source: rtems/c/src/lib/libbsp/m68k/ods68302/clock/ckinit.c @ 7068e246

4.104.114.84.95
Last change on this file since 7068e246 was 08311cc3, checked in by Joel Sherrill <joel.sherrill@…>, on Nov 17, 1999 at 5:51:34 PM

Updated copyright notice.

  • Property mode set to 100644
File size: 3.7 KB
Line 
1/*  Clock_init()
2 *
3 *  This routine initializes Timer 1 for an MC68302.
4 *  The tick frequency is 1 millisecond.
5 *
6 *  Input parameters:  NONE
7 *
8 *  Output parameters:  NONE
9 *
10 *  COPYRIGHT (c) 1989-1999.
11 *  On-Line Applications Research Corporation (OAR).
12 *
13 *  The license and distribution terms for this file may be
14 *  found in the file LICENSE in this distribution or at
15 *  http://www.OARcorp.com/rtems/license.html.
16 *
17 *  $Id$
18 */
19
20#include <stdlib.h>                     /* for atexit() */
21
22#include <bsp.h>
23#include <rtems/libio.h>
24
25#include "m68302.h"
26
27#define CLOCK_VECTOR 137
28
29#define TMR1_VAL (  RBIT_TMR_RST        /* software reset the timer */\
30                  | RBIT_TMR_ICLK_MASTER16 /* master clock divided by 16 */\
31                  | RBIT_TMR_FRR        /* restart timer after ref reached */\
32                  | RBIT_TMR_ORI)       /* enable interrupt when ref reached */
33#define TRR1_VAL 1000                   /* 1000 ticks @ 16MHz/16
34                                         *    = 1 millisecond tick.
35                                         */
36
37/*
38 *  Clock_driver_ticks is a monotonically increasing counter of the
39 *  number of clock ticks since the driver was initialized.
40 */
41volatile rtems_unsigned32 Clock_driver_ticks;
42
43/*
44 *  Clock_isrs is the number of clock ISRs until the next invocation of
45 *  the RTEMS clock tick routine.  The clock tick device driver
46 *  gets an interrupt once a millisecond and counts down until the
47 *  length of time between the user configured microseconds per tick
48 *  has passed.
49 */
50rtems_unsigned32 Clock_isrs;
51
52void Clock_exit( void );
53 
54/*
55 * These are set by clock driver during its init
56 */
57 
58rtems_device_major_number rtems_clock_major = ~0;
59rtems_device_minor_number rtems_clock_minor;
60
61/*
62 *  ISR Handler
63 */
64
65rtems_isr Clock_isr(
66  rtems_vector_number vector
67)
68{
69  Clock_driver_ticks += 1;
70
71  m302.reg.isr  = RBIT_ISR_TIMER1;      /* clear in-service bit */
72  m302.reg.ter1 = (RBIT_TER_REF | RBIT_TER_CAP); /* clear timer intr request */
73
74  if ( Clock_isrs == 1 ) {
75    rtems_clock_tick();
76    Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000;
77  }
78  else
79    Clock_isrs -= 1;
80}
81
82void Install_clock(
83  rtems_isr_entry clock_isr
84)
85{
86
87  Clock_driver_ticks = 0;
88  Clock_isrs = BSP_Configuration.microseconds_per_tick / 1000;
89
90  if ( BSP_Configuration.ticks_per_timeslice ) {
91   set_vector( clock_isr, CLOCK_VECTOR, 1 );
92
93    m302.reg.trr1 = TRR1_VAL;           /* set timer reference register */
94    m302.reg.tmr1 = TMR1_VAL;           /* set timer mode register & enable */
95    /*
96     * Enable TIMER1 interrupts only.
97     */
98    m302.reg.imr  = RBIT_IMR_TIMER1;    /* set 68302 int-mask to allow ints */
99
100    atexit( Clock_exit );
101  }
102}
103
104void Clock_exit( void )
105{
106  if ( BSP_Configuration.ticks_per_timeslice ) {
107    /* TODO: figure out what to do here */
108    /* do not restore old vector */
109  }
110}
111
112rtems_device_driver Clock_initialize(
113  rtems_device_major_number major,
114  rtems_device_minor_number minor,
115  void *pargp
116)
117{
118  Install_clock( Clock_isr );
119 
120  /*
121   * make major/minor avail to others such as shared memory driver
122   */
123 
124  rtems_clock_major = major;
125  rtems_clock_minor = minor;
126 
127  return RTEMS_SUCCESSFUL;
128}
129 
130rtems_device_driver Clock_control(
131  rtems_device_major_number major,
132  rtems_device_minor_number minor,
133  void *pargp
134)
135{
136    rtems_unsigned32 isrlevel;
137    rtems_libio_ioctl_args_t *args = pargp;
138 
139    if (args == 0)
140        goto done;
141 
142    /*
143     * This is hokey, but until we get a defined interface
144     * to do this, it will just be this simple...
145     */
146 
147    if (args->command == rtems_build_name('I', 'S', 'R', ' '))
148    {
149        Clock_isr( CLOCK_VECTOR);
150    }
151    else if (args->command == rtems_build_name('N', 'E', 'W', ' '))
152    {
153      rtems_interrupt_disable( isrlevel );
154       (void) set_vector( args->buffer, CLOCK_VECTOR, 1 );
155      rtems_interrupt_enable( isrlevel );
156    }
157 
158done:
159    return RTEMS_SUCCESSFUL;
160}
161
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