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