arch/arm/plat-iop/time.c

   1 /*
   2  * arch/arm/plat-iop/time.c
   3  *
   4  * Timer code for IOP32x and IOP33x based systems
   5  *
   6  * Author: Deepak Saxena <dsaxena@mvista.com>
   7  *
   8  * Copyright 2002-2003 MontaVista Software Inc.
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the
  12  * Free Software Foundation; either version 2 of the License, or (at your
  13  * option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/time.h>
  19 #include <linux/init.h>
  20 #include <linux/timex.h>
  21 #include <linux/sched.h>
  22 #include <linux/io.h>
  23 #include <linux/clocksource.h>
  24 #include <linux/clockchips.h>
  25 #include <linux/export.h>
  26 #include <mach/hardware.h>
  27 #include <asm/irq.h>
  28 #include <asm/sched_clock.h>
  29 #include <asm/uaccess.h>
  30 #include <asm/mach/irq.h>
  31 #include <asm/mach/time.h>
  32 #include <mach/time.h>
  33
  34 /*
  35  * Minimum clocksource/clockevent timer range in seconds
  36  */
  37 #define IOP_MIN_RANGE 4
  38
  39 /*
  40  * IOP clocksource (free-running timer 1).
  41  */
  42 static cycle_t notrace iop_clocksource_read(struct clocksource *unused)
  43 {
  44         return 0xffffffffu - read_tcr1();
  45 }
  46
  47 static struct clocksource iop_clocksource = {
  48         .name           = "iop_timer1",
  49         .rating         = 300,
  50         .read           = iop_clocksource_read,
  51         .mask           = CLOCKSOURCE_MASK(32),
  52         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  53 };
  54
  55 static DEFINE_CLOCK_DATA(cd);
  56
  57 /*
  58  * IOP sched_clock() implementation via its clocksource.
  59  */
  60 unsigned long long notrace sched_clock(void)
  61 {
  62         u32 cyc = 0xffffffffu - read_tcr1();
  63         return cyc_to_sched_clock(&cd, cyc, (u32)~0);
  64 }
  65
  66 static void notrace iop_update_sched_clock(void)
  67 {
  68         u32 cyc = 0xffffffffu - read_tcr1();
  69         update_sched_clock(&cd, cyc, (u32)~0);
  70 }
  71
  72 /*
  73  * IOP clockevents (interrupting timer 0).
  74  */
  75 static int iop_set_next_event(unsigned long delta,
  76                               struct clock_event_device *unused)
  77 {
  78         u32 tmr = IOP_TMR_PRIVILEGED | IOP_TMR_RATIO_1_1;
  79
  80         BUG_ON(delta == 0);
  81         write_tmr0(tmr & ~(IOP_TMR_EN | IOP_TMR_RELOAD));
  82         write_tcr0(delta);
  83         write_tmr0((tmr & ~IOP_TMR_RELOAD) | IOP_TMR_EN);
  84
  85         return 0;
  86 }
  87
  88 static unsigned long ticks_per_jiffy;
  89
  90 static void iop_set_mode(enum clock_event_mode mode,
  91                          struct clock_event_device *unused)
  92 {
  93         u32 tmr = read_tmr0();
  94
  95         switch (mode) {
  96         case CLOCK_EVT_MODE_PERIODIC:
  97                 write_tmr0(tmr & ~IOP_TMR_EN);
  98                 write_tcr0(ticks_per_jiffy - 1);
  99                 write_trr0(ticks_per_jiffy - 1);
 100                 tmr |= (IOP_TMR_RELOAD | IOP_TMR_EN);
 101                 break;
 102         case CLOCK_EVT_MODE_ONESHOT:
 103                 /* ->set_next_event sets period and enables timer */
 104                 tmr &= ~(IOP_TMR_RELOAD | IOP_TMR_EN);
 105                 break;
 106         case CLOCK_EVT_MODE_RESUME:
 107                 tmr |= IOP_TMR_EN;
 108                 break;
 109         case CLOCK_EVT_MODE_SHUTDOWN:
 110         case CLOCK_EVT_MODE_UNUSED:
 111         default:
 112                 tmr &= ~IOP_TMR_EN;
 113                 break;
 114         }
 115
 116         write_tmr0(tmr);
 117 }
 118
 119 static struct clock_event_device iop_clockevent = {
 120         .name           = "iop_timer0",
 121         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 122         .rating         = 300,
 123         .set_next_event = iop_set_next_event,
 124         .set_mode       = iop_set_mode,
 125 };
 126
 127 static irqreturn_t
 128 iop_timer_interrupt(int irq, void *dev_id)
 129 {
 130         struct clock_event_device *evt = dev_id;
 131
 132         write_tisr(1);
 133         evt->event_handler(evt);
 134         return IRQ_HANDLED;
 135 }
 136
 137 static struct irqaction iop_timer_irq = {
 138         .name           = "IOP Timer Tick",
 139         .handler        = iop_timer_interrupt,
 140         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 141         .dev_id         = &iop_clockevent,
 142 };
 143
 144 static unsigned long iop_tick_rate;
 145 unsigned long get_iop_tick_rate(void)
 146 {
 147         return iop_tick_rate;
 148 }
 149 EXPORT_SYMBOL(get_iop_tick_rate);
 150
 151 void __init iop_init_time(unsigned long tick_rate)
 152 {
 153         u32 timer_ctl;
 154
 155         init_sched_clock(&cd, iop_update_sched_clock, 32, tick_rate);
 156
 157         ticks_per_jiffy = DIV_ROUND_CLOSEST(tick_rate, HZ);
 158         iop_tick_rate = tick_rate;
 159
 160         timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
 161                         IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;
 162
 163         /*
 164          * Set up interrupting clockevent timer 0.
 165          */
 166         write_tmr0(timer_ctl & ~IOP_TMR_EN);
 167         write_tisr(1);
 168         setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
 169         clockevents_calc_mult_shift(&iop_clockevent,
 170                                     tick_rate, IOP_MIN_RANGE);
 171         iop_clockevent.max_delta_ns =
 172                 clockevent_delta2ns(0xfffffffe, &iop_clockevent);
 173         iop_clockevent.min_delta_ns =
 174                 clockevent_delta2ns(0xf, &iop_clockevent);
 175         iop_clockevent.cpumask = cpumask_of(0);
 176         clockevents_register_device(&iop_clockevent);
 177
 178         /*
 179          * Set up free-running clocksource timer 1.
 180          */
 181         write_trr1(0xffffffff);
 182         write_tcr1(0xffffffff);
 183         write_tmr1(timer_ctl);
 184         clocksource_register_hz(&iop_clocksource, tick_rate);
 185 }