drivers/pps/pps.c

   1 /*
   2  * PPS core file
   3  *
   4  *
   5  * Copyright (C) 2005-2009   Rodolfo Giometti <giometti@linux.it>
   6  *
   7  *   This program is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License as published by
   9  *   the Free Software Foundation; either version 2 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This program is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with this program; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/sched.h>
  27 #include <linux/uaccess.h>
  28 #include <linux/idr.h>
  29 #include <linux/cdev.h>
  30 #include <linux/poll.h>
  31 #include <linux/pps_kernel.h>
  32
  33 /*
  34  * Local variables
  35  */
  36
  37 static dev_t pps_devt;
  38 static struct class *pps_class;
  39
  40 /*
  41  * Char device methods
  42  */
  43
  44 static unsigned int pps_cdev_poll(struct file *file, poll_table *wait)
  45 {
  46         struct pps_device *pps = file->private_data;
  47
  48         poll_wait(file, &pps->queue, wait);
  49
  50         return POLLIN | POLLRDNORM;
  51 }
  52
  53 static int pps_cdev_fasync(int fd, struct file *file, int on)
  54 {
  55         struct pps_device *pps = file->private_data;
  56         return fasync_helper(fd, file, on, &pps->async_queue);
  57 }
  58
  59 static long pps_cdev_ioctl(struct file *file,
  60                 unsigned int cmd, unsigned long arg)
  61 {
  62         struct pps_device *pps = file->private_data;
  63         struct pps_kparams params;
  64         struct pps_fdata fdata;
  65         unsigned long ticks;
  66         void __user *uarg = (void __user *) arg;
  67         int __user *iuarg = (int __user *) arg;
  68         int err;
  69
  70         switch (cmd) {
  71         case PPS_GETPARAMS:
  72                 pr_debug("PPS_GETPARAMS: source %d\n", pps->id);
  73
  74                 /* Return current parameters */
  75                 err = copy_to_user(uarg, &pps->params,
  76                                                 sizeof(struct pps_kparams));
  77                 if (err)
  78                         return -EFAULT;
  79
  80                 break;
  81
  82         case PPS_SETPARAMS:
  83                 pr_debug("PPS_SETPARAMS: source %d\n", pps->id);
  84
  85                 /* Check the capabilities */
  86                 if (!capable(CAP_SYS_TIME))
  87                         return -EPERM;
  88
  89                 err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
  90                 if (err)
  91                         return -EFAULT;
  92                 if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
  93                         pr_debug("capture mode unspecified (%x)\n",
  94                                                                 params.mode);
  95                         return -EINVAL;
  96                 }
  97
  98                 /* Check for supported capabilities */
  99                 if ((params.mode & ~pps->info.mode) != 0) {
 100                         pr_debug("unsupported capabilities (%x)\n",
 101                                                                 params.mode);
 102                         return -EINVAL;
 103                 }
 104
 105                 spin_lock_irq(&pps->lock);
 106
 107                 /* Save the new parameters */
 108                 pps->params = params;
 109
 110                 /* Restore the read only parameters */
 111                 if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
 112                         /* section 3.3 of RFC 2783 interpreted */
 113                         pr_debug("time format unspecified (%x)\n",
 114                                                                 params.mode);
 115                         pps->params.mode |= PPS_TSFMT_TSPEC;
 116                 }
 117                 if (pps->info.mode & PPS_CANWAIT)
 118                         pps->params.mode |= PPS_CANWAIT;
 119                 pps->params.api_version = PPS_API_VERS;
 120
 121                 spin_unlock_irq(&pps->lock);
 122
 123                 break;
 124
 125         case PPS_GETCAP:
 126                 pr_debug("PPS_GETCAP: source %d\n", pps->id);
 127
 128                 err = put_user(pps->info.mode, iuarg);
 129                 if (err)
 130                         return -EFAULT;
 131
 132                 break;
 133
 134         case PPS_FETCH:
 135                 pr_debug("PPS_FETCH: source %d\n", pps->id);
 136
 137                 err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
 138                 if (err)
 139                         return -EFAULT;
 140
 141                 pps->go = 0;
 142
 143                 /* Manage the timeout */
 144                 if (fdata.timeout.flags & PPS_TIME_INVALID)
 145                         err = wait_event_interruptible(pps->queue, pps->go);
 146                 else {
 147                         pr_debug("timeout %lld.%09d\n",
 148                                         (long long) fdata.timeout.sec,
 149                                         fdata.timeout.nsec);
 150                         ticks = fdata.timeout.sec * HZ;
 151                         ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
