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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16#include <linux/module.h> 17#include <linux/rtc.h> 18#include <linux/sched.h> 19#include "rtc-core.h" 20 21static dev_t rtc_devt; 22 23#define RTC_DEV_MAX 16 /* 16 RTCs should be enough for everyone... */ 24 25static int rtc_dev_open(struct inode *inode, struct file *file) 26{ 27 int err; 28 struct rtc_device *rtc = container_of(inode->i_cdev, 29 struct rtc_device, char_dev); 30 const struct rtc_class_ops *ops = rtc->ops; 31 32 if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) 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 */ 47 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); 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 spin_lock_irq(&rtc->irq_lock); 67 if (rtc->stop_uie_polling || err) { 68 rtc->uie_task_active = 0; 69 } else if (rtc->oldsecs != tm.tm_sec) { 70 num = (tm.tm_sec + 60 - rtc->oldsecs) % 60; 71 rtc->oldsecs = tm.tm_sec; 72 rtc->uie_timer.expires = jiffies + HZ - (HZ/10); 73 rtc->uie_timer_active = 1; 74 rtc->uie_task_active = 0; 75 add_timer(&rtc->uie_timer); 76 } else if (schedule_work(&rtc->uie_task) == 0) { 77 rtc->uie_task_active = 0; 78 } 79 spin_unlock_irq(&rtc->irq_lock); 80 if (num) 81 rtc_handle_legacy_irq(rtc, num, RTC_UF); 82} 83static void rtc_uie_timer(unsigned long data) 84{ 85 struct rtc_device *rtc = (struct rtc_device *)data; 86 unsigned long flags; 87 88 spin_lock_irqsave(&rtc->irq_lock, flags); 89 rtc->uie_timer_active = 0; 90 rtc->uie_task_active = 1; 91 if ((schedule_work(&rtc->uie_task) == 0)) 92 rtc->uie_task_active = 0; 93 spin_unlock_irqrestore(&rtc->irq_lock, flags); 94} 95 96static int clear_uie(struct rtc_device *rtc) 97{ 98 spin_lock_irq(&rtc->irq_lock); 99 if (rtc->uie_irq_active) { 100 rtc->stop_uie_polling = 1; 101 if (rtc->uie_timer_active) { 102 spin_unlock_irq(&rtc->irq_lock); 103 del_timer_sync(&rtc->uie_timer); 104 spin_lock_irq(&rtc->irq_lock); 105 rtc->uie_timer_active = 0; 106 } 107 if (rtc->uie_task_active) { 108 spin_unlock_irq(&rtc->irq_lock); 109 flush_scheduled_work(); 110 spin_lock_irq(&rtc->irq_lock); 111 } 112 rtc->uie_irq_active = 0; 113 } 114 spin_unlock_irq(&rtc->irq_lock); 115 return 0; 116} 117 118static int set_uie(struct rtc_device *rtc) 119{ 120 struct rtc_time tm; 121 int err; 122 123 err = rtc_read_time(rtc, &tm); 124 if (err) 125 return err; 126 spin_lock_irq(&rtc->irq_lock); 127 if (!rtc->uie_irq_active) { 128 rtc->uie_irq_active = 1; 129 rtc->stop_uie_polling = 0; 130 rtc->oldsecs = tm.tm_sec; 131 rtc->uie_task_active = 1; 132 if (schedule_work(&rtc->uie_task) == 0) 133 rtc->uie_task_active = 0; 134 } 135 rtc->irq_data = 0; 136 spin_unlock_irq(&rtc->irq_lock); 137 return 0; 138} 139 140int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled) 141{ 142 if (enabled) 143 return set_uie(rtc); 144 else 145 return clear_uie(rtc); 146} 147EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul); 148 149#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */ 150 151static ssize_t 152rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 153{ 154 struct rtc_device *rtc = file->private_data; 155 156 DECLARE_WAITQUEUE(wait, current); 157 unsigned long data; 158 ssize_t ret; 159 160 if (count != sizeof(unsigned int) && count < sizeof(unsigned long)) 161 return -EINVAL; 162 163 add_wait_queue(&rtc->irq_queue, &wait); 164 do { 165 __set_current_state(TASK_INTERRUPTIBLE); 166 167 spin_lock_irq(&rtc->irq_lock); 168 data = rtc->irq_data; 169 rtc->irq_data = 0; 170 spin_unlock_irq(&rtc->irq_lock); 171 172 if (data != 0) { 173 ret = 0; 174 break; 175 } 176 if (file->f_flags & O_NONBLOCK) { 177 ret = -EAGAIN; 178 break; 179 } 180 if (signal_pending(current)) { 181 ret = -ERESTARTSYS; 182 break; 183 } 184 schedule(); 185 } while (1); 186 set_current_state(TASK_RUNNING); 187 remove_wait_queue(&rtc->irq_queue, &wait); 188 189 if (ret == 0) { 190 /* Check for any data updates */ 191 if (rtc->ops->read_callback) 192 data = rtc->ops->read_callback(rtc->dev.parent, 193 data); 194 195 if (sizeof(int) != sizeof(long) && 196 count == sizeof(unsigned int)) 197 ret = put_user(data, (unsigned int __user *)buf) ?: 198 sizeof(unsigned int); 199 else 200 ret = put_user(data, (unsigned long __user *)buf) ?: 201 sizeof(unsigned long); 202 } 203 return ret; 204} 205 206static unsigned int rtc_dev_poll(struct file *file, poll_table *wait) 207{ 208 struct rtc_device *rtc = file->private_data; 209 unsigned long data; 210 211 poll_wait(file, &rtc->irq_queue, wait); 212 213 data = rtc->irq_data; 214 215 return (data != 0) ? (POLLIN | POLLRDNORM) : 0; 216} 217 218static long rtc_dev_ioctl(struct file *file, 219 unsigned int cmd, unsigned long arg) 220{ 221 int err = 0; 222 struct rtc_device *rtc = file->private_data; 223 const struct rtc_class_ops *ops = rtc->ops; 224 struct rtc_time tm; 225 struct rtc_wkalrm alarm; 226 void __user *uarg = (void __user *) arg; 227 228 err = mutex_lock_interruptible(&rtc->ops_lock); 229 if (err) 230 return err; 231 232 /* check that the calling task has appropriate permissions 233 * for certain ioctls. doing this check here is useful 234 * to avoid duplicate code in each driver. 235 */ 236 switch (cmd) { 237 case RTC_EPOCH_SET: 238 case RTC_SET_TIME: 239 if (!capable(CAP_SYS_TIME)) 240 err = -EACCES; 241 break; 242 243 case RTC_IRQP_SET: 244 if (arg > rtc->max_user_freq && !capable(CAP_SYS_RESOURCE)) 245 err = -EACCES; 246 break; 247 248 case RTC_PIE_ON: 249 if (rtc->irq_freq > rtc->max_user_freq && 250 !capable(CAP_SYS_RESOURCE)) 251 err = -EACCES; 252 break; 253 } 254 255 if (err) 256 goto done; 257 258 /* 259 * Drivers *SHOULD NOT* provide ioctl implementations 260 * for these requests. Instead, provide methods to 261 * support the following code, so that the RTC's main 262 * features are accessible without using ioctls. 