arch/sh/kernel/time_64.c

   1 /*
   2  * arch/sh/kernel/time_64.c
   3  *
   4  * Copyright (C) 2000, 2001  Paolo Alberelli
   5  * Copyright (C) 2003 - 2007  Paul Mundt
   6  * Copyright (C) 2003  Richard Curnow
   7  *
   8  *    Original TMU/RTC code taken from sh version.
   9  *    Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
  10  *      Some code taken from i386 version.
  11  *      Copyright (C) 1991, 1992, 1995  Linus Torvalds
  12  *
  13  * This file is subject to the terms and conditions of the GNU General Public
  14  * License.  See the file "COPYING" in the main directory of this archive
  15  * for more details.
  16  */
  17 #include <linux/errno.h>
  18 #include <linux/rwsem.h>
  19 #include <linux/sched.h>
  20 #include <linux/kernel.h>
  21 #include <linux/param.h>
  22 #include <linux/string.h>
  23 #include <linux/mm.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/time.h>
  26 #include <linux/delay.h>
  27 #include <linux/init.h>
  28 #include <linux/profile.h>
  29 #include <linux/smp.h>
  30 #include <linux/module.h>
  31 #include <linux/bcd.h>
  32 #include <linux/timex.h>
  33 #include <linux/irq.h>
  34 #include <linux/io.h>
  35 #include <linux/platform_device.h>
  36 #include <cpu/registers.h>       /* required by inline __asm__ stmt. */
  37 #include <cpu/irq.h>
  38 #include <asm/addrspace.h>
  39 #include <asm/processor.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/delay.h>
  42 #include <asm/clock.h>
  43
  44 #define TMU_TOCR_INIT   0x00
  45 #define TMU0_TCR_INIT   0x0020
  46 #define TMU_TSTR_INIT   1
  47 #define TMU_TSTR_OFF    0
  48
  49 /* Real Time Clock */
  50 #define RTC_BLOCK_OFF   0x01040000
  51 #define RTC_BASE        PHYS_PERIPHERAL_BLOCK + RTC_BLOCK_OFF
  52 #define RTC_RCR1_CIE    0x10    /* Carry Interrupt Enable */
  53 #define RTC_RCR1        (rtc_base + 0x38)
  54
  55 /* Time Management Unit */
  56 #define TMU_BLOCK_OFF   0x01020000
  57 #define TMU_BASE        PHYS_PERIPHERAL_BLOCK + TMU_BLOCK_OFF
  58 #define TMU0_BASE       tmu_base + 0x8 + (0xc * 0x0)
  59 #define TMU1_BASE       tmu_base + 0x8 + (0xc * 0x1)
  60 #define TMU2_BASE       tmu_base + 0x8 + (0xc * 0x2)
  61
  62 #define TMU_TOCR        tmu_base+0x0    /* Byte access */
  63 #define TMU_TSTR        tmu_base+0x4    /* Byte access */
  64
  65 #define TMU0_TCOR       TMU0_BASE+0x0   /* Long access */
  66 #define TMU0_TCNT       TMU0_BASE+0x4   /* Long access */
  67 #define TMU0_TCR        TMU0_BASE+0x8   /* Word access */
  68
  69 #define TICK_SIZE (tick_nsec / 1000)
  70
  71 static unsigned long tmu_base, rtc_base;
  72 unsigned long cprc_base;
  73
  74 /* Variables to allow interpolation of time of day to resolution better than a
  75  * jiffy. */
  76
  77 /* This is effectively protected by xtime_lock */
  78 static unsigned long ctc_last_interrupt;
  79 static unsigned long long usecs_per_jiffy = 1000000/HZ; /* Approximation */
  80
  81 #define CTC_JIFFY_SCALE_SHIFT 40
  82
  83 /* 2**CTC_JIFFY_SCALE_SHIFT / ctc_ticks_per_jiffy */
  84 static unsigned long long scaled_recip_ctc_ticks_per_jiffy;
  85
  86 /* Estimate number of microseconds that have elapsed since the last timer tick,
  87    by scaling the delta that has occurred in the CTC register.
  88
  89    WARNING WARNING WARNING : This algorithm relies on the CTC decrementing at
  90    the CPU clock rate.  If the CPU sleeps, the CTC stops counting.  Bear this
  91    in mind if enabling SLEEP_WORKS in process.c.  In that case, this algorithm
  92    probably needs to use TMU.TCNT0 instead.  This will work even if the CPU is
  93    sleeping, though will be coarser.
  94
  95    FIXME : What if usecs_per_tick is moving around too much, e.g. if an adjtime
  96    is running or if the freq or tick arguments of adjtimex are modified after
  97    we have calibrated the scaling factor?  This will result in either a jump at
  98    the end of a tick period, or a wrap backwards at the start of the next one,
  99    if the application is reading the time of day often enough.  I think we
 100    ought to do better than this.  For this reason, usecs_per_jiffy is left
 101    separated out in the calculation below.  This allows some future hook into
 102    the adjtime-related stuff in kernel/timer.c to remove this hazard.
