Add rtask module.

[bertos.git] / bertos / kern / rtask.c

diff --git a/bertos/kern/rtask.c b/bertos/kern/rtask.c
new file mode 100644 (file)
index 0000000..dddbd6d
--- /dev/null
+++ b/bertos/kern/rtask.c
@@ -0,0 +1,153 @@
+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2010 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief Recurrent task module implementation.
+ *
+ * \author Luca Ottaviano <lottaviano@develer.com>
+ * \author Francesco Sacchi <batt@develer.com>
+ *
+ */
+
+#include "rtask.h"
+#include "cfg/cfg_rtask.h"
+#include <cfg/module.h> // MOD_CHECK
+
+#define LOG_LEVEL RTASK_LOG_LEVEL
+#define LOG_FORMAT RTASK_LOG_FORMAT
+#include <cfg/log.h>
+
+#include <drv/timer.h>
+
+#include <struct/pool.h>
+#include <struct/list.h>
+
+#include <kern/proc.h>
+#include <kern/signal.h>
+#include <kern/sem.h>
+
+#define NEW_TASK SIG_USER0
+
+// TODO: Mixing static and dynamic tests in kernel must be tested with care,
+// until then use this workaround
+#if CONFIG_KERN_HEAP
+       #define PROC_NEW() proc_new(rtask_proc, NULL, CONFIG_RTASK_STACK, NULL)
+#else
+       PROC_DEFINE_STACK(rtask_stack, CONFIG_RTASK_STACK);
+       #define PROC_NEW() proc_new(rtask_proc, NULL, sizeof(rtask_stack), rtask_stack)
+#endif
+
+
+struct RTask
+{
+       Timer t;
+       rtask_cb_t callback;
+       void *user_data;
+};
+
+DECLARE_POOL_STATIC(rtask_pool, RTask, CONFIG_RTASK_POOL_SIZE);
+static Process *process = NULL;
+static List rt_list;
+static Semaphore rtask_sem;
+#define RTASK_ATOMIC(code) \
+       do {                         \
+               sem_obtain(&rtask_sem);  \
+               code;                    \
+               sem_release(&rtask_sem); \
+       } while (0)
+
+#warning "Remove synctimer_poll and use a list directly"
+static NORETURN void rtask_proc(void)
+{
+       while (1)
+       {
+               bool empty;
+               RTASK_ATOMIC(
+                       empty = LIST_EMPTY(&rt_list);
+                       sig_check(NEW_TASK);
+               );
+               if (empty)
+                       sig_wait(NEW_TASK);
+
+               ticks_t delay;
+               RTASK_ATOMIC(delay = synctimer_nextTimeout(&rt_list));
+               timer_delayTicks(delay);
+               RTASK_ATOMIC(synctimer_poll(&rt_list));
+       }
+}
+
+static void rtask_trampoline(void *_rtask)
+{
+       // Access the pool and the list freely since this callback is called
+       // with the semaphore held in rtask_proc.
+       RTask *rtask = _rtask;
+       if (rtask->callback(rtask->user_data))
+               synctimer_readd(&rtask->t, &rt_list);
+       else
+               pool_free(&rtask_pool, rtask);
+}
+
+RTask *rtask_add(rtask_cb_t cb, mtime_t delay, void *cb_data)
+{
+       // Beware: this function is called from a different process
+       // than rtask_proc, so each access to rtask_pool and rt_list
+       // must be protected with a semaphore.
+
+       // The semaphore is not yet initialized, disable preemption
+       // altogether.
+       proc_forbid();
+       if (UNLIKELY(process == NULL))
+       {
+               MOD_CHECK(proc);
+
+               LIST_INIT(&rt_list);
+               pool_init(rtask_pool, NULL);
+               sem_init(&rtask_sem);
+               process = PROC_NEW();
+               ASSERT(process);
+       }
+       proc_permit();
+
+       RTask *rt = NULL;
+       RTASK_ATOMIC(rt = (RTask *)pool_alloc(&rtask_pool));
+       if (rt)
+       {
+               rt->callback = cb;
+               rt->user_data = cb_data;
+               timer_setSoftint(&rt->t, rtask_trampoline, rt);
+               timer_setDelay(&rt->t, delay);
+               RTASK_ATOMIC(synctimer_add(&rt->t, &rt_list));
+               sig_send(process, NEW_TASK);
+       }
+       else
+               LOG_ERR("Failed to allocate RTask\n");
+       return rt;
+}