/*
   * TI Common Platform Time Sync
   *
   * Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   */
  #include <linux/err.h>
  #include <linux/if.h>
  #include <linux/hrtimer.h>
  #include <linux/module.h>
  #include <linux/net_tstamp.h>
  #include <linux/ptp_classify.h>
  #include <linux/time.h>
  #include <linux/uaccess.h>
  #include <linux/workqueue.h>
  #include <linux/if_ether.h>
  #include <linux/if_vlan.h>
  
  #include "cpts.h"
  
  #define CPTS_TS_COMP_PULSE_LENGTH_DEF	3
  
  #define cpts_read32(c, r)	readl_relaxed(&c->reg->r)
  #define cpts_write32(c, v, r)	writel_relaxed(v, &c->reg->r)
  
  static int cpts_report_ts_events(struct cpts *cpts, bool pps_reload);
  
  static int cpts_event_port(struct cpts_event *event)
  {
  	return (event->high >> PORT_NUMBER_SHIFT) & PORT_NUMBER_MASK;
  }
  
  static int event_expired(struct cpts_event *event)
  {
  	return time_after(jiffies, event->tmo);
  }
  
  static int event_type(struct cpts_event *event)
  {
  	return (event->high >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
  }
  
  static int cpts_fifo_pop(struct cpts *cpts, u32 *high, u32 *low)
  {
  	u32 r = cpts_read32(cpts, intstat_raw);
  
  	if (r & TS_PEND_RAW) {
  		*high = cpts_read32(cpts, event_high);
  		*low  = cpts_read32(cpts, event_low);
  		cpts_write32(cpts, EVENT_POP, event_pop);
  		return 0;
  	}
  	return -1;
  }
  
  static int cpts_purge_events(struct cpts *cpts)
  {
  	struct list_head *this, *next;
  	struct cpts_event *event;
  	int removed = 0;
  
  	list_for_each_safe(this, next, &cpts->events) {
  		event = list_entry(this, struct cpts_event, list);
  		if (event_expired(event)) {
  			list_del_init(&event->list);
  			list_add(&event->list, &cpts->pool);
  			++removed;
  		}
  	}
  
  	if (removed)
  		dev_dbg(cpts->dev, "cpts: event pool cleaned up %d
  ", removed);
  	return removed ? 0 : -1;
  }
  
  /*
   * Returns zero if matching event type was found.
   */
  static int cpts_fifo_read(struct cpts *cpts, int match)
  {
  	int i, type = -1;
  	u32 hi, lo;
  	struct cpts_event *event;
  
  	for (i = 0; i < CPTS_FIFO_DEPTH; i++) {
  		if (cpts_fifo_pop(cpts, &hi, &lo))
  			break;
  
  		if (list_empty(&cpts->pool) && cpts_purge_events(cpts)) {
  			dev_err(cpts->dev, "cpts: event pool empty
  ");
  			return -1;
  		}
  
  		event = list_first_entry(&cpts->pool, struct cpts_event, list);
  		event->tmo = jiffies +
  			     msecs_to_jiffies(CPTS_EVENT_RX_TX_TIMEOUT);
  		event->high = hi;
  		event->low = lo;
  		type = event_type(event);
  		switch (type) {
  		case CPTS_EV_HW:
  		case CPTS_EV_COMP:
  			event->tmo +=
  				msecs_to_jiffies(CPTS_EVENT_HWSTAMP_TIMEOUT);
  		case CPTS_EV_PUSH:
  		case CPTS_EV_RX:
  		case CPTS_EV_TX:
  			list_del_init(&event->list);
  			list_add_tail(&event->list, &cpts->events);
  			break;
  		case CPTS_EV_ROLL:
  		case CPTS_EV_HALF:
  			break;
  		default:
  			pr_err("cpts: unknown event type
  ");
  			break;
  		}
  		if (type == match)
  			break;
  	}
  	return type == match ? 0 : -1;
  }
  
  static cycle_t cpts_systim_read(const struct cyclecounter *cc)
  {
  	u64 val = 0;
  	struct cpts_event *event;
  	struct list_head *this, *next;
  	struct cpts *cpts = container_of(cc, struct cpts, cc);
  