 152
 153                         if (ticks != 0) {
 154                                 err = wait_event_interruptible_timeout(
 155                                                 pps->queue, pps->go, ticks);
 156                                 if (err == 0)
 157                                         return -ETIMEDOUT;
 158                         }
 159                 }
 160
 161                 /* Check for pending signals */
 162                 if (err == -ERESTARTSYS) {
 163                         pr_debug("pending signal caught\n");
 164                         return -EINTR;
 165                 }
 166
 167                 /* Return the fetched timestamp */
 168                 spin_lock_irq(&pps->lock);
 169
 170                 fdata.info.assert_sequence = pps->assert_sequence;
 171                 fdata.info.clear_sequence = pps->clear_sequence;
 172                 fdata.info.assert_tu = pps->assert_tu;
 173                 fdata.info.clear_tu = pps->clear_tu;
 174                 fdata.info.current_mode = pps->current_mode;
 175
 176                 spin_unlock_irq(&pps->lock);
 177
 178                 err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
 179                 if (err)
 180                         return -EFAULT;
 181
 182                 break;
 183
 184         default:
 185                 return -ENOTTY;
 186                 break;
 187         }
 188
 189         return 0;
 190 }
 191
 192 static int pps_cdev_open(struct inode *inode, struct file *file)
 193 {
 194         struct pps_device *pps = container_of(inode->i_cdev,
 195                                                 struct pps_device, cdev);
 196         int found;
 197
 198         found = pps_get_source(pps->id) != 0;
 199         if (!found)
 200                 return -ENODEV;
 201
 202         file->private_data = pps;
 203
 204         return 0;
 205 }
 206
 207 static int pps_cdev_release(struct inode *inode, struct file *file)
 208 {
 209         struct pps_device *pps = file->private_data;
 210
 211         /* Free the PPS source and wake up (possible) deregistration */
 212         pps_put_source(pps);
 213
 214         return 0;
 215 }
 216
 217 /*
 218  * Char device stuff
 219  */
 220
 221 static const struct file_operations pps_cdev_fops = {
 222         .owner          = THIS_MODULE,
 223         .llseek         = no_llseek,
 224         .poll           = pps_cdev_poll,
 225         .fasync         = pps_cdev_fasync,
 226         .unlocked_ioctl = pps_cdev_ioctl,
 227         .open           = pps_cdev_open,
 228         .release        = pps_cdev_release,
 229 };
 230
 231 int pps_register_cdev(struct pps_device *pps)
 232 {
 233         int err;
 234
 235         pps->devno = MKDEV(MAJOR(pps_devt), pps->id);
 236         cdev_init(&pps->cdev, &pps_cdev_fops);
 237         pps->cdev.owner = pps->info.owner;
 238
 239         err = cdev_add(&pps->cdev, pps->devno, 1);
 240         if (err) {
 241                 printk(KERN_ERR "pps: %s: failed to add char device %d:%d\n",
 242                                 pps->info.name, MAJOR(pps_devt), pps->id);
 243                 return err;
 244         }
 245         pps->dev = device_create(pps_class, pps->info.dev, pps->devno, NULL,
 246                                                         "pps%d", pps->id);
 247         if (err)
 248                 goto del_cdev;
 249         dev_set_drvdata(pps->dev, pps);
 250
 251         pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
 252                         MAJOR(pps_devt), pps->id);
 253
 254         return 0;
 255
 256 del_cdev:
 257         cdev_del(&pps->cdev);
 258
 259         return err;
 260 }
 261
 262 void pps_unregister_cdev(struct pps_device *pps)
 263 {
 264         device_destroy(pps_class, pps->devno);
 265         cdev_del(&pps->cdev);
 266 }
 267
 268 /*
 269  * Module stuff
 270  */
 271
 272 static void __exit pps_exit(void)
 273 {
 274         class_destroy(pps_class);
 275         unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
 276 }
 277
 278 static int __init pps_init(void)
 279 {
 280         int err;
 281
 282         pps_class = class_create(THIS_MODULE, "pps");
 283         if (!pps_class) {
 284                 printk(KERN_ERR "pps: failed to allocate class\n");
 285                 return -ENOMEM;
 286         }
 287         pps_class->dev_attrs = pps_attrs;
 288
 289         err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
 290         if (err < 0) {
 291                 printk(KERN_ERR "pps: failed to allocate char device region\n");
 292                 goto remove_class;
 293         }
 294
 295         pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
 296         pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
 297                 "<giometti@linux.it>\n", PPS_VERSION);
 298
 299         return 0;
 300
 301 remove_class:
 302         class_destroy(pps_class);
 303
 304         return err;
 305 }
 306
 307 subsys_initcall(pps_init);
 308 module_exit(pps_exit);
 309
 310 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 311 MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
 312 MODULE_LICENSE("GPL");