drivers/ptp/ptp_chardev.c

   1 /*
   2  * PTP 1588 clock support - character device implementation.
   3  *
   4  * Copyright (C) 2010 OMICRON electronics GmbH
   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., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #include <linux/module.h>
  21 #include <linux/posix-clock.h>
  22 #include <linux/poll.h>
  23 #include <linux/sched.h>
  24
  25 #include "ptp_private.h"
  26
  27 int ptp_open(struct posix_clock *pc, fmode_t fmode)
  28 {
  29         return 0;
  30 }
  31
  32 long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
  33 {
  34         struct ptp_clock_caps caps;
  35         struct ptp_clock_request req;
  36         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  37         struct ptp_clock_info *ops = ptp->info;
  38         int enable, err = 0;
  39
  40         switch (cmd) {
  41
  42         case PTP_CLOCK_GETCAPS:
  43                 memset(&caps, 0, sizeof(caps));
  44                 caps.max_adj = ptp->info->max_adj;
  45                 caps.n_alarm = ptp->info->n_alarm;
  46                 caps.n_ext_ts = ptp->info->n_ext_ts;
  47                 caps.n_per_out = ptp->info->n_per_out;
  48                 caps.pps = ptp->info->pps;
  49                 if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
  50                         err = -EFAULT;
  51                 break;
  52
  53         case PTP_EXTTS_REQUEST:
  54                 if (copy_from_user(&req.extts, (void __user *)arg,
  55                                    sizeof(req.extts))) {
  56                         err = -EFAULT;
  57                         break;
  58                 }
  59                 if (req.extts.index >= ops->n_ext_ts) {
  60                         err = -EINVAL;
  61                         break;
  62                 }
  63                 req.type = PTP_CLK_REQ_EXTTS;
  64                 enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
  65                 err = ops->enable(ops, &req, enable);
  66                 break;
  67
  68         case PTP_PEROUT_REQUEST:
  69                 if (copy_from_user(&req.perout, (void __user *)arg,
  70                                    sizeof(req.perout))) {
  71                         err = -EFAULT;
  72                         break;
  73                 }
  74                 if (req.perout.index >= ops->n_per_out) {
  75                         err = -EINVAL;
  76                         break;
  77                 }
  78                 req.type = PTP_CLK_REQ_PEROUT;
  79                 enable = req.perout.period.sec || req.perout.period.nsec;
  80                 err = ops->enable(ops, &req, enable);
  81                 break;
  82
  83         case PTP_ENABLE_PPS:
  84                 if (!capable(CAP_SYS_TIME))
  85                         return -EPERM;
  86                 req.type = PTP_CLK_REQ_PPS;
  87                 enable = arg ? 1 : 0;
  88                 err = ops->enable(ops, &req, enable);
  89                 break;
  90
  91         default:
  92                 err = -ENOTTY;
  93                 break;
  94         }
  95         return err;
  96 }
  97
  98 unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
  99 {
 100         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 101
 102         poll_wait(fp, &ptp->tsev_wq, wait);
 103
 104         return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
 105 }
 106
 107 ssize_t ptp_read(struct posix_clock *pc,
 108                  uint rdflags, char __user *buf, size_t cnt)
 109 {
 110         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 111         struct timestamp_event_queue *queue = &ptp->tsevq;
 112         struct ptp_extts_event event[PTP_BUF_TIMESTAMPS];
 113         unsigned long flags;
 114         size_t qcnt, i;
 115
 116         if (cnt % sizeof(struct ptp_extts_event) != 0)
 117                 return -EINVAL;
 118
 119         if (cnt > sizeof(event))
 120                 cnt = sizeof(event);
 121
 122         cnt = cnt / sizeof(struct ptp_extts_event);
 123
 124         if (mutex_lock_interruptible(&ptp->tsevq_mux))
 125                 return -ERESTARTSYS;
 126
 127         if (wait_event_interruptible(ptp->tsev_wq,
 128                                      ptp->defunct || queue_cnt(queue))) {
 129                 mutex_unlock(&ptp->tsevq_mux);
 130                 return -ERESTARTSYS;
 131         }
 132
 133         if (ptp->defunct) {
 134                 mutex_unlock(&ptp->tsevq_mux);
 135                 return -ENODEV;
 136         }
 137
 138         spin_lock_irqsave(&queue->lock, flags);
 139
 140         qcnt = queue_cnt(queue);
 141
 142         if (cnt > qcnt)
 143                 cnt = qcnt;
 144
 145         for (i = 0; i < cnt; i++) {
 146                 event[i] = queue->buf[queue->head];
 147                 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
 148         }
 149
 150         spin_unlock_irqrestore(&queue->lock, flags);
 151
 152         cnt = cnt * sizeof(struct ptp_extts_event);
 153
 154         mutex_unlock(&ptp->tsevq_mux);
 155
 156         if (copy_to_user(buf, event, cnt))
 157                 return -EFAULT;
 158
 159         return cnt;
 160 }