263 * 264 * RTC and alarm times will be in UTC, by preference, 265 * but dual-booting with MS-Windows implies RTCs must 266 * use the local wall clock time. 267 */ 268 269 switch (cmd) { 270 case RTC_ALM_READ: 271 mutex_unlock(&rtc->ops_lock); 272 273 err = rtc_read_alarm(rtc, &alarm); 274 if (err < 0) 275 return err; 276 277 if (copy_to_user(uarg, &alarm.time, sizeof(tm))) 278 err = -EFAULT; 279 return err; 280 281 case RTC_ALM_SET: 282 mutex_unlock(&rtc->ops_lock); 283 284 if (copy_from_user(&alarm.time, uarg, sizeof(tm))) 285 return -EFAULT; 286 287 alarm.enabled = 0; 288 alarm.pending = 0; 289 alarm.time.tm_wday = -1; 290 alarm.time.tm_yday = -1; 291 alarm.time.tm_isdst = -1; 292 293 /* RTC_ALM_SET alarms may be up to 24 hours in the future. 294 * Rather than expecting every RTC to implement "don't care" 295 * for day/month/year fields, just force the alarm to have 296 * the right values for those fields. 297 * 298 * RTC_WKALM_SET should be used instead. Not only does it 299 * eliminate the need for a separate RTC_AIE_ON call, it 300 * doesn't have the "alarm 23:59:59 in the future" race. 301 * 302 * NOTE: some legacy code may have used invalid fields as 303 * wildcards, exposing hardware "periodic alarm" capabilities. 304 * Not supported here. 305 */ 306 { 307 time64_t now, then; 308 309 err = rtc_read_time(rtc, &tm); 310 if (err < 0) 311 return err; 312 now = rtc_tm_to_time64(&tm); 313 314 alarm.time.tm_mday = tm.tm_mday; 315 alarm.time.tm_mon = tm.tm_mon; 316 alarm.time.tm_year = tm.tm_year; 317 err = rtc_valid_tm(&alarm.time); 318 if (err < 0) 319 return err; 320 then = rtc_tm_to_time64(&alarm.time); 321 322 /* alarm may need to wrap into tomorrow */ 323 if (then < now) { 324 rtc_time64_to_tm(now + 24 * 60 * 60, &tm); 325 alarm.time.tm_mday = tm.tm_mday; 326 alarm.time.tm_mon = tm.tm_mon; 327 alarm.time.tm_year = tm.tm_year; 328 } 329 } 330 331 return rtc_set_alarm(rtc, &alarm); 332 333 case RTC_RD_TIME: 334 mutex_unlock(&rtc->ops_lock); 335 336 err = rtc_read_time(rtc, &tm); 337 if (err < 0) 338 return err; 339 340 if (copy_to_user(uarg, &tm, sizeof(tm))) 341 err = -EFAULT; 342 return err; 343 344 case RTC_SET_TIME: 345 mutex_unlock(&rtc->ops_lock); 346 347 if (copy_from_user(&tm, uarg, sizeof(tm))) 348 return -EFAULT; 349 350 return rtc_set_time(rtc, &tm); 351 352 case RTC_PIE_ON: 353 err = rtc_irq_set_state(rtc, NULL, 1); 354 break; 355 356 case RTC_PIE_OFF: 357 err = rtc_irq_set_state(rtc, NULL, 0); 358 break; 359 360 case RTC_AIE_ON: 361 mutex_unlock(&rtc->ops_lock); 362 return rtc_alarm_irq_enable(rtc, 1); 363 364 case RTC_AIE_OFF: 365 mutex_unlock(&rtc->ops_lock); 366 return rtc_alarm_irq_enable(rtc, 0); 367 368 case RTC_UIE_ON: 369 mutex_unlock(&rtc->ops_lock); 370 return rtc_update_irq_enable(rtc, 1); 371 372 case RTC_UIE_OFF: 373 mutex_unlock(&rtc->ops_lock); 374 return rtc_update_irq_enable(rtc, 0); 375 376 case RTC_IRQP_SET: 377 err = rtc_irq_set_freq(rtc, NULL, arg); 378 break; 379 380 case RTC_IRQP_READ: 381 err = put_user(rtc->irq_freq, (unsigned long __user *)uarg); 382 break; 383 384 case RTC_WKALM_SET: 385 mutex_unlock(&rtc->ops_lock); 386 if (copy_from_user(&alarm, uarg, sizeof(alarm))) 387 return -EFAULT; 388 389 return rtc_set_alarm(rtc, &alarm); 390 391 case RTC_WKALM_RD: 392 mutex_unlock(&rtc->ops_lock); 393 err = rtc_read_alarm(rtc, &alarm); 394 if (err < 0) 395 return err; 