- add a simple implementation of a mailbox

git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@20 315a16e6-25f9-4109-90ae-ca3045a26c18

include/metalsvm/mailbox.h

@@ -0,0 +1,97 @@
+/* 
+ * Copyright 2010 Stefan Lankes, Chair for Operating Systems,
+ *                               RWTH Aachen University
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is part of MetalSVM.
+ */
+
+#ifndef __MAILBOX_H__
+#define __MAILBOX_H__
+
+#include <metalsvm/string.h>
+#include <metalsvm/tasks.h>
+#include <metalsvm/semaphore.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+	void* mail;
+	sem_t consume, produce;
+} mailbox_t;
+
+inline static int mailbox_init(mailbox_t* m) {
+	if (BUILTIN_EXPECT(!m, 0))
+		return -1;
+
+	m->mail = NULL;
+	sem_init(&m->consume, 0);
+	sem_init(&m->produce, 1);
+
+	return 0;
+}
+
+inline static int mailbox_destroy(mailbox_t* m) {
+	if (BUILTIN_EXPECT(!m, 0))
+		return -1;
+
+	sem_destroy(&m->consume);
+	sem_destroy(&m->produce);
+
+	return 0;
+}
+
+inline static int mailbox_post(mailbox_t* m, void* mail) {
+	if (BUILTIN_EXPECT(!m, 0))
+		return -1;
+
+	sem_wait(&m->produce);
+	m->mail = mail;
+	sem_post(&m->consume);
+
+	return 0;
+}
+
+inline static int mailbox_fetch(mailbox_t* m, void** mail) {
+	if (BUILTIN_EXPECT(!m || !mail, 0))
+		return -1;
+
+        sem_wait(&m->consume);
+        *mail = m->mail;
+	m->mail = NULL;
+        sem_post(&m->produce);
+
+	return 0;
+}
+
+inline static int mailbox_tryfetch(mailbox_t* m, void** mail) {
+	if (BUILTIN_EXPECT(!m || !mail, 0))
+		return -1;
+
+	if (sem_trywait(&m->consume) != 0)
+		return -1;
+        *mail = m->mail;
+	m->mail = NULL;
+        sem_post(&m->produce);
+
+        return 0;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

kernel/main.c

@@ -26,14 +26,40 @@
 #include <metalsvm/tasks.h>
 #include <metalsvm/processor.h>
 #include <metalsvm/semaphore.h>
+#include <metalsvm/mailbox.h>
 #include <asm/kb.h>
 
-static sem_t consuming, producing;
-static int val = 0;
+static sem_t 		consuming, producing;
+static mailbox_t	mbox;
+static int 		val = 0;
+
+void* STDCALL consumer(void* arg)
+{
+	int 	i;
+	int* 	m = NULL;
+
+	for(i=0; i<5; i++) {
+		sem_wait(&consuming);
+                kprintf("Consumer got %d\n", val);
+                val = 0;
+                sem_post(&producing);
+        }
+
+	for(i=0; i<5; i++) {
+		mailbox_fetch(&mbox, (void**) &m);
+		kprintf("Got mail %d\n", *m);
+	}
+
+	return NULL;
+}
 
 void* STDCALL producer(void* arg)
 {
-	int i;
+	int 	i;
+	int 	mail[5] = {1, 2, 3, 4, 5};
+	tid_t	id;
+
+	create_kernel_task(&id, consumer, NULL, 0);
 
 	for(i=0; i<5; i++) {
 		sem_wait(&producing);
@@ -42,19 +68,12 @@ void* STDCALL producer(void* arg)
 		sem_post(&consuming);
 	}
 
-	return NULL;
-}
-
-void* STDCALL consumer(void* arg)
-{
-	int i;
-
 	for(i=0; i<5; i++) {
-		sem_wait(&consuming);
-                kprintf("Consumer got %d\n", val);
-                val = 0;
-                sem_post(&producing);
-        }
+		kprintf("Send mail %d\n", mail[i]);
+		mailbox_post(&mbox, mail+i);
+	}
+
+	join_kernel_task(id);
 
 	return NULL;
 }
@@ -89,7 +108,7 @@ void* STDCALL join_test(void* arg)
 
 int main(void)
 {
-	tid_t id1, id2, id3, id4;
+	tid_t id1, id2, id3;
 
 	system_init();
 	irq_init();
@@ -115,11 +134,11 @@ int main(void)
 
 	sem_init(&producing, 1);
 	sem_init(&consuming, 0);
+	mailbox_init(&mbox);
 
 	create_kernel_task(&id1, foo, "Hello from foo1\n", 8192);
 	create_kernel_task(&id2, join_test, NULL, 0);
 	create_kernel_task(&id3, producer, NULL, 0);
-	create_kernel_task(&id4, consumer, NULL, 0);
 	current_task->idle = 1;
 	schedule();