arch/um/kernel/time_kern.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/kernel.h"
   7 #include "linux/module.h"
   8 #include "linux/unistd.h"
   9 #include "linux/stddef.h"
  10 #include "linux/spinlock.h"
  11 #include "linux/time.h"
  12 #include "linux/sched.h"
  13 #include "linux/interrupt.h"
  14 #include "linux/init.h"
  15 #include "linux/delay.h"
  16 #include "asm/irq.h"
  17 #include "asm/param.h"
  18 #include "asm/current.h"
  19 #include "kern_util.h"
  20 #include "user_util.h"
  21 #include "time_user.h"
  22 #include "mode.h"
  23 #include "os.h"
  24
  25 u64 jiffies_64 = INITIAL_JIFFIES;
  26
  27 EXPORT_SYMBOL(jiffies_64);
  28
  29 int hz(void)
  30 {
  31         return(HZ);
  32 }
  33
  34 /*
  35  * Scheduler clock - returns current time in nanosec units.
  36  */
  37 unsigned long long sched_clock(void)
  38 {
  39         return (unsigned long long)jiffies_64 * (1000000000 / HZ);
  40 }
  41
  42 /* Changed at early boot */
  43 int timer_irq_inited = 0;
  44
  45 static int first_tick;
  46 static unsigned long long prev_usecs;
  47 #ifdef CONFIG_UML_REAL_TIME_CLOCK
  48 static long long delta;                 /* Deviation per interval */
  49 #endif
  50
  51 #define MILLION 1000000
  52
  53 void timer_irq(union uml_pt_regs *regs)
  54 {
  55         unsigned long long ticks = 0;
  56
  57         if(!timer_irq_inited){
  58                 /* This is to ensure that ticks don't pile up when
  59                  * the timer handler is suspended */
  60                 first_tick = 0;
  61                 return;
  62         }
  63
  64         if(first_tick){
  65 #ifdef CONFIG_UML_REAL_TIME_CLOCK
  66                 /* We've had 1 tick */
  67                 unsigned long long usecs = os_usecs();
  68
  69                 delta += usecs - prev_usecs;
  70                 prev_usecs = usecs;
  71
  72                 /* Protect against the host clock being set backwards */
  73                 if(delta < 0)
  74                         delta = 0;
  75
  76                 ticks += (delta * HZ) / MILLION;
  77                 delta -= (ticks * MILLION) / HZ;
  78 #else
  79                 ticks = 1;
  80 #endif
  81         }
  82         else {
  83                 prev_usecs = os_usecs();
  84                 first_tick = 1;
  85         }
  86
  87         while(ticks > 0){
  88                 do_IRQ(TIMER_IRQ, regs);
  89                 ticks--;
  90         }
  91 }
  92
  93 void boot_timer_handler(int sig)
  94 {
  95         struct pt_regs regs;
  96
  97         CHOOSE_MODE((void)
  98                     (UPT_SC(&regs.regs) = (struct sigcontext *) (&sig + 1)),
  99                     (void) (regs.regs.skas.is_user = 0));
 100         do_timer(&regs);
 101 }
 102
 103 irqreturn_t um_timer(int irq, void *dev, struct pt_regs *regs)
 104 {
 105         unsigned long flags;
 106
 107         do_timer(regs);
 108         write_seqlock_irqsave(&xtime_lock, flags);
 109         timer();
 110         write_sequnlock_irqrestore(&xtime_lock, flags);
 111         return(IRQ_HANDLED);
 112 }
 113
 114 long um_time(int __user *tloc)
 115 {
 116         struct timeval now;
 117
 118         do_gettimeofday(&now);
 119         if (tloc) {
 120                 if (put_user(now.tv_sec, tloc))
 121                         now.tv_sec = -EFAULT;
 122         }
 123         return now.tv_sec;
 124 }
 125
 126 long um_stime(int __user *tptr)
 127 {
 128         int value;
 129         struct timespec new;
 130
 131         if (get_user(value, tptr))
 132                 return -EFAULT;
 133         new.tv_sec = value;
 134         new.tv_nsec = 0;
 135         do_settimeofday(&new);
 136         return 0;
 137 }
 138
 139 void __udelay(unsigned long usecs)
 140 {
 141         int i, n;
 142
 143         n = (loops_per_jiffy * HZ * usecs) / MILLION;
 144         for(i=0;i<n;i++) ;
 145 }
 146
 147 void __const_udelay(unsigned long usecs)
 148 {
 149         int i, n;
 150
 151         n = (loops_per_jiffy * HZ * usecs) / MILLION;
 152         for(i=0;i<n;i++) ;
 153 }
 154
 155 void timer_handler(int sig, union uml_pt_regs *regs)
 156 {
 157         local_irq_disable();
 158         update_process_times(CHOOSE_MODE(user_context(UPT_SP(regs)), (regs)->skas.is_user));
 159         local_irq_enable();
 160         if(current_thread->cpu == 0)
 161                 timer_irq(regs);
 162 }
 163
 164 static DEFINE_SPINLOCK(timer_spinlock);
 165
 166 unsigned long time_lock(void)
 167 {
 168         unsigned long flags;
 169
 170         spin_lock_irqsave(&timer_spinlock, flags);
 171         return(flags);
 172 }
 173
 174 void time_unlock(unsigned long flags)
 175 {
 176         spin_unlock_irqrestore(&timer_spinlock, flags);
 177 }
 178
 179 int __init timer_init(void)
 180 {
 181         int err;
 182
 183         CHOOSE_MODE(user_time_init_tt(), user_time_init_skas());
 184         err = request_irq(TIMER_IRQ, um_timer, SA_INTERRUPT, "timer", NULL);
 185         if(err != 0)
 186                 printk(KERN_ERR "timer_init : request_irq failed - "
 187                        "errno = %d\n", -err);
 188         timer_irq_inited = 1;
 189         return(0);
 190 }
 191
 192 __initcall(timer_init);
 193
 194 /*
 195  * Overrides for Emacs so that we follow Linus's tabbing style.
 196  * Emacs will notice this stuff at the end of the file and automatically
 197  * adjust the settings for this buffer only.  This must remain at the end
 198  * of the file.
 199  * ---------------------------------------------------------------------------
 200  * Local variables:
 201  * c-file-style: "linux"
 202  * End:
 203  */