1/* 2 * Real Time Clock interface for 3 * - q40 and other m68k machines, 4 * - HP PARISC machines 5 * - PowerPC machines 6 * emulate some RTC irq capabilities in software 7 * 8 * Copyright (C) 1999 Richard Zidlicky 9 * 10 * based on Paul Gortmaker's rtc.c device and 11 * Sam Creasey Generic rtc driver 12 * 13 * This driver allows use of the real time clock (built into 14 * nearly all computers) from user space. It exports the /dev/rtc 15 * interface supporting various ioctl() and also the /proc/driver/rtc 16 * pseudo-file for status information. 17 * 18 * The ioctls can be used to set the interrupt behaviour where 19 * supported. 20 * 21 * The /dev/rtc interface will block on reads until an interrupt 22 * has been received. If a RTC interrupt has already happened, 23 * it will output an unsigned long and then block. The output value 24 * contains the interrupt status in the low byte and the number of 25 * interrupts since the last read in the remaining high bytes. The 26 * /dev/rtc interface can also be used with the select(2) call. 27 * 28 * This program is free software; you can redistribute it and/or 29 * modify it under the terms of the GNU General Public License 30 * as published by the Free Software Foundation; either version 31 * 2 of the License, or (at your option) any later version. 32 * 33 34 * 1.01 fix for 2.3.X rz@linux-m68k.org 35 * 1.02 merged with code from genrtc.c rz@linux-m68k.org 36 * 1.03 make it more portable zippel@linux-m68k.org 37 * 1.04 removed useless timer code rz@linux-m68k.org 38 * 1.05 portable RTC_UIE emulation rz@linux-m68k.org 39 * 1.06 set_rtc_time can return an error trini@kernel.crashing.org 40 * 1.07 ported to HP PARISC (hppa) Helge Deller <deller@gmx.de> 41 */ 42 43#define RTC_VERSION "1.07" 44 45#include <linux/module.h> 46#include <linux/errno.h> 47#include <linux/miscdevice.h> 48#include <linux/fcntl.h> 49 50#include <linux/rtc.h> 51#include <linux/init.h> 52#include <linux/poll.h> 53#include <linux/proc_fs.h> 54#include <linux/workqueue.h> 55 56#include <asm/uaccess.h> 57#include <asm/system.h> 58#include <asm/rtc.h> 59 60/* 61 * We sponge a minor off of the misc major. No need slurping 62 * up another valuable major dev number for this. If you add 63 * an ioctl, make sure you don't conflict with SPARC's RTC 64 * ioctls. 65 */ 66 67static DECLARE_WAIT_QUEUE_HEAD(gen_rtc_wait); 68 69/* 70 * Bits in gen_rtc_status. 71 */ 72 73#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */ 74 75static unsigned char gen_rtc_status; /* bitmapped status byte. */ 76static unsigned long gen_rtc_irq_data; /* our output to the world */ 77 78/* months start at 0 now */ 79static unsigned char days_in_mo[] = 80{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 81 82static int irq_active; 83 84#ifdef CONFIG_GEN_RTC_X 85static struct work_struct genrtc_task; 86static struct timer_list timer_task; 87 88static unsigned int oldsecs; 89static int lostint; 90static unsigned long tt_exp; 91 92static void gen_rtc_timer(unsigned long data); 93 94static volatile int stask_active; /* schedule_work */ 95static volatile int ttask_active; /* timer_task */ 96static int stop_rtc_timers; /* don't requeue tasks */ 97static DEFINE_SPINLOCK(gen_rtc_lock); 98 99static void gen_rtc_interrupt(unsigned long arg); 100 101/* 102 * Routine to poll RTC seconds field for change as often as possible, 103 * after first RTC_UIE use timer to reduce polling 104 */ 105static void genrtc_troutine(struct work_struct *work) 