/*
   * PTP 1588 clock support - character device implementation.
   *
   * Copyright (C) 2010 OMICRON electronics GmbH
   *
   *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  #include <linux/module.h>
  #include <linux/posix-clock.h>
  #include <linux/poll.h>
  #include <linux/sched.h>

  #include <linux/slab.h>

  #include <linux/timekeeping.h>

  
  #include "ptp_private.h"

  static int ptp_disable_pinfunc(struct ptp_clock_info *ops,
  			       enum ptp_pin_function func, unsigned int chan)
  {
  	struct ptp_clock_request rq;
  	int err = 0;
  
  	memset(&rq, 0, sizeof(rq));
  
  	switch (func) {
  	case PTP_PF_NONE:
  		break;
  	case PTP_PF_EXTTS:
  		rq.type = PTP_CLK_REQ_EXTTS;
  		rq.extts.index = chan;
  		err = ops->enable(ops, &rq, 0);
  		break;
  	case PTP_PF_PEROUT:
  		rq.type = PTP_CLK_REQ_PEROUT;
  		rq.perout.index = chan;
  		err = ops->enable(ops, &rq, 0);
  		break;
  	case PTP_PF_PHYSYNC:
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return err;
  }
  
  int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
  		    enum ptp_pin_function func, unsigned int chan)
  {
  	struct ptp_clock_info *info = ptp->info;
  	struct ptp_pin_desc *pin1 = NULL, *pin2 = &info->pin_config[pin];
  	unsigned int i;
  
  	/* Check to see if any other pin previously had this function. */
  	for (i = 0; i < info->n_pins; i++) {
  		if (info->pin_config[i].func == func &&
  		    info->pin_config[i].chan == chan) {
  			pin1 = &info->pin_config[i];
  			break;
  		}
  	}
  	if (pin1 && i == pin)
  		return 0;
  
  	/* Check the desired function and channel. */
  	switch (func) {
  	case PTP_PF_NONE:
  		break;
  	case PTP_PF_EXTTS:
  		if (chan >= info->n_ext_ts)
  			return -EINVAL;
  		break;
  	case PTP_PF_PEROUT:
  		if (chan >= info->n_per_out)
  			return -EINVAL;
  		break;
  	case PTP_PF_PHYSYNC:

  		if (chan != 0)
  			return -EINVAL;

  		break;

  	default:
  		return -EINVAL;
  	}

  	if (info->verify(info, pin, func, chan)) {
  		pr_err("driver cannot use function %u on pin %u
  ", func, chan);
  		return -EOPNOTSUPP;
  	}
  
  	/* Disable whatever function was previously assigned. */
  	if (pin1) {
  		ptp_disable_pinfunc(info, func, chan);
  		pin1->func = PTP_PF_NONE;
  		pin1->chan = 0;
  	}
  	ptp_disable_pinfunc(info, pin2->func, pin2->chan);
  	pin2->func = func;
  	pin2->chan = chan;
  
  	return 0;
  }

  int ptp_open(struct posix_clock *pc, fmode_t fmode)
  {
  	return 0;
  }
  
  long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
  {
  	struct ptp_clock_caps caps;
  	struct ptp_clock_request req;

  	struct ptp_sys_offset *sysoff = NULL;

  	struct ptp_sys_offset_precise precise_offset;

  	struct ptp_pin_desc pd;

  	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  	struct ptp_clock_info *ops = ptp->info;

  	struct ptp_clock_time *pct;

  	struct timespec64 ts;

  	struct system_device_crosststamp xtstamp;

  	int enable, err = 0;

  	unsigned int i, pin_index;

  
  	switch (cmd) {
  
  	case PTP_CLOCK_GETCAPS:
  		memset(&caps, 0, sizeof(caps));
  		caps.max_adj = ptp->info->max_adj;
  		caps.n_alarm = ptp->info->n_alarm;
  		caps.n_ext_ts = ptp->info->n_ext_ts;
  		caps.n_per_out = ptp->info->n_per_out;
  		caps.pps = ptp->info->pps;

  		caps.n_pins = ptp->info->n_pins;

  		caps.cross_timestamping = ptp->info->getcrosststamp != NULL;

  		if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
  			err = -EFAULT;

  		break;
  
  	case PTP_EXTTS_REQUEST:
  		if (copy_from_user(&req.extts, (void __user *)arg,
  				   sizeof(req.extts))) {
  			err = -EFAULT;
  			break;
  		}
  		if (req.extts.index >= ops->n_ext_ts) {
  			err = -EINVAL;
  			break;
  		}
  		req.type = PTP_CLK_REQ_EXTTS;
  		enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
  		err = ops->enable(ops, &req, enable);
  		break;
  
  	case PTP_PEROUT_REQUEST:
  		if (copy_from_user(&req.perout, (void __user *)arg,
  				   sizeof(req.perout))) {
  			err = -EFAULT;
  			break;
  		}
  		if (req.perout.index >= ops->n_per_out) {
  			err = -EINVAL;
  			break;
  		}
  		req.type = PTP_CLK_REQ_PEROUT;
  		enable = req.perout.period.sec || req.perout.period.nsec;
  		err = ops->enable(ops, &req, enable);
  		break;
  
  	case PTP_ENABLE_PPS:
  		if (!capable(CAP_SYS_TIME))
  			return -EPERM;
  		req.type = PTP_CLK_REQ_PPS;
  		enable = arg ? 1 : 0;
  		err = ops->enable(ops, &req, enable);
  		break;

