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_read32(c, r)       readl_relaxed(&c->reg->r)
  35 #define cpts_write32(c, v, r)   writel_relaxed(v, &c->reg->r)
  36
  37 static int event_expired(struct cpts_event *event)
  38 {
  39         return time_after(jiffies, event->tmo);
  40 }
  41
  42 static int event_type(struct cpts_event *event)
  43 {
  44         return (event->high >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
  45 }
  46
  47 static int cpts_fifo_pop(struct cpts *cpts, u32 *high, u32 *low)
  48 {
  49         u32 r = cpts_read32(cpts, intstat_raw);
  50
  51         if (r & TS_PEND_RAW) {
  52                 *high = cpts_read32(cpts, event_high);
  53                 *low  = cpts_read32(cpts, event_low);
  54                 cpts_write32(cpts, EVENT_POP, event_pop);
  55                 return 0;
  56         }
  57         return -1;
  58 }
  59
  60 static int cpts_purge_events(struct cpts *cpts)
  61 {
  62         struct list_head *this, *next;
  63         struct cpts_event *event;
  64         int removed = 0;
  65
  66         list_for_each_safe(this, next, &cpts->events) {
  67                 event = list_entry(this, struct cpts_event, list);
  68                 if (event_expired(event)) {
  69                         list_del_init(&event->list);
  70                         list_add(&event->list, &cpts->pool);
  71                         ++removed;
  72                 }
  73         }
  74
  75         if (removed)
  76                 pr_debug("cpts: event pool cleaned up %d\n", removed);
  77         return removed ? 0 : -1;
  78 }
  79
  80 /*
  81  * Returns zero if matching event type was found.
  82  */
  83 static int cpts_fifo_read(struct cpts *cpts, int match)
  84 {
  85         int i, type = -1;
  86         u32 hi, lo;
  87         struct cpts_event *event;
  88
  89         for (i = 0; i < CPTS_FIFO_DEPTH; i++) {
  90                 if (cpts_fifo_pop(cpts, &hi, &lo))
  91                         break;
  92
  93                 if (list_empty(&cpts->pool) && cpts_purge_events(cpts)) {
  94                         pr_err("cpts: event pool empty\n");
  95                         return -1;
  96                 }
  97
  98                 event = list_first_entry(&cpts->pool, struct cpts_event, list);
  99                 event->tmo = jiffies + 2;
 100                 event->high = hi;
 101                 event->low = lo;
 102                 type = event_type(event);
 103                 switch (type) {
 104                 case CPTS_EV_PUSH:
 105                 case CPTS_EV_RX:
 106                 case CPTS_EV_TX:
 107                         list_del_init(&event->list);
 108                         list_add_tail(&event->list, &cpts->events);
 109                         break;
 110                 case CPTS_EV_ROLL:
 111                 case CPTS_EV_HALF:
 112                 case CPTS_EV_HW:
 113                         break;
 114                 default:
 115                         pr_err("cpts: unknown event type\n");
 116                         break;
 117                 }
 118                 if (type == match)
 119                         break;
 120         }
 121         return type == match ? 0 : -1;
 122 }
 123
 124 static u64 cpts_systim_read(const struct cyclecounter *cc)
 125 {
 126         u64 val = 0;
 127         struct cpts_event *event;
 128         struct list_head *this, *next;
 129         struct cpts *cpts = container_of(cc, struct cpts, cc);
 130
 131         cpts_write32(cpts, TS_PUSH, ts_push);
 132         if (cpts_fifo_read(cpts, CPTS_EV_PUSH))
 133                 pr_err("cpts: unable to obtain a time stamp\n");
 134
 135         list_for_each_safe(this, next, &cpts->events) {
 136                 event = list_entry(this, struct cpts_event, list);
 137                 if (event_type(event) == CPTS_EV_PUSH) {
 138                         list_del_init(&event->list);
 139                         list_add(&event->list, &cpts->pool);
 140                         val = event->low;
 141                         break;
 142                 }
 143         }
 144
 145         return val;
 146 }
 147
 148 /* PTP clock operations */
 149
 150 static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 151 {
 152         u64 adj;
 153         u32 diff, mult;
 154         int neg_adj = 0;
 155         unsigned long flags;