106{ 107 unsigned int tmp = get_rtc_ss(); 108 109 if (stop_rtc_timers) { 110 stask_active = 0; 111 return; 112 } 113 114 if (oldsecs != tmp){ 115 oldsecs = tmp; 116 117 timer_task.function = gen_rtc_timer; 118 timer_task.expires = jiffies + HZ - (HZ/10); 119 tt_exp=timer_task.expires; 120 ttask_active=1; 121 stask_active=0; 122 add_timer(&timer_task); 123 124 gen_rtc_interrupt(0); 125 } else if (schedule_work(&genrtc_task) == 0) 126 stask_active = 0; 127} 128 129static void gen_rtc_timer(unsigned long data) 130{ 131 lostint = get_rtc_ss() - oldsecs ; 132 if (lostint<0) 133 lostint = 60 - lostint; 134 if (time_after(jiffies, tt_exp)) 135 printk(KERN_INFO "genrtc: timer task delayed by %ld jiffies\n", 136 jiffies-tt_exp); 137 ttask_active=0; 138 stask_active=1; 139 if ((schedule_work(&genrtc_task) == 0)) 140 stask_active = 0; 141} 142 143/* 144 * call gen_rtc_interrupt function to signal an RTC_UIE, 145 * arg is unused. 146 * Could be invoked either from a real interrupt handler or 147 * from some routine that periodically (eg 100HZ) monitors 148 * whether RTC_SECS changed 149 */ 150static void gen_rtc_interrupt(unsigned long arg) 151{ 152 /* We store the status in the low byte and the number of 153 * interrupts received since the last read in the remainder 154 * of rtc_irq_data. */ 155 156 gen_rtc_irq_data += 0x100; 157 gen_rtc_irq_data &= ~0xff; 158 gen_rtc_irq_data |= RTC_UIE; 159 160 if (lostint){ 161 printk("genrtc: system delaying clock ticks?\n"); 162 /* increment count so that userspace knows something is wrong */ 163 gen_rtc_irq_data += ((lostint-1)<<8); 164 lostint = 0; 165 } 166 167 wake_up_interruptible(&gen_rtc_wait); 168} 169 170/* 171 * Now all the various file operations that we export. 172 */ 173static ssize_t gen_rtc_read(struct file *file, char __user *buf, 174 size_t count, loff_t *ppos) 175{ 176 DECLARE_WAITQUEUE(wait, current); 177 unsigned long data; 178 ssize_t retval; 179 180 if (count != sizeof (unsigned int) && count != sizeof (unsigned long)) 181 return -EINVAL; 182 183 if (file->f_flags & O_NONBLOCK && !gen_rtc_irq_data) 184 return -EAGAIN; 185 186 add_wait_queue(&gen_rtc_wait, &wait); 187 retval = -ERESTARTSYS; 188 189 while (1) { 190 set_current_state(TASK_INTERRUPTIBLE); 191 data = xchg(&gen_rtc_irq_data, 0); 192 if (data) 193 break; 194 if (signal_pending(current)) 195 goto out; 196 schedule(); 197 } 198 199 /* first test allows optimizer to nuke this case for 32-bit machines */ 200 if (sizeof (int) != sizeof (long) && count == sizeof (unsigned int)) { 201 unsigned int uidata = data; 202 retval = put_user(uidata, (unsigned int __user *)buf) ?: 203 sizeof(unsigned int); 204 } 205 else { 206 retval = put_user(data, (unsigned long __user *)buf) ?: 207 sizeof(unsigned long); 208 } 209 out: 210 __set_current_state(TASK_RUNNING); 211 remove_wait_queue(&gen_rtc_wait, &wait); 212 213 return retval; 214} 215 216static unsigned int gen_rtc_poll(struct file *file, 217 struct poll_table_struct *wait) 218{ 219 poll_wait(file, &gen_rtc_wait, wait); 220 if (gen_rtc_irq_data != 0) 221 return POLLIN | POLLRDNORM; 222 return 0; 223} 224 225#endif 226 227/* 228 * Used to disable/enable interrupts, only RTC_UIE supported 229 * We also clear out any old irq data after an ioctl() that 230 * meddles with the interrupt enable/disable bits. 231 */ 232 233static inline void gen_clear_rtc_irq_bit(unsigned char bit) 234{ 235#ifdef CONFIG_GEN_RTC_X 236 stop_rtc_timers = 1; 237 if (ttask_active){ 238 