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
|
/* MN10300 Low level time management
*
* Copyright (C) 2007-2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
* - Derived from arch/i386/kernel/time.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/profile.h>
#include <linux/cnt32_to_63.h>
#include <asm/irq.h>
#include <asm/div64.h>
#include <asm/processor.h>
#include <asm/intctl-regs.h>
#include <asm/rtc.h>
#ifdef CONFIG_MN10300_RTC
unsigned long mn10300_ioclk; /* system I/O clock frequency */
unsigned long mn10300_iobclk; /* system I/O clock frequency */
unsigned long mn10300_tsc_per_HZ; /* number of ioclks per jiffy */
#endif /* CONFIG_MN10300_RTC */
static unsigned long mn10300_last_tsc; /* time-stamp counter at last time
* interrupt occurred */
static irqreturn_t timer_interrupt(int irq, void *dev_id);
static struct irqaction timer_irq = {
.handler = timer_interrupt,
.flags = IRQF_DISABLED | IRQF_SHARED | IRQF_TIMER,
.mask = CPU_MASK_NONE,
.name = "timer",
};
static unsigned long sched_clock_multiplier;
/*
* scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
union {
unsigned long long ll;
unsigned l[2];
} tsc64, result;
unsigned long tsc, tmp;
unsigned product[3]; /* 96-bit intermediate value */
/* read the TSC value
*/
tsc = 0 - get_cycles(); /* get_cycles() counts down */
/* expand to 64-bits.
* - sched_clock() must be called once a minute or better or the
* following will go horribly wrong - see cnt32_to_63()
*/
tsc64.ll = cnt32_to_63(tsc) & 0x7fffffffffffffffULL;
/* scale the 64-bit TSC value to a nanosecond value via a 96-bit
* intermediate
*/
asm("mulu %2,%0,%3,%0 \n" /* LSW * mult -> 0:%3:%0 */
"mulu %2,%1,%2,%1 \n" /* MSW * mult -> %2:%1:0 */
"add %3,%1 \n"
"addc 0,%2 \n" /* result in %2:%1:%0 */
: "=r"(product[0]), "=r"(product[1]), "=r"(product[2]), "=r"(tmp)
: "0"(tsc64.l[0]), "1"(tsc64.l[1]), "2"(sched_clock_multiplier)
: "cc");
result.l[0] = product[1] << 16 | product[0] >> 16;
result.l[1] = product[2] << 16 | product[1] >> 16;
return result.ll;
}
/*
* initialise the scheduler clock
*/
static void __init mn10300_sched_clock_init(void)
{
sched_clock_multiplier =
__muldiv64u(NSEC_PER_SEC, 1 << 16, MN10300_TSCCLK);
}
/*
* advance the kernel's time keeping clocks (xtime and jiffies)
* - we use Timer 0 & 1 cascaded as a clock to nudge us the next time
* there's a need to update
*/
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
unsigned tsc, elapse;
write_seqlock(&xtime_lock);
while (tsc = get_cycles(),
elapse = mn10300_last_tsc - tsc, /* time elapsed since last
* tick */
elapse > MN10300_TSC_PER_HZ
) {
mn10300_last_tsc -= MN10300_TSC_PER_HZ;
/* advance the kernel's time tracking system */
profile_tick(CPU_PROFILING);
do_timer(1);
check_rtc_time();
}
write_sequnlock(&xtime_lock);
update_process_times(user_mode(get_irq_regs()));
return IRQ_HANDLED;
}
/*
* initialise the various timers used by the main part of the kernel
*/
void __init time_init(void)
{
/* we need the prescalar running to be able to use IOCLK/8
* - IOCLK runs at 1/4 (ST5 open) or 1/8 (ST5 closed) internal CPU clock
* - IOCLK runs at Fosc rate (crystal speed)
*/
TMPSCNT |= TMPSCNT_ENABLE;
startup_timestamp_counter();
printk(KERN_INFO
"timestamp counter I/O clock running at %lu.%02lu"
" (calibrated against RTC)\n",
MN10300_TSCCLK / 1000000, (MN10300_TSCCLK / 10000) % 100);
xtime.tv_sec = get_initial_rtc_time();
xtime.tv_nsec = 0;
mn10300_last_tsc = TMTSCBC;
/* use timer 0 & 1 cascaded to tick at as close to HZ as possible */
setup_irq(TMJCIRQ, &timer_irq);
set_intr_level(TMJCIRQ, TMJCICR_LEVEL);
startup_jiffies_counter();
#ifdef CONFIG_MN10300_WD_TIMER
/* start the watchdog timer */
watchdog_go();
#endif
mn10300_sched_clock_init();
}
|
