arch/sparc64/kernel/time.c

   1 /* $Id: time.c,v 1.42 2002/01/23 14:33:55 davem Exp $
   2  * time.c: UltraSparc timer and TOD clock support.
   3  *
   4  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
   5  * Copyright (C) 1998 Eddie C. Dost   (ecd@skynet.be)
   6  *
   7  * Based largely on code which is:
   8  *
   9  * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/errno.h>
  14 #include <linux/module.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/param.h>
  18 #include <linux/string.h>
  19 #include <linux/mm.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/time.h>
  22 #include <linux/timex.h>
  23 #include <linux/init.h>
  24 #include <linux/ioport.h>
  25 #include <linux/mc146818rtc.h>
  26 #include <linux/delay.h>
  27 #include <linux/profile.h>
  28 #include <linux/bcd.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/cpufreq.h>
  31 #include <linux/percpu.h>
  32
  33 #include <asm/oplib.h>
  34 #include <asm/mostek.h>
  35 #include <asm/timer.h>
  36 #include <asm/irq.h>
  37 #include <asm/io.h>
  38 #include <asm/sbus.h>
  39 #include <asm/fhc.h>
  40 #include <asm/pbm.h>
  41 #include <asm/ebus.h>
  42 #include <asm/isa.h>
  43 #include <asm/starfire.h>
  44 #include <asm/smp.h>
  45 #include <asm/sections.h>
  46 #include <asm/cpudata.h>
  47
  48 spinlock_t mostek_lock = SPIN_LOCK_UNLOCKED;
  49 spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
  50 unsigned long mstk48t02_regs = 0UL;
  51 #ifdef CONFIG_PCI
  52 unsigned long ds1287_regs = 0UL;
  53 #endif
  54
  55 extern unsigned long wall_jiffies;
  56
  57 u64 jiffies_64 = INITIAL_JIFFIES;
  58
  59 EXPORT_SYMBOL(jiffies_64);
  60
  61 static unsigned long mstk48t08_regs = 0UL;
  62 static unsigned long mstk48t59_regs = 0UL;
  63
  64 static int set_rtc_mmss(unsigned long);
  65
  66 struct sparc64_tick_ops *tick_ops;
  67
  68 #define TICK_PRIV_BIT   (1UL << 63)
  69
  70 static void tick_disable_protection(void)
  71 {
  72         /* Set things up so user can access tick register for profiling
  73          * purposes.  Also workaround BB_ERRATA_1 by doing a dummy
  74          * read back of %tick after writing it.
  75          */
  76         __asm__ __volatile__(
  77         "       ba,pt   %%xcc, 1f\n"
  78         "        nop\n"
  79         "       .align  64\n"
  80         "1:     rd      %%tick, %%g2\n"
  81         "       add     %%g2, 6, %%g2\n"
  82         "       andn    %%g2, %0, %%g2\n"
  83         "       wrpr    %%g2, 0, %%tick\n"
  84         "       rdpr    %%tick, %%g0"
  85         : /* no outputs */
  86         : "r" (TICK_PRIV_BIT)
  87         : "g2");
  88 }
  89
  90 static void tick_init_tick(unsigned long offset)
  91 {
  92         tick_disable_protection();
  93
  94         __asm__ __volatile__(
  95         "       rd      %%tick, %%g1\n"
  96         "       andn    %%g1, %1, %%g1\n"
  97         "       ba,pt   %%xcc, 1f\n"
  98         "        add    %%g1, %0, %%g1\n"
  99         "       .align  64\n"
 100         "1:     wr      %%g1, 0x0, %%tick_cmpr\n"
 101         "       rd      %%tick_cmpr, %%g0"
 102         : /* no outputs */
 103         : "r" (offset), "r" (TICK_PRIV_BIT)
 104         : "g1");
 105 }
 106
 107 static unsigned long tick_get_tick(void)
 108 {
 109         unsigned long ret;
 110
 111         __asm__ __volatile__("rd        %%tick, %0\n\t"
 112                              "mov       %0, %0"
 113                              : "=r" (ret));
 114
 115         return ret & ~TICK_PRIV_BIT;
 116 }
 117
 118 static unsigned long tick_get_compare(void)
 119 {
 120         unsigned long ret;
 121
 122         __asm__ __volatile__("rd        %%tick_cmpr, %0\n\t"
 123                              "mov       %0, %0"
 124                              : "=r" (ret));
 125
 126         return ret;
 127 }
 128
 129 static unsigned long tick_add_compare(unsigned long adj)
 130 {
 131         unsigned long new_compare;
 132
 133         /* Workaround for Spitfire Errata (#54 I think??), I discovered
 134          * this via Sun BugID 4008234, mentioned in Solaris-2.5.1 patch
 135          * number 103640.
