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                 } else if (time_after(jiffies, skb_cb->tmo)) {
 118                         /* timeout any expired skbs over 1s */
 119                         dev_dbg(cpts->dev,
 120                                 "expiring tx timestamp mtype %u seqid %04x\n",
 121                                 mtype, seqid);
 122                         __skb_unlink(skb, &cpts->txq);
 123                         dev_consume_skb_any(skb);
 124                 }
 125         }
 126
 127         return found;
 128 }
 129
 130 /*
 131  * Returns zero if matching event type was found.
 132  */
 133 static int cpts_fifo_read(struct cpts *cpts, int match)
 134 {
 135         int i, type = -1;
 136         u32 hi, lo;
 137         struct cpts_event *event;
 138
 139         for (i = 0; i < CPTS_FIFO_DEPTH; i++) {
 140                 if (cpts_fifo_pop(cpts, &hi, &lo))
 141                         break;
 142
 143                 if (list_empty(&cpts->pool) && cpts_purge_events(cpts)) {
 144                         pr_err("cpts: event pool empty\n");
 145                         return -1;
 146                 }
 147
 148                 event = list_first_entry(&cpts->pool, struct cpts_event, list);
 149                 event->tmo = jiffies + 2;
 150                 event->high = hi;
 151                 event->low = lo;
 152                 type = event_type(event);
 153                 switch (type) {
 154                 case CPTS_EV_TX:
 155                         if (cpts_match_tx_ts(cpts, event)) {
 156                                 /* if the new event matches an existing skb,
 157                                  * then don't queue it
 158                                  */
 159                                 break;
 160                         }
 161                 case CPTS_EV_PUSH:
 162                 case CPTS_EV_RX:
 163                         list_del_init(&event->list);
 164                         list_add_tail(&event->list, &cpts->events);
 165                         break;
 166                 case CPTS_EV_ROLL:
 167                 case CPTS_EV_HALF:
 168                 case CPTS_EV_HW:
 169                         break;
 170                 default:
 171                         pr_err("cpts: unknown event type\n");
 172                         break;
 173                 }
 174                 if (type == match)
 175                         break;
 176         }
 177         return type == match ? 0 : -1;
 178 }
 179
 180 static u64 cpts_systim_read(const struct cyclecounter *cc)
 181 {
 182         u64 val = 0;
 183         struct cpts_event *event;
 184         struct list_head *this, *next;
 185         struct cpts *cpts = container_of(cc, struct cpts, cc);
 186
 187         cpts_write32(cpts, TS_PUSH, ts_push);
 188         if (cpts_fifo_read(cpts, CPTS_EV_PUSH))
 189                 pr_err("cpts: unable to obtain a time stamp\n");
 190
 191         list_for_each_safe(this, next, &cpts->events) {
 192                 event = list_entry(this, struct cpts_event, list);
 193                 if (event_type(event) == CPTS_EV_PUSH) {
 194                         list_del_init(&event->list);
 195                         list_add(&event->list, &cpts->pool);
 196                         val = event->low;
 197                         break;
 198                 }
 199         }
 200
 201         return val;
 202 }
 203
 204 /* PTP clock operations */
 205
 206 static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 207 {
 208         u64 adj;
 209         u32 diff, mult;
 210         int neg_adj = 0;
 211         unsigned long flags;
 212         struct cpts *cpts = container_of(ptp, struct cpts, info);
 213
 214         if (ppb < 0) {
 215                 neg_adj = 1;
 216                 ppb = -ppb;
 217         }
 218         mult = cpts->cc_mult;
 219         adj = mult;
 220         adj *= ppb;
 221         diff = div_u64(adj, 1000000000ULL);
 222
 223         spin_lock_irqsave(&cpts->lock, flags);
 224
 225         timecounter_read(&cpts->tc);
 226
 227         cpts->cc.mult = neg_adj ? mult - diff : mult + diff;
 228
 229         spin_unlock_irqrestore(&cpts->lock, flags);
 230
 231         return 0;
 232 }
 233
 234 static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 235 {
 236         unsigned long flags;
 237         struct cpts *cpts = container_of(ptp, struct cpts, info);
 238
 239         spin_lock_irqsave(&cpts->lock, flags);
 240         timecounter_adjtime(&cpts->tc, delta);
 241         spin_unlock_irqrestore(&cpts->lock, flags);
 242
 243         return 0;
 244 }
 245
 246 static int cpts_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 247 {
 248         u64 ns;
 249         unsigned long flags;
 250         struct cpts *cpts = container_of(ptp, struct cpts, info);
 251
 252         spin_lock_irqsave(&cpts->lock, flags);
 253         ns = timecounter_read(&cpts->tc);
 254         spin_unlock_irqrestore(&cpts->lock, flags);
 255