  	cpts_write32(cpts, TS_PUSH, ts_push);
  	if (cpts_fifo_read(cpts, CPTS_EV_PUSH))
  		pr_err("cpts: unable to obtain a time stamp
  ");
  
  	list_for_each_safe(this, next, &cpts->events) {
  		event = list_entry(this, struct cpts_event, list);
  		if (event_type(event) == CPTS_EV_PUSH) {
  			list_del_init(&event->list);
  			list_add(&event->list, &cpts->pool);
  			val = event->low;
  			break;
  		}
  	}
  
  	return val;
  }
  
  static cycle_t cpts_cc_ns2cyc(struct cpts *cpts, u64 nsecs)
  {
  	cycle_t cyc = (nsecs << cpts->cc.shift) + nsecs;
  
  	do_div(cyc, cpts->cc.mult);
  
  	return cyc;
  }
  
  static void cpts_ts_comp_disable(struct cpts *cpts)
  {
  	cpts_write32(cpts, 0, ts_comp_length);
  }
  
  static void cpts_ts_comp_enable(struct cpts *cpts)
  {
  	/* TS_COMP_LENGTH should be 0 while the TS_COMP_VAL value is
  	 * being written
  	 */
  	cpts_write32(cpts, 0, ts_comp_length);
  	cpts_write32(cpts, cpts->ts_comp_next, ts_comp_val);
  	cpts_write32(cpts, cpts->ts_comp_length, ts_comp_length);
  }
  
  static void cpts_ts_comp_add_ns(struct cpts *cpts, s64 add_ns)
  {
  	cycle_t cyc_next;
  
  	if (add_ns == NSEC_PER_SEC)
  		/* avoid calculation */
  		cyc_next = cpts->ts_comp_one_sec_cycs;
  	else
  		cyc_next = cpts_cc_ns2cyc(cpts, add_ns);
  
  	cyc_next += cpts->ts_comp_next;
  	cpts->ts_comp_next = cyc_next & cpts->cc.mask;
  	pr_debug("cpts comp ts_comp_next: %u
  ", cpts->ts_comp_next);
  }
  
  static void cpts_ts_comp_settime(struct cpts *cpts, s64 now_ns)
  {
  	struct timespec64 ts;
  
  	if (cpts->ts_comp_enabled) {
  		ts = ns_to_timespec64(now_ns);
  
  		/* align pulse to next sec boundary and add one sec */
  		cpts_ts_comp_add_ns(cpts, NSEC_PER_SEC - ts.tv_nsec);
  
  		/* enable ts_comp pulse */
  		cpts_ts_comp_enable(cpts);
  	}
  }
  
  /* PTP clock operations */
  
  static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
  {
  	u64 adj;
  	u32 diff, mult;
  	int neg_adj = 0;
  	unsigned long flags;
  	struct cpts *cpts = container_of(ptp, struct cpts, info);
  	u64 ns;
  
  	if (ppb < 0) {
  		neg_adj = 1;
  		ppb = -ppb;
  	}
  	mult = cpts->cc_mult;
  	adj = mult;
  	adj *= ppb;
  	diff = div_u64(adj, 1000000000ULL);
  
  	mutex_lock(&cpts->ptp_clk_mutex);
  
  	spin_lock_irqsave(&cpts->lock, flags);
  	if (cpts->ts_comp_enabled) {
  		cpts_ts_comp_disable(cpts);
  		/* if any, report existing pulse before adj */
  		cpts_fifo_read(cpts, CPTS_EV_COMP);
  		/* if any, report existing pulse before adj */
  		cpts_report_ts_events(cpts, false);
  	}
  
  	timecounter_read(&cpts->tc);
  
  	cpts->cc.mult = neg_adj ? mult - diff : mult + diff;
  	/* get updated time with adj */
  	ns = timecounter_read(&cpts->tc);
  	cpts->ts_comp_next = cpts->tc.cycle_last;
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	if (cpts->ts_comp_enabled)
  		cpts->ts_comp_one_sec_cycs = cpts_cc_ns2cyc(cpts, NSEC_PER_SEC);
  	cpts_ts_comp_settime(cpts, ns);
  
