1 /* 2 * arch/xtensa/kernel/time.c 3 * 4 * Timer and clock support. 5 * 6 * This file is subject to the terms and conditions of the GNU General Public 7 * License. See the file "COPYING" in the main directory of this archive 8 * for more details. 9 * 10 * Copyright (C) 2005 Tensilica Inc. 11 * 12 * Chris Zankel <chris@zankel.net> 13 */ 14 15 #include <linux/errno.h> 16 #include <linux/sched.h> 17 #include <linux/time.h> 18 #include <linux/clocksource.h> 19 #include <linux/clockchips.h> 20 #include <linux/interrupt.h> 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/irq.h> 24 #include <linux/profile.h> 25 #include <linux/delay.h> 26 #include <linux/irqdomain.h> 27 #include <linux/sched_clock.h> 28 29 #include <asm/timex.h> 30 #include <asm/platform.h> 31 32 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT 33 unsigned long ccount_freq; /* ccount Hz */ 34 #endif 35 36 static cycle_t ccount_read(struct clocksource *cs) 37 { 38 return (cycle_t)get_ccount(); 39 } 40 41 static u32 notrace ccount_sched_clock_read(void) 42 { 43 return get_ccount(); 44 } 45 46 static struct clocksource ccount_clocksource = { 47 .name = "ccount", 48 .rating = 200, 49 .read = ccount_read, 50 .mask = CLOCKSOURCE_MASK(32), 51 }; 52 53 static int ccount_timer_set_next_event(unsigned long delta, 54 struct clock_event_device *dev); 55 static void ccount_timer_set_mode(enum clock_event_mode mode, 56 struct clock_event_device *evt); 57 static struct ccount_timer_t { 58 struct clock_event_device evt; 59 int irq_enabled; 60 } ccount_timer = { 61 .evt = { 62 .name = "ccount_clockevent", 63 .features = CLOCK_EVT_FEAT_ONESHOT, 64 .rating = 300, 65 .set_next_event = ccount_timer_set_next_event, 66 .set_mode = ccount_timer_set_mode, 67 }, 68 }; 69 70 static int ccount_timer_set_next_event(unsigned long delta, 71 struct clock_event_device *dev) 72 { 73 unsigned long flags, next; 74 int ret = 0; 75 76 local_irq_save(flags); 77 next = get_ccount() + delta; 78 set_linux_timer(next); 79 if (next - get_ccount() > delta) 80 ret = -ETIME; 81 local_irq_restore(flags); 82 83 return ret; 84 } 85 86 static void ccount_timer_set_mode(enum clock_event_mode mode, 87 struct clock_event_device *evt) 88 { 89 struct ccount_timer_t *timer = 90 container_of(evt, struct ccount_timer_t, evt); 91 92 /* 93 * There is no way to disable the timer interrupt at the device level, 94 * only at the intenable register itself. Since enable_irq/disable_irq 95 * calls are nested, we need to make sure that these calls are 96 * balanced. 97 */ 98 switch (mode) { 99 case CLOCK_EVT_MODE_SHUTDOWN: 100 case CLOCK_EVT_MODE_UNUSED: 101 if (timer->irq_enabled) { 102 disable_irq(evt->irq); 103 timer->irq_enabled = 0; 104 } 105 break; 106 case CLOCK_EVT_MODE_RESUME: 107 case CLOCK_EVT_MODE_ONESHOT: 108 if (!timer->irq_enabled) { 109 enable_irq(evt->irq); 110 timer->irq_enabled = 1; 111 } 112 default: 113 break; 114 } 115 } 116 117 static irqreturn_t timer_interrupt(int irq, void *dev_id); 118 static struct irqaction timer_irqaction = { 119 .handler = timer_interrupt, 120 .flags = IRQF_TIMER, 121 .name = "timer", 122 .dev_id = &ccount_timer, 123 }; 124 125 void __init time_init(void) 126 { 127 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT 128 printk("Calibrating CPU frequency "); 129 platform_calibrate_ccount(); 130 printk("%d.%02d MHz\n", (int)ccount_freq/1000000, 131 (int)(ccount_freq/10000)%100); 132 #endif 133 clocksource_register_hz(&ccount_clocksource, CCOUNT_PER_JIFFY * HZ); 134 135 ccount_timer.evt.cpumask = cpumask_of(0); 136 ccount_timer.evt.irq = irq_create_mapping(NULL, LINUX_TIMER_INT); 137 if (WARN(!ccount_timer.evt.irq, "error: can't map timer irq")) 138 return; 139 clockevents_config_and_register(&ccount_timer.evt, ccount_freq, 0xf, 140 0xffffffff); 141 setup_irq(ccount_timer.evt.irq, &timer_irqaction); 142 ccount_timer.irq_enabled = 1; 143 144 setup_sched_clock(ccount_sched_clock_read, 32, ccount_freq); 145 } 146 147 /* 148 * The timer interrupt is called HZ times per second. 149 */ 150 151 irqreturn_t timer_interrupt (int irq, void *dev_id) 152 { 153 struct ccount_timer_t *timer = dev_id; 154 struct clock_event_device *evt = &timer->evt; 155 156 evt->event_handler(evt); 157 158 /* Allow platform to do something useful (Wdog). */ 159 platform_heartbeat(); 160 161 return IRQ_HANDLED; 162 } 163 164 #ifndef CONFIG_GENERIC_CALIBRATE_DELAY 165 void calibrate_delay(void) 166 { 167 loops_per_jiffy = CCOUNT_PER_JIFFY; 168 printk("Calibrating delay loop (skipped)... " 169 "%lu.%02lu BogoMIPS preset\n", 170 loops_per_jiffy/(1000000/HZ), 171 (loops_per_jiffy/(10000/HZ)) % 100); 172 } 173 #endif 174