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
|
// Copyright 2003 John Kasunich
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
/*
slave.c
Set up a periodic task that gives a semaphore every several
task cycles. Load this after master task, since that defines
the global semaphore 'master_sem'.
*/
#include "rtapi.h"
#include "rtapi_app.h" /* rtapi_app_main,exit() */
#include "common.h" /* semaphore key */
static int module;
static int slave_sem; /* the semaphore ID */
static int slave_task; /* the task ID */
static unsigned int slave_count = 0;
enum { SLAVE_STACKSIZE = 1024 }; /* how big the stack is */
/* task code, executed when semaphore is released by master task */
void slave_code(void *arg)
{
while (1) {
rtapi_sem_take(slave_sem);
slave_count++;
rtapi_print("slave: got sem, count = %d\n", slave_count);
}
return;
}
/* part of the Linux kernel module that kicks off the timer task */
int rtapi_app_main(void)
{
int retval;
int slave_prio;
module = rtapi_init("SEM_SLAVE");
if (module < 0) {
rtapi_print("sem slave init: rtapi_init returned %d\n", module);
return -1;
}
/* open the semaphore */
slave_sem = rtapi_sem_new(SEM_KEY, module);
if (slave_sem < 0) {
rtapi_print("sem slave init: rtapi_sem_new returned %d\n", slave_sem);
rtapi_exit(module);
return -1;
}
/* set the task priority to the lowest one; the master is higher */
slave_prio = rtapi_prio_lowest();
/* create the slave task */
slave_task = rtapi_task_new(slave_code, 0 /* arg */ , slave_prio, module,
SLAVE_STACKSIZE, RTAPI_NO_FP);
if (slave_task < 0) {
rtapi_print("sem slave init: rtapi_task_new returned %d\n",
slave_task);
rtapi_exit(module);
return -1;
}
/* start the slave task */
retval = rtapi_task_resume(slave_task);
if (retval < 0) {
rtapi_print("sem slave init: rtapi_task_start returned %d\n", retval);
rtapi_exit(module);
return -1;
}
rtapi_print("sem slave init: started slave task\n");
return 0;
}
/* part of the Linux kernel module that stops the slave task */
void rtapi_app_exit(void)
{
int retval;
retval = rtapi_task_pause(slave_task);
if (retval < 0) {
rtapi_print("sem slave exit: rtapi_task_stop returned %d\n", retval);
}
retval = rtapi_task_delete(slave_task);
if (retval < 0) {
rtapi_print("sem slave exit: rtapi_task_delete returned %d\n",
retval);
}
retval = rtapi_sem_delete(slave_sem, module);
if (retval < 0) {
rtapi_print("sem slave exit: rtapi_sem_delete returned %d\n", retval);
}
rtapi_print("sem slave exit: slave count is %d\n", slave_count);
rtapi_exit(module);
}
|