  	mutex_unlock(&cpts->ptp_clk_mutex);
  
  	return 0;
  }
  
  static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
  {
  	unsigned long flags;
  	struct cpts *cpts = container_of(ptp, struct cpts, info);
  	u64 ns;
  
  	mutex_lock(&cpts->ptp_clk_mutex);
  
  	spin_lock_irqsave(&cpts->lock, flags);
  	if (cpts->ts_comp_enabled) {
  		cpts_ts_comp_disable(cpts);
  		/* if any, report existing pulse before adj */
  		cpts_fifo_read(cpts, CPTS_EV_COMP);
  		/* if any, report existing pulse before adj */
  		cpts_report_ts_events(cpts, false);
  	}
  
  	timecounter_adjtime(&cpts->tc, delta);
  	ns = timecounter_read(&cpts->tc);
  	cpts->ts_comp_next = cpts->tc.cycle_last;
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	cpts_ts_comp_settime(cpts, ns);
  
  	mutex_unlock(&cpts->ptp_clk_mutex);
  
  	return 0;
  }
  
  static int cpts_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
  {
  	u64 ns;
  	unsigned long flags;
  	struct cpts *cpts = container_of(ptp, struct cpts, info);
  
  	spin_lock_irqsave(&cpts->lock, flags);
  	ns = timecounter_read(&cpts->tc);
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	*ts = ns_to_timespec64(ns);
  
  	return 0;
  }
  
  static int cpts_ptp_settime(struct ptp_clock_info *ptp,
  			    const struct timespec64 *ts)
  {
  	struct cpts *cpts = container_of(ptp, struct cpts, info);
  	unsigned long flags;
  	u64 ns;
  
  	ns = timespec64_to_ns(ts);
  
  	mutex_lock(&cpts->ptp_clk_mutex);
  
  	spin_lock_irqsave(&cpts->lock, flags);
  	if (cpts->ts_comp_enabled) {
  		cpts_ts_comp_disable(cpts);
  		/* if any, get existing pulse event before adj */
  		cpts_fifo_read(cpts, CPTS_EV_COMP);
  		/* if any, report existing pulse before adj */
  		cpts_report_ts_events(cpts, false);
  	}
  
  	timecounter_init(&cpts->tc, &cpts->cc, ns);
  	cpts->ts_comp_next = cpts->tc.cycle_last;
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	cpts_ts_comp_settime(cpts, ns);
  
  	mutex_unlock(&cpts->ptp_clk_mutex);
  
  	return 0;
  }
  
  static int cpts_pps_enable(struct cpts *cpts, int on)
  {
  	struct timespec64 ts;
  	unsigned long flags;
  	u64 ns;
  
  	if (cpts->ts_comp_enabled == on)
  		return 0;
  
  	mutex_lock(&cpts->ptp_clk_mutex);
  	cpts->ts_comp_enabled = on;
  
  	if (!on) {
  		cpts_ts_comp_disable(cpts);
  		mutex_unlock(&cpts->ptp_clk_mutex);
  		return 0;
  	}
  
  	/* get current counter value */
  	spin_lock_irqsave(&cpts->lock, flags);
  	ns = timecounter_read(&cpts->tc);
  	cpts->ts_comp_next = cpts->tc.cycle_last;
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	ts = ns_to_timespec64(ns);
  	/* align to next sec boundary and add one sec to avoid the situation
  	 * when the current time is very close to the next second point and
  	 * it might be possible that ts_comp_val will be configured to
  	 * the time in the past.
  	 */
  	cpts_ts_comp_add_ns(cpts, 2 * NSEC_PER_SEC - ts.tv_nsec);
  
