1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
/*
* arch/xtensa/kernel/time.c
*
* Timer and clock support.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2005 Tensilica Inc.
*
* Chris Zankel <chris@zankel.net>
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/profile.h>
#include <linux/delay.h>
#include <linux/irqdomain.h>
#include <linux/sched_clock.h>
#include <asm/timex.h>
#include <asm/platform.h>
unsigned long ccount_freq; /* ccount Hz */
EXPORT_SYMBOL(ccount_freq);
static u64 ccount_read(struct clocksource *cs)
{
return (u64)get_ccount();
}
static u64 notrace ccount_sched_clock_read(void)
{
return get_ccount();
}
static struct clocksource ccount_clocksource = {
.name = "ccount",
.rating = 200,
.read = ccount_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
struct ccount_timer {
struct clock_event_device evt;
int irq_enabled;
char name[24];
};
static int ccount_timer_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
unsigned long flags, next;
int ret = 0;
local_irq_save(flags);
next = get_ccount() + delta;
set_linux_timer(next);
if (next - get_ccount() > delta)
ret = -ETIME;
local_irq_restore(flags);
return ret;
}
/*
* There is no way to disable the timer interrupt at the device level,
* only at the intenable register itself. Since enable_irq/disable_irq
* calls are nested, we need to make sure that these calls are
* balanced.
*/
static int ccount_timer_shutdown(struct clock_event_device *evt)
{
struct ccount_timer *timer =
container_of(evt, struct ccount_timer, evt);
if (timer->irq_enabled) {
disable_irq_nosync(evt->irq);
timer->irq_enabled = 0;
}
return 0;
}
static int ccount_timer_set_oneshot(struct clock_event_device *evt)
{
struct ccount_timer *timer =
container_of(evt, struct ccount_timer, evt);
if (!timer->irq_enabled) {
enable_irq(evt->irq);
timer->irq_enabled = 1;
}
return 0;
}
static DEFINE_PER_CPU(struct ccount_timer, ccount_timer) = {
.evt = {
.features = CLOCK_EVT_FEAT_ONESHOT,
.rating = 300,
.set_next_event = ccount_timer_set_next_event,
.set_state_shutdown = ccount_timer_shutdown,
.set_state_oneshot = ccount_timer_set_oneshot,
.tick_resume = ccount_timer_set_oneshot,
},
};
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &this_cpu_ptr(&ccount_timer)->evt;
set_linux_timer(get_linux_timer());
evt->event_handler(evt);
/* Allow platform to do something useful (Wdog). */
platform_heartbeat();
return IRQ_HANDLED;
}
static struct irqaction timer_irqaction = {
.handler = timer_interrupt,
.flags = IRQF_TIMER,
.name = "timer",
};
void local_timer_setup(unsigned cpu)
{
struct ccount_timer *timer = &per_cpu(ccount_timer, cpu);
struct clock_event_device *clockevent = &timer->evt;
timer->irq_enabled = 1;
snprintf(timer->name, sizeof(timer->name), "ccount_clockevent_%u", cpu);
clockevent->name = timer->name;
clockevent->cpumask = cpumask_of(cpu);
clockevent->irq = irq_create_mapping(NULL, LINUX_TIMER_INT);
if (WARN(!clockevent->irq, "error: can't map timer irq"))
return;
clockevents_config_and_register(clockevent, ccount_freq,
0xf, 0xffffffff);
}
#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
#ifdef CONFIG_OF
static void __init calibrate_ccount(void)
{
struct device_node *cpu;
struct clk *clk;
cpu = of_find_compatible_node(NULL, NULL, "cdns,xtensa-cpu");
if (cpu) {
clk = of_clk_get(cpu, 0);
if (!IS_ERR(clk)) {
ccount_freq = clk_get_rate(clk);
return;
} else {
pr_warn("%s: CPU input clock not found\n",
__func__);
}
} else {
pr_warn("%s: CPU node not found in the device tree\n",
__func__);
}
platform_calibrate_ccount();
}
#else
static inline void calibrate_ccount(void)
{
platform_calibrate_ccount();
}
#endif
#endif
void __init time_init(void)
{
of_clk_init(NULL);
#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
pr_info("Calibrating CPU frequency ");
calibrate_ccount();
pr_cont("%d.%02d MHz\n",
(int)ccount_freq / 1000000,
(int)(ccount_freq / 10000) % 100);
#else
ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
#endif
WARN(!ccount_freq,
"%s: CPU clock frequency is not set up correctly\n",
__func__);
clocksource_register_hz(&ccount_clocksource, ccount_freq);
local_timer_setup(0);
setup_irq(this_cpu_ptr(&ccount_timer)->evt.irq, &timer_irqaction);
sched_clock_register(ccount_sched_clock_read, 32, ccount_freq);
timer_probe();
}
#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
void calibrate_delay(void)
{
loops_per_jiffy = ccount_freq / HZ;
pr_info("Calibrating delay loop (skipped)... %lu.%02lu BogoMIPS preset\n",
loops_per_jiffy / (1000000 / HZ),
(loops_per_jiffy / (10000 / HZ)) % 100);
}
#endif
|
