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(¶ms, 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 (IS_ERR(pps->dev)) 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"); 313