  	/* enable ts_comp pulse */
  	cpts_ts_comp_enable(cpts);
  
  	if (cpts->ts_comp_enabled)
  		/* poll for events faster - evry 200 ms */
  		cpts->ov_check_period =
  			msecs_to_jiffies(CPTS_EVENT_HWSTAMP_TIMEOUT);
  	else if (!cpts->hw_ts_enable)
  		cpts->ov_check_period = cpts->ov_check_period_slow;
  
  	mod_delayed_work(system_wq, &cpts->overflow_work,
  			 cpts->ov_check_period);
  
  	mutex_unlock(&cpts->ptp_clk_mutex);
  
  	return 0;
  }
  
  static int cpts_report_ts_events(struct cpts *cpts, bool pps_reload)
  {
  	struct list_head *this, *next;
  	struct ptp_clock_event pevent;
  	struct cpts_event *event;
  	int reported = 0, ev;
  	u64 ns;
  
  	list_for_each_safe(this, next, &cpts->events) {
  		event = list_entry(this, struct cpts_event, list);
  		ev = event_type(event);
  		if (ev == CPTS_EV_HW) {
  			list_del_init(&event->list);
  			list_add(&event->list, &cpts->pool);
  			/* report the event */
  			pevent.timestamp =
  				timecounter_cyc2time(&cpts->tc, event->low);
  			pevent.type = PTP_CLOCK_EXTTS;
  			pevent.index = cpts_event_port(event) - 1;
  			ptp_clock_event(cpts->clock, &pevent);
  			++reported;
  			continue;
  		}
  
  		if (event_type(event) == CPTS_EV_COMP) {
  			list_del_init(&event->list);
  			list_add(&event->list, &cpts->pool);
  			if (cpts->ts_comp_next != event->low) {
  				pr_err("cpts ts_comp mismatch: %08x %08x
  ",
  				       cpts->ts_comp_next, event->low);
  				continue;
  			} else
  				pr_debug("cpts comp ev tstamp: %u
  ",
  					 event->low);
  
  			/* report the event */
  			ns = timecounter_cyc2time(&cpts->tc, event->low);
  			pevent.type = PTP_CLOCK_PPSUSR;
  			pevent.pps_times.ts_real = ns_to_timespec64(ns);
  			ptp_clock_event(cpts->clock, &pevent);
  
  			if (pps_reload) {
  				/* reload: add ns to ts_comp */
  				cpts_ts_comp_add_ns(cpts, NSEC_PER_SEC);
  				/* enable ts_comp pulse with new val */
  				cpts_ts_comp_enable(cpts);
  			}
  			++reported;
  			continue;
  		}
  	}
  	return reported;
  }
  
  /* HW TS */
  static int cpts_extts_enable(struct cpts *cpts, u32 index, int on)
  {
  	unsigned long flags;
  	u32 v;
  
  	if (index >= cpts->info.n_ext_ts)
  		return -ENXIO;
  
  	if (((cpts->hw_ts_enable & BIT(index)) >> index) == on)
  		return 0;
  
  	mutex_lock(&cpts->ptp_clk_mutex);
  
  	spin_lock_irqsave(&cpts->lock, flags);
  
  	v = cpts_read32(cpts, control);
  	if (on) {
  		v |= BIT(8 + index);
  		cpts->hw_ts_enable |= BIT(index);
  	} else {
  		v &= ~BIT(8 + index);
  		cpts->hw_ts_enable &= ~BIT(index);
  	}
  	cpts_write32(cpts, v, control);
  
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	if (cpts->hw_ts_enable)
  		/* poll for events faster - evry 200 ms */
  		cpts->ov_check_period =
  			msecs_to_jiffies(CPTS_EVENT_HWSTAMP_TIMEOUT);
  	else if (!cpts->ts_comp_enabled)
  		cpts->ov_check_period = cpts->ov_check_period_slow;
  
  	mod_delayed_work(system_wq, &cpts->overflow_work,
  			 cpts->ov_check_period);
  	mutex_unlock(&cpts->ptp_clk_mutex);
  	return 0;
  }
  
  static int cpts_ptp_enable(struct ptp_clock_info *ptp,
  			   struct ptp_clock_request *rq, int on)
  {
  	struct cpts *cpts = container_of(ptp, struct cpts, info);
  
  	switch (rq->type) {
  	case PTP_CLK_REQ_EXTTS:
  		return cpts_extts_enable(cpts, rq->extts.index, on);
  	case PTP_CLK_REQ_PPS:
  		return cpts_pps_enable(cpts, on);
  	default:
  		break;
  	}
  