 136          *
 137          * On Blackbird writes to %tick_cmpr can fail, the
 138          * workaround seems to be to execute the wr instruction
 139          * at the start of an I-cache line, and perform a dummy
 140          * read back from %tick_cmpr right after writing to it. -DaveM
 141          */
 142         __asm__ __volatile__("rd        %%tick_cmpr, %0\n\t"
 143                              "ba,pt     %%xcc, 1f\n\t"
 144                              " add      %0, %1, %0\n\t"
 145                              ".align    64\n"
 146                              "1:\n\t"
 147                              "wr        %0, 0, %%tick_cmpr\n\t"
 148                              "rd        %%tick_cmpr, %%g0"
 149                              : "=&r" (new_compare)
 150                              : "r" (adj));
 151
 152         return new_compare;
 153 }
 154
 155 static unsigned long tick_add_tick(unsigned long adj, unsigned long offset)
 156 {
 157         unsigned long new_tick, tmp;
 158
 159         /* Also need to handle Blackbird bug here too. */
 160         __asm__ __volatile__("rd        %%tick, %0\n\t"
 161                              "add       %0, %2, %0\n\t"
 162                              "wrpr      %0, 0, %%tick\n\t"
 163                              "andn      %0, %4, %1\n\t"
 164                              "ba,pt     %%xcc, 1f\n\t"
 165                              " add      %1, %3, %1\n\t"
 166                              ".align    64\n"
 167                              "1:\n\t"
 168                              "wr        %1, 0, %%tick_cmpr\n\t"
 169                              "rd        %%tick_cmpr, %%g0"
 170                              : "=&r" (new_tick), "=&r" (tmp)
 171                              : "r" (adj), "r" (offset), "r" (TICK_PRIV_BIT));
 172
 173         return new_tick;
 174 }
 175
 176 static struct sparc64_tick_ops tick_operations = {
 177         .init_tick      =       tick_init_tick,
 178         .get_tick       =       tick_get_tick,
 179         .get_compare    =       tick_get_compare,
 180         .add_tick       =       tick_add_tick,
 181         .add_compare    =       tick_add_compare,
 182         .softint_mask   =       1UL << 0,
 183 };
 184
 185 static void stick_init_tick(unsigned long offset)
 186 {
 187         tick_disable_protection();
 188
 189         /* Let the user get at STICK too. */
 190         __asm__ __volatile__(
 191         "       rd      %%asr24, %%g2\n"
 192         "       andn    %%g2, %0, %%g2\n"
 193         "       wr      %%g2, 0, %%asr24"
 194         : /* no outputs */
 195         : "r" (TICK_PRIV_BIT)
 196         : "g1", "g2");
 197
 198         __asm__ __volatile__(
 199         "       rd      %%asr24, %%g1\n"
 200         "       andn    %%g1, %1, %%g1\n"
 201         "       add     %%g1, %0, %%g1\n"
 202         "       wr      %%g1, 0x0, %%asr25"
 203         : /* no outputs */
 204         : "r" (offset), "r" (TICK_PRIV_BIT)
 205         : "g1");
 206 }
 207
 208 static unsigned long stick_get_tick(void)
 209 {
 210         unsigned long ret;
 211
 212         __asm__ __volatile__("rd        %%asr24, %0"
 213                              : "=r" (ret));
 214
 215         return ret & ~TICK_PRIV_BIT;
 216 }
 217
 218 static unsigned long stick_get_compare(void)
 219 {
 220         unsigned long ret;
 221
 222         __asm__ __volatile__("rd        %%asr25, %0"
 223                              : "=r" (ret));
 224
 225         return ret;
 226 }
 227
 228 static unsigned long stick_add_tick(unsigned long adj, unsigned long offset)
 229 {
 230         unsigned long new_tick, tmp;
 231
 232         __asm__ __volatile__("rd        %%asr24, %0\n\t"
 233                              "add       %0, %2, %0\n\t"
 234                              "wr        %0, 0, %%asr24\n\t"
 235                              "andn      %0, %4, %1\n\t"
 236                              "add       %1, %3, %1\n\t"
 237                              "wr        %1, 0, %%asr25"
 238                              : "=&r" (new_tick), "=&r" (tmp)
 239                              : "r" (adj), "r" (offset), "r" (TICK_PRIV_BIT));
 240
 241         return new_tick;
 242 }
 243
 244 static unsigned long stick_add_compare(unsigned long adj)
 245 {
 246         unsigned long new_compare;
 247
 248         __asm__ __volatile__("rd        %%asr25, %0\n\t"
 249                              "add       %0, %1, %0\n\t"
 250                              "wr        %0, 0, %%asr25"
 251                              : "=&r" (new_compare)
 252                              : "r" (adj));
 253
 254         return new_compare;
 255 }
 256
 257 static struct sparc64_tick_ops stick_operations = {
 258         .init_tick      =       stick_init_tick,
 259         .get_tick       =       stick_get_tick,
 260         .get_compare    =       stick_get_compare,
 261         .add_tick       =       stick_add_tick,
 262         .add_compare    =       stick_add_compare,
 263         .softint_mask   =       1UL << 16,
 264 };
 265
 266 /* On Hummingbird the STICK/STICK_CMPR register is implemented
 267  * in I/O space.  There are two 64-bit registers each, the
 268  * first holds the low 32-bits of the value and the second holds
 269  * the high 32-bits.
 270  *
 271  * Since STICK is constantly updating, we have to access it carefully.
 272  *
 273  * The sequence we use to read is:
 274  * 1) read low
 275  * 2) read high
 276  * 3) read low again, if it rolled over increment high by 1
 277  *
 278  * Writing STICK safely is also tricky:
 279  * 1) write low to zero
 280  * 2) write high
 281  * 3) write low
 282  */
 283 #define HBIRD_STICKCMP_ADDR     0x1fe0000f060UL
 284 #define HBIRD_STICK_ADDR        0x1fe0000f070UL
 285
 286 static unsigned long __hbird_read_stick(void)
 287 {
 288         unsigned long ret, tmp1, tmp2, tmp3;
 289         unsigned long addr = HBIRD_STICK_ADDR;
 290
 291         __asm__ __volatile__("ldxa      [%1] %5, %2\n\t"
 292                              "add       %1, 0x8, %1\n\t"
 293                              "ldxa      [%1] %5, %3\n\t"
 294                              "sub       %1, 0x8, %1\n\t"
 295                              "ldxa      [%1] %5, %4\n\t"
 296                              "cmp       %4, %2\n\t"
 297                              "blu,a,pn  %%xcc, 1f\n\t"
 298                              " add      %3, 1, %3\n"
