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
|
/* Clock_initialize
*
* This routine initializes the 8254 timer under GO32.
* The tick frequency is 1 millisecond.
*
* Input parameters: NONE
*
* Output parameters: NONE
*
* $Id$
*/
#include <bsp.h>
#include <rtems/libio.h>
#include <stdlib.h>
volatile rtems_unsigned32 Clock_driver_ticks;
rtems_unsigned32 Clock_isrs_per_tick; /* ISRs per tick */
rtems_unsigned32 Clock_isrs; /* ISRs until next tick */
rtems_isr_entry Old_ticker;
#define CLOCK_VECTOR 0x8
void Clock_exit( void );
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_minor_number rtems_clock_minor;
rtems_isr Clock_isr(
rtems_vector_number vector
)
{
/* touch interrupt controller for irq0 (0x20+0) */
outport_byte( 0x20, 0x20 );
Clock_driver_ticks += 1;
#if 0 && defined(pentium)
{
extern long long Last_RDTSC;
__asm __volatile( ".byte 0x0F, 0x31" : "=A" (Last_RDTSC) );
}
#endif
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = Clock_isrs_per_tick;
} else {
Clock_isrs -= 1;
}
}
void Install_clock(
rtems_isr_entry clock_isr
)
{
unsigned int microseconds_per_isr;
#if 0
/* Initialize clock from on-board real time clock. This breaks the */
/* test code which assumes which assumes the application will do it. */
{
rtems_time_of_day Now;
extern void init_rtc( void );
extern long rtc_read( rtems_time_of_day * tod );
init_rtc();
if ( rtc_read( &Now ) >= 0 )
clock_set( &Now );
}
#endif
/* Start by assuming hardware counter is large enough, then */
/* scale it until it actually fits. */
Clock_driver_ticks = 0;
Clock_isrs_per_tick = 1;
if ( BSP_Configuration.microseconds_per_tick == 0 )
microseconds_per_isr = 10000; /* default 10 ms */
else
microseconds_per_isr = BSP_Configuration.microseconds_per_tick;
while ( US_TO_TICK(microseconds_per_isr) > 65535 ) {
Clock_isrs_per_tick *= 10;
microseconds_per_isr /= 10;
}
/* Initialize count in ckisr.c */
Clock_isrs = Clock_isrs_per_tick;
#if 0
/* This was dropped in the last revision. Its a nice thing to know. */
TICKS_PER_SECOND = 1000000 / (Clock_isrs_per_tick * microseconds_per_isr);
#endif
if ( BSP_Configuration.ticks_per_timeslice ) {
/* 105/88 approximates TIMER_TICK*1e-6 */
unsigned int count = US_TO_TICK( microseconds_per_isr );
Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );
outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN );
outport_byte( TIMER_CNTR0, count >> 0 & 0xff );
outport_byte( TIMER_CNTR0, count >> 8 & 0xff );
}
atexit( Clock_exit );
}
void ReInstall_clock(
rtems_isr_entry clock_isr
)
{
rtems_unsigned32 isrlevel = 0;
rtems_interrupt_disable( isrlevel );
(void) set_vector( clock_isr, CLOCK_VECTOR, 1 );
rtems_interrupt_enable( isrlevel );
}
void Clock_exit( void )
{
if ( BSP_Configuration.ticks_per_timeslice ) {
extern void rtc_set_dos_date( void );
/* reset to DOS value: */
outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN );
outport_byte( TIMER_CNTR0, 0 );
outport_byte( TIMER_CNTR0, 0 );
/* reset time-of-day */
rtc_set_dos_date();
/* re-enable old handler: assume it was one of ours */
set_vector( (rtems_isr_entry)Old_ticker, CLOCK_VECTOR, 1 );
}
}
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock( Clock_isr );
/*
* make major/minor avail to others such as shared memory driver
*/
rtems_clock_major = major;
rtems_clock_minor = minor;
return RTEMS_SUCCESSFUL;
}
rtems_device_driver Clock_control(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
rtems_libio_ioctl_args_t *args = pargp;
if (args == 0)
goto done;
/*
* This is hokey, but until we get a defined interface
* to do this, it will just be this simple...
*/
if (args->command == rtems_build_name('I', 'S', 'R', ' '))
{
Clock_isr(CLOCK_VECTOR);
}
else if (args->command == rtems_build_name('N', 'E', 'W', ' '))
{
ReInstall_clock(args->buffer);
}
done:
return RTEMS_SUCCESSFUL;
}
#if 0 && defined(pentium)
/* This can be used to get extremely accurate timing on a pentium. */
/* It isn't supported. [bryce] */
#define HZ 90.0
volatile long long Last_RDTSC;
#define RDTSC()\
({ long long _now; __asm __volatile (".byte 0x0F,0x31":"=A"(_now)); _now; })
long long Kernel_Time_ns( void )
{
extern rtems_unsigned32 _TOD_Ticks_per_second;
unsigned isrs_per_second = Clock_isrs_per_tick * _TOD_Ticks_per_second;
long long now;
int flags;
disable_intr( flags );
now = 1e9 * Clock_driver_ticks / isrs_per_second
+ (RDTSC() - Last_RDTSC) * (1000.0/HZ);
enable_intr( flags );
return now;
}
#endif
|
