1/* 2 * RTC subsystem, dev interface 3 * 4 * Copyright (C) 2005 Tower Technologies 5 * Author: Alessandro Zummo <a.zummo@towertech.it> 6 * 7 * based on arch/arm/common/rtctime.c 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12*/ 13 14#include <linux/module.h> 15#include <linux/rtc.h> 16#include "rtc-core.h" 17 18static dev_t rtc_devt; 19 20#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */ 21 22static int rtc_dev_open(struct inode *inode, struct file *file) 23{ 24 int err; 25 struct rtc_device *rtc = container_of(inode->i_cdev, 26 struct rtc_device, char_dev); 27 const struct rtc_class_ops *ops = rtc->ops; 28 29 /* We keep the lock as long as the device is in use 30 * and return immediately if busy 31 */ 32 if (!(mutex_trylock(&rtc->char_lock))) 33 return -EBUSY; 34 35 file->private_data = rtc; 36 37 err = ops->open ? ops->open(rtc->dev.parent) : 0; 38 if (err == 0) { 39 spin_lock_irq(&rtc->irq_lock); 40 rtc->irq_data = 0; 41 spin_unlock_irq(&rtc->irq_lock); 42 43 return 0; 44 } 45 46 /* something has gone wrong, release the lock */ 47 mutex_unlock(&rtc->char_lock); 48 return err; 49} 50 51#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 52/* 53 * Routine to poll RTC seconds field for change as often as possible, 54 * after first RTC_UIE use timer to reduce polling 55 */ 56static void rtc_uie_task(struct work_struct *work) 57{ 58 struct rtc_device *rtc = 59 container_of(work, struct rtc_device, uie_task); 60 struct rtc_time tm; 61 int num = 0; 62 int err; 63 64 err = rtc_read_time(rtc, &tm); 65 66 local_irq_disable(); 67 spin_lock(&rtc->irq_lock); 68 if (rtc->stop_uie_polling || err) { 69 rtc->uie_task_active = 0; 70 } else if (rtc->oldsecs != tm.tm_sec) { 71 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60; 72 rtc->oldsecs = tm.tm_sec; 73 rtc->uie_timer.expires = jiffies + HZ - (HZ/10); 74 rtc->uie_timer_active = 1; 75 rtc->uie_task_active = 0; 76 add_timer(&rtc->uie_timer); 77 } else if (schedule_work(&rtc->uie_task) == 0) { 78 rtc->uie_task_active = 0; 79 } 80 spin_unlock(&rtc->irq_lock); 81 if (num) 82 rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF); 83 local_irq_enable(); 84} 85static void rtc_uie_timer(unsigned long data) 86{ 87 struct rtc_device *rtc = (struct rtc_device *)data; 88 unsigned long flags; 89 90 spin_lock_irqsave(&rtc->irq_lock, flags); 91 rtc->uie_timer_active = 0; 92 rtc->uie_task_active = 1; 93 if ((schedule_work(&rtc->uie_task) == 0)) 94 rtc->uie_task_active = 0; 95 spin_unlock_irqrestore(&rtc->irq_lock, flags); 96} 97 98static void clear_uie(struct rtc_device *rtc) 99{ 100 spin_lock_irq(&rtc->irq_lock); 101 if (rtc->irq_active) { 102 rtc->stop_uie_polling = 1; 103 if (rtc->uie_timer_active) { 104 spin_unlock_irq(&rtc->irq_lock); 105 del_timer_sync(&rtc->uie_timer); 106 spin_lock_irq(&rtc->irq_lock); 107 rtc->uie_timer_active = 0; 108 } 109 if (rtc->uie_task_active) { 110 spin_unlock_irq(&rtc->irq_lock); 111 flush_scheduled_work(); 112 spin_lock_irq(&rtc->irq_lock); 113 } 114 rtc->irq_active = 0; 115 } 116 spin_unlock_irq(&rtc->irq_lock); 117} 118 119static int set_uie(struct rtc_device *rtc) 120{ 121 struct rtc_time tm; 122 int err; 123 124 err = rtc_read_time(rtc, &tm); 125 if (err) 126 return err; 127 spin_lock_irq(&rtc->irq_lock); 128 if (!rtc->irq_active) { 129 rtc->irq_active = 1; 130 rtc->stop_uie_polling = 0; 131 rtc->oldsecs = tm.tm_sec; 132 rtc->uie_task_active = 1; 133 if (schedule_work(&rtc->uie_task) == 0) 134 rtc->uie_task_active = 0; 135 } 136 rtc->irq_data = 0; 137 spin_unlock_irq(&rtc->irq_lock); 138 return 0; 139} 140#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */ 141 142static ssize_t 143rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 144{ 145 struct rtc_device *rtc = to_rtc_device(file->private_data); 146 147 DECLARE_WAITQUEUE(wait, current); 148 unsigned long data; 149 ssize_t ret; 150 151 if (count != sizeof(unsigned int) && count < sizeof(unsigned long)) 152 return -EINVAL; 153 154 