From bc192c953eb2fe80cac471ea4601c27e23512440 Mon Sep 17 00:00:00 2001
From: Michael Sevakis <jethead71@rockbox.org>
Date: Sun, 30 Mar 2008 04:59:51 +0000
Subject: Add a lightweight wakeup object for fast processors.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16885 a1c6a512-1295-4272-9138-f99709370657
---
 firmware/export/config.h |  4 +++
 firmware/export/kernel.h | 23 ++++++++++++++
 firmware/kernel.c        | 78 ++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+)

diff --git a/firmware/export/config.h b/firmware/export/config.h
index 1a288dd590..cd98fc9dca 100644
--- a/firmware/export/config.h
+++ b/firmware/export/config.h
@@ -335,6 +335,10 @@
 #endif /* SIMULATOR */
 #define HAVE_SEMAPHORE_OBJECTS
 #define HAVE_EVENT_OBJECTS
+
+#if defined (TOSHIBA_GIGABEAT_F) || defined (TOSHIBA_GIGABEAT_S)
+#define HAVE_WAKEUP_OBJECTS
+#endif
 #endif
 
 /* define for all cpus from SH family */
diff --git a/firmware/export/kernel.h b/firmware/export/kernel.h
index 78403c8b7d..337f249dfe 100644
--- a/firmware/export/kernel.h
+++ b/firmware/export/kernel.h
@@ -78,6 +78,11 @@
 
 #define IS_SYSEVENT(ev)           ((ev & SYS_EVENT) == SYS_EVENT)
 
+#ifndef TIMEOUT_BLOCK
+#define TIMEOUT_BLOCK   -1
+#define TIMEOUT_NOBLOCK  0
+#endif
+
 struct queue_event
 {
     long     id;
@@ -178,6 +183,17 @@ struct event
 };
 #endif
 
+
+#ifdef HAVE_WAKEUP_OBJECTS
+struct wakeup
+{
+    struct thread_entry *queue;         /* waiter list */
+    unsigned char signalled;            /* signalled status */
+    IF_COP( struct corelock cl; )       /* multiprocessor sync */
+};
+#endif
+
+
 /* global tick variable */
 #if defined(CPU_PP) && defined(BOOTLOADER)
 /* We don't enable interrupts in the iPod bootloader, so we need to fake
@@ -225,6 +241,7 @@ void timeout_cancel(struct timeout *tmo);
 #define STATE_SIGNALED    1
 
 #define WAIT_TIMEDOUT     (-1)
+#define WAIT_FAILED       0
 #define WAIT_SUCCEEDED    1
 
 extern void queue_init(struct event_queue *q, bool register_queue);
@@ -274,4 +291,10 @@ extern void event_wait(struct event *e, unsigned int for_state);
 extern void event_set_state(struct event *e, unsigned int state);
 #endif /* HAVE_EVENT_OBJECTS */
 
+#ifdef HAVE_WAKEUP_OBJECTS
+extern void wakeup_init(struct wakeup *w);
+extern int wakeup_wait(struct wakeup *w, int timeout);
+extern int wakeup_signal(struct wakeup *w);
+#endif /* HAVE_WAKEUP_OBJECTS */
+
 #endif /* _KERNEL_H_ */
diff --git a/firmware/kernel.c b/firmware/kernel.c
index 184d29fe93..439aea584a 100644
--- a/firmware/kernel.c
+++ b/firmware/kernel.c
@@ -1368,3 +1368,81 @@ void event_set_state(struct event *e, unsigned int state)
 #endif
 }
 #endif /* HAVE_EVENT_OBJECTS */
+
+
+#ifdef HAVE_WAKEUP_OBJECTS
+/****************************************************************************
+ * Lightweight IRQ-compatible wakeup object
+ */
+
+/* Initialize the wakeup object */
+void wakeup_init(struct wakeup *w)
+{
+    w->queue = NULL;
+    w->signalled = 0;
+    IF_COP( corelock_init(&w->cl); )
+}
+
+/* Wait for a signal blocking indefinitely or for a specified period */
+int wakeup_wait(struct wakeup *w, int timeout)
+{
+    int ret = WAIT_SUCCEEDED; /* Presume success */
+    int oldlevel = disable_irq_save();
+
+    corelock_lock(&w->cl);
+
+    if(w->signalled == 0 && timeout != TIMEOUT_NOBLOCK)
+    {
+        struct thread_entry * current = cores[CURRENT_CORE].running;
+
+        IF_COP( current->obj_cl = &w->cl; )
+        current->bqp = &w->queue;
+        
+        if (timeout != TIMEOUT_BLOCK)
+            block_thread_w_tmo(current, timeout);
+        else
+            block_thread(current);
+
+        corelock_unlock(&w->cl);
+        switch_thread();
+
+        oldlevel = disable_irq_save();
+        corelock_lock(&w->cl);
+    }
+
+    if(w->signalled == 0)
+    {
+        /* Timed-out or failed */
+        ret = (timeout != TIMEOUT_BLOCK) ? WAIT_TIMEDOUT : WAIT_FAILED;
+    }
+
+    w->signalled = 0;  /* Reset */
+
+    corelock_unlock(&w->cl);
+    restore_irq(oldlevel);
+
+    return ret;
+}
+
+/* Signal the thread waiting or leave the signal if the thread hasn't 
+ * waited yet.
+ *
+ * returns THREAD_NONE or THREAD_OK
+ */
+int wakeup_signal(struct wakeup *w)
+{
+    int oldlevel = disable_irq_save();
+    int ret;
+
+    corelock_lock(&w->cl);
+
+    w->signalled = 1;
+    ret = wakeup_thread(&w->queue);
+
+    corelock_unlock(&w->cl);
+    restore_irq(oldlevel);
+
+    return ret;
+}
+#endif /* HAVE_WAKEUP_OBJECTS */
+
-- 
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