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
218
219
220
221
222
223
224
225
226
|
/*
* Copyright (c) 2014 Zhang, Keguang <keguang.zhang@gmail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <asm/time.h>
#include <loongson1.h>
#include <platform.h>
#ifdef CONFIG_CEVT_CSRC_LS1X
#if defined(CONFIG_TIMER_USE_PWM1)
#define LS1X_TIMER_BASE LS1X_PWM1_BASE
#define LS1X_TIMER_IRQ LS1X_PWM1_IRQ
#elif defined(CONFIG_TIMER_USE_PWM2)
#define LS1X_TIMER_BASE LS1X_PWM2_BASE
#define LS1X_TIMER_IRQ LS1X_PWM2_IRQ
#elif defined(CONFIG_TIMER_USE_PWM3)
#define LS1X_TIMER_BASE LS1X_PWM3_BASE
#define LS1X_TIMER_IRQ LS1X_PWM3_IRQ
#else
#define LS1X_TIMER_BASE LS1X_PWM0_BASE
#define LS1X_TIMER_IRQ LS1X_PWM0_IRQ
#endif
DEFINE_RAW_SPINLOCK(ls1x_timer_lock);
static void __iomem *timer_base;
static uint32_t ls1x_jiffies_per_tick;
static inline void ls1x_pwmtimer_set_period(uint32_t period)
{
__raw_writel(period, timer_base + PWM_HRC);
__raw_writel(period, timer_base + PWM_LRC);
}
static inline void ls1x_pwmtimer_restart(void)
{
__raw_writel(0x0, timer_base + PWM_CNT);
__raw_writel(INT_EN | CNT_EN, timer_base + PWM_CTRL);
}
void __init ls1x_pwmtimer_init(void)
{
timer_base = ioremap(LS1X_TIMER_BASE, 0xf);
if (!timer_base)
panic("Failed to remap timer registers");
ls1x_jiffies_per_tick = DIV_ROUND_CLOSEST(mips_hpt_frequency, HZ);
ls1x_pwmtimer_set_period(ls1x_jiffies_per_tick);
ls1x_pwmtimer_restart();
}
static cycle_t ls1x_clocksource_read(struct clocksource *cs)
{
unsigned long flags;
int count;
u32 jifs;
static int old_count;
static u32 old_jifs;
raw_spin_lock_irqsave(&ls1x_timer_lock, flags);
/*
* Although our caller may have the read side of xtime_lock,
* this is now a seqlock, and we are cheating in this routine
* by having side effects on state that we cannot undo if
* there is a collision on the seqlock and our caller has to
* retry. (Namely, old_jifs and old_count.) So we must treat
* jiffies as volatile despite the lock. We read jiffies
* before latching the timer count to guarantee that although
* the jiffies value might be older than the count (that is,
* the counter may underflow between the last point where
* jiffies was incremented and the point where we latch the
* count), it cannot be newer.
*/
jifs = jiffies;
/* read the count */
count = __raw_readl(timer_base + PWM_CNT);
/*
* It's possible for count to appear to go the wrong way for this
* reason:
*
* The timer counter underflows, but we haven't handled the resulting
* interrupt and incremented jiffies yet.
*
* Previous attempts to handle these cases intelligently were buggy, so
* we just do the simple thing now.
*/
if (count < old_count && jifs == old_jifs)
count = old_count;
old_count = count;
old_jifs = jifs;
raw_spin_unlock_irqrestore(&ls1x_timer_lock, flags);
return (cycle_t) (jifs * ls1x_jiffies_per_tick) + count;
}
static struct clocksource ls1x_clocksource = {
.name = "ls1x-pwmtimer",
.read = ls1x_clocksource_read,
.mask = CLOCKSOURCE_MASK(24),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static irqreturn_t ls1x_clockevent_isr(int irq, void *devid)
{
struct clock_event_device *cd = devid;
ls1x_pwmtimer_restart();
cd->event_handler(cd);
return IRQ_HANDLED;
}
static void ls1x_clockevent_set_mode(enum clock_event_mode mode,
struct clock_event_device *cd)
{
raw_spin_lock(&ls1x_timer_lock);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
ls1x_pwmtimer_set_period(ls1x_jiffies_per_tick);
ls1x_pwmtimer_restart();
case CLOCK_EVT_MODE_RESUME:
__raw_writel(INT_EN | CNT_EN, timer_base + PWM_CTRL);
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_SHUTDOWN:
__raw_writel(__raw_readl(timer_base + PWM_CTRL) & ~CNT_EN,
timer_base + PWM_CTRL);
break;
default:
break;
}
raw_spin_unlock(&ls1x_timer_lock);
}
static int ls1x_clockevent_set_next(unsigned long evt,
struct clock_event_device *cd)
{
raw_spin_lock(&ls1x_timer_lock);
ls1x_pwmtimer_set_period(evt);
ls1x_pwmtimer_restart();
raw_spin_unlock(&ls1x_timer_lock);
return 0;
}
static struct clock_event_device ls1x_clockevent = {
.name = "ls1x-pwmtimer",
.features = CLOCK_EVT_FEAT_PERIODIC,
.rating = 300,
.irq = LS1X_TIMER_IRQ,
.set_next_event = ls1x_clockevent_set_next,
.set_mode = ls1x_clockevent_set_mode,
};
static struct irqaction ls1x_pwmtimer_irqaction = {
.name = "ls1x-pwmtimer",
.handler = ls1x_clockevent_isr,
.dev_id = &ls1x_clockevent,
.flags = IRQF_PERCPU | IRQF_TIMER,
};
static void __init ls1x_time_init(void)
{
struct clock_event_device *cd = &ls1x_clockevent;
int ret;
if (!mips_hpt_frequency)
panic("Invalid timer clock rate");
ls1x_pwmtimer_init();
clockevent_set_clock(cd, mips_hpt_frequency);
cd->max_delta_ns = clockevent_delta2ns(0xffffff, cd);
cd->min_delta_ns = clockevent_delta2ns(0x000300, cd);
cd->cpumask = cpumask_of(smp_processor_id());
clockevents_register_device(cd);
ls1x_clocksource.rating = 200 + mips_hpt_frequency / 10000000;
ret = clocksource_register_hz(&ls1x_clocksource, mips_hpt_frequency);
if (ret)
panic(KERN_ERR "Failed to register clocksource: %d\n", ret);
setup_irq(LS1X_TIMER_IRQ, &ls1x_pwmtimer_irqaction);
}
#endif /* CONFIG_CEVT_CSRC_LS1X */
void __init plat_time_init(void)
{
struct clk *clk = NULL;
/* initialize LS1X clocks */
ls1x_clk_init();
#ifdef CONFIG_CEVT_CSRC_LS1X
/* setup LS1X PWM timer */
clk = clk_get(NULL, "ls1x_pwmtimer");
if (IS_ERR(clk))
panic("unable to get timer clock, err=%ld", PTR_ERR(clk));
mips_hpt_frequency = clk_get_rate(clk);
ls1x_time_init();
#else
/* setup mips r4k timer */
clk = clk_get(NULL, "cpu_clk");
if (IS_ERR(clk))
panic("unable to get cpu clock, err=%ld", PTR_ERR(clk));
mips_hpt_frequency = clk_get_rate(clk) / 2;
#endif /* CONFIG_CEVT_CSRC_LS1X */
}
|
