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103 lines
2.4 KiB
C
103 lines
2.4 KiB
C
/*
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pseudo.h (c) 1997-8 Grant R. Guenther <grant@torque.net>
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Under the terms of the GNU General Public License.
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This is the "pseudo-interrupt" logic for parallel port drivers.
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This module is #included into each driver. It makes one
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function available:
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ps_set_intr( void (*continuation)(void),
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int (*ready)(void),
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int timeout,
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int nice )
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Which will arrange for ready() to be evaluated frequently and
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when either it returns true, or timeout jiffies have passed,
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continuation() will be invoked.
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If nice is 1, the test will done approximately once a
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jiffy. If nice is 0, the test will also be done whenever
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the scheduler runs (by adding it to a task queue). If
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nice is greater than 1, the test will be done once every
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(nice-1) jiffies.
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*/
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/* Changes:
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1.01 1998.05.03 Switched from cli()/sti() to spinlocks
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1.02 1998.12.14 Added support for nice > 1
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*/
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#define PS_VERSION "1.02"
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#include <linux/sched.h>
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#include <linux/workqueue.h>
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static void ps_tq_int(struct work_struct *work);
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static void (* ps_continuation)(void);
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static int (* ps_ready)(void);
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static unsigned long ps_timeout;
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static int ps_tq_active = 0;
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static int ps_nice = 0;
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static DEFINE_SPINLOCK(ps_spinlock __attribute__((unused)));
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static DECLARE_DELAYED_WORK(ps_tq, ps_tq_int);
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static void ps_set_intr(void (*continuation)(void),
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int (*ready)(void),
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int timeout, int nice)
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{
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unsigned long flags;
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spin_lock_irqsave(&ps_spinlock,flags);
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ps_continuation = continuation;
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ps_ready = ready;
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ps_timeout = jiffies + timeout;
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ps_nice = nice;
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if (!ps_tq_active) {
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ps_tq_active = 1;
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if (!ps_nice)
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schedule_delayed_work(&ps_tq, 0);
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else
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schedule_delayed_work(&ps_tq, ps_nice-1);
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}
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spin_unlock_irqrestore(&ps_spinlock,flags);
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}
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static void ps_tq_int(struct work_struct *work)
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{
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void (*con)(void);
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unsigned long flags;
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spin_lock_irqsave(&ps_spinlock,flags);
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con = ps_continuation;
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ps_tq_active = 0;
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if (!con) {
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spin_unlock_irqrestore(&ps_spinlock,flags);
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return;
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}
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if (!ps_ready || ps_ready() || time_after_eq(jiffies, ps_timeout)) {
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ps_continuation = NULL;
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spin_unlock_irqrestore(&ps_spinlock,flags);
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con();
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return;
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}
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ps_tq_active = 1;
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if (!ps_nice)
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schedule_delayed_work(&ps_tq, 0);
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else
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schedule_delayed_work(&ps_tq, ps_nice-1);
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spin_unlock_irqrestore(&ps_spinlock,flags);
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}
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/* end of pseudo.h */
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