arch/m68knommu/platform/5307/timers.c

   1 /***************************************************************************/
   2
   3 /*
   4  *      timers.c -- generic ColdFire hardware timer support.
   5  *
   6  *      Copyright (C) 1999-2003, Greg Ungerer (gerg@snapgear.com)
   7  */
   8
   9 /***************************************************************************/
  10
  11 #include <linux/config.h>
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/param.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/init.h>
  17 #include <asm/irq.h>
  18 #include <asm/traps.h>
  19 #include <asm/machdep.h>
  20 #include <asm/coldfire.h>
  21 #include <asm/mcftimer.h>
  22 #include <asm/mcfsim.h>
  23
  24 /***************************************************************************/
  25
  26 /*
  27  *      Default the timer and vector to use for ColdFire. Some ColdFire
  28  *      CPU's and some boards may want different. Their sub-architecture
  29  *      startup code (in config.c) can change these if they want.
  30  */
  31 unsigned int    mcf_timervector = 29;
  32 unsigned int    mcf_profilevector = 31;
  33 unsigned int    mcf_timerlevel = 5;
  34
  35 static volatile struct mcftimer *mcf_timerp;
  36
  37 /*
  38  *      These provide the underlying interrupt vector support.
  39  *      Unfortunately it is a little different on each ColdFire.
  40  */
  41 extern void mcf_settimericr(int timer, int level);
  42 extern int mcf_timerirqpending(int timer);
  43
  44 /***************************************************************************/
  45
  46 void coldfire_tick(void)
  47 {
  48         /* Reset the ColdFire timer */
  49         mcf_timerp->ter = MCFTIMER_TER_CAP | MCFTIMER_TER_REF;
  50 }
  51
  52 /***************************************************************************/
  53
  54 void coldfire_timer_init(irqreturn_t (*handler)(int, void *, struct pt_regs *))
  55 {
  56         /* Set up an internal TIMER as poll clock */
  57         mcf_timerp = (volatile struct mcftimer *) (MCF_MBAR + MCFTIMER_BASE1);
  58         mcf_timerp->tmr = MCFTIMER_TMR_DISABLE;
  59
  60         mcf_timerp->trr = (unsigned short) ((MCF_BUSCLK / 16) / HZ);
  61         mcf_timerp->tmr = MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
  62                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE;
  63
  64         request_irq(mcf_timervector, handler, SA_INTERRUPT, "timer", NULL);
  65         mcf_settimericr(1, mcf_timerlevel);
  66
  67 #ifdef CONFIG_HIGHPROFILE
  68         coldfire_profile_init();
  69 #endif
  70 }
  71
  72 /***************************************************************************/
  73
  74 unsigned long coldfire_timer_offset(void)
  75 {
  76         unsigned long trr, tcn, offset;
  77
  78         /*
  79          * The change to pointer and de-reference is to force the compiler
  80          * to read the registers with a single 16bit access. Otherwise it
  81          * does some crazy 8bit read combining.
  82          */
  83         tcn = *(&mcf_timerp->tcn);
  84         trr = *(&mcf_timerp->trr);
  85         offset = (tcn * (1000000 / HZ)) / trr;
  86
  87         /* Check if we just wrapped the counters and maybe missed a tick */
  88         if ((offset < (1000000 / HZ / 2)) && mcf_timerirqpending(1))
  89                 offset += 1000000 / HZ;
  90         return offset;
  91 }
  92
  93 /***************************************************************************/
  94 #ifdef CONFIG_HIGHPROFILE
  95 /***************************************************************************/
  96
  97 /*
  98  *      Choose a reasonably fast profile timer. Make it an odd value to
  99  *      try and get good coverage of kernal operations.
 100  */
 101 #define PROFILEHZ       1013
 102
 103 static volatile struct mcftimer *mcf_proftp;
 104
 105 /*
 106  *      Use the other timer to provide high accuracy profiling info.
 107  */
 108
 109 void coldfire_profile_tick(int irq, void *dummy, struct pt_regs *regs)
 110 {
 111         /* Reset ColdFire timer2 */
 112         mcf_proftp->ter = MCFTIMER_TER_CAP | MCFTIMER_TER_REF;
 113         if (current->pid)
 114                 profile_tick(CPU_PROFILING, regs);
 115 }
 116
 117 /***************************************************************************/
 118
 119 void coldfire_profile_init(void)
 120 {
 121         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n", PROFILEHZ);
 122
 123         /* Set up TIMER 2 as high speed profile clock */
 124         mcf_proftp = (volatile struct mcftimer *) (MCF_MBAR + MCFTIMER_BASE2);
 125         mcf_proftp->tmr = MCFTIMER_TMR_DISABLE;
 126
 127         mcf_proftp->trr = (unsigned short) ((MCF_CLK / 16) / PROFILEHZ);
 128         mcf_proftp->tmr = MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 129                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE;
 130
 131         request_irq(mcf_profilevector, coldfire_profile_tick,
 132                 (SA_INTERRUPT | IRQ_FLG_FAST), "profile timer", NULL);
 133         mcf_settimericr(2, 7);
 134 }
 135
 136 /***************************************************************************/
 137 #endif  /* CONFIG_HIGHPROFILE */
 138 /***************************************************************************/