arch/m68knommu/platform/coldfire/timers.c

   1 /***************************************************************************/
   2
   3 /*
   4  *      timers.c -- generic ColdFire hardware timer support.
   5  *
   6  *      Copyright (C) 1999-2008, 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 <linux/profile.h>
  17 #include <linux/clocksource.h>
  18 #include <asm/io.h>
  19 #include <asm/traps.h>
  20 #include <asm/machdep.h>
  21 #include <asm/coldfire.h>
  22 #include <asm/mcftimer.h>
  23 #include <asm/mcfsim.h>
  24
  25 /***************************************************************************/
  26
  27 /*
  28  *      By default use timer1 as the system clock timer.
  29  */
  30 #define FREQ    (MCF_BUSCLK / 16)
  31 #define TA(a)   (MCF_MBAR + MCFTIMER_BASE1 + (a))
  32
  33 /*
  34  *      These provide the underlying interrupt vector support.
  35  *      Unfortunately it is a little different on each ColdFire.
  36  */
  37 void coldfire_profile_init(void);
  38
  39 #if defined(CONFIG_M532x)
  40 #define __raw_readtrr   __raw_readl
  41 #define __raw_writetrr  __raw_writel
  42 #else
  43 #define __raw_readtrr   __raw_readw
  44 #define __raw_writetrr  __raw_writew
  45 #endif
  46
  47 static u32 mcftmr_cycles_per_jiffy;
  48 static u32 mcftmr_cnt;
  49
  50 /***************************************************************************/
  51
  52 static irqreturn_t mcftmr_tick(int irq, void *dummy)
  53 {
  54         /* Reset the ColdFire timer */
  55         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
  56
  57         mcftmr_cnt += mcftmr_cycles_per_jiffy;
  58         return arch_timer_interrupt(irq, dummy);
  59 }
  60
  61 /***************************************************************************/
  62
  63 static struct irqaction mcftmr_timer_irq = {
  64         .name    = "timer",
  65         .flags   = IRQF_DISABLED | IRQF_TIMER,
  66         .handler = mcftmr_tick,
  67 };
  68
  69 /***************************************************************************/
  70
  71 static cycle_t mcftmr_read_clk(struct clocksource *cs)
  72 {
  73         unsigned long flags;
  74         u32 cycles;
  75         u16 tcn;
  76
  77         local_irq_save(flags);
  78         tcn = __raw_readw(TA(MCFTIMER_TCN));
  79         cycles = mcftmr_cnt;
  80         local_irq_restore(flags);
  81
  82         return cycles + tcn;
  83 }
  84
  85 /***************************************************************************/
  86
  87 static struct clocksource mcftmr_clk = {
  88         .name   = "tmr",
  89         .rating = 250,
  90         .read   = mcftmr_read_clk,
  91         .shift  = 20,
  92         .mask   = CLOCKSOURCE_MASK(32),
  93         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  94 };
  95
  96 /***************************************************************************/
  97
  98 void hw_timer_init(void)
  99 {
 100         __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
 101         mcftmr_cycles_per_jiffy = FREQ / HZ;
 102         /*
 103          *      The coldfire timer runs from 0 to TRR included, then 0
 104          *      again and so on.  It counts thus actually TRR + 1 steps
 105          *      for 1 tick, not TRR.  So if you want n cycles,
 106          *      initialize TRR with n - 1.
 107          */
 108         __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
 109         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 110                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
 111
 112         mcftmr_clk.mult = clocksource_hz2mult(FREQ, mcftmr_clk.shift);
 113         clocksource_register(&mcftmr_clk);
 114
 115         setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq);
 116
 117 #ifdef CONFIG_HIGHPROFILE
 118         coldfire_profile_init();
 119 #endif
 120 }
 121
 122 /***************************************************************************/
 123 #ifdef CONFIG_HIGHPROFILE
 124 /***************************************************************************/
 125
 126 /*
 127  *      By default use timer2 as the profiler clock timer.
 128  */
 129 #define PA(a)   (MCF_MBAR + MCFTIMER_BASE2 + (a))
 130
 131 /*
 132  *      Choose a reasonably fast profile timer. Make it an odd value to
 133  *      try and get good coverage of kernel operations.
 134  */
 135 #define PROFILEHZ       1013
 136
 137 /*
 138  *      Use the other timer to provide high accuracy profiling info.
 139  */
 140 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
 141 {
 142         /* Reset ColdFire timer2 */
 143         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
 144         if (current->pid)
 145                 profile_tick(CPU_PROFILING);
 146         return IRQ_HANDLED;
 147 }
 148
 149 /***************************************************************************/
 150
 151 static struct irqaction coldfire_profile_irq = {
 152         .name    = "profile timer",
 153         .flags   = IRQF_DISABLED | IRQF_TIMER,
 154         .handler = coldfire_profile_tick,
 155 };
 156
 157 void coldfire_profile_init(void)
 158 {
 159         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
 160                PROFILEHZ);
 161
 162         /* Set up TIMER 2 as high speed profile clock */
 163         __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
 164
 165         __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
 166         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 167                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
 168
 169         setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq);
 170 }
 171
 172 /***************************************************************************/
 173 #endif  /* CONFIG_HIGHPROFILE */
 174 /***************************************************************************/