blob: e099d91fb673cff313946bed8ebc679a5d7f3e6a (
plain) (
blame)
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
|
/*
* This routine initializes the MC68340/349 Periodic Interval Timer
*/
/*
* Based on the `gen68360' board support package, and covered by the
* original distribution terms.
*
* Geoffroy Montel
* France Telecom - CNET/DSM/TAM/CAT
* 4, rue du Clos Courtel
* 35512 CESSON-SEVIGNE
* FRANCE
*
* e-mail: g_montel@yahoo.com
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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.org/license/LICENSE.
*/
#include <stdlib.h> /* for atexit() */
#include <bsp.h>
#include <m68340.h>
#include <rtems/clockdrv.h>
#define CLOCK_VECTOR 120 /* clock isr routine vector in the vbr */
#define CLOCK_IRQ_LEVEL 6 /* clock isr level */
/*
* Clock_driver_ticks is a monotonically increasing counter of the
* number of clock ticks since the driver was initialized.
*/
volatile uint32_t Clock_driver_ticks;
/*
* Periodic interval timer interrupt handler
*/
static rtems_isr
Clock_isr (rtems_vector_number vector)
{
/*
* Announce the clock tick
*/
Clock_driver_ticks++;
rtems_clock_tick();
}
void
Clock_exit (void)
{
/*
* Turn off periodic interval timer
*/
SIMPITR = 0;
}
static void
Install_clock (rtems_isr_entry clock_isr)
{
uint32_t pitr_tmp;
uint32_t usecs_per_tick;
Clock_driver_ticks = 0;
set_vector (clock_isr, CLOCK_VECTOR, 1);
/* sets the Periodic Interrupt Control Register PICR */
SIMPICR = ( CLOCK_IRQ_LEVEL << 8 ) | ( CLOCK_VECTOR );
/* sets the PITR count value */
/* this assumes a 32.765 kHz crystal */
usecs_per_tick = rtems_configuration_get_microseconds_per_tick();
/* find out whether prescaler should be enabled or not */
if ( usecs_per_tick <= 31128 ) {
pitr_tmp = ( usecs_per_tick * 8192 ) / 1000000 ;
} else {
pitr_tmp = ( usecs_per_tick / 1000000 ) * 16;
/* enable it */
pitr_tmp |= 0x100;
}
SIMPITR = (unsigned char) pitr_tmp;
atexit (Clock_exit);
}
rtems_device_driver
Clock_initialize(
rtems_device_major_number major,
rtems_device_minor_number minor,
void *pargp
)
{
Install_clock (Clock_isr);
return RTEMS_SUCCESSFUL;
}
|