kernel/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/clk.h>
  17 #include <linux/clk-provider.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/kernel.h>
  20 #include <linux/time.h>
  21
  22 #include <linux/clockchips.h>
  23 #include <linux/sched_clock.h>
  24
  25 #include <asm/mach-jz4740/clock.h>
  26 #include <asm/mach-jz4740/irq.h>
  27 #include <asm/mach-jz4740/timer.h>
  28 #include <asm/time.h>
  29
  30 #include "clock.h"
  31
  32 #define TIMER_CLOCKEVENT 0
  33 #define TIMER_CLOCKSOURCE 1
  34
  35 static uint16_t jz4740_jiffies_per_tick;
  36
  37 static cycle_t jz4740_clocksource_read(struct clocksource *cs)
  38 {
  39         return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
  40 }
  41
  42 static struct clocksource jz4740_clocksource = {
  43         .name = "jz4740-timer",
  44         .rating = 200,
  45         .read = jz4740_clocksource_read,
  46         .mask = CLOCKSOURCE_MASK(16),
  47         .flags = CLOCK_SOURCE_IS_CONTINUOUS,
  48 };
  49
  50 static u64 notrace jz4740_read_sched_clock(void)
  51 {
  52         return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
  53 }
  54
  55 static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
  56 {
  57         struct clock_event_device *cd = devid;
  58
  59         jz4740_timer_ack_full(TIMER_CLOCKEVENT);
  60
  61         if (!clockevent_state_periodic(cd))
  62                 jz4740_timer_disable(TIMER_CLOCKEVENT);
  63
  64         cd->event_handler(cd);
  65
  66         return IRQ_HANDLED;
  67 }
  68
  69 static int jz4740_clockevent_set_periodic(struct clock_event_device *evt)
  70 {
  71         jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
  72         jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
  73         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
  74         jz4740_timer_enable(TIMER_CLOCKEVENT);
  75
  76         return 0;
  77 }
  78
  79 static int jz4740_clockevent_resume(struct clock_event_device *evt)
  80 {
  81         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
  82         jz4740_timer_enable(TIMER_CLOCKEVENT);
  83
  84         return 0;
  85 }
  86
  87 static int jz4740_clockevent_shutdown(struct clock_event_device *evt)
  88 {
  89         jz4740_timer_disable(TIMER_CLOCKEVENT);
  90
  91         return 0;
  92 }
  93
  94 static int jz4740_clockevent_set_next(unsigned long evt,
  95         struct clock_event_device *cd)
  96 {
  97         jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
  98         jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
  99         jz4740_timer_enable(TIMER_CLOCKEVENT);
 100
 101         return 0;
 102 }
 103
 104 static struct clock_event_device jz4740_clockevent = {
 105         .name = "jz4740-timer",
 106         .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 107         .set_next_event = jz4740_clockevent_set_next,
 108         .set_state_shutdown = jz4740_clockevent_shutdown,
 109         .set_state_periodic = jz4740_clockevent_set_periodic,
 110         .set_state_oneshot = jz4740_clockevent_shutdown,
 111         .tick_resume = jz4740_clockevent_resume,
 112         .rating = 200,
 113 #ifdef CONFIG_MACH_JZ4740
 114         .irq = JZ4740_IRQ_TCU0,
 115 #endif
 116 #ifdef CONFIG_MACH_JZ4780
 117         .irq = JZ4780_IRQ_TCU2,
 118 #endif
 119 };
 120
 121 static struct irqaction timer_irqaction = {
 122         .handler        = jz4740_clockevent_irq,
 123         .flags          = IRQF_PERCPU | IRQF_TIMER,
 124         .name           = "jz4740-timerirq",
 125         .dev_id         = &jz4740_clockevent,
 126 };
 127
 128 void __init plat_time_init(void)
 129 {
 130         int ret;
 131         uint32_t clk_rate;
 132         uint16_t ctrl;
 133         struct clk *ext_clk;
 134
 135         of_clk_init(NULL);
 136         jz4740_timer_init();
 137
 138         ext_clk = clk_get(NULL, "ext");
 139         if (IS_ERR(ext_clk))
 140                 panic("unable to get ext clock");
 141         clk_rate = clk_get_rate(ext_clk) >> 4;
 142         clk_put(ext_clk);
 143
 144         jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
 145
 146         clockevent_set_clock(&jz4740_clockevent, clk_rate);
 147         jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
 148         jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
 149         jz4740_clockevent.cpumask = cpumask_of(0);
 150
 151         clockevents_register_device(&jz4740_clockevent);
 152
 153         ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
 154
 155         if (ret)
 156                 printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
 157
 158         sched_clock_register(jz4740_read_sched_clock, 16, clk_rate);
 159
 160         setup_irq(jz4740_clockevent.irq, &timer_irqaction);
 161
 162         ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
 163
 164         jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
 165         jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
 166
 167         jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
 168         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
 169
 170         jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
 171
 172         jz4740_timer_enable(TIMER_CLOCKEVENT);
 173         jz4740_timer_enable(TIMER_CLOCKSOURCE);
 174 }