From 22441375bb2253b0f1f82f6ef5e4d6fb4cade0dd Mon Sep 17 00:00:00 2001
From: Stefan Lankes <lankes@lfbs.rwth-aachen.de>
Date: Wed, 3 Aug 2011 21:41:06 +0200
Subject: [PATCH] add blocking timers

only the idle tasks use the polling mode
---
 arch/x86/kernel/timer.c | 56 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 47 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/timer.c b/arch/x86/kernel/timer.c
index 251f71f8..66c4ac82 100644
--- a/arch/x86/kernel/timer.c
+++ b/arch/x86/kernel/timer.c
@@ -23,17 +23,26 @@
 #include <metalsvm/time.h>
 #include <metalsvm/processor.h>
 #include <metalsvm/errno.h>
+#include <metalsvm/spinlock.h>
 #include <asm/irq.h>
 #include <asm/irqflags.h>
 #include <asm/gdt.h>
 #include <asm/tss.h>
 #include <asm/vga.h>
 
+typedef struct {
+	uint8_t active;
+	uint64_t timeout;
+} timer_t;
+
+static timer_t timers[MAX_TASKS] = {[0 ... MAX_TASKS-1] = {0, 0}};
+static spinlock_irqsave_t timers_lock = SPINLOCK_IRQSAVE_INIT;
+
 /* 
  * This will keep track of how many ticks the system
  * has been running for 
  */
-static volatile uint64_t timer_ticks __attribute__ ((aligned (CACHE_LINE))) = 0;
+static volatile uint64_t timer_ticks = 0;
 
 uint64_t get_clock_tick(void)
 {
@@ -60,13 +69,24 @@ int sys_times(struct tms* buffer, clock_t* clock)
  */
 static void timer_handler(struct state *s)
 {
+	uint32_t i;
+
 	/* Increment our 'tick counter' */
 #if MAX_CORES > 1
 	if (smp_id() == 0)
-		timer_ticks++;
-#else
-	timer_ticks++;
 #endif
+	{
+		timer_ticks++;
+
+		spinlock_irqsave_lock(&timers_lock);
+		for(i=1; i<MAX_TASKS; i++) {
+			if (timers[i].active && (timer_ticks >= timers[i].timeout)) {
+				timers[i].active = 0;
+				wakeup_task(i);
+			}
+		}
+		spinlock_irqsave_unlock(&timers_lock);
+	}
 
 	/* 
 	 * Every TIMER_FREQ clocks (approximately 1 second), we will
@@ -84,15 +104,33 @@ static void timer_handler(struct state *s)
 void timer_wait(unsigned int ticks)
 {
 	uint64_t eticks = timer_ticks + ticks;
+	task_t* curr_task = per_core(current_task);
 
-	while (timer_ticks < eticks) {
+	// Task 0 is always an idle task
+	// Perhaps, the status is not set correctly...
+	if ((curr_task->status == TASK_IDLE) || (curr_task->id == 0))
+	{
+		while (timer_ticks < eticks) {
+			check_workqueues();
+
+			// recheck break condition
+			if (timer_ticks >= eticks)
+				break;
+
+			HALT;
+		}
+	} else if (timer_ticks < eticks) {
 		check_workqueues();
 
-		// recheck break condition
-		if (timer_ticks >= eticks)
-			break;
+		spinlock_irqsave_lock(&timers_lock);
+		if (timer_ticks < eticks) {
+			timers[curr_task->id].active = 1;
+			timers[curr_task->id].timeout = eticks;
+			block_task(curr_task->id);
+			spinlock_irqsave_unlock(&timers_lock);
 
-		reschedule();
+			reschedule();
+		} else spinlock_irqsave_unlock(&timers_lock);
 	}
 }