source: rtems/c/src/lib/libbsp/m68k/idp/clock/ckinit.c @ c3db3251

4.104.114.84.9
Last change on this file since c3db3251 was c3db3251, checked in by Joel Sherrill <joel.sherrill@…>, on Sep 4, 2003 at 6:51:54 PM

2003-09-04 Joel Sherrill <joel@…>

  • clock/ckinit.c, startup/bspstart.c, timer/timer.c, timer/timerisr.S: URL for license changed.
  • Property mode set to 100644
File size: 4.7 KB
Line 
1/*  Clock_init()
2 *
3 *
4 *  This is modified by Doug McBride to get it to work for the MC68EC040
5 *  IDP board.  The below comments are kept to show that some prior work
6 *  was done in the area and the modifications performed was application
7 *  specific for the IDP board to port it to.
8 *
9 *  This routine initializes the mc68230 on the MC68EC040 board.
10 *  The tick frequency is 40 milliseconds.
11 *
12 *  Input parameters:  NONE
13 *
14 *  Output parameters:  NONE
15 *
16 *  COPYRIGHT (c) 1989-1999.
17 *  On-Line Applications Research Corporation (OAR).
18 *
19 *  The license and distribution terms for this file may be
20 *  found in the file LICENSE in this distribution or at
21 *  http://www.rtems.com/license/LICENSE.
22 *
23 *  $Id$
24 */
25
26#include <stdlib.h>
27
28#include <bsp.h>
29#include <rtems/libio.h>
30
31rtems_unsigned32 Clock_isrs;        /* ISRs until next tick */
32volatile rtems_unsigned32 Clock_driver_ticks;
33                                    /* ticks since initialization */
34rtems_isr_entry  Old_ticker;
35
36extern rtems_configuration_table Configuration;
37extern void led_putnum();
38void Disable_clock();
39
40#define CLOCK_VECTOR 0x4D
41
42void Clock_exit( void );
43 
44/*
45 * These are set by clock driver during its init
46 */
47 
48rtems_device_major_number rtems_clock_major = ~0;
49rtems_device_minor_number rtems_clock_minor;
50 
51
52/*
53 *  ISR Handler
54 *
55 *
56 * ((1ms * 6.5 MHz) / 2^5) = 203.125) where 6.5 MHz is the clock rate of the
57 * MC68230, 2^5 is the prescaler factor, and 1ms is the common interrupt
58 * interval for the Clock_isr routine.
59 * Therefore, 203 (decimal) is the number to program into the CPRH-L registers
60 * of the MC68230 for countdown.  However, I have found that 193 instead of
61 * 203 provides greater accuracy -- why?  The crystal should be more accurate
62 * than that
63 */
64
65rtems_isr Clock_isr(
66  rtems_vector_number vector
67)
68{
69  Clock_driver_ticks += 1;
70  /* acknowledge interrupt
71        TSR = 1; */
72  MC68230_WRITE (TSR, 1);
73
74  if ( Clock_isrs == 1 ) {
75    rtems_clock_tick();
76        /* Cast to an integer so that 68EC040 IDP which doesn't have an FPU doesn't
77           have a heart attack -- if you use newlib1.6 or greater and get
78           libgcc.a for gcc with software floating point support, this is not
79           a problem */
80    Clock_isrs = 
81      (int)(BSP_Configuration.microseconds_per_tick / 1000);
82  }
83  else 
84    Clock_isrs -= 1;
85}
86
87void Disable_clock()
88{
89        /* Disable timer */
90        MC68230_WRITE (TCR, 0x00);
91}
92
93void Install_clock( clock_isr )
94rtems_isr_entry clock_isr;
95{
96  Clock_driver_ticks = 0;
97  Clock_isrs = (int)(Configuration.microseconds_per_tick / 1000);
98
99/*    led_putnum('c'); * for debugging purposes */
100    Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 );
101
102  /* Disable timer for initialization */
103  MC68230_WRITE (TCR, 0x00);
104
105  /* some PI/T initialization stuff here -- see comment in the ckisr.c
106     file in this directory to understand why I use the values that I do */
107  /* Set up the interrupt vector on the MC68230 chip:
108  TIVR = CLOCK_VECTOR; */
109  MC68230_WRITE (TIVR, CLOCK_VECTOR);
110
111  /* Set CPRH through CPRL to 193 (not 203) decimal for countdown--see ckisr.c
112        CPRH = 0x00;
113        CPRM = 0x00;
114        CPRL = 0xC1; */
115  MC68230_WRITE (CPRH, 0x00);
116  MC68230_WRITE (CPRM, 0x00);
117  MC68230_WRITE (CPRL, 0xC1);
118
119  /* Enable timer and use it as an external periodic interrupt generator
120        TCR = 0xA1; */
121/*    led_putnum('a'); * for debugging purposes */
122  MC68230_WRITE (TCR, 0xA1);
123
124  /*
125   *  Schedule the clock cleanup routine to execute if the application exits.
126   */
127  atexit( Clock_exit );
128}
129
130/* The following was added for debugging purposes */
131void Clock_exit( void )
132{
133  rtems_unsigned8 data;
134
135  /* disable timer
136        data = TCR;
137        TCR = (data & 0xFE); */
138  MC68230_READ (TCR, data);
139  MC68230_WRITE (TCR, (data & 0xFE));
140
141  /* do not restore old vector */
142}
143
144rtems_device_driver Clock_initialize(
145  rtems_device_major_number major,
146  rtems_device_minor_number minor,
147  void *pargp
148)
149{
150  Install_clock( Clock_isr );
151 
152  /*
153   * make major/minor avail to others such as shared memory driver
154   */
155 
156  rtems_clock_major = major;
157  rtems_clock_minor = minor;
158 
159  return RTEMS_SUCCESSFUL;
160}
161 
162rtems_device_driver Clock_control(
163  rtems_device_major_number major,
164  rtems_device_minor_number minor,
165  void *pargp
166)
167{
168    rtems_unsigned32 isrlevel;
169    rtems_libio_ioctl_args_t *args = pargp;
170 
171    if (args == 0)
172        goto done;
173 
174    /*
175     * This is hokey, but until we get a defined interface
176     * to do this, it will just be this simple...
177     */
178 
179    if (args->command == rtems_build_name('I', 'S', 'R', ' '))
180    {
181        Clock_isr(CLOCK_VECTOR);
182    }
183    else if (args->command == rtems_build_name('N', 'E', 'W', ' '))
184    {
185      rtems_interrupt_disable( isrlevel );
186       (void) set_vector( args->buffer, CLOCK_VECTOR, 1 );
187      rtems_interrupt_enable( isrlevel );
188    }
189 
190done:
191    return RTEMS_SUCCESSFUL;
192}
193
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