arch/arm/mach-orion/time.c

   1 /*
   2  * arch/arm/mach-orion/time.c
   3  *
   4  * Core time functions for Marvell Orion System On Chip
   5  *
   6  * Maintainer: Tzachi Perelstein <tzachi@marvell.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2. This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/clockchips.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/irq.h>
  17 #include <asm/mach/time.h>
  18 #include <asm/arch/orion.h>
  19 #include "common.h"
  20
  21 /*
  22  * Timer0: clock_event_device, Tick.
  23  * Timer1: clocksource, Free running.
  24  * WatchDog: Not used.
  25  *
  26  * Timers are counting down.
  27  */
  28 #define CLOCKEVENT      0
  29 #define CLOCKSOURCE     1
  30
  31 /*
  32  * Timers bits
  33  */
  34 #define BRIDGE_INT_TIMER(x)     (1 << ((x) + 1))
  35 #define TIMER_EN(x)             (1 << ((x) * 2))
  36 #define TIMER_RELOAD_EN(x)      (1 << (((x) * 2) + 1))
  37 #define BRIDGE_INT_TIMER_WD     (1 << 3)
  38 #define TIMER_WD_EN             (1 << 4)
  39 #define TIMER_WD_RELOAD_EN      (1 << 5)
  40
  41 static cycle_t orion_clksrc_read(void)
  42 {
  43         return (0xffffffff - orion_read(TIMER_VAL(CLOCKSOURCE)));
  44 }
  45
  46 static struct clocksource orion_clksrc = {
  47         .name           = "orion_clocksource",
  48         .shift          = 20,
  49         .rating         = 300,
  50         .read           = orion_clksrc_read,
  51         .mask           = CLOCKSOURCE_MASK(32),
  52         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  53 };
  54
  55 static int
  56 orion_clkevt_next_event(unsigned long delta, struct clock_event_device *dev)
  57 {
  58         unsigned long flags;
  59
  60         if (delta == 0)
  61                 return -ETIME;
  62
  63         local_irq_save(flags);
  64
  65         /*
  66          * Clear and enable timer interrupt bit
  67          */
  68         orion_write(BRIDGE_CAUSE, ~BRIDGE_INT_TIMER(CLOCKEVENT));
  69         orion_setbits(BRIDGE_MASK, BRIDGE_INT_TIMER(CLOCKEVENT));
  70
  71         /*
  72          * Setup new timer value
  73          */
  74         orion_write(TIMER_VAL(CLOCKEVENT), delta);
  75
  76         /*
  77          * Disable auto reload and kickoff the timer
  78          */
  79         orion_clrbits(TIMER_CTRL, TIMER_RELOAD_EN(CLOCKEVENT));
  80         orion_setbits(TIMER_CTRL, TIMER_EN(CLOCKEVENT));
  81
  82         local_irq_restore(flags);
  83
  84         return 0;
  85 }
  86
  87 static void
  88 orion_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev)
  89 {
  90         unsigned long flags;
  91
  92         local_irq_save(flags);
  93
  94         if (mode == CLOCK_EVT_MODE_PERIODIC) {
  95                 /*
  96                  * Setup latch cycles in timer and enable reload interrupt.
  97                  */
  98                 orion_write(TIMER_VAL_RELOAD(CLOCKEVENT), LATCH);
  99                 orion_write(TIMER_VAL(CLOCKEVENT), LATCH);
 100                 orion_setbits(BRIDGE_MASK, BRIDGE_INT_TIMER(CLOCKEVENT));
 101                 orion_setbits(TIMER_CTRL, TIMER_RELOAD_EN(CLOCKEVENT) |
 102                                           TIMER_EN(CLOCKEVENT));
 103         } else {
 104                 /*
 105                  * Disable timer and interrupt
 106                  */
 107                 orion_clrbits(BRIDGE_MASK, BRIDGE_INT_TIMER(CLOCKEVENT));
 108                 orion_write(BRIDGE_CAUSE, ~BRIDGE_INT_TIMER(CLOCKEVENT));
 109                 orion_clrbits(TIMER_CTRL, TIMER_RELOAD_EN(CLOCKEVENT) |
 110                                           TIMER_EN(CLOCKEVENT));
 111         }
 112
 113         local_irq_restore(flags);
 114 }
 115
 116 static struct clock_event_device orion_clkevt = {
 117         .name           = "orion_tick",
 118         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 119         .shift          = 32,
 120         .rating         = 300,
 121         .cpumask        = CPU_MASK_CPU0,
 122         .set_next_event = orion_clkevt_next_event,
 123         .set_mode       = orion_clkevt_mode,
 124 };
 125
 126 static irqreturn_t orion_timer_interrupt(int irq, void *dev_id)
 127 {
 128         /*
 129          * Clear cause bit and do event
 130          */
 131         orion_write(BRIDGE_CAUSE, ~BRIDGE_INT_TIMER(CLOCKEVENT));
 132         orion_clkevt.event_handler(&orion_clkevt);
 133         return IRQ_HANDLED;
 134 }
 135
 136 static struct irqaction orion_timer_irq = {
 137         .name           = "orion_tick",
 138         .flags          = IRQF_DISABLED | IRQF_TIMER,
 139         .handler        = orion_timer_interrupt
 140 };
 141
 142 static void orion_timer_init(void)
 143 {
 144         /*
 145          * Setup clocksource free running timer (no interrupt on reload)
 146          */
 147         orion_write(TIMER_VAL(CLOCKSOURCE), 0xffffffff);
 148         orion_write(TIMER_VAL_RELOAD(CLOCKSOURCE), 0xffffffff);
 149         orion_clrbits(BRIDGE_MASK, BRIDGE_INT_TIMER(CLOCKSOURCE));
 150         orion_setbits(TIMER_CTRL, TIMER_RELOAD_EN(CLOCKSOURCE) |
 151                                   TIMER_EN(CLOCKSOURCE));
 152
 153         /*
 154          * Register clocksource
 155          */
 156         orion_clksrc.mult =
 157                 clocksource_hz2mult(CLOCK_TICK_RATE, orion_clksrc.shift);
 158
 159         clocksource_register(&orion_clksrc);
 160
 161         /*
 162          * Connect and enable tick handler
 163          */
 164         setup_irq(IRQ_ORION_BRIDGE, &orion_timer_irq);
 165
 166         /*
 167          * Register clockevent
 168          */
 169         orion_clkevt.mult =
 170                 div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, orion_clkevt.shift);
 171         orion_clkevt.max_delta_ns =
 172                 clockevent_delta2ns(0xfffffffe, &orion_clkevt);
 173         orion_clkevt.min_delta_ns =
 174                 clockevent_delta2ns(1, &orion_clkevt);
 175
 176         clockevents_register_device(&orion_clkevt);
 177 }
 178
 179 struct sys_timer orion_timer = {
 180         .init = orion_timer_init,
 181 };