arch/m68k/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)   (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) || defined(CONFIG_M5441x)
  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 static irq_handler_t timer_interrupt;
  51
  52 /***************************************************************************/
  53
  54 static void init_timer_irq(void)
  55 {
  56 #ifdef MCFSIM_ICR_AUTOVEC
  57         /* Timer1 is always used as system timer */
  58         writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL6 | MCFSIM_ICR_PRI3,
  59                 MCFSIM_TIMER1ICR);
  60         mcf_mapirq2imr(MCF_IRQ_TIMER, MCFINTC_TIMER1);
  61
  62 #ifdef CONFIG_HIGHPROFILE
  63         /* Timer2 is to be used as a high speed profile timer  */
  64         writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL7 | MCFSIM_ICR_PRI3,
  65                 MCFSIM_TIMER2ICR);
  66         mcf_mapirq2imr(MCF_IRQ_PROFILER, MCFINTC_TIMER2);
  67 #endif
  68 #endif /* MCFSIM_ICR_AUTOVEC */
  69 }
  70
  71 /***************************************************************************/
  72
  73 static irqreturn_t mcftmr_tick(int irq, void *dummy)
  74 {
  75         /* Reset the ColdFire timer */
  76         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
  77
  78         mcftmr_cnt += mcftmr_cycles_per_jiffy;
  79         return timer_interrupt(irq, dummy);
  80 }
  81
  82 /***************************************************************************/
  83
  84 static struct irqaction mcftmr_timer_irq = {
  85         .name    = "timer",
  86         .flags   = IRQF_DISABLED | IRQF_TIMER,
  87         .handler = mcftmr_tick,
  88 };
  89
  90 /***************************************************************************/
  91
  92 static cycle_t mcftmr_read_clk(struct clocksource *cs)
  93 {
  94         unsigned long flags;
  95         u32 cycles;
  96         u16 tcn;
  97
  98         local_irq_save(flags);
  99         tcn = __raw_readw(TA(MCFTIMER_TCN));
 100         cycles = mcftmr_cnt;
 101         local_irq_restore(flags);
 102
 103         return cycles + tcn;
 104 }
 105
 106 /***************************************************************************/
 107
 108 static struct clocksource mcftmr_clk = {
 109         .name   = "tmr",
 110         .rating = 250,
 111         .read   = mcftmr_read_clk,
 112         .mask   = CLOCKSOURCE_MASK(32),
 113         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 114 };
 115
 116 /***************************************************************************/
 117
 118 void hw_timer_init(irq_handler_t handler)
 119 {
 120         __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
 121         mcftmr_cycles_per_jiffy = FREQ / HZ;
 122         /*
 123          *      The coldfire timer runs from 0 to TRR included, then 0
 124          *      again and so on.  It counts thus actually TRR + 1 steps
 125          *      for 1 tick, not TRR.  So if you want n cycles,
 126          *      initialize TRR with n - 1.
 127          */
 128         __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
 129         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 130                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
 131
 132         clocksource_register_hz(&mcftmr_clk, FREQ);
 133
 134         timer_interrupt = handler;
 135         init_timer_irq();
 136         setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq);
 137
 138 #ifdef CONFIG_HIGHPROFILE
 139         coldfire_profile_init();
 140 #endif
 141 }
 142
 143 /***************************************************************************/
 144 #ifdef CONFIG_HIGHPROFILE
 145 /***************************************************************************/
 146
 147 /*
 148  *      By default use timer2 as the profiler clock timer.
 149  */
 150 #define PA(a)   (MCFTIMER_BASE2 + (a))
 151
 152 /*
 153  *      Choose a reasonably fast profile timer. Make it an odd value to
 154  *      try and get good coverage of kernel operations.
 155  */
 156 #define PROFILEHZ       1013
 157
 158 /*
 159  *      Use the other timer to provide high accuracy profiling info.
 160  */
 161 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
 162 {
 163         /* Reset ColdFire timer2 */
 164         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
 165         if (current->pid)
 166                 profile_tick(CPU_PROFILING);
 167         return IRQ_HANDLED;
 168 }
 169
 170 /***************************************************************************/
 171
 172 static struct irqaction coldfire_profile_irq = {
 173         .name    = "profile timer",
 174         .flags   = IRQF_DISABLED | IRQF_TIMER,
 175         .handler = coldfire_profile_tick,
 176 };
 177
 178 void coldfire_profile_init(void)
 179 {
 180         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
 181                PROFILEHZ);
 182
 183         /* Set up TIMER 2 as high speed profile clock */
 184         __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
 185
 186         __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
 187         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 188                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
 189
 190         setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq);
 191 }
 192
 193 /***************************************************************************/
 194 #endif  /* CONFIG_HIGHPROFILE */
 195 /***************************************************************************/