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 static irq_handler_t timer_interrupt;
  52
  53 /***************************************************************************/
  54
  55 static void init_timer_irq(void)
  56 {
  57 #ifdef MCFSIM_ICR_AUTOVEC
  58         /* Timer1 is always used as system timer */
  59         writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL6 | MCFSIM_ICR_PRI3,
  60                 MCFSIM_TIMER1ICR);
  61         mcf_mapirq2imr(MCF_IRQ_TIMER, MCFINTC_TIMER1);
  62
  63 #ifdef CONFIG_HIGHPROFILE
  64         /* Timer2 is to be used as a high speed profile timer  */
  65         writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL7 | MCFSIM_ICR_PRI3,
  66                 MCFSIM_TIMER2ICR);
  67         mcf_mapirq2imr(MCF_IRQ_PROFILER, MCFINTC_TIMER2);
  68 #endif
  69 #endif /* MCFSIM_ICR_AUTOVEC */
  70 }
  71
  72 /***************************************************************************/
  73
  74 static irqreturn_t mcftmr_tick(int irq, void *dummy)
  75 {
  76         /* Reset the ColdFire timer */
  77         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
  78
  79         mcftmr_cnt += mcftmr_cycles_per_jiffy;
  80         return timer_interrupt(irq, dummy);
  81 }
  82
  83 /***************************************************************************/
  84
  85 static struct irqaction mcftmr_timer_irq = {
  86         .name    = "timer",
  87         .flags   = IRQF_TIMER,
  88         .handler = mcftmr_tick,
  89 };
  90
  91 /***************************************************************************/
  92
  93 static u64 mcftmr_read_clk(struct clocksource *cs)
  94 {
  95         unsigned long flags;
  96         u32 cycles;
  97         u16 tcn;
  98
  99         local_irq_save(flags);
 100         tcn = __raw_readw(TA(MCFTIMER_TCN));
 101         cycles = mcftmr_cnt;
 102         local_irq_restore(flags);
 103
 104         return cycles + tcn;
 105 }
 106
 107 /***************************************************************************/
 108
 109 static struct clocksource mcftmr_clk = {
 110         .name   = "tmr",
 111         .rating = 250,
 112         .read   = mcftmr_read_clk,
 113         .mask   = CLOCKSOURCE_MASK(32),
 114         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 115 };
 116
 117 /***************************************************************************/
 118
 119 void hw_timer_init(irq_handler_t handler)
 120 {
 121         __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
 122         mcftmr_cycles_per_jiffy = FREQ / HZ;
 123         /*
 124          *      The coldfire timer runs from 0 to TRR included, then 0
 125          *      again and so on.  It counts thus actually TRR + 1 steps
 126          *      for 1 tick, not TRR.  So if you want n cycles,
 127          *      initialize TRR with n - 1.
 128          */
 129         __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
 130         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 131                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
 132
 133         clocksource_register_hz(&mcftmr_clk, FREQ);
 134
 135         timer_interrupt = handler;
 136         init_timer_irq();
 137         setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq);
 138
 139 #ifdef CONFIG_HIGHPROFILE
 140         coldfire_profile_init();
 141 #endif
 142 }
 143
 144 /***************************************************************************/
 145 #ifdef CONFIG_HIGHPROFILE
 146 /***************************************************************************/
 147
 148 /*
 149  *      By default use timer2 as the profiler clock timer.
 150  */
 151 #define PA(a)   (MCFTIMER_BASE2 + (a))
 152
 153 /*
 154  *      Choose a reasonably fast profile timer. Make it an odd value to
 155  *      try and get good coverage of kernel operations.
 156  */
 157 #define PROFILEHZ       1013
 158
 159 /*
 160  *      Use the other timer to provide high accuracy profiling info.
 161  */
 162 irqreturn_t coldfire_profile_tick(int irq, void *dummy)
 163 {
 164         /* Reset ColdFire timer2 */
 165         __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
 166         if (current->pid)
 167                 profile_tick(CPU_PROFILING);
 168         return IRQ_HANDLED;
 169 }
 170
 171 /***************************************************************************/
 172
 173 static struct irqaction coldfire_profile_irq = {
 174         .name    = "profile timer",
 175         .flags   = IRQF_TIMER,
 176         .handler = coldfire_profile_tick,
 177 };
 178
 179 void coldfire_profile_init(void)
 180 {
 181         printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
 182                PROFILEHZ);
 183
 184         /* Set up TIMER 2 as high speed profile clock */
 185         __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
 186
 187         __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
 188         __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
 189                 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
 190
 191         setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq);
 192 }
 193
 194 /***************************************************************************/
 195 #endif  /* CONFIG_HIGHPROFILE */
 196 /***************************************************************************/