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                 spin_lock_irq(&pps->lock);
  75
  76                 /* Get the current parameters */
  77                 params = pps->params;
  78
  79                 spin_unlock_irq(&pps->lock);
  80
  81                 err = copy_to_user(uarg, &params, sizeof(struct pps_kparams));
  82                 if (err)
  83                         return -EFAULT;
  84
  85                 break;
  86
  87         case PPS_SETPARAMS:
  88                 pr_debug("PPS_SETPARAMS: source %d\n", pps->id);
  89
  90                 /* Check the capabilities */
  91                 if (!capable(CAP_SYS_TIME))
  92                         return -EPERM;
  93
  94                 err = copy_from_user(&params, uarg, sizeof(struct pps_kparams));
  95                 if (err)
  96                         return -EFAULT;
  97                 if (!(params.mode & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR))) {
  98                         pr_debug("capture mode unspecified (%x)\n",
  99                                                                 params.mode);
 100                         return -EINVAL;
 101                 }
 102
 103                 /* Check for supported capabilities */
 104                 if ((params.mode & ~pps->info.mode) != 0) {
 105                         pr_debug("unsupported capabilities (%x)\n",
 106                                                                 params.mode);
 107                         return -EINVAL;
 108                 }
 109
 110                 spin_lock_irq(&pps->lock);
 111
 112                 /* Save the new parameters */
 113                 pps->params = params;
 114
 115                 /* Restore the read only parameters */
 116                 if ((params.mode & (PPS_TSFMT_TSPEC | PPS_TSFMT_NTPFP)) == 0) {
 117                         /* section 3.3 of RFC 2783 interpreted */
 118                         pr_debug("time format unspecified (%x)\n",
 119                                                                 params.mode);
 120                         pps->params.mode |= PPS_TSFMT_TSPEC;
 121                 }
 122                 if (pps->info.mode & PPS_CANWAIT)
 123                         pps->params.mode |= PPS_CANWAIT;
 124                 pps->params.api_version = PPS_API_VERS;
 125
 126                 spin_unlock_irq(&pps->lock);
 127
 128                 break;
 129
 130         case PPS_GETCAP:
 131                 pr_debug("PPS_GETCAP: source %d\n", pps->id);
 132
 133                 err = put_user(pps->info.mode, iuarg);
 134                 if (err)
 135                         return -EFAULT;
 136
 137                 break;
 138
 139         case PPS_FETCH:
 140                 pr_debug("PPS_FETCH: source %d\n", pps->id);
 141
 142                 err = copy_from_user(&fdata, uarg, sizeof(struct pps_fdata));
 143                 if (err)
 144                         return -EFAULT;
 145
 146                 pps->go = 0;
 147
 148                 /* Manage the timeout */
 149                 if (fdata.timeout.flags & PPS_TIME_INVALID)
 150                         err = wait_event_interruptible(pps->queue, pps->go);
 151                 else {
 152                         pr_debug("timeout %lld.%09d\n",
 153                                         (long long) fdata.timeout.sec,
 154                                         fdata.timeout.nsec);
 155                         ticks = fdata.timeout.sec * HZ;
 156                         ticks += fdata.timeout.nsec / (NSEC_PER_SEC / HZ);
 157
 158                         if (ticks != 0) {
 159                                 err = wait_event_interruptible_timeout(
 160                                                 pps->queue, pps->go, ticks);
 161                                 if (err == 0)
 162                                         return -ETIMEDOUT;
 163                         }
 164                 }
 165
 166                 /* Check for pending signals */
 167                 if (err == -ERESTARTSYS) {
 168                         pr_debug("pending signal caught\n");
 169                         return -EINTR;
 170                 }
 171
 172                 /* Return the fetched timestamp */
 173                 spin_lock_irq(&pps->lock);
 174
 175                 fdata.info.assert_sequence = pps->assert_sequence;