396 397 if (copy_to_user(uarg, &alarm, sizeof(alarm))) 398 err = -EFAULT; 399 return err; 400 401 default: 402 /* Finally try the driver's ioctl interface */ 403 if (ops->ioctl) { 404 err = ops->ioctl(rtc->dev.parent, cmd, arg); 405 if (err == -ENOIOCTLCMD) 406 err = -ENOTTY; 407 } else 408 err = -ENOTTY; 409 break; 410 } 411 412done: 413 mutex_unlock(&rtc->ops_lock); 414 return err; 415} 416 417static int rtc_dev_fasync(int fd, struct file *file, int on) 418{ 419 struct rtc_device *rtc = file->private_data; 420 return fasync_helper(fd, file, on, &rtc->async_queue); 421} 422 423static int rtc_dev_release(struct inode *inode, struct file *file) 424{ 425 struct rtc_device *rtc = file->private_data; 426 427 /* We shut down the repeating IRQs that userspace enabled, 428 * since nothing is listening to them. 429 * - Update (UIE) ... currently only managed through ioctls 430 * - Periodic (PIE) ... also used through rtc_*() interface calls 431 * 432 * Leave the alarm alone; it may be set to trigger a system wakeup 433 * later, or be used by kernel code, and is a one-shot event anyway. 434 */ 435 436 /* Keep ioctl until all drivers are converted */ 437 rtc_dev_ioctl(file, RTC_UIE_OFF, 0); 438 rtc_update_irq_enable(rtc, 0); 439 rtc_irq_set_state(rtc, NULL, 0); 440 441 if (rtc->ops->release) 442 rtc->ops->release(rtc->dev.parent); 443 444 clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); 445 return 0; 446} 447 448static const struct file_operations rtc_dev_fops = { 449 .owner = THIS_MODULE, 450 .llseek = no_llseek, 451 .read = rtc_dev_read, 452 .poll = rtc_dev_poll, 453 .unlocked_ioctl = rtc_dev_ioctl, 454 .open = rtc_dev_open, 455 .release = rtc_dev_release, 456 .fasync = rtc_dev_fasync, 457}; 458 459/* insertion/removal hooks */ 460 461void rtc_dev_prepare(struct rtc_device *rtc) 462{ 463 if (!rtc_devt) 464 return; 465 466 if (rtc->id >= RTC_DEV_MAX) { 467 dev_dbg(&rtc->dev, "%s: too many RTC devices\n", rtc->name); 468 return; 469 } 470 471 rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id); 472 473#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL 474 INIT_WORK(&rtc->uie_task, rtc_uie_task); 475 setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc); 476#endif 477 478 cdev_init(&rtc->char_dev, &rtc_dev_fops); 479 rtc->char_dev.owner = rtc->owner; 480} 481 482void rtc_dev_add_device(struct rtc_device *rtc) 483{ 484 if (cdev_add(&rtc->char_dev, rtc->dev.devt, 1)) 485 dev_warn(&rtc->dev, "%s: failed to add char device %d:%d\n", 486 rtc->name, MAJOR(rtc_devt), rtc->id); 487 else 488 dev_dbg(&rtc->dev, "%s: dev (%d:%d)\n", rtc->name, 489 MAJOR(rtc_devt), rtc->id); 490} 491 492void rtc_dev_del_device(struct rtc_device *rtc) 493{ 494 if (rtc->dev.devt) 495 cdev_del(&rtc->char_dev); 496} 497 498void __init rtc_dev_init(void) 499{ 500 int err; 501 502 err = alloc_chrdev_region(&rtc_devt, 0, RTC_DEV_MAX, "rtc"); 503 if (err < 0) 504 pr_err("failed to allocate char dev region\n"); 505} 506 507void __exit rtc_dev_exit(void) 508{ 509 if (rtc_devt) 510 unregister_chrdev_region(rtc_devt, RTC_DEV_MAX); 511} 512