From 311b32aef8cd42ea5877e4c61b270d0c4a170e1d Mon Sep 17 00:00:00 2001
From: stefan <stefan@315a16e6-25f9-4109-90ae-ca3045a26c18>
Date: Mon, 9 Aug 2010 15:43:45 +0000
Subject: [PATCH] - add macro for a static initialization of a semaphore -
 create a special process which reads the kernel messages from a buffer and
 dump them on the screen

git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@51 315a16e6-25f9-4109-90ae-ca3045a26c18
---
 include/metalsvm/semaphore.h |  2 ++
 kernel/main.c                |  2 +-
 libkern/stdio.c              | 35 +++++++++++++++++++++++++++--------
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/include/metalsvm/semaphore.h b/include/metalsvm/semaphore.h
index 1787d62a..7b708a06 100644
--- a/include/metalsvm/semaphore.h
+++ b/include/metalsvm/semaphore.h
@@ -35,6 +35,8 @@ typedef struct {
 	spinlock_t lock;
 } sem_t;
 
+#define SEM_INIT(v) {v, {[0 ... MAX_TASKS-1] = MAX_TASKS}, 0, SPINLOCK_INIT};
+
 inline static int sem_init(sem_t* s, unsigned int v) {
 	unsigned int i;
 
diff --git a/kernel/main.c b/kernel/main.c
index cd206b3c..cb3d1c59 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -192,13 +192,13 @@ int main(void)
 
 	system_init();
 	irq_init();
-	koutput_init();
 	timer_init();
 #ifdef CONFIG_KEYBOARD
 	keyboard_init();
 #endif
 	mmu_init();
 	multitasking_init();
+	koutput_init();
 
 	irq_enable();
 
diff --git a/libkern/stdio.c b/libkern/stdio.c
index 3ac198bb..f5a15f72 100644
--- a/libkern/stdio.c
+++ b/libkern/stdio.c
@@ -20,20 +20,41 @@
 #include <metalsvm/stdio.h>
 #include <metalsvm/string.h>
 #include <metalsvm/stdarg.h>
+#include <metalsvm/tasks.h>
+#include <metalsvm/semaphore.h>
 #include <asm/atomic.h>
 #ifdef CONFIG_VGA
 #include <asm/vga.h>
 #endif
 
 static atomic_int32_t kmsg_counter = ATOMIC_INIT(0);
-static unsigned char kmessages[KMSG_SIZE];
+static unsigned char kmessages[KMSG_SIZE] = {[0 ... KMSG_SIZE-1] = 0};
+
+#ifdef CONFIG_VGA
+static sem_t sem_output = SEM_INIT(0); 
+
+static int STDCALL output_task(void* arg)
+{
+	uint32_t rpos = 0;
+
+	do {
+		sem_wait(&sem_output);
+		vga_putchar((int) kmessages[rpos]);
+		rpos = (rpos + 1) % KMSG_SIZE;
+	} while(1);
+
+	return 0;
+}
+#endif
 
 int koutput_init(void)
 {
 #ifdef CONFIG_VGA
+	tid_t id;
+
 	vga_init();
+	create_kernel_task(&id, output_task, NULL);
 #endif
-	memset(kmessages, 0, sizeof(unsigned char)*KMSG_SIZE);
 
 	return 0;
 }
@@ -45,10 +66,9 @@ int kputchar(int c)
 
 	pos = atomic_int32_inc(&kmsg_counter);
 	kmessages[pos % KMSG_SIZE] = c;
-
 #ifdef CONFIG_VGA
-	ret = vga_putchar(c);
-#endif
+	sem_post(&sem_output);
+#endif 
 
 	return ret;
 }
@@ -61,11 +81,10 @@ int kputs(const char *str)
 	for(i=0; str[i] != '\0'; i++) {
 		pos = atomic_int32_inc(&kmsg_counter);
 		kmessages[pos % KMSG_SIZE] = str[i];
-	}
-
 #ifdef CONFIG_VGA
-	i = vga_puts(str);
+		sem_post(&sem_output);
 #endif
+	}
 
 	return i;
 }