 176                 fdata.info.clear_sequence = pps->clear_sequence;
 177                 fdata.info.assert_tu = pps->assert_tu;
 178                 fdata.info.clear_tu = pps->clear_tu;
 179                 fdata.info.current_mode = pps->current_mode;
 180
 181                 spin_unlock_irq(&pps->lock);
 182
 183                 err = copy_to_user(uarg, &fdata, sizeof(struct pps_fdata));
 184                 if (err)
 185                         return -EFAULT;
 186
 187                 break;
 188
 189         default:
 190                 return -ENOTTY;
 191                 break;
 192         }
 193
 194         return 0;
 195 }
 196
 197 static int pps_cdev_open(struct inode *inode, struct file *file)
 198 {
 199         struct pps_device *pps = container_of(inode->i_cdev,
 200                                                 struct pps_device, cdev);
 201         int found;
 202
 203         found = pps_get_source(pps->id) != 0;
 204         if (!found)
 205                 return -ENODEV;
 206
 207         file->private_data = pps;
 208
 209         return 0;
 210 }
 211
 212 static int pps_cdev_release(struct inode *inode, struct file *file)
 213 {
 214         struct pps_device *pps = file->private_data;
 215
 216         /* Free the PPS source and wake up (possible) deregistration */
 217         pps_put_source(pps);
 218
 219         return 0;
 220 }
 221
 222 /*
 223  * Char device stuff
 224  */
 225
 226 static const struct file_operations pps_cdev_fops = {
 227         .owner          = THIS_MODULE,
 228         .llseek         = no_llseek,
 229         .poll           = pps_cdev_poll,
 230         .fasync         = pps_cdev_fasync,
 231         .unlocked_ioctl = pps_cdev_ioctl,
 232         .open           = pps_cdev_open,
 233         .release        = pps_cdev_release,
 234 };
 235
 236 int pps_register_cdev(struct pps_device *pps)
 237 {
 238         int err;
 239
 240         pps->devno = MKDEV(MAJOR(pps_devt), pps->id);
 241         cdev_init(&pps->cdev, &pps_cdev_fops);
 242         pps->cdev.owner = pps->info.owner;
 243
 244         err = cdev_add(&pps->cdev, pps->devno, 1);
 245         if (err) {
 246                 printk(KERN_ERR "pps: %s: failed to add char device %d:%d\n",
 247                                 pps->info.name, MAJOR(pps_devt), pps->id);
 248                 return err;
 249         }
 250         pps->dev = device_create(pps_class, pps->info.dev, pps->devno, NULL,
 251                                                         "pps%d", pps->id);
 252         if (IS_ERR(pps->dev))
 253                 goto del_cdev;
 254         dev_set_drvdata(pps->dev, pps);
 255
 256         pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
 257                         MAJOR(pps_devt), pps->id);
 258
 259         return 0;
 260
 261 del_cdev:
 262         cdev_del(&pps->cdev);
 263
 264         return err;
 265 }
 266
 267 void pps_unregister_cdev(struct pps_device *pps)
 268 {
 269         device_destroy(pps_class, pps->devno);
 270         cdev_del(&pps->cdev);
 271 }
 272
 273 /*
 274  * Module stuff
 275  */
 276
 277 static void __exit pps_exit(void)
 278 {
 279         class_destroy(pps_class);
 280         unregister_chrdev_region(pps_devt, PPS_MAX_SOURCES);
 281 }
 282
 283 static int __init pps_init(void)
 284 {
 285         int err;
 286
 287         pps_class = class_create(THIS_MODULE, "pps");
 288         if (!pps_class) {
 289                 printk(KERN_ERR "pps: failed to allocate class\n");
 290                 return -ENOMEM;
 291         }
 292         pps_class->dev_attrs = pps_attrs;
 293
 294         err = alloc_chrdev_region(&pps_devt, 0, PPS_MAX_SOURCES, "pps");
 295         if (err < 0) {
 296                 printk(KERN_ERR "pps: failed to allocate char device region\n");
 297                 goto remove_class;
 298         }
 299
 300         pr_info("LinuxPPS API ver. %d registered\n", PPS_API_VERS);
 301         pr_info("Software ver. %s - Copyright 2005-2007 Rodolfo Giometti "
 302                 "<giometti@linux.it>\n", PPS_VERSION);
 303
 304         return 0;
 305
 306 remove_class:
 307         class_destroy(pps_class);
 308
 309         return err;
 310 }
 311
 312 subsys_initcall(pps_init);
 313 module_exit(pps_exit);
 314
 315 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 316 MODULE_DESCRIPTION("LinuxPPS support (RFC 2783) - ver. " PPS_VERSION);
 317 MODULE_LICENSE("GPL");