 156         struct cpts *cpts = container_of(ptp, struct cpts, info);
 157
 158         if (ppb < 0) {
 159                 neg_adj = 1;
 160                 ppb = -ppb;
 161         }
 162         mult = cpts->cc_mult;
 163         adj = mult;
 164         adj *= ppb;
 165         diff = div_u64(adj, 1000000000ULL);
 166
 167         spin_lock_irqsave(&cpts->lock, flags);
 168
 169         timecounter_read(&cpts->tc);
 170
 171         cpts->cc.mult = neg_adj ? mult - diff : mult + diff;
 172
 173         spin_unlock_irqrestore(&cpts->lock, flags);
 174
 175         return 0;
 176 }
 177
 178 static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 179 {
 180         unsigned long flags;
 181         struct cpts *cpts = container_of(ptp, struct cpts, info);
 182
 183         spin_lock_irqsave(&cpts->lock, flags);
 184         timecounter_adjtime(&cpts->tc, delta);
 185         spin_unlock_irqrestore(&cpts->lock, flags);
 186
 187         return 0;
 188 }
 189
 190 static int cpts_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 191 {
 192         u64 ns;
 193         unsigned long flags;
 194         struct cpts *cpts = container_of(ptp, struct cpts, info);
 195
 196         spin_lock_irqsave(&cpts->lock, flags);
 197         ns = timecounter_read(&cpts->tc);
 198         spin_unlock_irqrestore(&cpts->lock, flags);
 199
 200         *ts = ns_to_timespec64(ns);
 201
 202         return 0;
 203 }
 204
 205 static int cpts_ptp_settime(struct ptp_clock_info *ptp,
 206                             const struct timespec64 *ts)
 207 {
 208         u64 ns;
 209         unsigned long flags;
 210         struct cpts *cpts = container_of(ptp, struct cpts, info);
 211
 212         ns = timespec64_to_ns(ts);
 213
 214         spin_lock_irqsave(&cpts->lock, flags);
 215         timecounter_init(&cpts->tc, &cpts->cc, ns);
 216         spin_unlock_irqrestore(&cpts->lock, flags);
 217
 218         return 0;
 219 }
 220
 221 static int cpts_ptp_enable(struct ptp_clock_info *ptp,
 222                            struct ptp_clock_request *rq, int on)
 223 {
 224         return -EOPNOTSUPP;
 225 }
 226
 227 static struct ptp_clock_info cpts_info = {
 228         .owner          = THIS_MODULE,
 229         .name           = "CTPS timer",
 230         .max_adj        = 1000000,
 231         .n_ext_ts       = 0,
 232         .n_pins         = 0,
 233         .pps            = 0,
 234         .adjfreq        = cpts_ptp_adjfreq,
 235         .adjtime        = cpts_ptp_adjtime,
 236         .gettime64      = cpts_ptp_gettime,
 237         .settime64      = cpts_ptp_settime,
 238         .enable         = cpts_ptp_enable,
 239 };
 240
 241 static void cpts_overflow_check(struct work_struct *work)
 242 {
 243         struct timespec64 ts;
 244         struct cpts *cpts = container_of(work, struct cpts, overflow_work.work);
 245
 246         cpts_ptp_gettime(&cpts->info, &ts);
 247         pr_debug("cpts overflow check at %lld.%09lu\n", ts.tv_sec, ts.tv_nsec);
 248         schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
 249 }
 250
 251 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
 252                       u16 ts_seqid, u8 ts_msgtype)
 253 {
 254         u16 *seqid;
 255         unsigned int offset = 0;
 256         u8 *msgtype, *data = skb->data;
 257
 258         if (ptp_class & PTP_CLASS_VLAN)
 259                 offset += VLAN_HLEN;
 260
 261         switch (ptp_class & PTP_CLASS_PMASK) {
 262         case PTP_CLASS_IPV4:
 263                 offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
 264                 break;
 265         case PTP_CLASS_IPV6:
 266                 offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
 267                 break;
 268         case PTP_CLASS_L2:
 269                 offset += ETH_HLEN;
 270                 break;
 271         default:
 272                 return 0;
 273         }
 274
 275         if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
 276                 return 0;
 277
 278         if (unlikely(ptp_class & PTP_CLASS_V1))
 279                 msgtype = data + offset + OFF_PTP_CONTROL;
 280         else
 281                 msgtype = data + offset;
 282
 283         seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
 284
 285         return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
 286 }
 287
