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                 err = copy_to_user((void __user *)arg, &caps, sizeof(caps));
  50                 break;
  51
  52         case PTP_EXTTS_REQUEST:
  53                 if (copy_from_user(&req.extts, (void __user *)arg,
  54                                    sizeof(req.extts))) {
  55                         err = -EFAULT;
  56                         break;
  57                 }
  58                 if (req.extts.index >= ops->n_ext_ts) {
  59                         err = -EINVAL;
  60                         break;
  61                 }
  62                 req.type = PTP_CLK_REQ_EXTTS;
  63                 enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
  64                 err = ops->enable(ops, &req, enable);
  65                 break;
  66
  67         case PTP_PEROUT_REQUEST:
  68                 if (copy_from_user(&req.perout, (void __user *)arg,
  69                                    sizeof(req.perout))) {
  70                         err = -EFAULT;
  71                         break;
  72                 }
  73                 if (req.perout.index >= ops->n_per_out) {
  74                         err = -EINVAL;
  75                         break;
  76                 }
  77                 req.type = PTP_CLK_REQ_PEROUT;
  78                 enable = req.perout.period.sec || req.perout.period.nsec;
  79                 err = ops->enable(ops, &req, enable);
  80                 break;
  81
  82         case PTP_ENABLE_PPS:
  83                 if (!capable(CAP_SYS_TIME))
  84                         return -EPERM;
  85                 req.type = PTP_CLK_REQ_PPS;
  86                 enable = arg ? 1 : 0;
  87                 err = ops->enable(ops, &req, enable);
  88                 break;
  89
  90         default:
  91                 err = -ENOTTY;
  92                 break;
  93         }
  94         return err;
  95 }
  96
  97 unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
  98 {
  99         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 100
 101         poll_wait(fp, &ptp->tsev_wq, wait);
 102
 103         return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
 104 }
 105
 106 ssize_t ptp_read(struct posix_clock *pc,
 107                  uint rdflags, char __user *buf, size_t cnt)
 108 {
 109         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 110         struct timestamp_event_queue *queue = &ptp->tsevq;
 111         struct ptp_extts_event event[PTP_BUF_TIMESTAMPS];
 112         unsigned long flags;
 113         size_t qcnt, i;
 114
 115         if (cnt % sizeof(struct ptp_extts_event) != 0)
 116                 return -EINVAL;
 117
 118         if (cnt > sizeof(event))
 119                 cnt = sizeof(event);
 120
 121         cnt = cnt / sizeof(struct ptp_extts_event);
 122
 123         if (mutex_lock_interruptible(&ptp->tsevq_mux))
 124                 return -ERESTARTSYS;
 125
 126         if (wait_event_interruptible(ptp->tsev_wq,
 127                                      ptp->defunct || queue_cnt(queue))) {
 128                 mutex_unlock(&ptp->tsevq_mux);
 129                 return -ERESTARTSYS;
 130         }
 131
 132         if (ptp->defunct)
 133                 return -ENODEV;
 134
 135         spin_lock_irqsave(&queue->lock, flags);
 136
 137         qcnt = queue_cnt(queue);
 138
 139         if (cnt > qcnt)
 140                 cnt = qcnt;
 141
 142         for (i = 0; i < cnt; i++) {
 143                 event[i] = queue->buf[queue->head];
 144                 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
 145         }
 146
 147         spin_unlock_irqrestore(&queue->lock, flags);
 148
 149         cnt = cnt * sizeof(struct ptp_extts_event);
 150
 151         mutex_unlock(&ptp->tsevq_mux);
 152
 153         if (copy_to_user(buf, event, cnt)) {
 154                 mutex_unlock(&ptp->tsevq_mux);
 155                 return -EFAULT;
 156         }
 157
 158         return cnt;
 159 }