Re-commit r23070 - reboot to disk mode on the Nano2G when USB is inserted. This was accidentally reverted in r23099

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23148 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/s5l8700/usb-s5l8700.c

@@ -20,6 +20,9 @@
  ****************************************************************************/
 #include "config.h"
 #include "usb.h"
+#include "cpu.h"
+#include "system.h"
+#include "string.h"
 
 void usb_init_device(void)
 {
@@ -27,21 +30,27 @@ void usb_init_device(void)
 
 void usb_enable(bool on)
 {
-    (void)on;
+    /* This device specific code will eventually give way to proper USB
+       handling, which should be the same for all S5L870x targets. */
+    if (on)
+    {
+#ifdef IPOD_ARCH
+        /* For iPod, we can only do one thing with USB mode atm - reboot
+           into the flash-based disk-mode.  This does not return. */
+
+        memcpy((void *)0x0002bf00, "diskmodehotstuff\1\0\0\0", 20);
+
+        system_reboot(); /* Reboot */
+#endif
+    }
 }
 
-void usb_attach(void)
-{
-
-}
-
-static bool usb_pin_state(void)
-{
-    return false;
-}
-
-/* detect host or charger (INSERTED or EXTRACTED) */
 int usb_detect(void)
 {
-    return usb_pin_state() ? USB_INSERTED : USB_EXTRACTED;
+#if defined(IPOD_NANO2G)
+    if ((PDAT14 & 0x8) == 0x0)
+        return USB_INSERTED;
+#endif
+
+    return USB_EXTRACTED;
 }