 256         *ts = ns_to_timespec64(ns);
 257
 258         return 0;
 259 }
 260
 261 static int cpts_ptp_settime(struct ptp_clock_info *ptp,
 262                             const struct timespec64 *ts)
 263 {
 264         u64 ns;
 265         unsigned long flags;
 266         struct cpts *cpts = container_of(ptp, struct cpts, info);
 267
 268         ns = timespec64_to_ns(ts);
 269
 270         spin_lock_irqsave(&cpts->lock, flags);
 271         timecounter_init(&cpts->tc, &cpts->cc, ns);
 272         spin_unlock_irqrestore(&cpts->lock, flags);
 273
 274         return 0;
 275 }
 276
 277 static int cpts_ptp_enable(struct ptp_clock_info *ptp,
 278                            struct ptp_clock_request *rq, int on)
 279 {
 280         return -EOPNOTSUPP;
 281 }
 282
 283 static long cpts_overflow_check(struct ptp_clock_info *ptp)
 284 {
 285         struct cpts *cpts = container_of(ptp, struct cpts, info);
 286         unsigned long delay = cpts->ov_check_period;
 287         struct timespec64 ts;
 288         unsigned long flags;
 289
 290         spin_lock_irqsave(&cpts->lock, flags);
 291         ts = ns_to_timespec64(timecounter_read(&cpts->tc));
 292
 293         if (!skb_queue_empty(&cpts->txq))
 294                 delay = CPTS_SKB_TX_WORK_TIMEOUT;
 295         spin_unlock_irqrestore(&cpts->lock, flags);
 296
 297         pr_debug("cpts overflow check at %lld.%09ld\n",
 298                  (long long)ts.tv_sec, ts.tv_nsec);
 299         return (long)delay;
 300 }
 301
 302 static const struct ptp_clock_info cpts_info = {
 303         .owner          = THIS_MODULE,
 304         .name           = "CTPS timer",
 305         .max_adj        = 1000000,
 306         .n_ext_ts       = 0,
 307         .n_pins         = 0,
 308         .pps            = 0,
 309         .adjfreq        = cpts_ptp_adjfreq,
 310         .adjtime        = cpts_ptp_adjtime,
 311         .gettime64      = cpts_ptp_gettime,
 312         .settime64      = cpts_ptp_settime,
 313         .enable         = cpts_ptp_enable,
 314         .do_aux_work    = cpts_overflow_check,
 315 };
 316
 317 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
 318                       u16 ts_seqid, u8 ts_msgtype)
 319 {
 320         u16 *seqid;
 321         unsigned int offset = 0;
 322         u8 *msgtype, *data = skb->data;
 323
 324         if (ptp_class & PTP_CLASS_VLAN)
 325                 offset += VLAN_HLEN;
 326
 327         switch (ptp_class & PTP_CLASS_PMASK) {
 328         case PTP_CLASS_IPV4:
 329                 offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
 330                 break;
 331         case PTP_CLASS_IPV6:
 332                 offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
 333                 break;
 334         case PTP_CLASS_L2:
 335                 offset += ETH_HLEN;
 336                 break;
 337         default:
 338                 return 0;
 339         }
 340
 341         if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
 342                 return 0;
 343
 344         if (unlikely(ptp_class & PTP_CLASS_V1))
 345                 msgtype = data + offset + OFF_PTP_CONTROL;
 346         else
 347                 msgtype = data + offset;
 348
 349         seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
 350
 351         return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
 352 }
 353
 354 static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
 355 {
 356         u64 ns = 0;
 357         struct cpts_event *event;
 358         struct list_head *this, *next;
 359         unsigned int class = ptp_classify_raw(skb);
 360         unsigned long flags;
 361         u16 seqid;
 362         u8 mtype;
 363
 364         if (class == PTP_CLASS_NONE)
 365                 return 0;
 366
 367         spin_lock_irqsave(&cpts->lock, flags);
 368         cpts_fifo_read(cpts, -1);
 369         list_for_each_safe(this, next, &cpts->events) {
 370                 event = list_entry(this, struct cpts_event, list);
 371                 if (event_expired(event)) {
 372                         list_del_init(&event->list);
 373                         list_add(&event->list, &cpts->pool);
 374                         continue;
 375                 }
 376                 mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
 377                 seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
 378                 if (ev_type == event_type(event) &&
 379                     cpts_match(skb, class, seqid, mtype)) {
 380                         ns = timecounter_cyc2time(&cpts->tc, event->low);
 381                         list_del_init(&event->list);
 382                         list_add(&event->list, &cpts->pool);
 383                         break;
 384                 }
 385         }
 386
 387         if (ev_type == CPTS_EV_TX && !ns) {
 388                 struct cpts_skb_cb_data *skb_cb =
 389                                 (struct cpts_skb_cb_data *)skb->cb;
 390                 /* Not found, add frame to queue for processing later.