 299                              "1:\n\t"
 300                              "sllx      %3, 32, %3\n\t"
 301                              "or        %3, %4, %0\n\t"
 302                              : "=&r" (ret), "=&r" (addr),
 303                                "=&r" (tmp1), "=&r" (tmp2), "=&r" (tmp3)
 304                              : "i" (ASI_PHYS_BYPASS_EC_E), "1" (addr));
 305
 306         return ret;
 307 }
 308
 309 static unsigned long __hbird_read_compare(void)
 310 {
 311         unsigned long low, high;
 312         unsigned long addr = HBIRD_STICKCMP_ADDR;
 313
 314         __asm__ __volatile__("ldxa      [%2] %3, %0\n\t"
 315                              "add       %2, 0x8, %2\n\t"
 316                              "ldxa      [%2] %3, %1"
 317                              : "=&r" (low), "=&r" (high), "=&r" (addr)
 318                              : "i" (ASI_PHYS_BYPASS_EC_E), "2" (addr));
 319
 320         return (high << 32UL) | low;
 321 }
 322
 323 static void __hbird_write_stick(unsigned long val)
 324 {
 325         unsigned long low = (val & 0xffffffffUL);
 326         unsigned long high = (val >> 32UL);
 327         unsigned long addr = HBIRD_STICK_ADDR;
 328
 329         __asm__ __volatile__("stxa      %%g0, [%0] %4\n\t"
 330                              "add       %0, 0x8, %0\n\t"
 331                              "stxa      %3, [%0] %4\n\t"
 332                              "sub       %0, 0x8, %0\n\t"
 333                              "stxa      %2, [%0] %4"
 334                              : "=&r" (addr)
 335                              : "0" (addr), "r" (low), "r" (high),
 336                                "i" (ASI_PHYS_BYPASS_EC_E));
 337 }
 338
 339 static void __hbird_write_compare(unsigned long val)
 340 {
 341         unsigned long low = (val & 0xffffffffUL);
 342         unsigned long high = (val >> 32UL);
 343         unsigned long addr = HBIRD_STICKCMP_ADDR + 0x8UL;
 344
 345         __asm__ __volatile__("stxa      %3, [%0] %4\n\t"
 346                              "sub       %0, 0x8, %0\n\t"
 347                              "stxa      %2, [%0] %4"
 348                              : "=&r" (addr)
 349                              : "0" (addr), "r" (low), "r" (high),
 350                                "i" (ASI_PHYS_BYPASS_EC_E));
 351 }
 352
 353 static void hbtick_init_tick(unsigned long offset)
 354 {
 355         unsigned long val;
 356
 357         tick_disable_protection();
 358
 359         /* XXX This seems to be necessary to 'jumpstart' Hummingbird
 360          * XXX into actually sending STICK interrupts.  I think because
 361          * XXX of how we store %tick_cmpr in head.S this somehow resets the
 362          * XXX {TICK + STICK} interrupt mux.  -DaveM
 363          */
 364         __hbird_write_stick(__hbird_read_stick());
 365
 366         val = __hbird_read_stick() & ~TICK_PRIV_BIT;
 367         __hbird_write_compare(val + offset);
 368 }
 369
 370 static unsigned long hbtick_get_tick(void)
 371 {
 372         return __hbird_read_stick() & ~TICK_PRIV_BIT;
 373 }
 374
 375 static unsigned long hbtick_get_compare(void)
 376 {
 377         return __hbird_read_compare();
 378 }
 379
 380 static unsigned long hbtick_add_tick(unsigned long adj, unsigned long offset)
 381 {
 382         unsigned long val;
 383
 384         val = __hbird_read_stick() + adj;
 385         __hbird_write_stick(val);
 386
 387         val &= ~TICK_PRIV_BIT;
 388         __hbird_write_compare(val + offset);
 389
 390         return val;
 391 }
 392
 393 static unsigned long hbtick_add_compare(unsigned long adj)
 394 {
 395         unsigned long val = __hbird_read_compare() + adj;
 396
 397         val &= ~TICK_PRIV_BIT;
 398         __hbird_write_compare(val);
 399
 400         return val;
 401 }
 402
 403 static struct sparc64_tick_ops hbtick_operations = {
 404         .init_tick      =       hbtick_init_tick,
 405         .get_tick       =       hbtick_get_tick,
 406         .get_compare    =       hbtick_get_compare,
 407         .add_tick       =       hbtick_add_tick,
 408         .add_compare    =       hbtick_add_compare,
 409         .softint_mask   =       1UL << 0,
 410 };
 411
 412 /* timer_interrupt() needs to keep up the real-time clock,
 413  * as well as call the "do_timer()" routine every clocktick
 414  *
 415  * NOTE: On SUN5 systems the ticker interrupt comes in using 2
 416  *       interrupts, one at level14 and one with softint bit 0.
 417  */
 418 unsigned long timer_tick_offset;
 419 unsigned long timer_tick_compare;
 420
 421 static unsigned long timer_ticks_per_usec_quotient;
 422 static unsigned long timer_ticks_per_nsec_quotient;
 423
 424 #define TICK_SIZE (tick_nsec / 1000)
 425
 426 static inline void timer_check_rtc(void)
 427 {
 428         /* last time the cmos clock got updated */
 429         static long last_rtc_update;
 430
 431         /* Determine when to update the Mostek clock. */
 432         if ((time_status & STA_UNSYNC) == 0 &&
 433             xtime.tv_sec > last_rtc_update + 660 &&
 434             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 435             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 436                 if (set_rtc_mmss(xtime.tv_sec) == 0)
 437                         last_rtc_update = xtime.tv_sec;
 438                 else
 439                         last_rtc_update = xtime.tv_sec - 600;
 440                         /* do it again in 60 s */
 441         }
 442 }
 443
 444 void sparc64_do_profile(struct pt_regs *regs)
 445 {
 446         unsigned long pc;
 447
 448         profile_hook(regs);
 449
 450         if (user_mode(regs))
 451                 return;
 452
 453         if (!prof_buffer)
 454                 return;
 455
 456         pc = regs->tpc;
 457
 458         pc -= (unsigned long) _stext;
 459         pc >>= prof_shift;
 460
 461         if(pc >= prof_len)
 462                 pc = prof_len - 1;
 463         atomic_inc((atomic_t *)&prof_buffer[pc]);
 464 }
 465
 466 static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 467 {
 468         unsigned long ticks, pstate;
 469
 470         write_seqlock(&xtime_lock);
 471
 472         do {
 473 #ifndef CONFIG_SMP
 474                 sparc64_do_profile(regs);
 475 #endif
 476                 do_timer(regs);
 477
 478                 /* Guarantee that the following sequences execute
 479                  * uninterrupted.
