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
|
/*
* linux/arch/arm/mach-mmp/time.c
*
* Support for clocksource and clockevents
*
* Copyright (C) 2008 Marvell International Ltd.
* All rights reserved.
*
* 2008-04-11: Jason Chagas <Jason.chagas@marvell.com>
* 2008-10-08: Bin Yang <bin.yang@marvell.com>
*
* The timers module actually includes three timers, each timer with upto
* three match comparators. Timer #0 is used here in free-running mode as
* the clock source, and match comparator #1 used as clock event device.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/cnt32_to_63.h>
#include <mach/addr-map.h>
#include <mach/regs-timers.h>
#include <mach/regs-apbc.h>
#include <mach/irqs.h>
#include <mach/cputype.h>
#include <asm/mach/time.h>
#include "clock.h"
#define TIMERS_VIRT_BASE TIMERS1_VIRT_BASE
#define MAX_DELTA (0xfffffffe)
#define MIN_DELTA (16)
#define TCR2NS_SCALE_FACTOR 10
static unsigned long tcr2ns_scale;
static void __init set_tcr2ns_scale(unsigned long tcr_rate)
{
unsigned long long v = 1000000000ULL << TCR2NS_SCALE_FACTOR;
do_div(v, tcr_rate);
tcr2ns_scale = v;
/*
* We want an even value to automatically clear the top bit
* returned by cnt32_to_63() without an additional run time
* instruction. So if the LSB is 1 then round it up.
*/
if (tcr2ns_scale & 1)
tcr2ns_scale++;
}
/*
* FIXME: the timer needs some delay to stablize the counter capture
*/
static inline uint32_t timer_read(void)
{
int delay = 100;
__raw_writel(1, TIMERS_VIRT_BASE + TMR_CVWR(0));
while (delay--)
cpu_relax();
return __raw_readl(TIMERS_VIRT_BASE + TMR_CVWR(0));
}
unsigned long long notrace sched_clock(void)
{
unsigned long long v = cnt32_to_63(timer_read());
return (v * tcr2ns_scale) >> TCR2NS_SCALE_FACTOR;
}
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
/* disable and clear pending interrupt status */
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0));
__raw_writel(0x1, TIMERS_VIRT_BASE + TMR_ICR(0));
c->event_handler(c);
return IRQ_HANDLED;
}
static int timer_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
unsigned long flags, next;
local_irq_save(flags);
/* clear pending interrupt status and enable */
__raw_writel(0x01, TIMERS_VIRT_BASE + TMR_ICR(0));
__raw_writel(0x01, TIMERS_VIRT_BASE + TMR_IER(0));
next = timer_read() + delta;
__raw_writel(next, TIMERS_VIRT_BASE + TMR_TN_MM(0, 0));
local_irq_restore(flags);
return 0;
}
static void timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *dev)
{
unsigned long flags;
local_irq_save(flags);
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
/* disable the matching interrupt */
__raw_writel(0x00, TIMERS_VIRT_BASE + TMR_IER(0));
break;
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
}
local_irq_restore(flags);
}
static struct clock_event_device ckevt = {
.name = "clockevent",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.rating = 200,
.set_next_event = timer_set_next_event,
.set_mode = timer_set_mode,
};
static cycle_t clksrc_read(struct clocksource *cs)
{
return timer_read();
}
static struct clocksource cksrc = {
.name = "clocksource",
.rating = 200,
.read = clksrc_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static void __init timer_config(void)
{
uint32_t ccr = __raw_readl(TIMERS_VIRT_BASE + TMR_CCR);
uint32_t cer = __raw_readl(TIMERS_VIRT_BASE + TMR_CER);
uint32_t cmr = __raw_readl(TIMERS_VIRT_BASE + TMR_CMR);
__raw_writel(cer & ~0x1, TIMERS_VIRT_BASE + TMR_CER); /* disable */
ccr &= (cpu_is_mmp2()) ? TMR_CCR_CS_0(0) : TMR_CCR_CS_0(3);
__raw_writel(ccr, TIMERS_VIRT_BASE + TMR_CCR);
/* free-running mode */
__raw_writel(cmr | 0x01, TIMERS_VIRT_BASE + TMR_CMR);
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_PLCR(0)); /* free-running */
__raw_writel(0x7, TIMERS_VIRT_BASE + TMR_ICR(0)); /* clear status */
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0));
/* enable timer counter */
__raw_writel(cer | 0x01, TIMERS_VIRT_BASE + TMR_CER);
}
static struct irqaction timer_irq = {
.name = "timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = timer_interrupt,
.dev_id = &ckevt,
};
void __init timer_init(int irq)
{
timer_config();
set_tcr2ns_scale(CLOCK_TICK_RATE);
ckevt.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt.shift);
ckevt.max_delta_ns = clockevent_delta2ns(MAX_DELTA, &ckevt);
ckevt.min_delta_ns = clockevent_delta2ns(MIN_DELTA, &ckevt);
ckevt.cpumask = cpumask_of(0);
setup_irq(irq, &timer_irq);
clocksource_register_hz(&cksrc, CLOCK_TICK_RATE);
clockevents_register_device(&ckevt);
}
|
