Document AVR dependency.

[bertos.git] / drv / timer.h

diff --git a/drv/timer.h b/drv/timer.h
index 88d9f2496fd061359adbc347b688f11eb16101af..da5a5d1c87ec3e544f7165c44eefa80918c861c9 100755 (executable)
--- a/drv/timer.h
+++ b/drv/timer.h
@@ -1,7 +1,7 @@
 /*!
  * \file
  * <!--
- * Copyright 2003,2004 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
  * Copyright 2000 Bernardo Innocenti <bernie@develer.com>
  * This file is part of DevLib - See devlib/README for information.
  * -->
@@ -15,6 +15,15 @@
 
 /*
  * $Log$
+ * Revision 1.10  2004/07/21 00:13:57  bernie
+ * Put timer driver on diet.
+ *
+ * Revision 1.9  2004/07/20 23:45:01  bernie
+ * Finally remove redundant protos.
+ *
+ * Revision 1.8  2004/07/18 21:57:32  bernie
+ * timer_gettick(): Rename to timer_tick() and document better.
+ *
  * Revision 1.7  2004/06/27 15:26:17  aleph
  * Declaration fix for build with GCC 3.4
  *
@@ -43,11 +52,34 @@
 #include "cpu.h"
 #include "compiler.h"
 #include <mware/list.h>
-#include <kern/event.h>
 
 /*! Number of timer ticks per second. */
 #define TICKS_PER_SEC       1000
 
+/* Function protos */
+extern void timer_init(void);
+extern void timer_delay(time_t time);
+
+#ifndef CONFIG_TIMER_DISABLE_UDELAY
+extern void timer_udelay(utime_t utime);
+#endif
+
+
+#ifndef CONFIG_TIMER_DISABLE_EVENTS
+
+#ifdef CONFIG_KERNEL
+       #include <kern/event.h>
+#else
+       #include <mware/event.h>
+#endif
+
+/*!
+ * The timer driver supports multiple ssynchronous timers
+ * that can trigger an event when they expire.
+ *
+ * \sa timer_add()
+ * \sa timer_abort()
+ */
 typedef struct Timer
 {
        Node   link;      /*!< Link into timers queue */
@@ -56,21 +88,12 @@ typedef struct Timer
        Event  expire;    /*!< Event to execute when the timer expires */
 } Timer;
 
-/* Function protos */
-extern void timer_init(void);
 extern void timer_add(Timer *timer);
 extern Timer *timer_abort(Timer *timer);
-extern void timer_delay(time_t time);
-extern void timer_udelay(utime_t utime);
-INLINE time_t timer_gettick(void);
-INLINE time_t timer_gettick_irq(void);
-INLINE void timer_set_event_softint(Timer* timer, Hook func, void* user_data);
-INLINE void timer_set_delay(Timer* timer, time_t delay);
 
 #if defined(CONFIG_KERN_SIGNALS) && CONFIG_KERN_SIGNALS
 
 /*! Set the timer so that it sends a signal when it expires */
-INLINE void timer_set_event_signal(Timer* timer, struct Process* proc, sigset_t sigs);
 INLINE void timer_set_event_signal(Timer* timer, struct Process* proc, sigset_t sigs)
 {
        event_initSignal(&timer->expire, proc, sigs);
@@ -90,16 +113,35 @@ INLINE void timer_set_delay(Timer* timer, time_t delay)
        timer->delay = delay;
 }
 
+#endif /* CONFIG_TIMER_DISABLE_EVENTS */
 
 extern volatile time_t _clock;
 
 /*!
- * Return the system tick counter (expressed in ms)
- * This function must disable interrupts on 8/16bit CPUs because the
+ * \brief Return the system tick counter (expressed in ms)
+ *
+ * The result is guaranteed to increment monotonically,
+ * but client code must be tolerant with respect to overflows.
+ *
+ * The following code is safe:
+ *
+ * \example
+ *   time_t tea_start_time = get_tick();
+ *
+ *   boil_water();
+ *
+ *   if (get_tick() - tea_start_time > TEAPOT_DELAY)
+ *       printf("Your tea, Sir.\n");
+ * \endexample
+ *
+ * When the tick counter increments every millisecond and time_t
+ * is 32bit wide, the tick count will overflow every 49.7 days.
+ *
+ * \note This function must disable interrupts on 8/16bit CPUs because the
  * clock variable is larger than the processor word size and can't
  * be copied atomically.
  */
-INLINE time_t timer_gettick(void)
+INLINE time_t timer_tick(void)
 {
        time_t result;
        cpuflags_t flags;
@@ -111,15 +153,24 @@ INLINE time_t timer_gettick(void)
        return result;
 }
 
+/* OBSOLETE */
+#define timer_gettick timer_tick
+
 
 /*!
- * Like \c timer_gettick, faster version to be called
- * from interrupt context only.
+ * Faster version of timer_tick(), to be called only when the timer
+ * interrupt is disabled (DISABLE_INTS) or overridden by a
+ * higher-priority or non-nesting interrupt.
+ *
+ * \sa timer_tick
  */
-INLINE time_t timer_gettick_irq(void)
+INLINE time_t timer_tick_unlocked(void)
 {
        return _clock;
 }
 
+/* OBSOLETE */
+#define timer_gettick_irq timer_tick_unlocked
+
 #endif /* DRV_TIMER_H */