
 293         ts = ns_to_timespec64(timecounter_read(&cpts->tc));
 294
 295         if (!skb_queue_empty(&cpts->txq))
 296                 delay = CPTS_SKB_TX_WORK_TIMEOUT;
 297         spin_unlock_irqrestore(&cpts->lock, flags);
 298
 299         pr_debug("cpts overflow check at %lld.%09ld\n",
 300                  (long long)ts.tv_sec, ts.tv_nsec);
 301         return (long)delay;
 302 }
 303
 304 static const struct ptp_clock_info cpts_info = {
 305         .owner          = THIS_MODULE,
 306         .name           = "CTPS timer",
 307         .max_adj        = 1000000,
 308         .n_ext_ts       = 0,
 309         .n_pins         = 0,
 310         .pps            = 0,
 311         .adjfreq        = cpts_ptp_adjfreq,
 312         .adjtime        = cpts_ptp_adjtime,
 313         .gettime64      = cpts_ptp_gettime,
 314         .settime64      = cpts_ptp_settime,
 315         .enable         = cpts_ptp_enable,
 316         .do_aux_work    = cpts_overflow_check,
 317 };
 318
 319 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
 320                       u16 ts_seqid, u8 ts_msgtype)
 321 {
 322         u16 *seqid;
 323         unsigned int offset = 0;
 324         u8 *msgtype, *data = skb->data;
 325
 326         if (ptp_class & PTP_CLASS_VLAN)
 327                 offset += VLAN_HLEN;
 328
 329         switch (ptp_class & PTP_CLASS_PMASK) {
 330         case PTP_CLASS_IPV4:
 331                 offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
 332                 break;
 333         case PTP_CLASS_IPV6:
 334                 offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
 335                 break;
 336         case PTP_CLASS_L2:
 337                 offset += ETH_HLEN;
 338                 break;
 339         default:
 340                 return 0;
 341         }
 342
 343         if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
 344                 return 0;
 345
 346         if (unlikely(ptp_class & PTP_CLASS_V1))
 347                 msgtype = data + offset + OFF_PTP_CONTROL;
 348         else
 349                 msgtype = data + offset;
 350
 351         seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
 352
 353         return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
 354 }
 355
 356 static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
 357 {
 358         u64 ns = 0;
 359         struct cpts_event *event;
 360         struct list_head *this, *next;
 361         unsigned int class = ptp_classify_raw(skb);
 362         unsigned long flags;
 363         u16 seqid;
 364         u8 mtype;
 365
 366         if (class == PTP_CLASS_NONE)
 367                 return 0;
 368
 369         spin_lock_irqsave(&cpts->lock, flags);
 370         cpts_fifo_read(cpts, -1);
 371         list_for_each_safe(this, next, &cpts->events) {
 372                 event = list_entry(this, struct cpts_event, list);
 373                 if (event_expired(event)) {
 374                         list_del_init(&event->list);
 375                         list_add(&event->list, &cpts->pool);
 376                         continue;
 377                 }
 378                 mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
 379                 seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
 380                 if (ev_type == event_type(event) &&
 381                     cpts_match(skb, class, seqid, mtype)) {
 382                         ns = timecounter_cyc2time(&cpts->tc, event->low);
 383                         list_del_init(&event->list);
 384                         list_add(&event->list, &cpts->pool);
 385                         break;
 386                 }
 387         }
 388
 389         if (ev_type == CPTS_EV_TX && !ns) {
 390                 struct cpts_skb_cb_data *skb_cb =
 391                                 (struct cpts_skb_cb_data *)skb->cb;
 392                 /* Not found, add frame to queue for processing later.
 393                  * The periodic FIFO check will handle this.
 394                  */
 395                 skb_get(skb);
 396                 /* get the timestamp for timeouts */
 397                 skb_cb->tmo = jiffies + msecs_to_jiffies(100);
 398                 __skb_queue_tail(&cpts->txq, skb);
 399                 ptp_schedule_worker(cpts->clock, 0);
 400         }
 401         spin_unlock_irqrestore(&cpts->lock, flags);
 402
 403         return ns;
 404 }
 405
 406 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 407 {
 408         u64 ns;
 409         struct skb_shared_hwtstamps *ssh;
 410
 411         if (!cpts->rx_enable)
 412                 return;
 413         ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
 414         if (!ns)
 415                 return;
 416         ssh = skb_hwtstamps(skb);
 417         memset(ssh, 0, sizeof(*ssh));
 418         ssh->hwtstamp = ns_to_ktime(ns);
 419 }
 420 EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
 421
 422 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 423 {
 424         u64 ns;
 425         struct skb_shared_hwtstamps ssh;
 426
 427         if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
 428                 return;
 429         ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
 430         if (!ns)
 431                 return;
 432         memset(&ssh, 0, sizeof(ssh));
 433         ssh.hwtstamp = ns_to_ktime(ns);
 434         skb_tstamp_tx(skb, &ssh);
 435 }
 436 EXPORT_SYMBOL_GPL(cpts_tx_timestamp);
 437
 438 int cpts_register(struct cpts *cpts)
 439 {
 440         int err, i;