  	case PTP_SYS_OFFSET_PRECISE:
  		if (!ptp->info->getcrosststamp) {
  			err = -EOPNOTSUPP;
  			break;
  		}
  		err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
  		if (err)
  			break;

  		memset(&precise_offset, 0, sizeof(precise_offset));

  		ts = ktime_to_timespec64(xtstamp.device);
  		precise_offset.device.sec = ts.tv_sec;
  		precise_offset.device.nsec = ts.tv_nsec;
  		ts = ktime_to_timespec64(xtstamp.sys_realtime);
  		precise_offset.sys_realtime.sec = ts.tv_sec;
  		precise_offset.sys_realtime.nsec = ts.tv_nsec;
  		ts = ktime_to_timespec64(xtstamp.sys_monoraw);
  		precise_offset.sys_monoraw.sec = ts.tv_sec;
  		precise_offset.sys_monoraw.nsec = ts.tv_nsec;
  		if (copy_to_user((void __user *)arg, &precise_offset,
  				 sizeof(precise_offset)))
  			err = -EFAULT;
  		break;

  	case PTP_SYS_OFFSET:

  		sysoff = memdup_user((void __user *)arg, sizeof(*sysoff));
  		if (IS_ERR(sysoff)) {
  			err = PTR_ERR(sysoff);

  			sysoff = NULL;

  			break;
  		}

  		if (sysoff->n_samples > PTP_MAX_SAMPLES) {

  			err = -EINVAL;
  			break;
  		}

  		pct = &sysoff->ts[0];
  		for (i = 0; i < sysoff->n_samples; i++) {

  			getnstimeofday64(&ts);

  			pct->sec = ts.tv_sec;
  			pct->nsec = ts.tv_nsec;
  			pct++;

  			ptp->info->gettime64(ptp->info, &ts);

  			pct->sec = ts.tv_sec;
  			pct->nsec = ts.tv_nsec;
  			pct++;
  		}

  		getnstimeofday64(&ts);

  		pct->sec = ts.tv_sec;
  		pct->nsec = ts.tv_nsec;

  		if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))

  			err = -EFAULT;
  		break;

  	case PTP_PIN_GETFUNC:
  		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
  			err = -EFAULT;
  			break;
  		}
  		pin_index = pd.index;
  		if (pin_index >= ops->n_pins) {
  			err = -EINVAL;
  			break;
  		}
  		if (mutex_lock_interruptible(&ptp->pincfg_mux))
  			return -ERESTARTSYS;
  		pd = ops->pin_config[pin_index];
  		mutex_unlock(&ptp->pincfg_mux);
  		if (!err && copy_to_user((void __user *)arg, &pd, sizeof(pd)))
  			err = -EFAULT;
  		break;
  
  	case PTP_PIN_SETFUNC:
  		if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
  			err = -EFAULT;
  			break;
  		}
  		pin_index = pd.index;
  		if (pin_index >= ops->n_pins) {
  			err = -EINVAL;
  			break;
  		}
  		if (mutex_lock_interruptible(&ptp->pincfg_mux))
  			return -ERESTARTSYS;
  		err = ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
  		mutex_unlock(&ptp->pincfg_mux);
  		break;

  	default:
  		err = -ENOTTY;
  		break;
  	}

  
  	kfree(sysoff);

  	return err;
  }
  
  unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
  {
  	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  
  	poll_wait(fp, &ptp->tsev_wq, wait);
  
  	return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
  }

  #define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))

  ssize_t ptp_read(struct posix_clock *pc,
  		 uint rdflags, char __user *buf, size_t cnt)
  {
  	struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  	struct timestamp_event_queue *queue = &ptp->tsevq;

  	struct ptp_extts_event *event;

  	unsigned long flags;
  	size_t qcnt, i;

  	int result;

  
  	if (cnt % sizeof(struct ptp_extts_event) != 0)
  		return -EINVAL;

  	if (cnt > EXTTS_BUFSIZE)
  		cnt = EXTTS_BUFSIZE;

  
  	cnt = cnt / sizeof(struct ptp_extts_event);
  
  	if (mutex_lock_interruptible(&ptp->tsevq_mux))
  		return -ERESTARTSYS;
  
  	if (wait_event_interruptible(ptp->tsev_wq,
  				     ptp->defunct || queue_cnt(queue))) {
  		mutex_unlock(&ptp->tsevq_mux);
  		return -ERESTARTSYS;
  	}

  	if (ptp->defunct) {
  		mutex_unlock(&ptp->tsevq_mux);

  		return -ENODEV;

  	}

  	event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
  	if (!event) {
  		mutex_unlock(&ptp->tsevq_mux);
  		return -ENOMEM;
  	}

  	spin_lock_irqsave(&queue->lock, flags);
  
  	qcnt = queue_cnt(queue);
  
  	if (cnt > qcnt)
  		cnt = qcnt;
  
  	for (i = 0; i < cnt; i++) {
  		event[i] = queue->buf[queue->head];
  		queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
  	}
  
  	spin_unlock_irqrestore(&queue->lock, flags);
  
  	cnt = cnt * sizeof(struct ptp_extts_event);
  
  	mutex_unlock(&ptp->tsevq_mux);

  	result = cnt;

  	if (copy_to_user(buf, event, cnt))

  		result = -EFAULT;

  	kfree(event);
  	return result;

  }