release/src-rt-6.x/linux/linux-2.6/arch/m68knommu/platform/5307/timers.c

   1 /***************************************************************************/
   2
   3 /*
   4  *      timers.c -- generic ColdFire hardware timer support.
   5  *
   6  *      Copyright (C) 1999-2006, Greg Ungerer (gerg@snapgear.com)
   7  */
   8
   9 /***************************************************************************/
  10
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/param.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/init.h>
  16 #include <asm/io.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  *      By default use timer1 as the system clock timer.
  28  */
  29 #define TA(a)   (MCF_MBAR + MCFTIMER_BASE1 + (a))
  30
  31 /*
  32  *      Default the timer and vector to use for ColdFire. Some ColdFire
  33  *      CPU's and some boards may want different. Their sub-architecture
  34  *      startup code (in config.c) can change these if they want.
  35  */
  36 unsigned int    mcf_timervector = 29;
  37 unsigned int    mcf_profilevector = 31;
  38 unsigned int    mcf_timerlevel = 5;
  39
  40 /*
  41  *      These provide the underlying interrupt vector support.
  42  *      Unfortunately it is a little different on each ColdFire.
  43  */
  44 extern void mcf_settimericr(int timer, int level);
  45 extern int mcf_timerirqpending(int timer);
  46
  47 #if defined(CONFIG_M532x)
  48 #define __raw_readtrr   __raw_readl
  49 #define __raw_writetrr  __raw_writel
  50 #else
  51 #define __raw_readtrr   __raw_readw
  52 #define __raw_writetrr  __raw_writew
  53 #endif
  54
  55 /***************************************************************************/
  56
  57 void coldfire_tick(void)
  58 {
  59         /* Reset the ColdFire timer */
  60         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
  61 }
  62
  63 /***************************************************************************/
  64
  65 static int ticks_per_intr;
  66
  67 void coldfire_timer_init(irq_handler_t handler)
  68 {
  69         __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
  70         ticks_per_intr = (MCF_BUSCLK / 16) / HZ;
  71         __raw_writetrr(ticks_per_intr - 1, TA(MCFTIMER_TRR));
  72         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
  73                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
  74
  75         request_irq(mcf_timervector, handler, IRQF_DISABLED, "timer", NULL);
  76         mcf_settimericr(1, mcf_timerlevel);
  77
  78 #ifdef CONFIG_HIGHPROFILE
  79         coldfire_profile_init();
  80 #endif
  81 }
  82
  83 /***************************************************************************/
  84
  85 unsigned long coldfire_timer_offset(void)
  86 {
  87         unsigned long tcn, offset;
  88
  89         tcn = __raw_readw(TA(MCFTIMER_TCN));
  90         offset = ((tcn + 1) * (1000000 / HZ)) / ticks_per_intr;
  91
  92         /* Check if we just wrapped the counters and maybe missed a tick */
  93         if ((offset < (1000000 / HZ / 2)) && mcf_timerirqpending(1))
  94                 offset += 1000000 / HZ;
  95         return offset;
  96 }
  97
  98 /***************************************************************************/
  99 #ifdef CONFIG_HIGHPROFILE
 100 /***************************************************************************/
 101
 102 /*
 103  *      By default use timer2 as the profiler clock timer.
 104  */
 105 #define PA(a)   (MCF_MBAR + MCFTIMER_BASE2 + (a))
 106
 107 /*
 108  *      Choose a reasonably fast profile timer. Make it an odd value to
 109  *      try and get good coverage of kernel operations.
 110  */
 111 #define PROFILEHZ       1013
 112
 113 /*
 114  *      Use the other timer to provide high accuracy profiling info.
 115  */
 116 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
 117 {
 118         /* Reset ColdFire timer2 */
 119         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
 120         if (current->pid)
 121                 profile_tick(CPU_PROFILING, regs);
 122         return IRQ_HANDLED;
 123 }
 124
 125 /***************************************************************************/
 126
 127 void coldfire_profile_init(void)
 128 {
 129         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n", PROFILEHZ);
 130
 131         /* Set up TIMER 2 as high speed profile clock */
 132         __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
 133
 134         __raw_writetrr(((MCF_CLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
 135         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 136                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
 137
 138         request_irq(mcf_profilevector, coldfire_profile_tick,
 139                 (IRQF_DISABLED | IRQ_FLG_FAST), "profile timer", NULL);
 140         mcf_settimericr(2, 7);
 141 }
 142
 143 /***************************************************************************/
 144 #endif  /* CONFIG_HIGHPROFILE */
 145 /***************************************************************************/