 391                  * The periodic FIFO check will handle this.
 392                  */
 393                 skb_get(skb);
 394                 /* get the timestamp for timeouts */
 395                 skb_cb->tmo = jiffies + msecs_to_jiffies(100);
 396                 __skb_queue_tail(&cpts->txq, skb);
 397                 ptp_schedule_worker(cpts->clock, 0);
 398         }
 399         spin_unlock_irqrestore(&cpts->lock, flags);
 400
 401         return ns;
 402 }
 403
 404 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 405 {
 406         u64 ns;
 407         struct skb_shared_hwtstamps *ssh;
 408
 409         if (!cpts->rx_enable)
 410                 return;
 411         ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
 412         if (!ns)
 413                 return;
 414         ssh = skb_hwtstamps(skb);
 415         memset(ssh, 0, sizeof(*ssh));
 416         ssh->hwtstamp = ns_to_ktime(ns);
 417 }
 418 EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
 419
 420 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 421 {
 422         u64 ns;
 423         struct skb_shared_hwtstamps ssh;
 424
 425         if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
 426                 return;
 427         ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
 428         if (!ns)
 429                 return;
 430         memset(&ssh, 0, sizeof(ssh));
 431         ssh.hwtstamp = ns_to_ktime(ns);
 432         skb_tstamp_tx(skb, &ssh);
 433 }
 434 EXPORT_SYMBOL_GPL(cpts_tx_timestamp);
 435
 436 int cpts_register(struct cpts *cpts)
 437 {
 438         int err, i;
 439
 440         skb_queue_head_init(&cpts->txq);
 441         INIT_LIST_HEAD(&cpts->events);
 442         INIT_LIST_HEAD(&cpts->pool);
 443         for (i = 0; i < CPTS_MAX_EVENTS; i++)
 444                 list_add(&cpts->pool_data[i].list, &cpts->pool);
 445
 446         clk_enable(cpts->refclk);
 447
 448         cpts_write32(cpts, CPTS_EN, control);
 449         cpts_write32(cpts, TS_PEND_EN, int_enable);
 450
 451         timecounter_init(&cpts->tc, &cpts->cc, ktime_to_ns(ktime_get_real()));
 452
 453         cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
 454         if (IS_ERR(cpts->clock)) {
 455                 err = PTR_ERR(cpts->clock);
 456                 cpts->clock = NULL;
 457                 goto err_ptp;
 458         }
 459         cpts->phc_index = ptp_clock_index(cpts->clock);
 460
 461         ptp_schedule_worker(cpts->clock, cpts->ov_check_period);
 462         return 0;
 463
 464 err_ptp:
 465         clk_disable(cpts->refclk);
 466         return err;
 467 }
 468 EXPORT_SYMBOL_GPL(cpts_register);
 469
 470 void cpts_unregister(struct cpts *cpts)
 471 {
 472         if (WARN_ON(!cpts->clock))
 473                 return;
 474
 475         ptp_clock_unregister(cpts->clock);
 476         cpts->clock = NULL;
 477
 478         cpts_write32(cpts, 0, int_enable);
 479         cpts_write32(cpts, 0, control);
 480
 481         /* Drop all packet */
 482         skb_queue_purge(&cpts->txq);
 483
 484         clk_disable(cpts->refclk);
 485 }
 486 EXPORT_SYMBOL_GPL(cpts_unregister);
 487
 488 static void cpts_calc_mult_shift(struct cpts *cpts)
 489 {
 490         u64 frac, maxsec, ns;
 491         u32 freq;
 492
 493         freq = clk_get_rate(cpts->refclk);
 494
 495         /* Calc the maximum number of seconds which we can run before
 496          * wrapping around.
