/*
   * 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 "ptp_private.h"
  
  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_clock *ptp = container_of(pc, struct ptp_clock, clock);
  	struct ptp_clock_info *ops = ptp->info;
  	int enable, err = 0;
  
  	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;

  		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;
  
  	default:
  		err = -ENOTTY;
  		break;
  	}
  	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;
  }
  
  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[PTP_BUF_TIMESTAMPS];
  	unsigned long flags;
  	size_t qcnt, i;
  
  	if (cnt % sizeof(struct ptp_extts_event) != 0)
  		return -EINVAL;
  
  	if (cnt > sizeof(event))
  		cnt = sizeof(event);
  
  	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;

  	}

  
  	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);

  	if (copy_to_user(buf, event, cnt))

  		return -EFAULT;

  
  	return cnt;
  }