arch/mips/jz4740/time.c

   1 /*
   2  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
   3  *  JZ4740 platform time support
   4  *
   5  *  This program is free software; you can redistribute it and/or modify it
   6  *  under  the terms of the GNU General  Public License as published by the
   7  *  Free Software Foundation;  either version 2 of the License, or (at your
   8  *  option) any later version.
   9  *
  10  *  You should have received a copy of the GNU General Public License along
  11  *  with this program; if not, write to the Free Software Foundation, Inc.,
  12  *  675 Mass Ave, Cambridge, MA 02139, USA.
  13  *
  14  */
  15
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel.h>
  18 #include <linux/time.h>
  19
  20 #include <linux/clockchips.h>
  21 #include <linux/sched_clock.h>
  22
  23 #include <asm/mach-jz4740/clock.h>
  24 #include <asm/mach-jz4740/irq.h>
  25 #include <asm/mach-jz4740/timer.h>
  26 #include <asm/time.h>
  27
  28 #include "clock.h"
  29
  30 #define TIMER_CLOCKEVENT 0
  31 #define TIMER_CLOCKSOURCE 1
  32
  33 static uint16_t jz4740_jiffies_per_tick;
  34
  35 static cycle_t jz4740_clocksource_read(struct clocksource *cs)
  36 {
  37         return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
  38 }
  39
  40 static struct clocksource jz4740_clocksource = {
  41         .name = "jz4740-timer",
  42         .rating = 200,
  43         .read = jz4740_clocksource_read,
  44         .mask = CLOCKSOURCE_MASK(16),
  45         .flags = CLOCK_SOURCE_IS_CONTINUOUS,
  46 };
  47
  48 static u64 notrace jz4740_read_sched_clock(void)
  49 {
  50         return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
  51 }
  52
  53 static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
  54 {
  55         struct clock_event_device *cd = devid;
  56
  57         jz4740_timer_ack_full(TIMER_CLOCKEVENT);
  58
  59         if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
  60                 jz4740_timer_disable(TIMER_CLOCKEVENT);
  61
  62         cd->event_handler(cd);
  63
  64         return IRQ_HANDLED;
  65 }
  66
  67 static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
  68         struct clock_event_device *cd)
  69 {
  70         switch (mode) {
  71         case CLOCK_EVT_MODE_PERIODIC:
  72                 jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
  73                 jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
  74         case CLOCK_EVT_MODE_RESUME:
  75                 jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
  76                 jz4740_timer_enable(TIMER_CLOCKEVENT);
  77                 break;
  78         case CLOCK_EVT_MODE_ONESHOT:
  79         case CLOCK_EVT_MODE_SHUTDOWN:
  80                 jz4740_timer_disable(TIMER_CLOCKEVENT);
  81                 break;
  82         default:
  83                 break;
  84         }
  85 }
  86
  87 static int jz4740_clockevent_set_next(unsigned long evt,
  88         struct clock_event_device *cd)
  89 {
  90         jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
  91         jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
  92         jz4740_timer_enable(TIMER_CLOCKEVENT);
  93
  94         return 0;
  95 }
  96
  97 static struct clock_event_device jz4740_clockevent = {
  98         .name = "jz4740-timer",
  99         .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 100         .set_next_event = jz4740_clockevent_set_next,
 101         .set_mode = jz4740_clockevent_set_mode,
 102         .rating = 200,
 103         .irq = JZ4740_IRQ_TCU0,
 104 };
 105
 106 static struct irqaction timer_irqaction = {
 107         .handler        = jz4740_clockevent_irq,
 108         .flags          = IRQF_PERCPU | IRQF_TIMER,
 109         .name           = "jz4740-timerirq",
 110         .dev_id         = &jz4740_clockevent,
 111 };
 112
 113 void __init plat_time_init(void)
 114 {
 115         int ret;
 116         uint32_t clk_rate;
 117         uint16_t ctrl;
 118
 119         jz4740_clock_init();
 120         jz4740_timer_init();
 121
 122         clk_rate = jz4740_clock_bdata.ext_rate >> 4;
 123         jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
 124
 125         clockevent_set_clock(&jz4740_clockevent, clk_rate);
 126         jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
 127         jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
 128         jz4740_clockevent.cpumask = cpumask_of(0);
 129
 130         clockevents_register_device(&jz4740_clockevent);
 131
 132         ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
 133
 134         if (ret)
 135                 printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
 136
 137         sched_clock_register(jz4740_read_sched_clock, 16, clk_rate);
 138
 139         setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
 140
 141         ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
 142
 143         jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
 144         jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
 145
 146         jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
 147         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
 148
 149         jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
 150
 151         jz4740_timer_enable(TIMER_CLOCKEVENT);
 152         jz4740_timer_enable(TIMER_CLOCKSOURCE);
 153 }