add_wait_queue(&rtc->irq_queue, &wait); 155 do { 156 __set_current_state(TASK_INTERRUPTIBLE); 157 158 spin_lock_irq(&rtc->irq_lock); 159 data = rtc->irq_data; 160 rtc->irq_data = 0; 161 spin_unlock_irq(&rtc->irq_lock); 162 163 if (data != 0) { 164 ret = 0; 165 break; 166 } 167 if (file->f_flags & O_NONBLOCK) { 168 ret = -EAGAIN; 169 break; 170 } 171 if (signal_pending(current)) { 172 ret = -ERESTARTSYS; 173 break; 174 } 175 schedule(); 176 } while (1); 177 set_current_state(TASK_RUNNING); 178 remove_wait_queue(&rtc->irq_queue, &wait); 179 180 if (ret == 0) { 181 /* Check for any data updates */ 182 if (rtc->ops->read_callback) 183 data = rtc->ops->read_callback(rtc->dev.parent, 184 data); 185 186 if (sizeof(int) != sizeof(long) && 187 count == sizeof(unsigned int)) 188 ret = put_user(data, (unsigned int __user *)buf) ?: 189 sizeof(unsigned int); 190 else 191 ret = put_user(data, (unsigned long __user *)buf) ?: 192 sizeof(unsigned long); 193 } 194 return ret; 195} 196 197static unsigned int rtc_dev_poll(struct file *file, poll_table *wait) 198{ 199 struct rtc_device *rtc = to_rtc_device(file->private_data); 200 unsigned long data; 201 202 poll_wait(file, &rtc->irq_queue, wait); 203 204 data = rtc->irq_data; 205 206 return (data != 0) ? (POLLIN | POLLRDNORM) : 0; 207} 208 209static int rtc_dev_ioctl(struct inode *inode, struct file *file, 210 unsigned int cmd, unsigned long arg) 211{ 212 int err = 0; 213 struct rtc_device *rtc = file->private_data; 214 const struct rtc_class_ops *ops = rtc->ops; 215 struct rtc_time tm; 216 struct rtc_wkalrm alarm; 217 void __user *uarg = (void __user *) arg; 218 219 /* check that the calling task has appropriate permissions 220 * for certain ioctls. doing this check here is useful 221 * to avoid duplicate code in each driver. 222 */ 223 switch (cmd) { 224 case RTC_EPOCH_SET: 225 case RTC_SET_TIME: 226 if (!capable(CAP_SYS_TIME)) 227 return -EACCES; 228 break; 229 230 case RTC_IRQP_SET: 231 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE)) 232 return -EACCES; 233 break; 234 235 case RTC_PIE_ON: 236 if (!capable(CAP_SYS_RESOURCE)) 237 return -EACCES; 238 break; 239 } 240 241 /* avoid conflicting IRQ users */ 242 if (cmd == RTC_PIE_ON || cmd == RTC_PIE_OFF || cmd == RTC_IRQP_SET) { 243 spin_lock_irq(&rtc->irq_task_lock); 244 if (rtc->irq_task) 245 err = -EBUSY; 246 spin_unlock_irq(&rtc->irq_task_lock); 247 248 if (err < 0) 249 return err; 250 } 251 252 /* try the driver's ioctl interface */ 253 if (ops->ioctl) { 254 err = ops->ioctl(rtc->dev.parent, cmd, arg); 255 if (err != -ENOIOCTLCMD) 256 return err; 257 } 258 259 /* if the driver does not provide the ioctl interface 260 * or if that particular ioctl was not implemented 261 * (-ENOIOCTLCMD), we will try to emulate here. 262 */ 263 264 switch (cmd) { 265 case RTC_ALM_READ: 266 err = rtc_read_alarm(rtc, &alarm); 267 if (err < 0) 268 return err; 269 270 if (copy_to_user(uarg, &alarm.time, sizeof(tm))) 271 return -EFAULT; 272 break; 273 274 case RTC_ALM_SET: 275 if (copy_from_user(&alarm.time, uarg, sizeof(tm))) 276 return -EFAULT; 277 278 alarm.enabled = 0; 279 alarm.pending = 0; 280 alarm.time.tm_wday = -1; 281 alarm.time.tm_yday = -1; 282 alarm.time.tm_isdst = -1; 283 284 /* RTC_ALM_SET alarms may be up to 24 hours in the future. 285 * Rather than expecting every RTC to implement "don't care" 286 * for day/month/year fields, just force the alarm to have 287 * the right values for those fields. 288 * 289 * RTC_WKALM_SET should be used instead. Not only does it 290 * eliminate the need for a separate RTC_AIE_ON call, it 291 * doesn't have the "alarm 23:59:59 in the future" race. 292 * 293 * NOTE: some legacy code may have used invalid fields as 294 * wildcards, exposing hardware "periodic alarm" capabilities. 