 288 static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
 289 {
 290         u64 ns = 0;
 291         struct cpts_event *event;
 292         struct list_head *this, *next;
 293         unsigned int class = ptp_classify_raw(skb);
 294         unsigned long flags;
 295         u16 seqid;
 296         u8 mtype;
 297
 298         if (class == PTP_CLASS_NONE)
 299                 return 0;
 300
 301         spin_lock_irqsave(&cpts->lock, flags);
 302         cpts_fifo_read(cpts, CPTS_EV_PUSH);
 303         list_for_each_safe(this, next, &cpts->events) {
 304                 event = list_entry(this, struct cpts_event, list);
 305                 if (event_expired(event)) {
 306                         list_del_init(&event->list);
 307                         list_add(&event->list, &cpts->pool);
 308                         continue;
 309                 }
 310                 mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
 311                 seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
 312                 if (ev_type == event_type(event) &&
 313                     cpts_match(skb, class, seqid, mtype)) {
 314                         ns = timecounter_cyc2time(&cpts->tc, event->low);
 315                         list_del_init(&event->list);
 316                         list_add(&event->list, &cpts->pool);
 317                         break;
 318                 }
 319         }
 320         spin_unlock_irqrestore(&cpts->lock, flags);
 321
 322         return ns;
 323 }
 324
 325 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 326 {
 327         u64 ns;
 328         struct skb_shared_hwtstamps *ssh;
 329
 330         if (!cpts->rx_enable)
 331                 return;
 332         ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
 333         if (!ns)
 334                 return;
 335         ssh = skb_hwtstamps(skb);
 336         memset(ssh, 0, sizeof(*ssh));
 337         ssh->hwtstamp = ns_to_ktime(ns);
 338 }
 339 EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
 340
 341 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 342 {
 343         u64 ns;
 344         struct skb_shared_hwtstamps ssh;
 345
 346         if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
 347                 return;
 348         ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
 349         if (!ns)
 350                 return;
 351         memset(&ssh, 0, sizeof(ssh));
 352         ssh.hwtstamp = ns_to_ktime(ns);
 353         skb_tstamp_tx(skb, &ssh);
 354 }
 355 EXPORT_SYMBOL_GPL(cpts_tx_timestamp);
 356
 357 int cpts_register(struct cpts *cpts)
 358 {
 359         int err, i;
 360
 361         INIT_LIST_HEAD(&cpts->events);
 362         INIT_LIST_HEAD(&cpts->pool);
 363         for (i = 0; i < CPTS_MAX_EVENTS; i++)
 364                 list_add(&cpts->pool_data[i].list, &cpts->pool);
 365
 366         clk_enable(cpts->refclk);
 367
 368         cpts_write32(cpts, CPTS_EN, control);
 369         cpts_write32(cpts, TS_PEND_EN, int_enable);
 370
 371         timecounter_init(&cpts->tc, &cpts->cc, ktime_to_ns(ktime_get_real()));
 372
 373         cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
 374         if (IS_ERR(cpts->clock)) {
 375                 err = PTR_ERR(cpts->clock);
 376                 cpts->clock = NULL;
 377                 goto err_ptp;
 378         }
 379         cpts->phc_index = ptp_clock_index(cpts->clock);
 380
 381         schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
 382         return 0;
 383
 384 err_ptp:
 385         clk_disable(cpts->refclk);
 386         return err;
 387 }
 388 EXPORT_SYMBOL_GPL(cpts_register);
 389
 390 void cpts_unregister(struct cpts *cpts)
 391 {
 392         if (WARN_ON(!cpts->clock))
 393                 return;
 394
 395         cancel_delayed_work_sync(&cpts->overflow_work);
 396
 397         ptp_clock_unregister(cpts->clock);
 398         cpts->clock = NULL;
 399
 400         cpts_write32(cpts, 0, int_enable);
 401         cpts_write32(cpts, 0, control);
 402
 403         clk_disable(cpts->refclk);
 404 }
 405 EXPORT_SYMBOL_GPL(cpts_unregister);
 406
 407 static void cpts_calc_mult_shift(struct cpts *cpts)
 408 {
 409         u64 frac, maxsec, ns;
 410         u32 freq;
 411
 412         freq = clk_get_rate(cpts->refclk);
 413
 414         /* Calc the maximum number of seconds which we can run before
 415          * wrapping around.