  	return -EOPNOTSUPP;
  }
  
  static struct ptp_clock_info cpts_info = {
  	.owner		= THIS_MODULE,
  	.name		= "CTPS timer",
  	.max_adj	= 1000000,
  	.n_ext_ts	= 0,
  	.n_pins		= 0,
  	.pps		= 0,
  	.adjfreq	= cpts_ptp_adjfreq,
  	.adjtime	= cpts_ptp_adjtime,
  	.gettime64	= cpts_ptp_gettime,
  	.settime64	= cpts_ptp_settime,
  	.enable		= cpts_ptp_enable,
  };
  
  static void cpts_overflow_check(struct work_struct *work)
  {
  	struct cpts *cpts = container_of(work, struct cpts, overflow_work.work);
  	struct timespec64 ts;
  	unsigned long flags;
  
  	mutex_lock(&cpts->ptp_clk_mutex);
  	spin_lock_irqsave(&cpts->lock, flags);
  	ts = ns_to_timespec64(timecounter_read(&cpts->tc));
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	if (cpts->hw_ts_enable || cpts->ts_comp_enabled)
  		cpts_report_ts_events(cpts, true);
  	mutex_unlock(&cpts->ptp_clk_mutex);
  
  	pr_debug("cpts overflow check at %lld.%09lu
  ", ts.tv_sec, ts.tv_nsec);
  	schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
  }
  
  static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
  		      u16 ts_seqid, u8 ts_msgtype)
  {
  	u16 *seqid;
  	unsigned int offset = 0;
  	u8 *msgtype, *data = skb->data;
  
  	if (ptp_class & PTP_CLASS_VLAN)
  		offset += VLAN_HLEN;
  
  	switch (ptp_class & PTP_CLASS_PMASK) {
  	case PTP_CLASS_IPV4:
  		offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
  		break;
  	case PTP_CLASS_IPV6:
  		offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
  		break;
  	case PTP_CLASS_L2:
  		offset += ETH_HLEN;
  		break;
  	default:
  		return 0;
  	}
  
  	if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
  		return 0;
  
  	if (unlikely(ptp_class & PTP_CLASS_V1))
  		msgtype = data + offset + OFF_PTP_CONTROL;
  	else
  		msgtype = data + offset;
  
  	seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
  
  	return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
  }
  
  static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
  {
  	u64 ns = 0;
  	struct cpts_event *event;
  	struct list_head *this, *next;
  	unsigned int class = ptp_classify_raw(skb);
  	unsigned long flags;
  	u16 seqid;
  	u8 mtype;
  
  	if (class == PTP_CLASS_NONE)
  		return 0;
  
  	spin_lock_irqsave(&cpts->lock, flags);
  	cpts_fifo_read(cpts, CPTS_EV_PUSH);
  	list_for_each_safe(this, next, &cpts->events) {
  		event = list_entry(this, struct cpts_event, list);
  		if (event_expired(event)) {
  			list_del_init(&event->list);
  			list_add(&event->list, &cpts->pool);
  			continue;
  		}
  		mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
  		seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
  		if (ev_type == event_type(event) &&
  		    cpts_match(skb, class, seqid, mtype)) {
  			ns = timecounter_cyc2time(&cpts->tc, event->low);
  			list_del_init(&event->list);
  			list_add(&event->list, &cpts->pool);
  			break;
  		}
  	}
  	spin_unlock_irqrestore(&cpts->lock, flags);
  
  	return ns;
  }
  
  int cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
  {
  	u64 ns;
  	struct skb_shared_hwtstamps *ssh;
  
  	if (!cpts->rx_enable)
  		return -EPERM;
  	ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
  	if (!ns)
  		return -ENOENT;
  	ssh = skb_hwtstamps(skb);
  	memset(ssh, 0, sizeof(*ssh));
  	ssh->hwtstamp = ns_to_ktime(ns);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
  
  int cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
  {
  	u64 ns;
  	struct skb_shared_hwtstamps ssh;
  
  	if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
  		return -EPERM;
  	ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
  	if (!ns)
  		return -ENOENT;
  	memset(&ssh, 0, sizeof(ssh));
  	ssh.hwtstamp = ns_to_ktime(ns);
  	skb_tstamp_tx(skb, &ssh);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(cpts_tx_timestamp);
  
  int cpts_register(struct cpts *cpts)
  {
  	int err, i;
  	u32 control;
  
