From 836dfa601a62228d07c0509d12996e962a073313 Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Tue, 29 Nov 2011 23:18:41 +0800
Subject: [PATCH] Kernel - Added a FIFO to thread code

---
 Kernel/include/threads_int.h |  2 +
 Kernel/include/workqueue.h   | 31 +++++++++++++++
 Kernel/workqueue.c           | 75 ++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+)
 create mode 100644 Kernel/include/workqueue.h
 create mode 100644 Kernel/workqueue.c

diff --git a/Kernel/include/threads_int.h b/Kernel/include/threads_int.h
index 4cc11ec6..6516b35a 100644
--- a/Kernel/include/threads_int.h
+++ b/Kernel/include/threads_int.h
@@ -78,6 +78,7 @@ enum {
 	THREAD_STAT_SLEEPING,	// Message Sleep
 	THREAD_STAT_MUTEXSLEEP,	// Mutex Sleep
 	THREAD_STAT_SEMAPHORESLEEP,	// Semaphore Sleep
+	THREAD_STAT_QUEUESLEEP,	// Queue
 	THREAD_STAT_WAITING,	// ??? (Waiting for a thread)
 	THREAD_STAT_PREINIT,	// Being created
 	THREAD_STAT_ZOMBIE,	// Died/Killed, but parent not informed
@@ -90,6 +91,7 @@ static const char * const casTHREAD_STAT[] = {
 	"THREAD_STAT_SLEEPING",
 	"THREAD_STAT_MUTEXSLEEP",
 	"THREAD_STAT_SEMAPHORESLEEP",
+	"THREAD_STAT_QUEUESLEEP",
 	"THREAD_STAT_WAITING",
 	"THREAD_STAT_PREINIT",
 	"THREAD_STAT_ZOMBIE",
diff --git a/Kernel/include/workqueue.h b/Kernel/include/workqueue.h
new file mode 100644
index 00000000..ff0c7f4c
--- /dev/null
+++ b/Kernel/include/workqueue.h
@@ -0,0 +1,31 @@
+/**
+ * Acess2 Kernel
+ * - By John Hodge (thePowersGang)
+ *
+ * workqueue.h
+ * - FIFO Queue
+ */
+#ifndef _WORKQUEUE_H_
+#define _WORKQUEUE_H_
+
+#include <acess.h>
+
+typedef struct sWorkqueue	tWorkqueue;
+
+struct sWorkqueue
+{
+	tShortSpinlock	Protector;
+	const char	*Name;
+	 int	NextOffset;
+	
+	void	*Head;
+	void	*Tail;
+	struct sThread	*Sleeper;
+};
+
+extern void	Workqueue_Init(tWorkqueue *Queue, const char *Name, size_t NextOfset);
+extern void	*Workqueue_GetWork(tWorkqueue *Queue);
+extern void	Workqueue_AddWork(tWorkqueue *Queue, void *Ptr);
+
+#endif
+
diff --git a/Kernel/workqueue.c b/Kernel/workqueue.c
new file mode 100644
index 00000000..38bf932c
--- /dev/null
+++ b/Kernel/workqueue.c
@@ -0,0 +1,75 @@
+/*
+ * Acess2 Kernel
+ * - By John Hodge (thePowersGang)
+ *
+ * workqueue.c
+ * - Worker FIFO Queue (Single Consumer, Interrupt Producer)
+ */
+#include <acess.h>
+#include <workqueue.h>
+#include <threads_int.h>
+
+// === CODE ===
+void Workqueue_Init(tWorkqueue *Queue, const char *Name, size_t NextOfset)
+{
+	Queue->Name = Name;
+	Queue->NextOffset = NextOfset;
+}
+
+void *Workqueue_GetWork(tWorkqueue *Queue)
+{
+	tThread	*us;
+
+	for( ;; )
+	{
+		// Check for work
+		SHORTLOCK(&Queue->Protector);
+		if(Queue->Head)
+		{
+			void *ret = Queue->Head;
+			Queue->Head = *(void**)( (char*)ret + Queue->NextOffset );
+			if(Queue->Tail == ret)
+				Queue->Tail = NULL;
+			SHORTREL(&Queue->Protector);	
+			return ret;
+		}
+		
+		// Go to sleep
+		SHORTLOCK(&glThreadListLock);
+		us = Threads_RemActive();
+		us->WaitPointer = Queue;
+		us->Status = THREAD_STAT_QUEUESLEEP;
+		Queue->Sleeper = us;
+		SHORTREL(&Queue->Protector);	
+		SHORTREL(&glThreadListLock);
+		
+		// Yield and sleep
+		Threads_Yield();
+		if(us->Status == THREAD_STAT_QUEUESLEEP) {
+			// Why are we awake?!
+		}
+
+		us->WaitPointer = NULL;
+	}
+}
+
+void Workqueue_AddWork(tWorkqueue *Queue, void *Ptr)
+{
+	SHORTLOCK(&Queue->Protector);
+
+	if( Queue->Tail )
+		*(void**)( (char*)Queue->Tail + Queue->NextOffset ) = Ptr;
+	else
+		Queue->Head = Ptr;
+	Queue->Tail = Ptr;
+	
+	if( Queue->Sleeper )
+	{	
+		SHORTLOCK( &glThreadListLock );
+		if( Queue->Sleeper->Status != THREAD_STAT_ACTIVE )
+			Threads_AddActive(Queue->Sleeper);
+		SHORTREL( &glThreadListLock );
+		Queue->Sleeper = NULL;
+	}
+	SHORTREL(&Queue->Protector);
+}
-- 
2.20.1