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
|
/*
* OMAP 32ksynctimer/counter_32k-related code
*
* Copyright (C) 2009 Texas Instruments
* Copyright (C) 2010 Nokia Corporation
* Tony Lindgren <tony@atomide.com>
* Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* 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.
*
* NOTE: This timer is not the same timer as the old OMAP1 MPU timer.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/err.h>
#include <plat/common.h>
#include <plat/board.h>
#include <plat/clock.h>
/*
* 32KHz clocksource ... always available, on pretty most chips except
* OMAP 730 and 1510. Other timers could be used as clocksources, with
* higher resolution in free-running counter modes (e.g. 12 MHz xtal),
* but systems won't necessarily want to spend resources that way.
*/
#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410
#if !(defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP15XX))
#include <linux/clocksource.h>
/*
* offset_32k holds the init time counter value. It is then subtracted
* from every counter read to achieve a counter that counts time from the
* kernel boot (needed for sched_clock()).
*/
static u32 offset_32k __read_mostly;
#ifdef CONFIG_ARCH_OMAP16XX
static cycle_t omap16xx_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP16XX_TIMER_32K_SYNCHRONIZED) - offset_32k;
}
#else
#define omap16xx_32k_read NULL
#endif
#ifdef CONFIG_ARCH_OMAP2420
static cycle_t omap2420_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP2420_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap2420_32k_read NULL
#endif
#ifdef CONFIG_ARCH_OMAP2430
static cycle_t omap2430_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP2430_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap2430_32k_read NULL
#endif
#ifdef CONFIG_ARCH_OMAP3
static cycle_t omap34xx_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP3430_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap34xx_32k_read NULL
#endif
#ifdef CONFIG_ARCH_OMAP4
static cycle_t omap44xx_32k_read(struct clocksource *cs)
{
return omap_readl(OMAP4430_32KSYNCT_BASE + 0x10) - offset_32k;
}
#else
#define omap44xx_32k_read NULL
#endif
/*
* Kernel assumes that sched_clock can be called early but may not have
* things ready yet.
*/
static cycle_t omap_32k_read_dummy(struct clocksource *cs)
{
return 0;
}
static struct clocksource clocksource_32k = {
.name = "32k_counter",
.rating = 250,
.read = omap_32k_read_dummy,
.mask = CLOCKSOURCE_MASK(32),
.shift = 10,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* Returns current time from boot in nsecs. It's OK for this to wrap
* around for now, as it's just a relative time stamp.
*/
unsigned long long sched_clock(void)
{
return clocksource_cyc2ns(clocksource_32k.read(&clocksource_32k),
clocksource_32k.mult, clocksource_32k.shift);
}
/**
* read_persistent_clock - Return time from a persistent clock.
*
* Reads the time from a source which isn't disabled during PM, the
* 32k sync timer. Convert the cycles elapsed since last read into
* nsecs and adds to a monotonically increasing timespec.
*/
static struct timespec persistent_ts;
static cycles_t cycles, last_cycles;
void read_persistent_clock(struct timespec *ts)
{
unsigned long long nsecs;
cycles_t delta;
struct timespec *tsp = &persistent_ts;
last_cycles = cycles;
cycles = clocksource_32k.read(&clocksource_32k);
delta = cycles - last_cycles;
nsecs = clocksource_cyc2ns(delta,
clocksource_32k.mult, clocksource_32k.shift);
timespec_add_ns(tsp, nsecs);
*ts = *tsp;
}
static int __init omap_init_clocksource_32k(void)
{
static char err[] __initdata = KERN_ERR
"%s: can't register clocksource!\n";
if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
struct clk *sync_32k_ick;
if (cpu_is_omap16xx())
clocksource_32k.read = omap16xx_32k_read;
else if (cpu_is_omap2420())
clocksource_32k.read = omap2420_32k_read;
else if (cpu_is_omap2430())
clocksource_32k.read = omap2430_32k_read;
else if (cpu_is_omap34xx())
clocksource_32k.read = omap34xx_32k_read;
else if (cpu_is_omap44xx())
clocksource_32k.read = omap44xx_32k_read;
else
return -ENODEV;
sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
if (!IS_ERR(sync_32k_ick))
clk_enable(sync_32k_ick);
clocksource_32k.mult = clocksource_hz2mult(32768,
clocksource_32k.shift);
offset_32k = clocksource_32k.read(&clocksource_32k);
if (clocksource_register(&clocksource_32k))
printk(err, clocksource_32k.name);
}
return 0;
}
arch_initcall(omap_init_clocksource_32k);
#endif /* !(defined(CONFIG_ARCH_OMAP730) || defined(CONFIG_ARCH_OMAP15XX)) */
|