 103
 104 */
 105
 106 static unsigned long usecs_since_tick(void)
 107 {
 108         unsigned long long current_ctc;
 109         long ctc_ticks_since_interrupt;
 110         unsigned long long ull_ctc_ticks_since_interrupt;
 111         unsigned long result;
 112
 113         unsigned long long mul1_out;
 114         unsigned long long mul1_out_high;
 115         unsigned long long mul2_out_low, mul2_out_high;
 116
 117         /* Read CTC register */
 118         asm ("getcon cr62, %0" : "=r" (current_ctc));
 119         /* Note, the CTC counts down on each CPU clock, not up.
 120            Note(2), use long type to get correct wraparound arithmetic when
 121            the counter crosses zero. */
 122         ctc_ticks_since_interrupt = (long) ctc_last_interrupt - (long) current_ctc;
 123         ull_ctc_ticks_since_interrupt = (unsigned long long) ctc_ticks_since_interrupt;
 124
 125         /* Inline assembly to do 32x32x32->64 multiplier */
 126         asm volatile ("mulu.l %1, %2, %0" :
 127              "=r" (mul1_out) :
 128              "r" (ull_ctc_ticks_since_interrupt), "r" (usecs_per_jiffy));
 129
 130         mul1_out_high = mul1_out >> 32;
 131
 132         asm volatile ("mulu.l %1, %2, %0" :
 133              "=r" (mul2_out_low) :
 134              "r" (mul1_out), "r" (scaled_recip_ctc_ticks_per_jiffy));
 135
 136 #if 1
 137         asm volatile ("mulu.l %1, %2, %0" :
 138              "=r" (mul2_out_high) :
 139              "r" (mul1_out_high), "r" (scaled_recip_ctc_ticks_per_jiffy));
 140 #endif
 141
 142         result = (unsigned long) (((mul2_out_high << 32) + mul2_out_low) >> CTC_JIFFY_SCALE_SHIFT);
 143
 144         return result;
 145 }
 146
 147 void do_gettimeofday(struct timeval *tv)
 148 {
 149         unsigned long flags;
 150         unsigned long seq;
 151         unsigned long usec, sec;
 152
 153         do {
 154                 seq = read_seqbegin_irqsave(&xtime_lock, flags);
 155                 usec = usecs_since_tick();
 156                 sec = xtime.tv_sec;
 157                 usec += xtime.tv_nsec / 1000;
 158         } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
 159
 160         while (usec >= 1000000) {
 161                 usec -= 1000000;
 162                 sec++;
 163         }
 164
 165         tv->tv_sec = sec;
 166         tv->tv_usec = usec;
 167 }
 168 EXPORT_SYMBOL(do_gettimeofday);
 169
 170 int do_settimeofday(struct timespec *tv)
 171 {
 172         time_t wtm_sec, sec = tv->tv_sec;
 173         long wtm_nsec, nsec = tv->tv_nsec;
 174
 175         if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
 176                 return -EINVAL;
 177
 178         write_seqlock_irq(&xtime_lock);
 179         /*
 180          * This is revolting. We need to set "xtime" correctly. However, the
 181          * value in this location is the value at the most recent update of
 182          * wall time.  Discover what correction gettimeofday() would have
 183          * made, and then undo it!
 184          */
 185         nsec -= 1000 * usecs_since_tick();
 186
 187         wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
 188         wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
 189
 190         set_normalized_timespec(&xtime, sec, nsec);
 191         set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
 192
 193         ntp_clear();
 194         write_sequnlock_irq(&xtime_lock);
 195         clock_was_set();
 196
 197         return 0;
 198 }
 199 EXPORT_SYMBOL(do_settimeofday);
 200
 201 /* Dummy RTC ops */
 202 static void null_rtc_get_time(struct timespec *tv)
 203 {
 204         tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
 205         tv->tv_nsec = 0;
 206 }
 207
 208 static int null_rtc_set_time(const time_t secs)
 209 {
 210         return 0;
 211 }
 212
 213 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
 214 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
 215
 216 /* last time the RTC clock got updated */
 217 static long last_rtc_update;
 218
 219 /*
 220  * timer_interrupt() needs to keep up the real-time clock,
 221  * as well as call the "do_timer()" routine every clocktick
 222  */
 223 static inline void do_timer_interrupt(void)
 224 {
 225         unsigned long long current_ctc;
 226
 227         if (current->pid)
 228                 profile_tick(CPU_PROFILING);
 229
 230         /*
 231          * Here we are in the timer irq handler. We just have irqs locally
 232          * disabled but we don't know if the timer_bh is running on the other
 233          * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
 234          * the irq version of write_lock because as just said we have irq
 235          * locally disabled. -arca
 236          */
 237         write_seqlock(&xtime_lock);
 238         asm ("getcon cr62, %0" : "=r" (current_ctc));
 239         ctc_last_interrupt = (unsigned long) current_ctc;
 240
 241         do_timer(1);
 242
 243         /*
 244          * If we have an externally synchronized Linux clock, then update
 245          * RTC clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 246          * called as close as possible to 500 ms before the new second starts.