295 * Not supported here. 296 */ 297 { 298 unsigned long now, then; 299 300 err = rtc_read_time(rtc, &tm); 301 if (err < 0) 302 return err; 303 rtc_tm_to_time(&tm, &now); 304 305 alarm.time.tm_mday = tm.tm_mday; 306 alarm.time.tm_mon = tm.tm_mon; 307 alarm.time.tm_year = tm.tm_year; 308 err = rtc_valid_tm(&alarm.time); 309 if (err < 0) 310 return err; 311 rtc_tm_to_time(&alarm.time, &then); 312 313 /* alarm may need to wrap into tomorrow */ 314 if (then < now) { 315 rtc_time_to_tm(now + 24 * 60 * 60, &tm); 316 alarm.time.tm_mday = tm.tm_mday; 317 alarm.time.tm_mon = tm.tm_mon; 318 alarm.time.tm_year = tm.tm_year; 319 } 320 } 321 322 err = rtc_set_alarm(rtc, &alarm); 323 break; 324 325 case RTC_RD_TIME: 326 err = rtc_read_time(rtc, &tm); 327 if (err < 0) 328 return err; 329 330 if (copy_to_user(uarg, &tm, sizeof(tm))) 331 return -EFAULT; 332 break; 333 334 case RTC_SET_TIME: 335 if (copy_from_user(&tm, uarg, sizeof(tm))) 336 return -EFAULT; 337 338 err = rtc_set_time(rtc, &tm); 339 break; 340 341 case RTC_IRQP_READ: 342 if (ops->irq_set_freq) 343 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg); 344 break; 345 346 case RTC_IRQP_SET: 347 if (ops->irq_set_freq) 348 err = rtc_irq_set_freq(rtc, rtc->irq_task, arg); 349 break; 350 351 case RTC_WKALM_SET: 352 if (copy_from_user(&alarm, uarg, sizeof(alarm))) 353 return -EFAULT; 354 355 err = rtc_set_alarm(rtc, &alarm); 356 break; 357 358 case RTC_WKALM_RD: 359 err = rtc_read_alarm(rtc, &alarm); 360 if (err < 0) 361 return err; 362 363 if (copy_to_user(uarg, &alarm, sizeof(alarm))) 364 return -EFAULT; 365 break; 366 367#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 368 case RTC_UIE_OFF: 369 clear_uie(rtc); 370 return 0; 371 372 case RTC_UIE_ON: 373 return set_uie(rtc); 374#endif 375 default: 376 err = -ENOTTY; 377 break; 378 } 379 380 return err; 381} 382 383static int rtc_dev_release(struct inode *inode, struct file *file) 384{ 385 struct rtc_device *rtc = to_rtc_device(file->private_data); 386 387#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 388 clear_uie(rtc); 389#endif 390 if (rtc->ops->release) 391 rtc->ops->release(rtc->dev.parent); 392 393 mutex_unlock(&rtc->char_lock); 394 return 0; 395} 396 397static int rtc_dev_fasync(int fd, struct file *file, int on) 398{ 399 struct rtc_device *rtc = to_rtc_device(file->private_data); 400 return fasync_helper(fd, file, on, &rtc->async_queue); 401} 402 403static const struct file_operations rtc_dev_fops = { 404 .owner = THIS_MODULE, 405 .llseek = no_llseek, 406 .read = rtc_dev_read, 407 .poll = rtc_dev_poll, 408 .ioctl = rtc_dev_ioctl, 409 .open = rtc_dev_open, 410 .release = rtc_dev_release, 411 .fasync = rtc_dev_fasync, 412}; 413 414/* insertion/removal hooks */ 415 416void rtc_dev_prepare(struct rtc_device *rtc) 417{ 418 if (!rtc_devt) 419 return; 420 421 if (rtc->id >= RTC_DEV_MAX) { 422 pr_debug("%s: too many RTC devices\n", rtc->name); 423 return; 424 } 425 426 rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id); 427 428 mutex_init(&rtc->char_lock); 429 spin_lock_init(&rtc->irq_lock); 430 init_waitqueue_head(&rtc->irq_queue); 431#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 432 INIT_WORK(&rtc->uie_task, rtc_uie_task); 433 setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc); 434#endif 435 436 cdev_init(&rtc->char_dev, &rtc_dev_fops); 437 rtc->char_dev.owner = rtc->owner; 438} 439 440void rtc_dev_add_device(struct rtc_device *rtc) 441{ 442 if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1)) 443 printk(KERN_WARNING "%s: failed to add char device %d:%d\n", 444 rtc->name, MAJOR(rtc_devt), rtc->id); 445 else 446 pr_debug("%s: dev (%d:%d)\n", rtc->name, 447 MAJOR(rtc_devt), rtc->id); 448} 449 450void rtc_dev_del_device(struct rtc_device *rtc) 451{ 452 if (rtc->dev.devt) 453 cdev_del(&rtc->char_dev); 454} 455 456void __init rtc_dev_init(void) 457{ 458 int err; 459 460 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc"); 461 if (err < 0) 462 printk(KERN_ERR "%s: failed to allocate char dev region\n", 463 __FILE__); 464} 465 466void __exit rtc_dev_exit(void) 467{ 468 if (rtc_devt) 469 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX); 470} 471