 497          */
 498         maxsec = cpts->cc.mask;
 499         do_div(maxsec, freq);
 500         /* limit conversation rate to 10 sec as higher values will produce
 501          * too small mult factors and so reduce the conversion accuracy
 502          */
 503         if (maxsec > 10)
 504                 maxsec = 10;
 505
 506         /* Calc overflow check period (maxsec / 2) */
 507         cpts->ov_check_period = (HZ * maxsec) / 2;
 508         dev_info(cpts->dev, "cpts: overflow check period %lu (jiffies)\n",
 509                  cpts->ov_check_period);
 510
 511         if (cpts->cc.mult || cpts->cc.shift)
 512                 return;
 513
 514         clocks_calc_mult_shift(&cpts->cc.mult, &cpts->cc.shift,
 515                                freq, NSEC_PER_SEC, maxsec);
 516
 517         frac = 0;
 518         ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
 519
 520         dev_info(cpts->dev,
 521                  "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld nsec/sec\n",
 522                  freq, cpts->cc.mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
 523 }
 524
 525 static int cpts_of_parse(struct cpts *cpts, struct device_node *node)
 526 {
 527         int ret = -EINVAL;
 528         u32 prop;
 529
 530         if (!of_property_read_u32(node, "cpts_clock_mult", &prop))
 531                 cpts->cc.mult = prop;
 532
 533         if (!of_property_read_u32(node, "cpts_clock_shift", &prop))
 534                 cpts->cc.shift = prop;
 535
 536         if ((cpts->cc.mult && !cpts->cc.shift) ||
 537             (!cpts->cc.mult && cpts->cc.shift))
 538                 goto of_error;
 539
 540         return 0;
 541
 542 of_error:
 543         dev_err(cpts->dev, "CPTS: Missing property in the DT.\n");
 544         return ret;
 545 }
 546
 547 struct cpts *cpts_create(struct device *dev, void __iomem *regs,
 548                          struct device_node *node)
 549 {
 550         struct cpts *cpts;
 551         int ret;
 552
 553         cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
 554         if (!cpts)
 555                 return ERR_PTR(-ENOMEM);
 556
 557         cpts->dev = dev;
 558         cpts->reg = (struct cpsw_cpts __iomem *)regs;
 559         spin_lock_init(&cpts->lock);
 560
 561         ret = cpts_of_parse(cpts, node);
 562         if (ret)
 563                 return ERR_PTR(ret);
 564
 565         cpts->refclk = devm_clk_get(dev, "cpts");
 566         if (IS_ERR(cpts->refclk)) {
 567                 dev_err(dev, "Failed to get cpts refclk\n");
 568                 return ERR_CAST(cpts->refclk);
 569         }
 570
 571         clk_prepare(cpts->refclk);
 572
 573         cpts->cc.read = cpts_systim_read;
 574         cpts->cc.mask = CLOCKSOURCE_MASK(32);
 575         cpts->info = cpts_info;
 576
 577         cpts_calc_mult_shift(cpts);
 578         /* save cc.mult original value as it can be modified
 579          * by cpts_ptp_adjfreq().
 580          */
 581         cpts->cc_mult = cpts->cc.mult;
 582
 583         return cpts;
 584 }
 585 EXPORT_SYMBOL_GPL(cpts_create);
 586
 587 void cpts_release(struct cpts *cpts)
 588 {
 589         if (!cpts)
 590                 return;
 591
 592         if (WARN_ON(!cpts->refclk))
 593                 return;
 594
 595         clk_unprepare(cpts->refclk);
 596 }
 597 EXPORT_SYMBOL_GPL(cpts_release);
 598
 599 MODULE_LICENSE("GPL v2");
 600 MODULE_DESCRIPTION("TI CPTS driver");
 601 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");