arch/arm/common/timer-sp.c

   1 /*
   2  *  linux/arch/arm/common/timer-sp.c
   3  *
   4  *  Copyright (C) 1999 - 2003 ARM Limited
   5  *  Copyright (C) 2000 Deep Blue Solutions Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 #include <linux/clocksource.h>
  22 #include <linux/clockchips.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/irq.h>
  25 #include <linux/io.h>
  26
  27 #include <asm/hardware/arm_timer.h>
  28
  29 /*
  30  * These timers are currently always setup to be clocked at 1MHz.
  31  */
  32 #define TIMER_FREQ_KHZ  (1000)
  33 #define TIMER_RELOAD    (TIMER_FREQ_KHZ * 1000 / HZ)
  34
  35 static void __iomem *clksrc_base;
  36
  37 static cycle_t sp804_read(struct clocksource *cs)
  38 {
  39         return ~readl(clksrc_base + TIMER_VALUE);
  40 }
  41
  42 static struct clocksource clocksource_sp804 = {
  43         .name           = "timer3",
  44         .rating         = 200,
  45         .read           = sp804_read,
  46         .mask           = CLOCKSOURCE_MASK(32),
  47         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  48 };
  49
  50 void __init sp804_clocksource_init(void __iomem *base)
  51 {
  52         struct clocksource *cs = &clocksource_sp804;
  53
  54         clksrc_base = base;
  55
  56         /* setup timer 0 as free-running clocksource */
  57         writel(0, clksrc_base + TIMER_CTRL);
  58         writel(0xffffffff, clksrc_base + TIMER_LOAD);
  59         writel(0xffffffff, clksrc_base + TIMER_VALUE);
  60         writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
  61                 clksrc_base + TIMER_CTRL);
  62
  63         clocksource_register_khz(cs, TIMER_FREQ_KHZ);
  64 }
  65
  66
  67 static void __iomem *clkevt_base;
  68
  69 /*
  70  * IRQ handler for the timer
  71  */
  72 static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
  73 {
  74         struct clock_event_device *evt = dev_id;
  75
  76         /* clear the interrupt */
  77         writel(1, clkevt_base + TIMER_INTCLR);
  78
  79         evt->event_handler(evt);
  80
  81         return IRQ_HANDLED;
  82 }
  83
  84 static void sp804_set_mode(enum clock_event_mode mode,
  85         struct clock_event_device *evt)
  86 {
  87         unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
  88
  89         writel(ctrl, clkevt_base + TIMER_CTRL);
  90
  91         switch (mode) {
  92         case CLOCK_EVT_MODE_PERIODIC:
  93                 writel(TIMER_RELOAD, clkevt_base + TIMER_LOAD);
  94                 ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
  95                 break;
  96
  97         case CLOCK_EVT_MODE_ONESHOT:
  98                 /* period set, and timer enabled in 'next_event' hook */
  99                 ctrl |= TIMER_CTRL_ONESHOT;
 100                 break;
 101
 102         case CLOCK_EVT_MODE_UNUSED:
 103         case CLOCK_EVT_MODE_SHUTDOWN:
 104         default:
 105                 break;
 106         }
 107
 108         writel(ctrl, clkevt_base + TIMER_CTRL);
 109 }
 110
 111 static int sp804_set_next_event(unsigned long next,
 112         struct clock_event_device *evt)
 113 {
 114         unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
 115
 116         writel(next, clkevt_base + TIMER_LOAD);
 117         writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
 118
 119         return 0;
 120 }
 121
 122 static struct clock_event_device sp804_clockevent = {
 123         .name           = "timer0",
 124         .shift          = 32,
 125         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 126         .set_mode       = sp804_set_mode,
 127         .set_next_event = sp804_set_next_event,
 128         .rating         = 300,
 129         .cpumask        = cpu_all_mask,
 130 };
 131
 132 static struct irqaction sp804_timer_irq = {
 133         .name           = "timer",
 134         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 135         .handler        = sp804_timer_interrupt,
 136         .dev_id         = &sp804_clockevent,
 137 };
 138
 139 void __init sp804_clockevents_init(void __iomem *base, unsigned int timer_irq)
 140 {
 141         struct clock_event_device *evt = &sp804_clockevent;
 142
 143         clkevt_base = base;
 144
 145         evt->irq = timer_irq;
 146         evt->mult = div_sc(TIMER_FREQ_KHZ, NSEC_PER_MSEC, evt->shift);
 147         evt->max_delta_ns = clockevent_delta2ns(0xffffffff, evt);
 148         evt->min_delta_ns = clockevent_delta2ns(0xf, evt);
 149
 150         setup_irq(timer_irq, &sp804_timer_irq);
 151         clockevents_register_device(evt);
 152 }