del_timer_sync(&timer_task); 239 ttask_active = 0; 240 } 241 while (stask_active) 242 schedule(); 243 244 spin_lock(&gen_rtc_lock); 245 irq_active = 0; 246 spin_unlock(&gen_rtc_lock); 247#endif 248} 249 250static inline int gen_set_rtc_irq_bit(unsigned char bit) 251{ 252#ifdef CONFIG_GEN_RTC_X 253 spin_lock(&gen_rtc_lock); 254 if ( !irq_active ) { 255 irq_active = 1; 256 stop_rtc_timers = 0; 257 lostint = 0; 258 INIT_WORK(&genrtc_task, genrtc_troutine); 259 oldsecs = get_rtc_ss(); 260 init_timer(&timer_task); 261 262 stask_active = 1; 263 if (schedule_work(&genrtc_task) == 0){ 264 stask_active = 0; 265 } 266 } 267 spin_unlock(&gen_rtc_lock); 268 gen_rtc_irq_data = 0; 269 return 0; 270#else 271 return -EINVAL; 272#endif 273} 274 275static int gen_rtc_ioctl(struct inode *inode, struct file *file, 276 unsigned int cmd, unsigned long arg) 277{ 278 struct rtc_time wtime; 279 struct rtc_pll_info pll; 280 void __user *argp = (void __user *)arg; 281 282 switch (cmd) { 283 284 case RTC_PLL_GET: 285 if (get_rtc_pll(&pll)) 286 return -EINVAL; 287 else 288 return copy_to_user(argp, &pll, sizeof pll) ? -EFAULT : 0; 289 290 case RTC_PLL_SET: 291 if (!capable(CAP_SYS_TIME)) 292 return -EACCES; 293 if (copy_from_user(&pll, argp, sizeof(pll))) 294 return -EFAULT; 295 return set_rtc_pll(&pll); 296 297 case RTC_UIE_OFF: /* disable ints from RTC updates. */ 298 gen_clear_rtc_irq_bit(RTC_UIE); 299 return 0; 300 301 case RTC_UIE_ON: /* enable ints for RTC updates. */ 302 return gen_set_rtc_irq_bit(RTC_UIE); 303 304 case RTC_RD_TIME: /* Read the time/date from RTC */ 305 /* this doesn't get week-day, who cares */ 306 memset(&wtime, 0, sizeof(wtime)); 307 get_rtc_time(&wtime); 308 309 return copy_to_user(argp, &wtime, sizeof(wtime)) ? -EFAULT : 0; 310 311 case RTC_SET_TIME: /* Set the RTC */ 312 { 313 int year; 314 unsigned char leap_yr; 315 316 if (!capable(CAP_SYS_TIME)) 317 return -EACCES; 318 319 if (copy_from_user(&wtime, argp, sizeof(wtime))) 320 return -EFAULT; 321 322 year = wtime.tm_year + 1900; 323 leap_yr = ((!(year % 4) && (year % 100)) || 324 !(year % 400)); 325 326 if ((wtime.tm_mon < 0 || wtime.tm_mon > 11) || (wtime.tm_mday < 1)) 327 return -EINVAL; 328 329 if (wtime.tm_mday < 0 || wtime.tm_mday > 330 (days_in_mo[wtime.tm_mon] + ((wtime.tm_mon == 1) && leap_yr))) 331 return -EINVAL; 332 333 if (wtime.tm_hour < 0 || wtime.tm_hour >= 24 || 334 wtime.tm_min < 0 || wtime.tm_min >= 60 || 335 wtime.tm_sec < 0 || wtime.tm_sec >= 60) 336 return -EINVAL; 337 338 return set_rtc_time(&wtime); 339 } 340 } 341 342 return -EINVAL; 343} 344 345/* 346 * We enforce only one user at a time here with the open/close. 347 * Also clear the previous interrupt data on an open, and clean 348 * up things on a close. 349 */ 350 351static int gen_rtc_open(struct inode *inode, struct file *file) 352{ 353 if (gen_rtc_status & RTC_IS_OPEN) 354 return -EBUSY; 355 356 gen_rtc_status |= RTC_IS_OPEN; 357 gen_rtc_irq_data = 0; 358 irq_active = 0; 359 360 return 0; 361} 362 363static int gen_rtc_release(struct inode *inode, struct file *file) 364{ 365 /* 366 * Turn off all interrupts once the device is no longer 367 * in use and clear the data. 368 */ 369 370 gen_clear_rtc_irq_bit(RTC_PIE|RTC_AIE|RTC_UIE); 371 372 gen_rtc_status &= ~RTC_IS_OPEN; 373 return 0; 374} 375 376 377#ifdef CONFIG_PROC_FS 378 379/* 380 * Info exported via "/proc/driver/rtc". 