  	INIT_LIST_HEAD(&cpts->events);
  	INIT_LIST_HEAD(&cpts->pool);
  	for (i = 0; i < CPTS_MAX_EVENTS; i++)
  		list_add(&cpts->pool_data[i].list, &cpts->pool);
  
  	clk_enable(cpts->refclk);
  
  	control = CPTS_EN;
  	if (cpts->caps & CPTS_CAP_TS_COMP_EN) {
  		if (cpts->caps & CPTS_CAP_TS_COMP_POL_LOW_SEL)
  			control &= ~TS_COMP_POL;
  		else
  			control |= TS_COMP_POL;
  	}
  	cpts_write32(cpts, control, control);
  	cpts_write32(cpts, TS_PEND_EN, int_enable);
  
  	cpts->cc.mult = cpts->cc_mult;
  	timecounter_init(&cpts->tc, &cpts->cc, ktime_to_ns(ktime_get_real()));
  
  	cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
  	if (IS_ERR(cpts->clock)) {
  		err = PTR_ERR(cpts->clock);
  		cpts->clock = NULL;
  		goto err_ptp;
  	}
  	cpts->phc_index = ptp_clock_index(cpts->clock);
  
  	schedule_delayed_work(&cpts->overflow_work, cpts->ov_check_period);
  	return 0;
  
  err_ptp:
  	clk_enable(cpts->refclk);
  	return err;
  }
  EXPORT_SYMBOL_GPL(cpts_register);
  
  void cpts_unregister(struct cpts *cpts)
  {
  	if (WARN_ON(!cpts->clock))
  		return;
  
  	cancel_delayed_work_sync(&cpts->overflow_work);
  
  	ptp_clock_unregister(cpts->clock);
  	cpts->clock = NULL;
  
  	cpts_write32(cpts, 0, int_enable);
  	cpts_write32(cpts, 0, control);
  
  	clk_disable(cpts->refclk);
  }
  EXPORT_SYMBOL_GPL(cpts_unregister);
  
  static void cpts_calc_mult_shift(struct cpts *cpts)
  {
  	u64 frac, maxsec, ns;
  	u32 freq, mult, shift;
  
  	freq = clk_get_rate(cpts->refclk);
  
  	/* Calc the maximum number of seconds which we can run before
  	 * wrapping around.
  	 */
  	maxsec = cpts->cc.mask;
  	do_div(maxsec, freq);
  	if (maxsec > 600 && cpts->cc.mask > UINT_MAX)
  		maxsec = 600;
  
  	/* Calc overflow check period (maxsec / 2) */
  	cpts->ov_check_period = (HZ * maxsec) / 2;
  	cpts->ov_check_period_slow = cpts->ov_check_period;
  
  	dev_info(cpts->dev, "cpts: overflow check period %lu
  ",
  		 cpts->ov_check_period);
  
  	if (cpts->cc_mult || cpts->cc.shift)
  		return;
  
  	clocks_calc_mult_shift(&mult, &shift, freq, NSEC_PER_SEC, maxsec);
  
  	cpts->cc_mult = mult;
  	cpts->cc.mult = mult;
  	cpts->cc.shift = shift;
  
  	frac = 0;
  	ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
  
  	dev_info(cpts->dev,
  		 "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld nsec/sec
  ",
  		 freq, cpts->cc_mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
  }
  
  static int cpts_of_parse(struct cpts *cpts, struct device_node *node)
  {
  	int ret = -EINVAL;
  	u32 prop;
  
  	cpts->cc_mult = 0;
  	if (!of_property_read_u32(node, "cpts_clock_mult", &prop))
  		cpts->cc_mult = prop;
  
  	cpts->cc.shift = 0;
  	if (!of_property_read_u32(node, "cpts_clock_shift", &prop))
  		cpts->cc.shift = prop;
  
