arch/m68k/coldfire/timers.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /***************************************************************************/
   3
   4 /*
   5  *      timers.c -- generic ColdFire hardware timer support.
   6  *
   7  *      Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
   8  */
   9
  10 /***************************************************************************/
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/sched.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/irq.h>
  17 #include <linux/profile.h>
  18 #include <linux/clocksource.h>
  19 #include <asm/io.h>
  20 #include <asm/traps.h>
  21 #include <asm/machdep.h>
  22 #include <asm/coldfire.h>
  23 #include <asm/mcftimer.h>
  24 #include <asm/mcfsim.h>
  25
  26 /***************************************************************************/
  27
  28 /*
  29  *      By default use timer1 as the system clock timer.
  30  */
  31 #define FREQ    (MCF_BUSCLK / 16)
  32 #define TA(a)   (MCFTIMER_BASE1 + (a))
  33
  34 /*
  35  *      These provide the underlying interrupt vector support.
  36  *      Unfortunately it is a little different on each ColdFire.
  37  */
  38 void coldfire_profile_init(void);
  39
  40 #if defined(CONFIG_M53xx) || defined(CONFIG_M5441x)
  41 #define __raw_readtrr   __raw_readl
  42 #define __raw_writetrr  __raw_writel
  43 #else
  44 #define __raw_readtrr   __raw_readw
  45 #define __raw_writetrr  __raw_writew
  46 #endif
  47
  48 static u32 mcftmr_cycles_per_jiffy;
  49 static u32 mcftmr_cnt;
  50
  51 /***************************************************************************/
  52
  53 static void init_timer_irq(void)
  54 {
  55 #ifdef MCFSIM_ICR_AUTOVEC
  56         /* Timer1 is always used as system timer */
  57         writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL6 | MCFSIM_ICR_PRI3,
  58                 MCFSIM_TIMER1ICR);
  59         mcf_mapirq2imr(MCF_IRQ_TIMER, MCFINTC_TIMER1);
  60
  61 #ifdef CONFIG_HIGHPROFILE
  62         /* Timer2 is to be used as a high speed profile timer  */
  63         writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL7 | MCFSIM_ICR_PRI3,
  64                 MCFSIM_TIMER2ICR);
  65         mcf_mapirq2imr(MCF_IRQ_PROFILER, MCFINTC_TIMER2);
  66 #endif
  67 #endif /* MCFSIM_ICR_AUTOVEC */
  68 }
  69
  70 /***************************************************************************/
  71
  72 static irqreturn_t mcftmr_tick(int irq, void *dummy)
  73 {
  74         /* Reset the ColdFire timer */
  75         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
  76
  77         mcftmr_cnt += mcftmr_cycles_per_jiffy;
  78         legacy_timer_tick(1);
  79         return IRQ_HANDLED;
  80 }
  81
  82 /***************************************************************************/
  83
  84 static u64 mcftmr_read_clk(struct clocksource *cs)
  85 {
  86         unsigned long flags;
  87         u32 cycles;
  88         u16 tcn;
  89
  90         local_irq_save(flags);
  91         tcn = __raw_readw(TA(MCFTIMER_TCN));
  92         cycles = mcftmr_cnt;
  93         local_irq_restore(flags);
  94
  95         return cycles + tcn;
  96 }
  97
  98 /***************************************************************************/
  99
 100 static struct clocksource mcftmr_clk = {
 101         .name   = "tmr",
 102         .rating = 250,
 103         .read   = mcftmr_read_clk,
 104         .mask   = CLOCKSOURCE_MASK(32),
 105         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 106 };
 107
 108 /***************************************************************************/
 109
 110 void hw_timer_init(void)
 111 {
 112         int r;
 113
 114         __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
 115         mcftmr_cycles_per_jiffy = FREQ / HZ;
 116         /*
 117          *      The coldfire timer runs from 0 to TRR included, then 0
 118          *      again and so on.  It counts thus actually TRR + 1 steps
 119          *      for 1 tick, not TRR.  So if you want n cycles,
 120          *      initialize TRR with n - 1.
 121          */
 122         __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
 123         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 124                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
 125
 126         clocksource_register_hz(&mcftmr_clk, FREQ);
 127
 128         init_timer_irq();
 129         r = request_irq(MCF_IRQ_TIMER, mcftmr_tick, IRQF_TIMER, "timer", NULL);
 130         if (r) {
 131                 pr_err("Failed to request irq %d (timer): %pe\n", MCF_IRQ_TIMER,
 132                        ERR_PTR(r));
 133         }
 134
 135 #ifdef CONFIG_HIGHPROFILE
 136         coldfire_profile_init();
 137 #endif
 138 }
 139
 140 /***************************************************************************/
 141 #ifdef CONFIG_HIGHPROFILE
 142 /***************************************************************************/
 143
 144 /*
 145  *      By default use timer2 as the profiler clock timer.
 146  */
 147 #define PA(a)   (MCFTIMER_BASE2 + (a))
 148
 149 /*
 150  *      Choose a reasonably fast profile timer. Make it an odd value to
 151  *      try and get good coverage of kernel operations.
 152  */
 153 #define PROFILEHZ       1013
 154
 155 /*
 156  *      Use the other timer to provide high accuracy profiling info.
 157  */
 158 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
 159 {
 160         /* Reset ColdFire timer2 */
 161         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
 162         if (current->pid)
 163                 profile_tick(CPU_PROFILING);
 164         return IRQ_HANDLED;
 165 }
 166
 167 /***************************************************************************/
 168
 169 void coldfire_profile_init(void)
 170 {
 171         int ret;
 172
 173         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
 174                PROFILEHZ);
 175
 176         /* Set up TIMER 2 as high speed profile clock */
 177         __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
 178
 179         __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
 180         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 181                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
 182
 183         ret = request_irq(MCF_IRQ_PROFILER, coldfire_profile_tick, IRQF_TIMER,
 184                           "profile timer", NULL);
 185         if (ret) {
 186                 pr_err("Failed to request irq %d (profile timer): %pe\n",
 187                        MCF_IRQ_PROFILER, ERR_PTR(ret));
 188         }
 189 }
 190
 191 /***************************************************************************/
 192 #endif  /* CONFIG_HIGHPROFILE */
 193 /***************************************************************************/