 480                  */
 481                 __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
 482                                      "wrpr      %0, %1, %%pstate"
 483                                      : "=r" (pstate)
 484                                      : "i" (PSTATE_IE));
 485
 486                 timer_tick_compare = tick_ops->add_compare(timer_tick_offset);
 487                 ticks = tick_ops->get_tick();
 488
 489                 /* Restore PSTATE_IE. */
 490                 __asm__ __volatile__("wrpr      %0, 0x0, %%pstate"
 491                                      : /* no outputs */
 492                                      : "r" (pstate));
 493         } while (time_after_eq(ticks, timer_tick_compare));
 494
 495         timer_check_rtc();
 496
 497         write_sequnlock(&xtime_lock);
 498
 499         return IRQ_HANDLED;
 500 }
 501
 502 #ifdef CONFIG_SMP
 503 void timer_tick_interrupt(struct pt_regs *regs)
 504 {
 505         write_seqlock(&xtime_lock);
 506
 507         do_timer(regs);
 508
 509         /*
 510          * Only keep timer_tick_offset uptodate, but don't set TICK_CMPR.
 511          */
 512         timer_tick_compare = tick_ops->get_compare() + timer_tick_offset;
 513
 514         timer_check_rtc();
 515
 516         write_sequnlock(&xtime_lock);
 517 }
 518 #endif
 519
 520 /* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */
 521 static void __init kick_start_clock(void)
 522 {
 523         unsigned long regs = mstk48t02_regs;
 524         u8 sec, tmp;
 525         int i, count;
 526
 527         prom_printf("CLOCK: Clock was stopped. Kick start ");
 528
 529         spin_lock_irq(&mostek_lock);
 530
 531         /* Turn on the kick start bit to start the oscillator. */
 532         tmp = mostek_read(regs + MOSTEK_CREG);
 533         tmp |= MSTK_CREG_WRITE;
 534         mostek_write(regs + MOSTEK_CREG, tmp);
 535         tmp = mostek_read(regs + MOSTEK_SEC);
 536         tmp &= ~MSTK_STOP;
 537         mostek_write(regs + MOSTEK_SEC, tmp);
 538         tmp = mostek_read(regs + MOSTEK_HOUR);
 539         tmp |= MSTK_KICK_START;
 540         mostek_write(regs + MOSTEK_HOUR, tmp);
 541         tmp = mostek_read(regs + MOSTEK_CREG);
 542         tmp &= ~MSTK_CREG_WRITE;
 543         mostek_write(regs + MOSTEK_CREG, tmp);
 544
 545         spin_unlock_irq(&mostek_lock);
 546
 547         /* Delay to allow the clock oscillator to start. */
 548         sec = MSTK_REG_SEC(regs);
 549         for (i = 0; i < 3; i++) {
 550                 while (sec == MSTK_REG_SEC(regs))
 551                         for (count = 0; count < 100000; count++)
 552                                 /* nothing */ ;
 553                 prom_printf(".");
 554                 sec = MSTK_REG_SEC(regs);
 555         }
 556         prom_printf("\n");
 557
 558         spin_lock_irq(&mostek_lock);
 559
 560         /* Turn off kick start and set a "valid" time and date. */
 561         tmp = mostek_read(regs + MOSTEK_CREG);
 562         tmp |= MSTK_CREG_WRITE;
 563         mostek_write(regs + MOSTEK_CREG, tmp);
 564         tmp = mostek_read(regs + MOSTEK_HOUR);
 565         tmp &= ~MSTK_KICK_START;
 566         mostek_write(regs + MOSTEK_HOUR, tmp);
 567         MSTK_SET_REG_SEC(regs,0);
 568         MSTK_SET_REG_MIN(regs,0);
 569         MSTK_SET_REG_HOUR(regs,0);
 570         MSTK_SET_REG_DOW(regs,5);
 571         MSTK_SET_REG_DOM(regs,1);
 572         MSTK_SET_REG_MONTH(regs,8);
 573         MSTK_SET_REG_YEAR(regs,1996 - MSTK_YEAR_ZERO);
 574         tmp = mostek_read(regs + MOSTEK_CREG);
 575         tmp &= ~MSTK_CREG_WRITE;
 576         mostek_write(regs + MOSTEK_CREG, tmp);
 577
 578         spin_unlock_irq(&mostek_lock);
 579
 580         /* Ensure the kick start bit is off. If it isn't, turn it off. */
 581         while (mostek_read(regs + MOSTEK_HOUR) & MSTK_KICK_START) {
 582                 prom_printf("CLOCK: Kick start still on!\n");
 583
 584                 spin_lock_irq(&mostek_lock);
 585
 586                 tmp = mostek_read(regs + MOSTEK_CREG);
 587                 tmp |= MSTK_CREG_WRITE;
 588                 mostek_write(regs + MOSTEK_CREG, tmp);
 589
 590                 tmp = mostek_read(regs + MOSTEK_HOUR);
 591                 tmp &= ~MSTK_KICK_START;
 592                 mostek_write(regs + MOSTEK_HOUR, tmp);
 593
 594                 tmp = mostek_read(regs + MOSTEK_CREG);
 595                 tmp &= ~MSTK_CREG_WRITE;
 596                 mostek_write(regs + MOSTEK_CREG, tmp);
 597
 598                 spin_unlock_irq(&mostek_lock);
 599         }
 600
 601         prom_printf("CLOCK: Kick start procedure successful.\n");
 602 }
 603
 604 /* Return nonzero if the clock chip battery is low. */
 605 static int __init has_low_battery(void)
 606 {
 607         unsigned long regs = mstk48t02_regs;
 608         u8 data1, data2;
 609
 610         spin_lock_irq(&mostek_lock);
 611
 612         data1 = mostek_read(regs + MOSTEK_EEPROM);      /* Read some data. */
 613         mostek_write(regs + MOSTEK_EEPROM, ~data1);     /* Write back the complement. */
 614         data2 = mostek_read(regs + MOSTEK_EEPROM);      /* Read back the complement. */
 615         mostek_write(regs + MOSTEK_EEPROM, data1);      /* Restore original value. */
 616
 617         spin_unlock_irq(&mostek_lock);
 618
 619         return (data1 == data2);        /* Was the write blocked? */
 620 }
 621
 622 /* Probe for the real time clock chip. */
 623 static void __init set_system_time(void)
 624 {
 625         unsigned int year, mon, day, hour, min, sec;
 626         unsigned long mregs = mstk48t02_regs;
 627 #ifdef CONFIG_PCI
 628         unsigned long dregs = ds1287_regs;
 629 #else
 630         unsigned long dregs = 0UL;
 631 #endif
 632         u8 tmp;
 633
 634         if (!mregs && !dregs) {
 635                 prom_printf("Something wrong, clock regs not mapped yet.\n");
 636                 prom_halt();
 637         }
 638
 639         if (mregs) {
 640                 spin_lock_irq(&mostek_lock);
 641
 642                 /* Traditional Mostek chip. */
 643                 tmp = mostek_read(mregs + MOSTEK_CREG);
 644                 tmp |= MSTK_CREG_READ;
 645                 mostek_write(mregs + MOSTEK_CREG, tmp);
 646
 647                 sec = MSTK_REG_SEC(mregs);
 648                 min = MSTK_REG_MIN(mregs);
 649                 hour = MSTK_REG_HOUR(mregs);
 650                 day = MSTK_REG_DOM(mregs);
 651                 mon = MSTK_REG_MONTH(mregs);
 652                 year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) );
 653         } else {
 654                 int i;
 655
 656                 /* Dallas 12887 RTC chip. */
 657
 658                 /* Stolen from arch/i386/kernel/time.c, see there for
 659                  * credits and descriptive comments.
