arch/m68knommu/platform/coldfire/timers.c

   1 /***************************************************************************/
   2
   3 /*
   4  *      timers.c -- generic ColdFire hardware timer support.
   5  *
   6  *      Copyright (C) 1999-2007, Greg Ungerer (gerg@snapgear.com)
   7  */
   8
   9 /***************************************************************************/
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/sched.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <asm/io.h>
  17 #include <asm/traps.h>
  18 #include <asm/machdep.h>
  19 #include <asm/coldfire.h>
  20 #include <asm/mcftimer.h>
  21 #include <asm/mcfsim.h>
  22
  23 /***************************************************************************/
  24
  25 /*
  26  *      By default use timer1 as the system clock timer.
  27  */
  28 #define TA(a)   (MCF_MBAR + MCFTIMER_BASE1 + (a))
  29
  30 /*
  31  *      Default the timer and vector to use for ColdFire. Some ColdFire
  32  *      CPU's and some boards may want different. Their sub-architecture
  33  *      startup code (in config.c) can change these if they want.
  34  */
  35 unsigned int    mcf_timervector = 29;
  36 unsigned int    mcf_profilevector = 31;
  37 unsigned int    mcf_timerlevel = 5;
  38
  39 /*
  40  *      These provide the underlying interrupt vector support.
  41  *      Unfortunately it is a little different on each ColdFire.
  42  */
  43 extern void mcf_settimericr(int timer, int level);
  44 extern int mcf_timerirqpending(int timer);
  45
  46 #if defined(CONFIG_M532x)
  47 #define __raw_readtrr   __raw_readl
  48 #define __raw_writetrr  __raw_writel
  49 #else
  50 #define __raw_readtrr   __raw_readw
  51 #define __raw_writetrr  __raw_writew
  52 #endif
  53
  54 /***************************************************************************/
  55
  56 static irqreturn_t hw_tick(int irq, void *dummy)
  57 {
  58         /* Reset the ColdFire timer */
  59         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
  60
  61         return arch_timer_interrupt(irq, dummy);
  62 }
  63
  64 /***************************************************************************/
  65
  66 static struct irqaction coldfire_timer_irq = {
  67         .name    = "timer",
  68         .flags   = IRQF_DISABLED | IRQF_TIMER,
  69         .handler = hw_tick,
  70 };
  71
  72 /***************************************************************************/
  73
  74 static int ticks_per_intr;
  75
  76 void hw_timer_init(void)
  77 {
  78         setup_irq(mcf_timervector, &coldfire_timer_irq);
  79
  80         __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
  81         ticks_per_intr = (MCF_BUSCLK / 16) / HZ;
  82         __raw_writetrr(ticks_per_intr - 1, TA(MCFTIMER_TRR));
  83         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
  84                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
  85
  86         mcf_settimericr(1, mcf_timerlevel);
  87
  88 #ifdef CONFIG_HIGHPROFILE
  89         coldfire_profile_init();
  90 #endif
  91 }
  92
  93 /***************************************************************************/
  94
  95 unsigned long hw_timer_offset(void)
  96 {
  97         unsigned long tcn, offset;
  98
  99         tcn = __raw_readw(TA(MCFTIMER_TCN));
 100         offset = ((tcn + 1) * (1000000 / HZ)) / ticks_per_intr;
 101
 102         /* Check if we just wrapped the counters and maybe missed a tick */
 103         if ((offset < (1000000 / HZ / 2)) && mcf_timerirqpending(1))
 104                 offset += 1000000 / HZ;
 105         return offset;
 106 }
 107
 108 /***************************************************************************/
 109 #ifdef CONFIG_HIGHPROFILE
 110 /***************************************************************************/
 111
 112 /*
 113  *      By default use timer2 as the profiler clock timer.
 114  */
 115 #define PA(a)   (MCF_MBAR + MCFTIMER_BASE2 + (a))
 116
 117 /*
 118  *      Choose a reasonably fast profile timer. Make it an odd value to
 119  *      try and get good coverage of kernel operations.
 120  */
 121 #define PROFILEHZ       1013
 122
 123 /*
 124  *      Use the other timer to provide high accuracy profiling info.
 125  */
 126 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
 127 {
 128         /* Reset ColdFire timer2 */
 129         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
 130         if (current->pid)
 131                 profile_tick(CPU_PROFILING, regs);
 132         return IRQ_HANDLED;
 133 }
 134
 135 /***************************************************************************/
 136
 137 void coldfire_profile_init(void)
 138 {
 139         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n", PROFILEHZ);
 140
 141         /* Set up TIMER 2 as high speed profile clock */
 142         __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
 143
 144         __raw_writetrr(((MCF_CLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
 145         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 146                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
 147
 148         request_irq(mcf_profilevector, coldfire_profile_tick,
 149                 (IRQF_DISABLED | IRQ_FLG_FAST), "profile timer", NULL);
 150         mcf_settimericr(2, 7);
 151 }
 152
 153 /***************************************************************************/
 154 #endif  /* CONFIG_HIGHPROFILE */
 155 /***************************************************************************/