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
216
217
|
/*
* System timer for CSR SiRFprimaII
*
* Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
*
* Licensed under GPLv2 or later.
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <mach/map.h>
#include <asm/mach/time.h>
#define SIRFSOC_TIMER_COUNTER_LO 0x0000
#define SIRFSOC_TIMER_COUNTER_HI 0x0004
#define SIRFSOC_TIMER_MATCH_0 0x0008
#define SIRFSOC_TIMER_MATCH_1 0x000C
#define SIRFSOC_TIMER_MATCH_2 0x0010
#define SIRFSOC_TIMER_MATCH_3 0x0014
#define SIRFSOC_TIMER_MATCH_4 0x0018
#define SIRFSOC_TIMER_MATCH_5 0x001C
#define SIRFSOC_TIMER_STATUS 0x0020
#define SIRFSOC_TIMER_INT_EN 0x0024
#define SIRFSOC_TIMER_WATCHDOG_EN 0x0028
#define SIRFSOC_TIMER_DIV 0x002C
#define SIRFSOC_TIMER_LATCH 0x0030
#define SIRFSOC_TIMER_LATCHED_LO 0x0034
#define SIRFSOC_TIMER_LATCHED_HI 0x0038
#define SIRFSOC_TIMER_WDT_INDEX 5
#define SIRFSOC_TIMER_LATCH_BIT BIT(0)
static void __iomem *sirfsoc_timer_base;
static void __init sirfsoc_of_timer_map(void);
/* timer0 interrupt handler */
static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *ce = dev_id;
WARN_ON(!(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_STATUS) & BIT(0)));
/* clear timer0 interrupt */
writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS);
ce->event_handler(ce);
return IRQ_HANDLED;
}
/* read 64-bit timer counter */
static cycle_t sirfsoc_timer_read(struct clocksource *cs)
{
u64 cycles;
/* latch the 64-bit timer counter */
writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_HI);
cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
return cycles;
}
static int sirfsoc_timer_set_next_event(unsigned long delta,
struct clock_event_device *ce)
{
unsigned long now, next;
writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
next = now + delta;
writel_relaxed(next, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0);
writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, sirfsoc_timer_base + SIRFSOC_TIMER_LATCH);
now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO);
return next - now > delta ? -ETIME : 0;
}
static void sirfsoc_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *ce)
{
u32 val = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
WARN_ON(1);
break;
case CLOCK_EVT_MODE_ONESHOT:
writel_relaxed(val | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
writel_relaxed(val & ~BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_RESUME:
break;
}
}
static struct clock_event_device sirfsoc_clockevent = {
.name = "sirfsoc_clockevent",
.rating = 200,
.features = CLOCK_EVT_FEAT_ONESHOT,
.set_mode = sirfsoc_timer_set_mode,
.set_next_event = sirfsoc_timer_set_next_event,
};
static struct clocksource sirfsoc_clocksource = {
.name = "sirfsoc_clocksource",
.rating = 200,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.read = sirfsoc_timer_read,
};
static struct irqaction sirfsoc_timer_irq = {
.name = "sirfsoc_timer0",
.flags = IRQF_TIMER,
.irq = 0,
.handler = sirfsoc_timer_interrupt,
.dev_id = &sirfsoc_clockevent,
};
/* Overwrite weak default sched_clock with more precise one */
unsigned long long notrace sched_clock(void)
{
static int is_mapped = 0;
/*
* sched_clock is called earlier than .init of sys_timer
* if we map timer memory in .init of sys_timer, system
* will panic due to illegal memory access
*/
if(!is_mapped) {
sirfsoc_of_timer_map();
is_mapped = 1;
}
return sirfsoc_timer_read(NULL) * (NSEC_PER_SEC / CLOCK_TICK_RATE);
}
static void __init sirfsoc_clockevent_init(void)
{
clockevents_calc_mult_shift(&sirfsoc_clockevent, CLOCK_TICK_RATE, 60);
sirfsoc_clockevent.max_delta_ns =
clockevent_delta2ns(-2, &sirfsoc_clockevent);
sirfsoc_clockevent.min_delta_ns =
clockevent_delta2ns(2, &sirfsoc_clockevent);
sirfsoc_clockevent.cpumask = cpumask_of(0);
clockevents_register_device(&sirfsoc_clockevent);
}
/* initialize the kernel jiffy timer source */
static void __init sirfsoc_timer_init(void)
{
unsigned long rate;
/* timer's input clock is io clock */
struct clk *clk = clk_get_sys("io", NULL);
BUG_ON(IS_ERR(clk));
rate = clk_get_rate(clk);
BUG_ON(rate < CLOCK_TICK_RATE);
BUG_ON(rate % CLOCK_TICK_RATE);
writel_relaxed(rate / CLOCK_TICK_RATE / 2 - 1, sirfsoc_timer_base + SIRFSOC_TIMER_DIV);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO);
writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI);
writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS);
BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, CLOCK_TICK_RATE));
BUG_ON(setup_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq));
sirfsoc_clockevent_init();
}
static struct of_device_id timer_ids[] = {
{ .compatible = "sirf,prima2-tick" },
};
static void __init sirfsoc_of_timer_map(void)
{
struct device_node *np;
const unsigned int *intspec;
np = of_find_matching_node(NULL, timer_ids);
if (!np)
panic("unable to find compatible timer node in dtb\n");
sirfsoc_timer_base = of_iomap(np, 0);
if (!sirfsoc_timer_base)
panic("unable to map timer cpu registers\n");
/* Get the interrupts property */
intspec = of_get_property(np, "interrupts", NULL);
BUG_ON(!intspec);
sirfsoc_timer_irq.irq = be32_to_cpup(intspec);
of_node_put(np);
}
struct sys_timer sirfsoc_timer = {
.init = sirfsoc_timer_init,
};
|
