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
|
/* Clock_initialize
*
* This routine initializes the Timer/Counter on the Intel
* 386ex evaluation board.
*
* The tick frequency is 1 millisecond.
*
* Input parameters: NONE
*
* Output parameters: NONE
*
* COPYRIGHT (c) 1989-1999.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#include <bsp.h>
#include <bsp/irq.h>
#include <rtems/libio.h>
#include <stdlib.h>
uint32_t Clock_isrs; /* ISRs until next tick */
static uint32_t Clock_initial_isr_value;
volatile uint32_t Clock_driver_ticks;
void Clock_exit( void );
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_major_number rtems_clock_minor = 0;
/*
* This is the ISR handler.
*/
void Clock_isr(void)
{
/* enable_tracing(); */
Clock_driver_ticks += 1;
if ( Clock_isrs == 1 ) {
rtems_clock_tick();
Clock_isrs = Clock_initial_isr_value; /* rtems_configuration_get_microseconds_per_tick() / 1000;*/
}
else
Clock_isrs -= 1;
}
void ClockOff(const rtems_irq_connect_data* unused)
{
outport_byte (TIMER_CONFIG, 0x80 ); /* disable the counter timer */
}
void ClockOn(const rtems_irq_connect_data* unused)
{
outport_byte (TIMER_CONFIG, 0x00 ); /* enable the counter timer */
}
int ClockIsOn(const rtems_irq_connect_data* unused)
{
return ((i8259s_cache & 0x1) == 0);
}
static rtems_irq_connect_data clockIrqData = {BSP_PERIODIC_TIMER,
Clock_isr,
0,
ClockOn,
ClockOff,
ClockIsOn};
rtems_device_driver Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
unsigned timer_counter_init_value;
unsigned char clock_lsb, clock_msb;
#ifdef BSP_DEBUG
printk("Initializing clock driver in Clock_initialize().\n");
#endif
#ifdef LOAD_RTC_AT_START
/* 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;
/* External Prototypes */
extern void init_rtc(void); /* defined in 'rtc.c' */
extern long rtc_read(rtems_time_of_day *); /* defined in 'rtc.c' */
#ifdef BSP_DEBUG
printk("Loading clock from on-board real-time clock.\n");
#endif
init_rtc();
if (rtc_read(&now) >= 0)
rtems_clock_set(&now);
}
#endif
Clock_driver_ticks = 0;
Clock_isrs =
Clock_initial_isr_value =
rtems_configuration_get_microseconds_per_tick() / 1000; /* ticks per clock_isr */
/*
* configure the counter timer ( should be based on microsecs/tick )
* NB. The divisor(Clock_isrs) resolves the is the same number that appears in confdefs.h
* when setting the microseconds_per_tick value.
*/
ClockOff ( &clockIrqData );
timer_counter_init_value = rtems_configuration_get_microseconds_per_tick() / Clock_isrs;
clock_lsb = (unsigned char)timer_counter_init_value;
clock_msb = timer_counter_init_value >> 8;
outport_byte (TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN);
outport_byte (TIMER_CNTR0, clock_lsb ); /* load LSB first */
outport_byte (TIMER_CNTR0, clock_msb ); /* then MSB */
if (!BSP_install_rtems_irq_handler (&clockIrqData)) {
printk("Unable to initialize system clock\n");
rtems_fatal_error_occurred(1);
}
/*
* make major/minor avail to others such as shared memory driver
*/
rtems_clock_major = major;
rtems_clock_minor = minor;
return RTEMS_SUCCESSFUL;
}
void Clock_exit()
{
ClockOff(&clockIrqData);
BSP_remove_rtems_irq_handler (&clockIrqData);
}
|
