1 files changed, 103 insertions, 0 deletions
diff --git a/kern/timer.h b/kern/timer.h
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index 00000000..46616686
--- /dev/null
+++ b/kern/timer.h
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+/*
+ * Copyright (c) 2017 Richard Braun.
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Low resolution timer system.
+ */
+
+#ifndef _KERN_TIMER_H
+#define _KERN_TIMER_H
+
+#include <stdint.h>
+
+#include <kern/init.h>
+
+/*
+ * Scheduling flags.
+ */
+#define TIMER_DETACHED      0x1     /* Timer completion isn't synchronized */
+#define TIMER_INTR          0x2     /* Handler is run from interrupt context */
+#define TIMER_HIGH_PRIO     0x4     /* Handler is run in high priority thread */
+
+struct timer;
+
+/*
+ * Type for timer functions.
+ */
+typedef void (*timer_fn_t)(struct timer *);
+
+#include <kern/timer_i.h>
+
+/*
+ * Return the absolute expiration time of the timer, in ticks.
+ */
+static inline uint64_t
+timer_get_time(const struct timer *timer)
+{
+    return timer->ticks; /* TODO atomic */
+}
+
+/*
+ * Initialize a timer.
+ *
+ * Timers that are reponsible for releasing their own resources must
+ * be detached.
+ */
+void timer_init(struct timer *timer, timer_fn_t fn, int flags);
+
+/*
+ * Schedule a timer.
+ *
+ * The time of expiration is an absolute time in ticks.
+ *
+ * Timers may safely be rescheduled after completion. Periodic timers are
+ * implemented by rescheduling from the handler.
+ *
+ * If the timer has been canceled, this function does nothing. A
+ * canceled timer must be reinitialized before being scheduled again.
+ */
+void timer_schedule(struct timer *timer, uint64_t ticks);
+
+/*
+ * Cancel a timer.
+ *
+ * The given timer must not be detached.
+ *
+ * If the timer has already expired, this function waits until the timer
+ * function completes, or returns immediately if the function has already
+ * completed.
+ *
+ * This function may safely be called from the timer handler, but not on
+ * the current timer. Canceling a timer from the handler is achieved by
+ * simply not rescheduling it.
+ */
+void timer_cancel(struct timer *timer);
+
+/*
+ * Report a periodic event on the current processor.
+ *
+ * Interrupts and preemption must be disabled when calling this function.
+ */
+void timer_report_periodic_event(void);
+
+/*
+ * This init operation provides :
+ *  - timer initialization and scheduling
+ *  - module fully initialized
+ */
+INIT_OP_DECLARE(timer_setup);
+
+#endif /* _KERN_TIMER_H */