 660                  */
 661                 for (i = 0; i < 1000000; i++) {
 662                         if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
 663                                 break;
 664                         udelay(10);
 665                 }
 666                 for (i = 0; i < 1000000; i++) {
 667                         if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
 668                                 break;
 669                         udelay(10);
 670                 }
 671                 do {
 672                         sec  = CMOS_READ(RTC_SECONDS);
 673                         min  = CMOS_READ(RTC_MINUTES);
 674                         hour = CMOS_READ(RTC_HOURS);
 675                         day  = CMOS_READ(RTC_DAY_OF_MONTH);
 676                         mon  = CMOS_READ(RTC_MONTH);
 677                         year = CMOS_READ(RTC_YEAR);
 678                 } while (sec != CMOS_READ(RTC_SECONDS));
 679                 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 680                         BCD_TO_BIN(sec);
 681                         BCD_TO_BIN(min);
 682                         BCD_TO_BIN(hour);
 683                         BCD_TO_BIN(day);
 684                         BCD_TO_BIN(mon);
 685                         BCD_TO_BIN(year);
 686                 }
 687                 if ((year += 1900) < 1970)
 688                         year += 100;
 689         }
 690
 691         xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
 692         xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
 693         set_normalized_timespec(&wall_to_monotonic,
 694                                 -xtime.tv_sec, -xtime.tv_nsec);
 695
 696         if (mregs) {
 697                 tmp = mostek_read(mregs + MOSTEK_CREG);
 698                 tmp &= ~MSTK_CREG_READ;
 699                 mostek_write(mregs + MOSTEK_CREG, tmp);
 700
 701                 spin_unlock_irq(&mostek_lock);
 702         }
 703 }
 704
 705 void __init clock_probe(void)
 706 {
 707         struct linux_prom_registers clk_reg[2];
 708         char model[128];
 709         int node, busnd = -1, err;
 710         unsigned long flags;
 711         struct linux_central *cbus;
 712 #ifdef CONFIG_PCI
 713         struct linux_ebus *ebus = NULL;
 714         struct sparc_isa_bridge *isa_br = NULL;
 715 #endif
 716         static int invoked;
 717
 718         if (invoked)
 719                 return;
 720         invoked = 1;
 721
 722
 723         if (this_is_starfire) {
 724                 /* davem suggests we keep this within the 4M locked kernel image */
 725                 static char obp_gettod[256];
 726                 static u32 unix_tod;
 727
 728                 sprintf(obp_gettod, "h# %08x unix-gettod",
 729                         (unsigned int) (long) &unix_tod);
 730                 prom_feval(obp_gettod);
 731                 xtime.tv_sec = unix_tod;
 732                 xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
 733                 set_normalized_timespec(&wall_to_monotonic,
 734                                         -xtime.tv_sec, -xtime.tv_nsec);
 735                 return;
 736         }
 737
 738         local_irq_save(flags);
 739
 740         cbus = central_bus;
 741         if (cbus != NULL)
 742                 busnd = central_bus->child->prom_node;
 743
 744         /* Check FHC Central then EBUSs then ISA bridges then SBUSs.
 745          * That way we handle the presence of multiple properly.
 746          *
 747          * As a special case, machines with Central must provide the
 748          * timer chip there.
 749          */
 750 #ifdef CONFIG_PCI
 751         if (ebus_chain != NULL) {
 752                 ebus = ebus_chain;
 753                 if (busnd == -1)
 754                         busnd = ebus->prom_node;
 755         }
 756         if (isa_chain != NULL) {
 757                 isa_br = isa_chain;
 758                 if (busnd == -1)
 759                         busnd = isa_br->prom_node;
 760         }
 761 #endif
 762         if (sbus_root != NULL && busnd == -1)
 763                 busnd = sbus_root->prom_node;
 764
 765         if (busnd == -1) {
 766                 prom_printf("clock_probe: problem, cannot find bus to search.\n");
 767                 prom_halt();
 768         }
 769
 770         node = prom_getchild(busnd);
 771
 772         while (1) {
 773                 if (!node)
 774                         model[0] = 0;
 775                 else
 776                         prom_getstring(node, "model", model, sizeof(model));
 777                 if (strcmp(model, "mk48t02") &&
 778                     strcmp(model, "mk48t08") &&
 779                     strcmp(model, "mk48t59") &&
 780                     strcmp(model, "m5819") &&
 781                     strcmp(model, "m5819p") &&
 782                     strcmp(model, "ds1287")) {
 783                         if (cbus != NULL) {
 784                                 prom_printf("clock_probe: Central bus lacks timer chip.\n");
 785                                 prom_halt();
 786                         }
 787
 788                         if (node != 0)
 789                                 node = prom_getsibling(node);
 790 #ifdef CONFIG_PCI
 791                         while ((node == 0) && ebus != NULL) {
 792                                 ebus = ebus->next;
 793                                 if (ebus != NULL) {
 794                                         busnd = ebus->prom_node;
 795                                         node = prom_getchild(busnd);
 796                                 }
 797                         }
 798                         while ((node == 0) && isa_br != NULL) {
 799                                 isa_br = isa_br->next;
 800                                 if (isa_br != NULL) {
 801                                         busnd = isa_br->prom_node;
 802                                         node = prom_getchild(busnd);
 803                                 }
 804                         }
 805 #endif
 806                         if (node == 0) {
 807                                 prom_printf("clock_probe: Cannot find timer chip\n");
 808                                 prom_halt();
 809                         }
 810                         continue;
 811                 }
 812
 813                 err = prom_getproperty(node, "reg", (char *)clk_reg,
 814                                        sizeof(clk_reg));
 815                 if(err == -1) {
 816                         prom_printf("clock_probe: Cannot get Mostek reg property\n");
 817                         prom_halt();
 818                 }
 819
 820                 if (cbus != NULL) {
 821                         apply_fhc_ranges(central_bus->child, clk_reg, 1);
 822                         apply_central_ranges(central_bus, clk_reg, 1);
 823                 }
 824 #ifdef CONFIG_PCI
