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 #include <linux/slab.h>
  25
  26 #include "ptp_private.h"
  27
  28 int ptp_open(struct posix_clock *pc, fmode_t fmode)
  29 {
  30         return 0;
  31 }
  32
  33 long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
  34 {
  35         struct ptp_clock_caps caps;
  36         struct ptp_clock_request req;
  37         struct ptp_sys_offset *sysoff = NULL;
  38         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
  39         struct ptp_clock_info *ops = ptp->info;
  40         struct ptp_clock_time *pct;
  41         struct timespec ts;
  42         int enable, err = 0;
  43         unsigned int i;
  44
  45         switch (cmd) {
  46
  47         case PTP_CLOCK_GETCAPS:
  48                 memset(&caps, 0, sizeof(caps));
  49                 caps.max_adj = ptp->info->max_adj;
  50                 caps.n_alarm = ptp->info->n_alarm;
  51                 caps.n_ext_ts = ptp->info->n_ext_ts;
  52                 caps.n_per_out = ptp->info->n_per_out;
  53                 caps.pps = ptp->info->pps;
  54                 if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
  55                         err = -EFAULT;
  56                 break;
  57
  58         case PTP_EXTTS_REQUEST:
  59                 if (copy_from_user(&req.extts, (void __user *)arg,
  60                                    sizeof(req.extts))) {
  61                         err = -EFAULT;
  62                         break;
  63                 }
  64                 if (req.extts.index >= ops->n_ext_ts) {
  65                         err = -EINVAL;
  66                         break;
  67                 }
  68                 req.type = PTP_CLK_REQ_EXTTS;
  69                 enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
  70                 err = ops->enable(ops, &req, enable);
  71                 break;
  72
  73         case PTP_PEROUT_REQUEST:
  74                 if (copy_from_user(&req.perout, (void __user *)arg,
  75                                    sizeof(req.perout))) {
  76                         err = -EFAULT;
  77                         break;
  78                 }
  79                 if (req.perout.index >= ops->n_per_out) {
  80                         err = -EINVAL;
  81                         break;
  82                 }
  83                 req.type = PTP_CLK_REQ_PEROUT;
  84                 enable = req.perout.period.sec || req.perout.period.nsec;
  85                 err = ops->enable(ops, &req, enable);
  86                 break;
  87
  88         case PTP_ENABLE_PPS:
  89                 if (!capable(CAP_SYS_TIME))
  90                         return -EPERM;
  91                 req.type = PTP_CLK_REQ_PPS;
  92                 enable = arg ? 1 : 0;
  93                 err = ops->enable(ops, &req, enable);
  94                 break;
  95
  96         case PTP_SYS_OFFSET:
  97                 sysoff = kmalloc(sizeof(*sysoff), GFP_KERNEL);
  98                 if (!sysoff) {
  99                         err = -ENOMEM;
 100                         break;
 101                 }
 102                 if (copy_from_user(sysoff, (void __user *)arg,
 103                                    sizeof(*sysoff))) {
 104                         err = -EFAULT;
 105                         break;
 106                 }
 107                 if (sysoff->n_samples > PTP_MAX_SAMPLES) {
 108                         err = -EINVAL;
 109                         break;
 110                 }
 111                 pct = &sysoff->ts[0];
 112                 for (i = 0; i < sysoff->n_samples; i++) {
 113                         getnstimeofday(&ts);
 114                         pct->sec = ts.tv_sec;
 115                         pct->nsec = ts.tv_nsec;
 116                         pct++;
 117                         ptp->info->gettime(ptp->info, &ts);
 118                         pct->sec = ts.tv_sec;
 119                         pct->nsec = ts.tv_nsec;
 120                         pct++;
 121                 }
 122                 getnstimeofday(&ts);
 123                 pct->sec = ts.tv_sec;
 124                 pct->nsec = ts.tv_nsec;
 125                 if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))
 126                         err = -EFAULT;
 127                 break;
 128
 129         default:
 130                 err = -ENOTTY;
 131                 break;
 132         }
 133
 134         kfree(sysoff);
 135         return err;
 136 }
 137
 138 unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
 139 {
 140         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 141
 142         poll_wait(fp, &ptp->tsev_wq, wait);
 143
 144         return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
 145 }
 146
 147 #define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))
 148
 149 ssize_t ptp_read(struct posix_clock *pc,
 150                  uint rdflags, char __user *buf, size_t cnt)
 151 {
 152         struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
 153         struct timestamp_event_queue *queue = &ptp->tsevq;
 154         struct ptp_extts_event *event;
 155         unsigned long flags;
 156         size_t qcnt, i;
 157         int result;
 158
 159         if (cnt % sizeof(struct ptp_extts_event) != 0)
 160                 return -EINVAL;
 161
 162         if (cnt > EXTTS_BUFSIZE)
 163                 cnt = EXTTS_BUFSIZE;
 164
 165         cnt = cnt / sizeof(struct ptp_extts_event);
 166
 167         if (mutex_lock_interruptible(&ptp->tsevq_mux))
 168                 return -ERESTARTSYS;
 169
 170         if (wait_event_interruptible(ptp->tsev_wq,
 171                                      ptp->defunct || queue_cnt(queue))) {
 172                 mutex_unlock(&ptp->tsevq_mux);
 173                 return -ERESTARTSYS;
 174         }
 175
 176         if (ptp->defunct) {
 177                 mutex_unlock(&ptp->tsevq_mux);
 178                 return -ENODEV;
 179         }
 180
 181         event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
 182         if (!event) {
 183                 mutex_unlock(&ptp->tsevq_mux);
 184                 return -ENOMEM;
 185         }
 186
 187         spin_lock_irqsave(&queue->lock, flags);
 188
 189         qcnt = queue_cnt(queue);
 190
 191         if (cnt > qcnt)
 192                 cnt = qcnt;
 193
 194         for (i = 0; i < cnt; i++) {
 195                 event[i] = queue->buf[queue->head];
 196                 queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
 197         }
 198
 199         spin_unlock_irqrestore(&queue->lock, flags);
 200
 201         cnt = cnt * sizeof(struct ptp_extts_event);
 202
 203         mutex_unlock(&ptp->tsevq_mux);
 204
 205         result = cnt;
 206         if (copy_to_user(buf, event, cnt))
 207                 result = -EFAULT;
 208
 209         kfree(event);
 210         return result;
 211 }