  	if ((cpts->cc_mult && !cpts->cc.shift) ||
  	    (!cpts->cc_mult && cpts->cc.shift))
  		goto of_error;
  
  	if (!of_property_read_u32(node, "cpts-rftclk-sel", &prop)) {
  		if (prop & ~CPTS_RFTCLK_SEL_MASK) {
  			dev_err(cpts->dev, "cpts: invalid cpts_rftclk_sel.
  ");
  			goto of_error;
  		}
  		cpts->caps |= CPTS_CAP_RFTCLK_SEL;
  		cpts->rftclk_sel = prop & CPTS_RFTCLK_SEL_MASK;
  	}
  
  	if (of_property_read_bool(node, "cpts-ts-comp-length")) {
  		cpts->caps |= CPTS_CAP_TS_COMP_EN;
  		cpts->ts_comp_length = CPTS_TS_COMP_PULSE_LENGTH_DEF;
  	}
  
  	if (cpts->caps & CPTS_CAP_TS_COMP_EN) {
  		ret = of_property_read_u32(node, "cpts-ts-comp-length", &prop);
  		if (!ret)
  			cpts->ts_comp_length = prop;
  
  		if (of_property_read_bool(node, "cpts-ts-comp-polarity-low"))
  			cpts->caps |= CPTS_CAP_TS_COMP_POL_LOW_SEL;
  	}
  
  	if (!of_property_read_u32(node, "cpts-ext-ts-inputs", &prop))
  		cpts->ext_ts_inputs = prop;
  
  	return 0;
  
  of_error:
  	dev_err(cpts->dev, "CPTS: Missing property in the DT.
  ");
  	return ret;
  }
  
  struct cpts *cpts_create(struct device *dev, void __iomem *regs,
  			 struct device_node *node)
  {
  	struct cpts *cpts;
  	int ret;
  
  	if (!regs || !dev)
  		return ERR_PTR(-EINVAL);
  
  	cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
  	if (!cpts)
  		return ERR_PTR(-ENOMEM);
  
  	cpts->dev = dev;
  	cpts->reg = (struct cpsw_cpts __iomem *)regs;
  	spin_lock_init(&cpts->lock);
  	mutex_init(&cpts->ptp_clk_mutex);
  	INIT_DELAYED_WORK(&cpts->overflow_work, cpts_overflow_check);
  
  	ret = cpts_of_parse(cpts, node);
  	if (ret)
  		return ERR_PTR(ret);
  
  	cpts->refclk = devm_clk_get(dev, "cpts");
  	if (IS_ERR(cpts->refclk)) {
  		dev_err(dev, "Failed to get cpts refclk
  ");
  		return ERR_PTR(PTR_ERR(cpts->refclk));
  	}
  
  	clk_prepare(cpts->refclk);
  
  	if (cpts->caps & CPTS_CAP_RFTCLK_SEL)
  		cpts_write32(cpts, cpts->rftclk_sel, rftclk_sel);
  
  	cpts->cc.read = cpts_systim_read;
  	cpts->cc.mask = CLOCKSOURCE_MASK(32);
  	cpts->info = cpts_info;
  
  	if (cpts->ext_ts_inputs)
  		cpts->info.n_ext_ts = cpts->ext_ts_inputs;
  
  	cpts_calc_mult_shift(cpts);
  
  	if (cpts->caps & CPTS_CAP_TS_COMP_EN) {
  		cpts->info.pps = 1;
  		cpts->ts_comp_one_sec_cycs = clk_get_rate(cpts->refclk);
  	}
  
  	return cpts;
  }
  EXPORT_SYMBOL_GPL(cpts_create);
  
  void cpts_release(struct cpts *cpts)
  {
  	if (!cpts)
  		return;
  
  	if (WARN_ON(!cpts->refclk))
  		return;
  
  	clk_unprepare(cpts->refclk);
  }
  EXPORT_SYMBOL_GPL(cpts_release);
  
  MODULE_LICENSE("GPL v2");
  MODULE_DESCRIPTION("TI CPTS ALE driver");