4 * This file is part of BeRTOS.
6 * Bertos is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 * As a special exception, you may use this file as part of a free software
21 * library without restriction. Specifically, if other files instantiate
22 * templates or use macros or inline functions from this file, or you compile
23 * this file and link it with other files to produce an executable, this
24 * file does not by itself cause the resulting executable to be covered by
25 * the GNU General Public License. This exception does not however
26 * invalidate any other reasons why the executable file might be covered by
27 * the GNU General Public License.
29 * Copyright 2003, 2004, 2005, 2006 Develer S.r.l. (http://www.develer.com/)
30 * Copyright 2000, 2008 Bernie Innocenti <bernie@codewiz.org>
33 * \brief Hardware independent timer driver (implementation)
35 * \author Bernie Innocenti <bernie@codewiz.org>
36 * \author Francesco Sacchi <batt@develer.com>
40 #include "hw/hw_timer.h"
42 #include "cfg/cfg_timer.h"
43 #include "cfg/cfg_wdt.h"
44 #include "cfg/cfg_proc.h"
45 #include "cfg/cfg_signal.h"
47 #include <cfg/debug.h>
48 #include <cfg/module.h>
51 #include <cpu/types.h>
53 #include <cpu/power.h> // cpu_relax()
55 #include <kern/proc_p.h> // proc_decQuantun()
58 * Include platform-specific binding code if we're hosted.
59 * Try the CPU specific one for bare-metal environments.
62 //#include OS_CSOURCE(timer)
63 #include <emul/timer_posix.c>
66 #warning Deprecated: now you should include timer_<cpu> directly in the makefile. Remove this line and the following once done.
67 #include CPU_CSOURCE(timer)
72 * Sanity check for config parameters required by this module.
74 #if !defined(CONFIG_KERN) || ((CONFIG_KERN != 0) && CONFIG_KERN != 1)
75 #error CONFIG_KERN must be set to either 0 or 1 in config.h
77 #if !defined(CONFIG_WATCHDOG) || ((CONFIG_WATCHDOG != 0) && CONFIG_WATCHDOG != 1)
78 #error CONFIG_WATCHDOG must be set to either 0 or 1 in config.h
85 #if defined (CONFIG_KERN_SIGNALS) && CONFIG_KERN_SIGNALS
86 #include <kern/signal.h> /* sig_wait(), sig_check() */
87 #include <kern/proc.h> /* proc_current() */
88 #include <cfg/macros.h> /* BV() */
93 * \def CONFIG_TIMER_STROBE
95 * This is a debug facility that can be used to
96 * monitor timer interrupt activity on an external pin.
98 * To use strobes, redefine the macros TIMER_STROBE_ON,
99 * TIMER_STROBE_OFF and TIMER_STROBE_INIT and set
100 * CONFIG_TIMER_STROBE to 1.
102 #if !defined(CONFIG_TIMER_STROBE) || !CONFIG_TIMER_STROBE
103 #define TIMER_STROBE_ON do {/*nop*/} while(0)
104 #define TIMER_STROBE_OFF do {/*nop*/} while(0)
105 #define TIMER_STROBE_INIT do {/*nop*/} while(0)
109 /// Master system clock (1 tick accuracy)
110 volatile ticks_t _clock;
113 #if CONFIG_TIMER_EVENTS
116 * List of active asynchronous timers.
118 REGISTER static List timers_queue;
121 * This function really does the job. It adds \a timer to \a queue.
122 * \see timer_add for details.
124 INLINE void timer_addToList(Timer *timer, List *queue)
126 /* Inserting timers twice causes mayhem. */
127 ASSERT(timer->magic != TIMER_MAGIC_ACTIVE);
128 DB(timer->magic = TIMER_MAGIC_ACTIVE;)
131 * Search for the first node whose expiration time is
132 * greater than the timer we want to add.
134 Timer *node = (Timer *)LIST_HEAD(queue);
135 while (node->link.succ)
138 * Stop just after the insertion point.
139 * (this fancy compare takes care of wrap-arounds).
141 if (node->tick - timer->tick > 0)
144 /* Go to next node */
145 node = (Timer *)node->link.succ;
148 /* Enqueue timer request into the list */
149 INSERT_BEFORE(&timer->link, &node->link);
153 * Add the specified timer to the software timer service queue.
154 * When the delay indicated by the timer expires, the timer
155 * device will execute the event associated with it.
157 * \note Interrupt safe
159 void timer_add(Timer *timer)
162 /* Calculate expiration time for this timer */
163 timer->tick = _clock + timer->_delay;
165 timer_addToList(timer, &timers_queue);
170 * Remove a timer from the timers queue before it has expired.
172 * \note Attempting to remove a timer already expired cause
173 * undefined behaviour.
