File: /usr/src/linux/drivers/block/paride/pseudo.h
1 /*
2 pseudo.h (c) 1997-8 Grant R. Guenther <grant@torque.net>
3 Under the terms of the GNU General Public License.
4
5 This is the "pseudo-interrupt" logic for parallel port drivers.
6
7 This module is #included into each driver. It makes one
8 function available:
9
10 ps_set_intr( void (*continuation)(void),
11 int (*ready)(void),
12 int timeout,
13 int nice )
14
15 Which will arrange for ready() to be evaluated frequently and
16 when either it returns true, or timeout jiffies have passed,
17 continuation() will be invoked.
18
19 If nice is 1, the test will done approximately once a
20 jiffy. If nice is 0, the test will also be done whenever
21 the scheduler runs (by adding it to a task queue). If
22 nice is greater than 1, the test will be done once every
23 (nice-1) jiffies.
24
25 */
26
27 /* Changes:
28
29 1.01 1998.05.03 Switched from cli()/sti() to spinlocks
30 1.02 1998.12.14 Added support for nice > 1
31 */
32
33 #define PS_VERSION "1.02"
34
35 #include <linux/sched.h>
36 #include <linux/timer.h>
37 #include <linux/tqueue.h>
38
39 static void ps_timer_int( unsigned long data);
40 static void ps_tq_int( void *data);
41
42 static void (* ps_continuation)(void);
43 static int (* ps_ready)(void);
44 static int ps_then;
45 static int ps_timeout;
46 static int ps_timer_active = 0;
47 static int ps_tq_active = 0;
48 static int ps_nice = 0;
49
50 static spinlock_t ps_spinlock __attribute__((unused)) = SPIN_LOCK_UNLOCKED;
51
52 static struct timer_list ps_timer = { function: ps_timer_int };
53 static struct tq_struct ps_tq = { routine: ps_tq_int };
54
55 static void ps_set_intr( void (*continuation)(void),
56 int (*ready)(void),
57 int timeout, int nice )
58
59 { long flags;
60
61 spin_lock_irqsave(&ps_spinlock,flags);
62
63 ps_continuation = continuation;
64 ps_ready = ready;
65 ps_then = jiffies;
66 ps_timeout = jiffies + timeout;
67 ps_nice = nice;
68
69 if (!ps_nice && !ps_tq_active) {
70 #ifdef HAVE_DISABLE_HLT
71 disable_hlt();
72 #endif
73 ps_tq_active = 1;
74 schedule_task(&ps_tq);
75 }
76
77 if (!ps_timer_active) {
78 ps_timer_active = 1;
79 ps_timer.expires = jiffies + ((ps_nice>0)?(ps_nice-1):0);
80 add_timer(&ps_timer);
81 }
82
83 spin_unlock_irqrestore(&ps_spinlock,flags);
84 }
85
86 static void ps_tq_int( void *data )
87
88 { void (*con)(void);
89 long flags;
90
91 spin_lock_irqsave(&ps_spinlock,flags);
92
93 con = ps_continuation;
94
95 #ifdef HAVE_DISABLE_HLT
96 enable_hlt();
97 #endif
98
99 ps_tq_active = 0;
100
101 if (!con) {
102 spin_unlock_irqrestore(&ps_spinlock,flags);
103 return;
104 }
105 if (!ps_ready || ps_ready() || (jiffies >= ps_timeout)) {
106 ps_continuation = NULL;
107 spin_unlock_irqrestore(&ps_spinlock,flags);
108 con();
109 return;
110 }
111
112 #ifdef HAVE_DISABLE_HLT
113 disable_hlt();
114 #endif
115
116 ps_tq_active = 1;
117 schedule_task(&ps_tq);
118 spin_unlock_irqrestore(&ps_spinlock,flags);
119 }
120
121 static void ps_timer_int( unsigned long data)
122
123 { void (*con)(void);
124 long flags;
125
126 spin_lock_irqsave(&ps_spinlock,flags);
127
128 con = ps_continuation;
129 ps_timer_active = 0;
130 if (!con) {
131 spin_unlock_irqrestore(&ps_spinlock,flags);
132 return;
133 }
134 if (!ps_ready || ps_ready() || (jiffies >= ps_timeout)) {
135 ps_continuation = NULL;
136 spin_unlock_irqrestore(&ps_spinlock,flags);
137 con();
138 return;
139 }
140 ps_timer_active = 1;
141 ps_timer.expires = jiffies + ((ps_nice>0)?(ps_nice-1):0);
142 add_timer(&ps_timer);
143 spin_unlock_irqrestore(&ps_spinlock,flags);
144 }
145
146 /* end of pseudo.h */
147
148