 825                 else if (ebus != NULL) {
 826                         struct linux_ebus_device *edev;
 827
 828                         for_each_ebusdev(edev, ebus)
 829                                 if (edev->prom_node == node)
 830                                         break;
 831                         if (edev == NULL) {
 832                                 if (isa_chain != NULL)
 833                                         goto try_isa_clock;
 834                                 prom_printf("%s: Mostek not probed by EBUS\n",
 835                                             __FUNCTION__);
 836                                 prom_halt();
 837                         }
 838
 839                         if (!strcmp(model, "ds1287") ||
 840                             !strcmp(model, "m5819") ||
 841                             !strcmp(model, "m5819p")) {
 842                                 ds1287_regs = edev->resource[0].start;
 843                         } else {
 844                                 mstk48t59_regs = edev->resource[0].start;
 845                                 mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
 846                         }
 847                         break;
 848                 }
 849                 else if (isa_br != NULL) {
 850                         struct sparc_isa_device *isadev;
 851
 852 try_isa_clock:
 853                         for_each_isadev(isadev, isa_br)
 854                                 if (isadev->prom_node == node)
 855                                         break;
 856                         if (isadev == NULL) {
 857                                 prom_printf("%s: Mostek not probed by ISA\n");
 858                                 prom_halt();
 859                         }
 860                         if (!strcmp(model, "ds1287") ||
 861                             !strcmp(model, "m5819") ||
 862                             !strcmp(model, "m5819p")) {
 863                                 ds1287_regs = isadev->resource.start;
 864                         } else {
 865                                 mstk48t59_regs = isadev->resource.start;
 866                                 mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
 867                         }
 868                         break;
 869                 }
 870 #endif
 871                 else {
 872                         if (sbus_root->num_sbus_ranges) {
 873                                 int nranges = sbus_root->num_sbus_ranges;
 874                                 int rngc;
 875
 876                                 for (rngc = 0; rngc < nranges; rngc++)
 877                                         if (clk_reg[0].which_io ==
 878                                             sbus_root->sbus_ranges[rngc].ot_child_space)
 879                                                 break;
 880                                 if (rngc == nranges) {
 881                                         prom_printf("clock_probe: Cannot find ranges for "
 882                                                     "clock regs.\n");
 883                                         prom_halt();
 884                                 }
 885                                 clk_reg[0].which_io =
 886                                         sbus_root->sbus_ranges[rngc].ot_parent_space;
 887                                 clk_reg[0].phys_addr +=
 888                                         sbus_root->sbus_ranges[rngc].ot_parent_base;
 889                         }
 890                 }
 891
 892                 if(model[5] == '0' && model[6] == '2') {
 893                         mstk48t02_regs = (((u64)clk_reg[0].phys_addr) |
 894                                           (((u64)clk_reg[0].which_io)<<32UL));
 895                 } else if(model[5] == '0' && model[6] == '8') {
 896                         mstk48t08_regs = (((u64)clk_reg[0].phys_addr) |
 897                                           (((u64)clk_reg[0].which_io)<<32UL));
 898                         mstk48t02_regs = mstk48t08_regs + MOSTEK_48T08_48T02;
 899                 } else {
 900                         mstk48t59_regs = (((u64)clk_reg[0].phys_addr) |
 901                                           (((u64)clk_reg[0].which_io)<<32UL));
 902                         mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
 903                 }
 904                 break;
 905         }
 906
 907         if (mstk48t02_regs != 0UL) {
 908                 /* Report a low battery voltage condition. */
 909                 if (has_low_battery())
 910                         prom_printf("NVRAM: Low battery voltage!\n");
 911
 912                 /* Kick start the clock if it is completely stopped. */
 913                 if (mostek_read(mstk48t02_regs + MOSTEK_SEC) & MSTK_STOP)
 914                         kick_start_clock();
 915         }
 916
 917         set_system_time();
 918
 919         local_irq_restore(flags);
 920 }
 921
 922 /* This is gets the master TICK_INT timer going. */
 923 static unsigned long sparc64_init_timers(irqreturn_t (*cfunc)(int, void *, struct pt_regs *))
 924 {
 925         unsigned long pstate, clock;
 926         int node, err;
 927 #ifdef CONFIG_SMP
 928         extern void smp_tick_init(void);
 929 #endif
 930
 931         if (tlb_type == spitfire) {
 932                 unsigned long ver, manuf, impl;
 933
 934                 __asm__ __volatile__ ("rdpr %%ver, %0"
 935                                       : "=&r" (ver));
 936                 manuf = ((ver >> 48) & 0xffff);
 937                 impl = ((ver >> 32) & 0xffff);
 938                 if (manuf == 0x17 && impl == 0x13) {
 939                         /* Hummingbird, aka Ultra-IIe */
 940                         tick_ops = &hbtick_operations;
 941                         node = prom_root_node;
 942                         clock = prom_getint(node, "stick-frequency");
 943                 } else {
 944                         tick_ops = &tick_operations;
 945                         cpu_find_by_instance(0, &node, NULL);
 946                         clock = prom_getint(node, "clock-frequency");
 947                 }
 948         } else {
 949                 tick_ops = &stick_operations;
 950                 node = prom_root_node;
 951                 clock = prom_getint(node, "stick-frequency");
 952         }
 953         timer_tick_offset = clock / HZ;
 954
 955 #ifdef CONFIG_SMP
 956         smp_tick_init();
 957 #endif
 958
 959         /* Register IRQ handler. */
 960         err = request_irq(build_irq(0, 0, 0UL, 0UL), cfunc, SA_STATIC_ALLOC,
 961                           "timer", NULL);
 962
 963         if (err) {
 964                 prom_printf("Serious problem, cannot register TICK_INT\n");
 965                 prom_halt();
 966         }
 967
 968         /* Guarantee that the following sequences execute
 969          * uninterrupted.
