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 22#include <asm/mach-jz4740/irq.h> 23#include <asm/time.h> 24 25#include "clock.h" 26#include "timer.h" 27 28#define TIMER_CLOCKEVENT 0 29#define TIMER_CLOCKSOURCE 1 30 31static uint16_t jz4740_jiffies_per_tick; 32 33static cycle_t jz4740_clocksource_read(struct clocksource *cs) 34{ 35 return jz4740_timer_get_count(TIMER_CLOCKSOURCE); 36} 37 38static struct clocksource jz4740_clocksource = { 39 .name = "jz4740-timer", 40 .rating = 200, 41 .read = jz4740_clocksource_read, 42 .mask = CLOCKSOURCE_MASK(16), 43 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 44}; 45 46static irqreturn_t jz4740_clockevent_irq(int irq, void *devid) 47{ 48 struct clock_event_device *cd = devid; 49 50 jz4740_timer_ack_full(TIMER_CLOCKEVENT); 51 52 if (cd->mode != CLOCK_EVT_MODE_PERIODIC) 53 jz4740_timer_disable(TIMER_CLOCKEVENT); 54 55 cd->event_handler(cd); 56 57 return IRQ_HANDLED; 58} 59 60static void jz4740_clockevent_set_mode(enum clock_event_mode mode, 61 struct clock_event_device *cd) 62{ 63 switch (mode) { 64 case CLOCK_EVT_MODE_PERIODIC: 65 jz4740_timer_set_count(TIMER_CLOCKEVENT, 0); 66 jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick); 67 case CLOCK_EVT_MODE_RESUME: 68 jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT); 69 jz4740_timer_enable(TIMER_CLOCKEVENT); 70 break; 71 case CLOCK_EVT_MODE_ONESHOT: 72 case CLOCK_EVT_MODE_SHUTDOWN: 73 jz4740_timer_disable(TIMER_CLOCKEVENT); 74 break; 75 default: 76 break; 77 } 78} 79 80static int jz4740_clockevent_set_next(unsigned long evt, 81 struct clock_event_device *cd) 82{ 83 jz4740_timer_set_count(TIMER_CLOCKEVENT, 0); 84 jz4740_timer_set_period(TIMER_CLOCKEVENT, evt); 85 jz4740_timer_enable(TIMER_CLOCKEVENT); 86 87 return 0; 88} 89 90static struct clock_event_device jz4740_clockevent = { 91 .name = "jz4740-timer", 92 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, 93 .set_next_event = jz4740_clockevent_set_next, 94 .set_mode = jz4740_clockevent_set_mode, 95 .rating = 200, 96 .irq = JZ4740_IRQ_TCU0, 97}; 98 99static struct irqaction timer_irqaction = { 100 .handler = jz4740_clockevent_irq, 101 .flags = IRQF_PERCPU | IRQF_TIMER, 102 .name = "jz4740-timerirq", 103 .dev_id = &jz4740_clockevent, 104}; 105 106void __init plat_time_init(void) 107{ 108 int ret; 109 uint32_t clk_rate; 110 uint16_t ctrl; 111 112 jz4740_timer_init(); 113 114 clk_rate = jz4740_clock_bdata.ext_rate >> 4; 115 jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ); 116 117 clockevent_set_clock(&jz4740_clockevent, clk_rate); 118 jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent); 119 jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent); 120 jz4740_clockevent.cpumask = cpumask_of(0); 121 122 clockevents_register_device(&jz4740_clockevent); 123 124 ret = clocksource_register_hz(&jz4740_clocksource, clk_rate); 125 126 if (ret) 127 printk(KERN_ERR "Failed to register clocksource: %d\n", ret); 128 129 setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction); 130 131 ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT; 132 133 jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl); 134 jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl); 135 136 jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick); 137 jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT); 138 139 jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff); 140 141 jz4740_timer_enable(TIMER_CLOCKEVENT); 142 jz4740_timer_enable(TIMER_CLOCKSOURCE); 143} 144