381 */ 382 383static int gen_rtc_proc_output(char *buf) 384{ 385 char *p; 386 struct rtc_time tm; 387 unsigned int flags; 388 struct rtc_pll_info pll; 389 390 p = buf; 391 392 flags = get_rtc_time(&tm); 393 394 p += sprintf(p, 395 "rtc_time\t: %02d:%02d:%02d\n" 396 "rtc_date\t: %04d-%02d-%02d\n" 397 "rtc_epoch\t: %04u\n", 398 tm.tm_hour, tm.tm_min, tm.tm_sec, 399 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 1900); 400 401 tm.tm_hour = tm.tm_min = tm.tm_sec = 0; 402 403 p += sprintf(p, "alarm\t\t: "); 404 if (tm.tm_hour <= 24) 405 p += sprintf(p, "%02d:", tm.tm_hour); 406 else 407 p += sprintf(p, "**:"); 408 409 if (tm.tm_min <= 59) 410 p += sprintf(p, "%02d:", tm.tm_min); 411 else 412 p += sprintf(p, "**:"); 413 414 if (tm.tm_sec <= 59) 415 p += sprintf(p, "%02d\n", tm.tm_sec); 416 else 417 p += sprintf(p, "**\n"); 418 419 p += sprintf(p, 420 "DST_enable\t: %s\n" 421 "BCD\t\t: %s\n" 422 "24hr\t\t: %s\n" 423 "square_wave\t: %s\n" 424 "alarm_IRQ\t: %s\n" 425 "update_IRQ\t: %s\n" 426 "periodic_IRQ\t: %s\n" 427 "periodic_freq\t: %ld\n" 428 "batt_status\t: %s\n", 429 (flags & RTC_DST_EN) ? "yes" : "no", 430 (flags & RTC_DM_BINARY) ? "no" : "yes", 431 (flags & RTC_24H) ? "yes" : "no", 432 (flags & RTC_SQWE) ? "yes" : "no", 433 (flags & RTC_AIE) ? "yes" : "no", 434 irq_active ? "yes" : "no", 435 (flags & RTC_PIE) ? "yes" : "no", 436 0L /* freq */, 437 (flags & RTC_BATT_BAD) ? "bad" : "okay"); 438 if (!get_rtc_pll(&pll)) 439 p += sprintf(p, 440 "PLL adjustment\t: %d\n" 441 "PLL max +ve adjustment\t: %d\n" 442 "PLL max -ve adjustment\t: %d\n" 443 "PLL +ve adjustment factor\t: %d\n" 444 "PLL -ve adjustment factor\t: %d\n" 445 "PLL frequency\t: %ld\n", 446 pll.pll_value, 447 pll.pll_max, 448 pll.pll_min, 449 pll.pll_posmult, 450 pll.pll_negmult, 451 pll.pll_clock); 452 return p - buf; 453} 454 455static int gen_rtc_read_proc(char *page, char **start, off_t off, 456 int count, int *eof, void *data) 457{ 458 int len = gen_rtc_proc_output (page); 459 if (len <= off+count) *eof = 1; 460 *start = page + off; 461 len -= off; 462 if (len>count) len = count; 463 if (len<0) len = 0; 464 return len; 465} 466 467static int __init gen_rtc_proc_init(void) 468{ 469 struct proc_dir_entry *r; 470 471 r = create_proc_read_entry("driver/rtc", 0, NULL, gen_rtc_read_proc, NULL); 472 if (!r) 473 return -ENOMEM; 474 return 0; 475} 476#else 477static inline int gen_rtc_proc_init(void) { return 0; } 478#endif /* CONFIG_PROC_FS */ 479 480 481/* 482 * The various file operations we support. 483 */ 484 485static const struct file_operations gen_rtc_fops = { 486 .owner = THIS_MODULE, 487#ifdef CONFIG_GEN_RTC_X 488 .read = gen_rtc_read, 489 .poll = gen_rtc_poll, 490#endif 491 .ioctl = gen_rtc_ioctl, 492 .open = gen_rtc_open, 493 .release = gen_rtc_release, 494}; 495 496static struct miscdevice rtc_gen_dev = 497{ 498 .minor = RTC_MINOR, 499 .name = "rtc", 500 .fops = &gen_rtc_fops, 501}; 502 503static int __init rtc_generic_init(void) 504{ 505 int retval; 506 507 printk(KERN_INFO "Generic RTC Driver v%s\n", RTC_VERSION); 508 509 retval = misc_register(&rtc_gen_dev); 510 if (retval < 0) 511 return retval; 512 513 retval = gen_rtc_proc_init(); 514 if (retval) { 515 misc_deregister(&rtc_gen_dev); 516 return retval; 517 } 518 519 return 0; 520} 521 522static void __exit rtc_generic_exit(void) 523{ 524 remove_proc_entry ("driver/rtc", NULL); 525 misc_deregister(&rtc_gen_dev); 526} 527 528 529module_init(rtc_generic_init); 530module_exit(rtc_generic_exit); 531 532MODULE_AUTHOR("Richard Zidlicky"); 533MODULE_LICENSE("GPL"); 534MODULE_ALIAS_MISCDEV(RTC_MINOR); 535