 970          */
 971         __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
 972                              "wrpr      %0, %1, %%pstate"
 973                              : "=r" (pstate)
 974                              : "i" (PSTATE_IE));
 975
 976         tick_ops->init_tick(timer_tick_offset);
 977
 978         /* Restore PSTATE_IE. */
 979         __asm__ __volatile__("wrpr      %0, 0x0, %%pstate"
 980                              : /* no outputs */
 981                              : "r" (pstate));
 982
 983         local_irq_enable();
 984
 985         return clock;
 986 }
 987
 988 struct freq_table {
 989         unsigned long udelay_val_ref;
 990         unsigned long clock_tick_ref;
 991         unsigned int ref_freq;
 992 };
 993 static DEFINE_PER_CPU(struct freq_table, sparc64_freq_table) = { 0, 0, 0 };
 994
 995 unsigned long sparc64_get_clock_tick(unsigned int cpu)
 996 {
 997         struct freq_table *ft = &per_cpu(sparc64_freq_table, cpu);
 998
 999         if (ft->clock_tick_ref)
1000                 return ft->clock_tick_ref;
1001         return cpu_data(cpu).clock_tick;
1002 }
1003
1004 #ifdef CONFIG_CPU_FREQ
1005
1006 static int sparc64_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
1007                                     void *data)
1008 {
1009         struct cpufreq_freqs *freq = data;
1010         unsigned int cpu = freq->cpu;
1011         struct freq_table *ft = &per_cpu(sparc64_freq_table, cpu);
1012
1013         if (!ft->ref_freq) {
1014                 ft->ref_freq = freq->old;
1015                 ft->udelay_val_ref = cpu_data(cpu).udelay_val;
1016                 ft->clock_tick_ref = cpu_data(cpu).clock_tick;
1017         }
1018         if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
1019             (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
1020             (val == CPUFREQ_RESUMECHANGE)) {
1021                 cpu_data(cpu).udelay_val =
1022                         cpufreq_scale(ft->udelay_val_ref,
1023                                       ft->ref_freq,
1024                                       freq->new);
1025                 cpu_data(cpu).clock_tick =
1026                         cpufreq_scale(ft->clock_tick_ref,
1027                                       ft->ref_freq,
1028                                       freq->new);
1029         }
1030
1031         return 0;
1032 }
1033
1034 static struct notifier_block sparc64_cpufreq_notifier_block = {
1035         .notifier_call  = sparc64_cpufreq_notifier
1036 };
1037 #endif
1038
1039 /* The quotient formula is taken from the IA64 port. */
1040 #define SPARC64_USEC_PER_CYC_SHIFT      30UL
1041 #define SPARC64_NSEC_PER_CYC_SHIFT      30UL
1042 void __init time_init(void)
1043 {
1044         unsigned long clock = sparc64_init_timers(timer_interrupt);
1045
1046         timer_ticks_per_usec_quotient =
1047                 (((1000000UL << SPARC64_USEC_PER_CYC_SHIFT) +
1048                   (clock / 2)) / clock);
1049
1050         timer_ticks_per_nsec_quotient =
1051                 (((NSEC_PER_SEC << SPARC64_NSEC_PER_CYC_SHIFT) +
1052                   (clock / 2)) / clock);
1053
1054 #ifdef CONFIG_CPU_FREQ
1055         cpufreq_register_notifier(&sparc64_cpufreq_notifier_block,
1056                                   CPUFREQ_TRANSITION_NOTIFIER);
1057 #endif
1058 }
1059
1060 static __inline__ unsigned long do_gettimeoffset(void)
1061 {
1062         unsigned long ticks = tick_ops->get_tick();
1063
1064         ticks += timer_tick_offset;
1065         ticks -= timer_tick_compare;
1066
1067         return (ticks * timer_ticks_per_usec_quotient)
1068                 >> SPARC64_USEC_PER_CYC_SHIFT;
1069 }
1070
1071 unsigned long long sched_clock(void)
1072 {
1073         unsigned long ticks = tick_ops->get_tick();
1074
1075         return (ticks * timer_ticks_per_nsec_quotient)
1076                 >> SPARC64_NSEC_PER_CYC_SHIFT;
1077 }
1078
1079 int do_settimeofday(struct timespec *tv)
1080 {
1081         time_t wtm_sec, sec = tv->tv_sec;
1082         long wtm_nsec, nsec = tv->tv_nsec;
1083
1084         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
1085                 return -EINVAL;
1086
1087         if (this_is_starfire)
1088                 return 0;
1089
1090         write_seqlock_irq(&xtime_lock);
1091         /*
1092          * This is revolting. We need to set "xtime" correctly. However, the
1093          * value in this location is the value at the most recent update of
1094          * wall time.  Discover what correction gettimeofday() would have
1095          * made, and then undo it!
1096          */
1097         nsec -= do_gettimeoffset() * 1000;
1098         nsec -= (jiffies - wall_jiffies) * (NSEC_PER_SEC / HZ);
1099
1100         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
1101         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
1102
1103         set_normalized_timespec(&xtime, sec, nsec);
1104         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
1105
1106         time_adjust = 0;                /* stop active adjtime() */
1107         time_status |= STA_UNSYNC;
1108         time_maxerror = NTP_PHASE_LIMIT;
1109         time_esterror = NTP_PHASE_LIMIT;
1110         write_sequnlock_irq(&xtime_lock);
1111         clock_was_set();
1112         return 0;
1113 }
1114
1115 EXPORT_SYMBOL(do_settimeofday);
1116
1117 /* Ok, my cute asm atomicity trick doesn't work anymore.
1118  * There are just too many variables that need to be protected
1119  * now (both members of xtime, wall_jiffies, et al.)