175 Timer *timer_abort(Timer *timer)
177 ATOMIC(REMOVE(&timer->link));
178 DB(timer->magic = TIMER_MAGIC_INACTIVE;)
184 INLINE void timer_poll(List *queue)
189 * Check the first timer request in the list and process
190 * it when it has expired. Repeat this check until the
191 * first node has not yet expired. Since the list is sorted
192 * by expiry time, all the following requests are guaranteed
195 while ((timer = (Timer *)LIST_HEAD(queue))->link.succ)
197 /* This request in list has not yet expired? */
198 if (timer_clock() - timer->tick < 0)
201 /* Retreat the expired timer */
202 REMOVE(&timer->link);
203 DB(timer->magic = TIMER_MAGIC_INACTIVE;)
205 /* Execute the associated event */
206 event_do(&timer->expire);
211 * Add \a timer to \a queue.
212 * \see synctimer_poll() for details.
214 void synctimer_add(Timer *timer, List *queue)
216 timer->tick = timer_clock() + timer->_delay;
218 timer_addToList(timer, queue);
221 void synctimer_readd(Timer *timer, List *queue)
223 timer->tick += timer->_delay;
224 timer_addToList(timer, queue);
229 * Simple synchronous timer based scheduler polling routine.
231 * Sometimes you would like to have a proper scheduler,
232 * but you can't afford it due to memory constraints.
234 * This is a simple replacement: you can create events and call
235 * them periodically at specific time intervals.
236 * All you have to do is to set up normal timers, and call synctimer_add()
237 * instead of timer_add() to add the events to your specific queue.
238 * Then, in the main loop or wherever you want, you can call
239 * synctimer_poll() to process expired events. The associated callbacks will be
241 * As this is done synchronously you don't have to worry about race conditions.
242 * You can kill an event by simply calling synctimer_abort().
245 void synctimer_poll(List *queue)
250 #endif /* CONFIG_TIMER_EVENTS */
254 * Wait for the specified amount of timer ticks.
256 * \note Sleeping while preemption is disabled fallbacks to a busy wait sleep.
258 void timer_delayTicks(ticks_t delay)
260 /* We shouldn't sleep with interrupts disabled */
261 IRQ_ASSERT_ENABLED();
263 #if CONFIG_KERN_SIGNALS
265 DB(t.magic = TIMER_MAGIC_INACTIVE;)
266 if (proc_preemptAllowed())
268 ASSERT(!sig_check(SIG_SINGLE));
269 timer_setSignal(&t, proc_current(), SIG_SINGLE);
270 timer_setDelay(&t, delay);
272 sig_wait(SIG_SINGLE);
275 #endif /* !CONFIG_KERN_SIGNALS */
277 ticks_t start = timer_clock();
280 while (timer_clock() - start < delay)
286 #if CONFIG_TIMER_UDELAY
289 * Busy wait until the specified amount of high-precision ticks have elapsed.
291 * \note This function is interrupt safe, the only
292 * requirement is a running hardware timer.
294 void timer_busyWait(hptime_t delay)
296 hptime_t now, prev = timer_hw_hpread();
301 now = timer_hw_hpread();
303 * The timer counter may wrap here and "prev" can become
304 * greater than "now". So, be sure to always evaluate a
305 * coherent timer difference:
307 * 0 prev now TIMER_HW_CNT
308 * |_____|_______________|_____|
312 * 0 now prev TIMER_HW_CNT
313 * |_____|_______________|_____|
315 * delta = (TIMER_HW_CNT - prev) + now
317 * NOTE: TIMER_HW_CNT can be any value, not necessarily a power
318 * of 2. For this reason the "%" operator is not suitable for
321 delta = (now < prev) ? ((hptime_t)TIMER_HW_CNT - prev + now) :
331 * Wait for the specified amount of time (expressed in microseconds).
333 * \bug In AVR arch the maximum amount of time that can be used as
334 * delay could be very limited, depending on the hardware timer
335 * used. Check timer_avr.h, and what register is used as hptime_t.
337 void timer_delayHp(hptime_t delay)
339 if (UNLIKELY(delay > us_to_hptime(1000)))
341 timer_delayTicks(delay / (TIMER_HW_HPTICKS_PER_SEC / TIMER_TICKS_PER_SEC));
342 delay %= (TIMER_HW_HPTICKS_PER_SEC / TIMER_TICKS_PER_SEC);
345 timer_busyWait(delay);
347 #endif /* CONFIG_TIMER_UDELAY */
350 * Timer interrupt handler. Find soft timers expired and
351 * trigger corresponding events.
356 * With the Metrowerks compiler, the only way to force the compiler generate
357 * an interrupt service routine is to put a pragma directive within the function
361 #pragma interrupt saveall
365 * On systems sharing IRQ line and vector, this check is needed
366 * to ensure that IRQ is generated by timer source.
368 if (!timer_hw_triggered())
373 /* Update the master ms counter */
376 /* Update the current task's quantum (if enabled). */
379 #if CONFIG_TIMER_EVENTS
380 timer_poll(&timers_queue);
383 /* Perform hw IRQ handling */
394 void timer_init(void)
400 #if CONFIG_TIMER_EVENTS
401 LIST_INIT(&timers_queue);
414 #if (ARCH & ARCH_EMUL) || (CPU_ARM_AT91)
418 void timer_cleanup(void)