X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fkern%2Fpreempt.c;h=7ecd481d0cdf57c6d4c3679fc4ccfa43f5cc794e;hb=cfa8814ca45e8bae9b36713bc534ecb581834016;hp=f068a8a82c24d314d159e84a045422de18b55475;hpb=87302355709b6d5ac0592024b84207ba86baa82e;p=bertos.git

diff --git a/bertos/kern/preempt.c b/bertos/kern/preempt.c
index f068a8a8..7ecd481d 100644
--- a/bertos/kern/preempt.c
+++ b/bertos/kern/preempt.c
@@ -26,27 +26,27 @@
  * invalidate any other reasons why the executable file might be covered by
  * the GNU General Public License.
  *
- * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
+ * Copyright 2008 Bernie Innocenti <bernie@codewiz.org>
  * -->
  *
- * \brief Simple realtime multitasking scheduler.
- *        Context switching is only done cooperatively.
+ * \brief Simple preemptive multitasking scheduler.
  *
  * \version $Id: proc.c 1616 2008-08-10 19:41:26Z bernie $
  * \author Bernie Innocenti <bernie@codewiz.org>
- * \author Stefano Fedrigo <aleph@develer.com>
  */
 
 #include "proc_p.h"
 #include "proc.h"
 
+#include <kern/irq.h>
+#include <kern/monitor.h>
+#include <cpu/frame.h> // CPU_IDLE
+#include <drv/timer.h>
+#include <cfg/module.h>
+
 
-/*
- * The time sharing scheduler forces a task switch when the current
- * process has exhausted its quantum.
- */
-uint16_t Quantum;
+
+Timer preempt_timer;
 
 /**
  * Disable preemptive task switching.
@@ -78,3 +78,100 @@ void proc_permit(void)
 	/* No need to protect against interrupts here. */
 	--CurrentProcess->forbid_cnt;
 }
+
+
+void proc_preempt(void)
+{
+	IRQ_DISABLE;
+
+	LIST_ASSERT_VALID(&ProcReadyList);
+	CurrentProcess = (struct Process *)list_remHead(&ProcReadyList);
+	LIST_ASSERT_VALID(&ProcReadyList);
+	ASSERT2(CurrentProcess, "no idle proc?");
+
+	IRQ_ENABLE;
+
+	TRACEMSG("new proc: %p:%s", CurrentProcess, CurrentProcess ? CurrentProcess->monitor.name : "---");
+	monitor_report();
+}
+
+void proc_preempt_timer(UNUSED_ARG(void *, param))
+{
+	IRQ_DISABLE;
+/*
+	if (!CurrentProcess->forbid_cnt)
+	{
+		TRACEMSG("preempting %p:%s", CurrentProcess, CurrentProcess->monitor.name);
+		LIST_ASSERT_VALID(&ProcReadyList);
+		SCHED_ENQUEUE(CurrentProcess);
+		proc_preempt();
+	}
+*/
+	IRQ_ENABLE;
+
+	timer_setDelay(&preempt_timer, CONFIG_KERN_QUANTUM);
+	timer_add(&preempt_timer);
+}
+
+void proc_schedule(void)
+{
+	TRACE;
+
+	// Will invoke proc_preempt() in interrupt context
+	kill(0, SIGUSR1);
+}
+
+void proc_yield(void)
+{
+	TRACE;
+
+	ASSERT_IRQ_ENABLED();
+	IRQ_DISABLE;
+	SCHED_ENQUEUE(CurrentProcess);
+	LIST_ASSERT_VALID(&ProcReadyList);
+	proc_schedule();
+	IRQ_ENABLE;
+}
+
+void proc_entry(void (*user_entry)(void))
+{
+	user_entry();
+	proc_exit();
+}
+
+
+static cpustack_t idle_stack[CONFIG_PROC_DEFSTACKSIZE / sizeof(cpustack_t)];
+
+/*
+ * The idle process
+ *
+ * This process never dies and never sleeps.  It's also quite apathic
+ * and a bit antisocial.
+ *
+ * Having an idle process costs some stack space, but simplifies the
+ * interrupt-driven preemption logic because there is always a user
+ * context to which we can return.
+ */
+static NORETURN void idle(void)
+{
+	for (;;)
+	{
+		TRACE;
+		monitor_report();
+		proc_yield(); // FIXME: CPU_IDLE
+	}
+}
+
+void preempt_init(void)
+{
+	MOD_CHECK(irq);
+	MOD_CHECK(timer);
+
+	irq_register(SIGUSR1, proc_preempt);
+
+	timer_setSoftint(&preempt_timer, proc_preempt_timer, NULL);
+	timer_setDelay(&preempt_timer, CONFIG_KERN_QUANTUM);
+	timer_add(&preempt_timer);
+
+	proc_new(idle, NULL, sizeof(idle_stack), idle_stack);
+}