adds ata_idle_notify system which allows callbacks in apps/ to be called

when the hard disk is idle but spinning, and just before shutting down.
on SWCODEC targets with > 8MB RAM the playback engine will try to
refill the buffer if it is less than 75% full while the disk is spinning
(temporarily disabled on the nano)


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11451 a1c6a512-1295-4272-9138-f99709370657

firmware/ata_idle_notify.c

@@ -0,0 +1,96 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2006 Jonathan Gordon
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include <stdbool.h>
+#include "system.h"
+#include "ata_idle_notify.h"
+#include "logf.h"
+
+#if USING_ATA_CALLBACK
+static ata_idle_notify ata_idle_notify_funcs[MAX_ATA_CALLBACKS];
+static int ata_callback_count = 0;
+#endif
+
+bool register_ata_idle_func(ata_idle_notify function)
+{
+#if USING_ATA_CALLBACK
+    int i;
+    for (i=0; i<MAX_ATA_CALLBACKS; i++)
+    {
+        if (ata_idle_notify_funcs[i] == NULL)
+        {
+            ata_idle_notify_funcs[i] = function;
+            ata_callback_count++;
+            return true;
+        }
+        else if (ata_idle_notify_funcs[i] == function)
+            return true;
+    }
+    return false;
+#else
+    function(); /* just call the function now */
+/* this _may_ cause problems later if the calling function
+   sets a variable expecting the callback to unset it, because
+   the callback will be run before this function exits, so before the var is set */
+    return true;
+#endif
+}
+
+#if USING_ATA_CALLBACK
+void unregister_ata_idle_func(ata_idle_notify func)
+{
+    int i;
+    for (i=0; i<MAX_ATA_CALLBACKS; i++)
+    {
+        if (ata_idle_notify_funcs[i] == func)
+        {
+            ata_idle_notify_funcs[i] = NULL;
+            ata_callback_count--;
+        }
+    }
+    return;
+}
+
+bool call_ata_idle_notifys(void)
+{
+    int i;
+    ata_idle_notify function;
+    if (ata_callback_count == 0)
+        return false;
+    ata_callback_count = 0; /* so we dont re-enter every time the callbacks read/write */
+    for (i = 0; i < MAX_ATA_CALLBACKS; i++)
+    {
+        if (ata_idle_notify_funcs[i])
+        {
+            function = ata_idle_notify_funcs[i];
+            ata_idle_notify_funcs[i] = NULL;
+            function();
+        }
+    }
+    return true;
+}
+
+void ata_idle_notify_init(void)
+{
+    int i;
+    for (i=0; i<MAX_ATA_CALLBACKS; i++)
+    {
+        ata_idle_notify_funcs[i] = NULL;
+    }
+}
+#endif