This patch contains updated scripts to reduce qemu build time by
[kvmfornfv.git] / kernel / arch / xtensa / kernel / time.c
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 unsigned long ccount_freq;              /* ccount Hz */
33 EXPORT_SYMBOL(ccount_freq);
34
35 static cycle_t ccount_read(struct clocksource *cs)
36 {
37         return (cycle_t)get_ccount();
38 }
39
40 static u64 notrace ccount_sched_clock_read(void)
41 {
42         return get_ccount();
43 }
44
45 static struct clocksource ccount_clocksource = {
46         .name = "ccount",
47         .rating = 200,
48         .read = ccount_read,
49         .mask = CLOCKSOURCE_MASK(32),
50         .flags = CLOCK_SOURCE_IS_CONTINUOUS,
51 };
52
53 static int ccount_timer_set_next_event(unsigned long delta,
54                 struct clock_event_device *dev);
55 struct ccount_timer {
56         struct clock_event_device evt;
57         int irq_enabled;
58         char name[24];
59 };
60 static DEFINE_PER_CPU(struct ccount_timer, ccount_timer);
61
62 static int ccount_timer_set_next_event(unsigned long delta,
63                 struct clock_event_device *dev)
64 {
65         unsigned long flags, next;
66         int ret = 0;
67
68         local_irq_save(flags);
69         next = get_ccount() + delta;
70         set_linux_timer(next);
71         if (next - get_ccount() > delta)
72                 ret = -ETIME;
73         local_irq_restore(flags);
74
75         return ret;
76 }
77
78 /*
79  * There is no way to disable the timer interrupt at the device level,
80  * only at the intenable register itself. Since enable_irq/disable_irq
81  * calls are nested, we need to make sure that these calls are
82  * balanced.
83  */
84 static int ccount_timer_shutdown(struct clock_event_device *evt)
85 {
86         struct ccount_timer *timer =
87                 container_of(evt, struct ccount_timer, evt);
88
89         if (timer->irq_enabled) {
90                 disable_irq(evt->irq);
91                 timer->irq_enabled = 0;
92         }
93         return 0;
94 }
95
96 static int ccount_timer_set_oneshot(struct clock_event_device *evt)
97 {
98         struct ccount_timer *timer =
99                 container_of(evt, struct ccount_timer, evt);
100
101         if (!timer->irq_enabled) {
102                 enable_irq(evt->irq);
103                 timer->irq_enabled = 1;
104         }
105         return 0;
106 }
107
108 static irqreturn_t timer_interrupt(int irq, void *dev_id);
109 static struct irqaction timer_irqaction = {
110         .handler =      timer_interrupt,
111         .flags =        IRQF_TIMER,
112         .name =         "timer",
113 };
114
115 void local_timer_setup(unsigned cpu)
116 {
117         struct ccount_timer *timer = &per_cpu(ccount_timer, cpu);
118         struct clock_event_device *clockevent = &timer->evt;
119
120         timer->irq_enabled = 1;
121         clockevent->name = timer->name;
122         snprintf(timer->name, sizeof(timer->name), "ccount_clockevent_%u", cpu);
123         clockevent->features = CLOCK_EVT_FEAT_ONESHOT;
124         clockevent->rating = 300;
125         clockevent->set_next_event = ccount_timer_set_next_event;
126         clockevent->set_state_shutdown = ccount_timer_shutdown;
127         clockevent->set_state_oneshot = ccount_timer_set_oneshot;
128         clockevent->tick_resume = ccount_timer_set_oneshot;
129         clockevent->cpumask = cpumask_of(cpu);
130         clockevent->irq = irq_create_mapping(NULL, LINUX_TIMER_INT);
131         if (WARN(!clockevent->irq, "error: can't map timer irq"))
132                 return;
133         clockevents_config_and_register(clockevent, ccount_freq,
134                                         0xf, 0xffffffff);
135 }
136
137 void __init time_init(void)
138 {
139 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
140         printk("Calibrating CPU frequency ");
141         platform_calibrate_ccount();
142         printk("%d.%02d MHz\n", (int)ccount_freq/1000000,
143                         (int)(ccount_freq/10000)%100);
144 #else
145         ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
146 #endif
147         clocksource_register_hz(&ccount_clocksource, ccount_freq);
148         local_timer_setup(0);
149         setup_irq(this_cpu_ptr(&ccount_timer)->evt.irq, &timer_irqaction);
150         sched_clock_register(ccount_sched_clock_read, 32, ccount_freq);
151         clocksource_probe();
152 }
153
154 /*
155  * The timer interrupt is called HZ times per second.
156  */
157
158 irqreturn_t timer_interrupt(int irq, void *dev_id)
159 {
160         struct clock_event_device *evt = &this_cpu_ptr(&ccount_timer)->evt;
161
162         set_linux_timer(get_linux_timer());
163         evt->event_handler(evt);
164
165         /* Allow platform to do something useful (Wdog). */
166         platform_heartbeat();
167
168         return IRQ_HANDLED;
169 }
170
171 #ifndef CONFIG_GENERIC_CALIBRATE_DELAY
172 void calibrate_delay(void)
173 {
174         loops_per_jiffy = ccount_freq / HZ;
175         printk("Calibrating delay loop (skipped)... "
176                "%lu.%02lu BogoMIPS preset\n",
177                loops_per_jiffy/(1000000/HZ),
178                (loops_per_jiffy/(10000/HZ)) % 100);
179 }
180 #endif