 416          */
 417         maxsec = cpts->cc.mask;
 418         do_div(maxsec, freq);
 419         /* limit conversation rate to 10 sec as higher values will produce
 420          * too small mult factors and so reduce the conversion accuracy
 421          */
 422         if (maxsec > 10)
 423                 maxsec = 10;
 424
 425         /* Calc overflow check period (maxsec / 2) */
 426         cpts->ov_check_period = (HZ * maxsec) / 2;
 427         dev_info(cpts->dev, "cpts: overflow check period %lu (jiffies)\n",
 428                  cpts->ov_check_period);
 429
 430         if (cpts->cc.mult || cpts->cc.shift)
 431                 return;
 432
 433         clocks_calc_mult_shift(&cpts->cc.mult, &cpts->cc.shift,
 434                                freq, NSEC_PER_SEC, maxsec);
 435
 436         frac = 0;
 437         ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
 438
 439         dev_info(cpts->dev,
 440                  "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld nsec/sec\n",
 441                  freq, cpts->cc.mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
 442 }
 443
 444 static int cpts_of_parse(struct cpts *cpts, struct device_node *node)
 445 {
 446         int ret = -EINVAL;
 447         u32 prop;
 448
 449         if (!of_property_read_u32(node, "cpts_clock_mult", &prop))
 450                 cpts->cc.mult = prop;
 451
 452         if (!of_property_read_u32(node, "cpts_clock_shift", &prop))
 453                 cpts->cc.shift = prop;
 454
 455         if ((cpts->cc.mult && !cpts->cc.shift) ||
 456             (!cpts->cc.mult && cpts->cc.shift))
 457                 goto of_error;
 458
 459         return 0;
 460
 461 of_error:
 462         dev_err(cpts->dev, "CPTS: Missing property in the DT.\n");
 463         return ret;
 464 }
 465
 466 struct cpts *cpts_create(struct device *dev, void __iomem *regs,
 467                          struct device_node *node)
 468 {
 469         struct cpts *cpts;
 470         int ret;
 471
 472         cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
 473         if (!cpts)
 474                 return ERR_PTR(-ENOMEM);
 475
 476         cpts->dev = dev;
 477         cpts->reg = (struct cpsw_cpts __iomem *)regs;
 478         spin_lock_init(&cpts->lock);
 479         INIT_DELAYED_WORK(&cpts->overflow_work, cpts_overflow_check);
 480
 481         ret = cpts_of_parse(cpts, node);
 482         if (ret)
 483                 return ERR_PTR(ret);
 484
 485         cpts->refclk = devm_clk_get(dev, "cpts");
 486         if (IS_ERR(cpts->refclk)) {
 487                 dev_err(dev, "Failed to get cpts refclk\n");
 488                 return ERR_PTR(PTR_ERR(cpts->refclk));
 489         }
 490
 491         clk_prepare(cpts->refclk);
 492
 493         cpts->cc.read = cpts_systim_read;
 494         cpts->cc.mask = CLOCKSOURCE_MASK(32);
 495         cpts->info = cpts_info;
 496
 497         cpts_calc_mult_shift(cpts);
 498         /* save cc.mult original value as it can be modified
 499          * by cpts_ptp_adjfreq().
 500          */
 501         cpts->cc_mult = cpts->cc.mult;
 502
 503         return cpts;
 504 }
 505 EXPORT_SYMBOL_GPL(cpts_create);
 506
 507 void cpts_release(struct cpts *cpts)
 508 {
 509         if (!cpts)
 510                 return;
 511
 512         if (WARN_ON(!cpts->refclk))
 513                 return;
 514
 515         clk_unprepare(cpts->refclk);
 516 }
 517 EXPORT_SYMBOL_GPL(cpts_release);
 518
 519 MODULE_LICENSE("GPL v2");
 520 MODULE_DESCRIPTION("TI CPTS driver");
 521 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");