1120  */
1121 void do_gettimeofday(struct timeval *tv)
1122 {
1123         unsigned long seq;
1124         unsigned long usec, sec;
1125         unsigned long max_ntp_tick = tick_usec - tickadj;
1126
1127         do {
1128                 unsigned long lost;
1129
1130                 seq = read_seqbegin(&xtime_lock);
1131                 usec = do_gettimeoffset();
1132                 lost = jiffies - wall_jiffies;
1133
1134                 /*
1135                  * If time_adjust is negative then NTP is slowing the clock
1136                  * so make sure not to go into next possible interval.
1137                  * Better to lose some accuracy than have time go backwards..
1138                  */
1139                 if (unlikely(time_adjust < 0)) {
1140                         usec = min(usec, max_ntp_tick);
1141
1142                         if (lost)
1143                                 usec += lost * max_ntp_tick;
1144                 }
1145                 else if (unlikely(lost))
1146                         usec += lost * tick_usec;
1147
1148                 sec = xtime.tv_sec;
1149
1150                 /* Believe it or not, this divide shows up on
1151                  * kernel profiles.  The problem is that it is
1152                  * both 64-bit and signed.  Happily, 32-bits
1153                  * of precision is all we really need and in
1154                  * doing so gcc ends up emitting a cheap multiply.
1155                  *
1156                  * XXX Why is tv_nsec 'long' and 'signed' in
1157                  * XXX the first place, can it even be negative?
1158                  */
1159                 usec += ((unsigned int) xtime.tv_nsec / 1000U);
1160         } while (read_seqretry(&xtime_lock, seq));
1161
1162         while (usec >= 1000000) {
1163                 usec -= 1000000;
1164                 sec++;
1165         }
1166
1167         tv->tv_sec = sec;
1168         tv->tv_usec = usec;
1169 }
1170
1171 EXPORT_SYMBOL(do_gettimeofday);
1172
1173 static int set_rtc_mmss(unsigned long nowtime)
1174 {
1175         int real_seconds, real_minutes, chip_minutes;
1176         unsigned long mregs = mstk48t02_regs;
1177 #ifdef CONFIG_PCI
1178         unsigned long dregs = ds1287_regs;
1179 #else
1180         unsigned long dregs = 0UL;
1181 #endif
1182         unsigned long flags;
1183         u8 tmp;
1184
1185         /*
1186          * Not having a register set can lead to trouble.
1187          * Also starfire doesn't have a tod clock.
1188          */
1189         if (!mregs && !dregs)
1190                 return -1;
1191
1192         if (mregs) {
1193                 spin_lock_irqsave(&mostek_lock, flags);
1194
1195                 /* Read the current RTC minutes. */
1196                 tmp = mostek_read(mregs + MOSTEK_CREG);
1197                 tmp |= MSTK_CREG_READ;
1198                 mostek_write(mregs + MOSTEK_CREG, tmp);
1199
1200                 chip_minutes = MSTK_REG_MIN(mregs);
1201
1202                 tmp = mostek_read(mregs + MOSTEK_CREG);
1203                 tmp &= ~MSTK_CREG_READ;
1204                 mostek_write(mregs + MOSTEK_CREG, tmp);
1205
1206                 /*
1207                  * since we're only adjusting minutes and seconds,
1208                  * don't interfere with hour overflow. This avoids
1209                  * messing with unknown time zones but requires your
1210                  * RTC not to be off by more than 15 minutes
1211                  */
1212                 real_seconds = nowtime % 60;
1213                 real_minutes = nowtime / 60;
1214                 if (((abs(real_minutes - chip_minutes) + 15)/30) & 1)
1215                         real_minutes += 30;     /* correct for half hour time zone */
1216                 real_minutes %= 60;
1217
1218                 if (abs(real_minutes - chip_minutes) < 30) {
1219                         tmp = mostek_read(mregs + MOSTEK_CREG);
1220                         tmp |= MSTK_CREG_WRITE;
1221                         mostek_write(mregs + MOSTEK_CREG, tmp);
1222
1223                         MSTK_SET_REG_SEC(mregs,real_seconds);
1224                         MSTK_SET_REG_MIN(mregs,real_minutes);
1225
1226                         tmp = mostek_read(mregs + MOSTEK_CREG);
1227                         tmp &= ~MSTK_CREG_WRITE;
1228                         mostek_write(mregs + MOSTEK_CREG, tmp);
1229
1230                         spin_unlock_irqrestore(&mostek_lock, flags);
1231
1232                         return 0;
1233                 } else {
1234                         spin_unlock_irqrestore(&mostek_lock, flags);
1235
1236                         return -1;
1237                 }
1238         } else {
1239                 int retval = 0;
1240                 unsigned char save_control, save_freq_select;
1241
1242                 /* Stolen from arch/i386/kernel/time.c, see there for
1243                  * credits and descriptive comments.
1244                  */
1245                 spin_lock_irqsave(&rtc_lock, flags);
1246                 save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
1247                 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
1248
1249                 save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
1250                 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
1251
1252                 chip_minutes = CMOS_READ(RTC_MINUTES);
1253                 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
1254                         BCD_TO_BIN(chip_minutes);
1255                 real_seconds = nowtime % 60;
1256                 real_minutes = nowtime / 60;
1257                 if (((abs(real_minutes - chip_minutes) + 15)/30) & 1)
1258                         real_minutes += 30;
1259                 real_minutes %= 60;
1260
1261                 if (abs(real_minutes - chip_minutes) < 30) {
1262                         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
1263                                 BIN_TO_BCD(real_seconds);
1264                                 BIN_TO_BCD(real_minutes);
1265                         }
1266                         CMOS_WRITE(real_seconds,RTC_SECONDS);
1267                         CMOS_WRITE(real_minutes,RTC_MINUTES);
1268                 } else {
1269                         printk(KERN_WARNING
1270                                "set_rtc_mmss: can't update from %d to %d\n",
1271                                chip_minutes, real_minutes);
1272                         retval = -1;
1273                 }
1274
1275                 CMOS_WRITE(save_control, RTC_CONTROL);
1276                 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
1277                 spin_unlock_irqrestore(&rtc_lock, flags);
1278
1279                 return retval;
1280         }
1281 }