 247          */
 248         if (ntp_synced() &&
 249             xtime.tv_sec > last_rtc_update + 660 &&
 250             (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
 251             (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
 252                 if (rtc_sh_set_time(xtime.tv_sec) == 0)
 253                         last_rtc_update = xtime.tv_sec;
 254                 else
 255                         /* do it again in 60 s */
 256                         last_rtc_update = xtime.tv_sec - 600;
 257         }
 258         write_sequnlock(&xtime_lock);
 259
 260 #ifndef CONFIG_SMP
 261         update_process_times(user_mode(get_irq_regs()));
 262 #endif
 263 }
 264
 265 /*
 266  * This is the same as the above, except we _also_ save the current
 267  * Time Stamp Counter value at the time of the timer interrupt, so that
 268  * we later on can estimate the time of day more exactly.
 269  */
 270 static irqreturn_t timer_interrupt(int irq, void *dev_id)
 271 {
 272         unsigned long timer_status;
 273
 274         /* Clear UNF bit */
 275         timer_status = ctrl_inw(TMU0_TCR);
 276         timer_status &= ~0x100;
 277         ctrl_outw(timer_status, TMU0_TCR);
 278
 279         do_timer_interrupt();
 280
 281         return IRQ_HANDLED;
 282 }
 283
 284 static struct irqaction irq0  = {
 285         .handler = timer_interrupt,
 286         .flags = IRQF_DISABLED,
 287         .mask = CPU_MASK_NONE,
 288         .name = "timer",
 289 };
 290
 291 void __init time_init(void)
 292 {
 293         unsigned long interval;
 294         struct clk *clk;
 295
 296         tmu_base = onchip_remap(TMU_BASE, 1024, "TMU");
 297         if (!tmu_base) {
 298                 panic("Unable to remap TMU\n");
 299         }
 300
 301         rtc_base = onchip_remap(RTC_BASE, 1024, "RTC");
 302         if (!rtc_base) {
 303                 panic("Unable to remap RTC\n");
 304         }
 305
 306         clk = clk_get(NULL, "cpu_clk");
 307         scaled_recip_ctc_ticks_per_jiffy = ((1ULL << CTC_JIFFY_SCALE_SHIFT) /
 308                         (unsigned long long)(clk_get_rate(clk) / HZ));
 309
 310         rtc_sh_get_time(&xtime);
 311
 312         setup_irq(TIMER_IRQ, &irq0);
 313
 314         clk = clk_get(NULL, "module_clk");
 315         interval = (clk_get_rate(clk)/(HZ*4));
 316
 317         printk("Interval = %ld\n", interval);
 318
 319         /* Start TMU0 */
 320         ctrl_outb(TMU_TSTR_OFF, TMU_TSTR);
 321         ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
 322         ctrl_outw(TMU0_TCR_INIT, TMU0_TCR);
 323         ctrl_outl(interval, TMU0_TCOR);
 324         ctrl_outl(interval, TMU0_TCNT);
 325         ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);
 326 }
 327
 328 static struct resource rtc_resources[] = {
 329         [0] = {
 330                 /* RTC base, filled in by rtc_init */
 331                 .flags  = IORESOURCE_IO,
 332         },
 333         [1] = {
 334                 /* Period IRQ */
 335                 .start  = IRQ_PRI,
 336                 .flags  = IORESOURCE_IRQ,
 337         },
 338         [2] = {
 339                 /* Carry IRQ */
 340                 .start  = IRQ_CUI,
 341                 .flags  = IORESOURCE_IRQ,
 342         },
 343         [3] = {
 344                 /* Alarm IRQ */
 345                 .start  = IRQ_ATI,
 346                 .flags  = IORESOURCE_IRQ,
 347         },
 348 };
 349
 350 static struct platform_device rtc_device = {
 351         .name           = "sh-rtc",
 352         .id             = -1,
 353         .num_resources  = ARRAY_SIZE(rtc_resources),
 354         .resource       = rtc_resources,
 355 };
 356
 357 static int __init rtc_init(void)
 358 {
 359         rtc_resources[0].start  = rtc_base;
 360         rtc_resources[0].end    = rtc_resources[0].start + 0x58 - 1;
 361
 362         return platform_device_register(&rtc_device);
 363 }
 364 device_initcall(rtc_init);