 441
 442         skb_queue_head_init(&cpts->txq);
 443         INIT_LIST_HEAD(&cpts->events);
 444         INIT_LIST_HEAD(&cpts->pool);
 445         for (i = 0; i < CPTS_MAX_EVENTS; i++)
 446                 list_add(&cpts->pool_data[i].list, &cpts->pool);
 447
 448         err = clk_enable(cpts->refclk);
 449         if (err)
 450                 return err;
 451
 452         cpts_write32(cpts, CPTS_EN, control);
 453         cpts_write32(cpts, TS_PEND_EN, int_enable);
 454
 455         timecounter_init(&cpts->tc, &cpts->cc, ktime_to_ns(ktime_get_real()));
 456
 457         cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
 458         if (IS_ERR(cpts->clock)) {
 459                 err = PTR_ERR(cpts->clock);
 460                 cpts->clock = NULL;
 461                 goto err_ptp;
 462         }
 463         cpts->phc_index = ptp_clock_index(cpts->clock);
 464
 465         ptp_schedule_worker(cpts->clock, cpts->ov_check_period);
 466         return 0;
 467
 468 err_ptp:
 469         clk_disable(cpts->refclk);
 470         return err;
 471 }
 472 EXPORT_SYMBOL_GPL(cpts_register);
 473
 474 void cpts_unregister(struct cpts *cpts)
 475 {
 476         if (WARN_ON(!cpts->clock))
 477                 return;
 478
 479         ptp_clock_unregister(cpts->clock);
 480         cpts->clock = NULL;
 481         cpts->phc_index = -1;
 482
 483         cpts_write32(cpts, 0, int_enable);
 484         cpts_write32(cpts, 0, control);
 485
 486         /* Drop all packet */
 487         skb_queue_purge(&cpts->txq);
 488
 489         clk_disable(cpts->refclk);
 490 }
 491 EXPORT_SYMBOL_GPL(cpts_unregister);
 492
 493 static void cpts_calc_mult_shift(struct cpts *cpts)
 494 {
 495         u64 frac, maxsec, ns;
 496         u32 freq;
 497
 498         freq = clk_get_rate(cpts->refclk);
 499
 500         /* Calc the maximum number of seconds which we can run before
 501          * wrapping around.
 502          */
 503         maxsec = cpts->cc.mask;
 504         do_div(maxsec, freq);
 505         /* limit conversation rate to 10 sec as higher values will produce
 506          * too small mult factors and so reduce the conversion accuracy
 507          */
 508         if (maxsec > 10)
 509                 maxsec = 10;
 510
 511         /* Calc overflow check period (maxsec / 2) */
 512         cpts->ov_check_period = (HZ * maxsec) / 2;
 513         dev_info(cpts->dev, "cpts: overflow check period %lu (jiffies)\n",
 514                  cpts->ov_check_period);
 515
 516         if (cpts->cc.mult || cpts->cc.shift)
 517                 return;
 518
 519         clocks_calc_mult_shift(&cpts->cc.mult, &cpts->cc.shift,
 520                                freq, NSEC_PER_SEC, maxsec);
 521
 522         frac = 0;
 523         ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
 524
 525         dev_info(cpts->dev,
 526                  "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld nsec/sec\n",
 527                  freq, cpts->cc.mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
 528 }
 529
 530 static int cpts_of_parse(struct cpts *cpts, struct device_node *node)
 531 {
 532         int ret = -EINVAL;
 533         u32 prop;
 534
 535         if (!of_property_read_u32(node, "cpts_clock_mult", &prop))
 536                 cpts->cc.mult = prop;
 537
 538         if (!of_property_read_u32(node, "cpts_clock_shift", &prop))
 539                 cpts->cc.shift = prop;
 540
 541         if ((cpts->cc.mult && !cpts->cc.shift) ||
 542             (!cpts->cc.mult && cpts->cc.shift))
 543                 goto of_error;
 544
 545         return 0;
 546
 547 of_error:
 548         dev_err(cpts->dev, "CPTS: Missing property in the DT.\n");
 549         return ret;
 550 }
 551
 552 struct cpts *cpts_create(struct device *dev, void __iomem *regs,
 553                          struct device_node *node)
 554 {
 555         struct cpts *cpts;
 556         int ret;
 557
 558         cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
 559         if (!cpts)
 560                 return ERR_PTR(-ENOMEM);
 561
 562         cpts->dev = dev;
 563         cpts->reg = (struct cpsw_cpts __iomem *)regs;
 564         spin_lock_init(&cpts->lock);
 565
 566         ret = cpts_of_parse(cpts, node);
 567         if (ret)
 568                 return ERR_PTR(ret);
 569
 570         cpts->refclk = devm_clk_get(dev, "cpts");
 571         if (IS_ERR(cpts->refclk)) {
 572                 dev_err(dev, "Failed to get cpts refclk\n");
 573                 return ERR_CAST(cpts->refclk);
 574         }
 575
 576         ret = clk_prepare(cpts->refclk);
 577         if (ret)
 578                 return ERR_PTR(ret);
 579
 580         cpts->cc.read = cpts_systim_read;
 581         cpts->cc.mask = CLOCKSOURCE_MASK(32);
 582         cpts->info = cpts_info;
 583         cpts->phc_index = -1;
 584
 585         cpts_calc_mult_shift(cpts);
 586         /* save cc.mult original value as it can be modified
 587          * by cpts_ptp_adjfreq().
 588          */
 589         cpts->cc_mult = cpts->cc.mult;
 590
 591         return cpts;
 592 }
 593 EXPORT_SYMBOL_GPL(cpts_create);
 594
 595 void cpts_release(struct cpts *cpts)
 596 {
 597         if (!cpts)
 598                 return;
 599
 600         if (WARN_ON(!cpts->refclk))
 601                 return;
 602
 603         clk_unprepare(cpts->refclk);
 604 }
 605 EXPORT_SYMBOL_GPL(cpts_release);
 606
 607 MODULE_LICENSE("GPL v2");
 608 MODULE_DESCRIPTION("TI CPTS driver");
 609 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");