staging: sw_sync: Add cpu based sync driver

Adds a base sync driver that uses the cpu for serialization.

Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Erik Gilling <konkers@android.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robclark@gmail.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Erik Gilling <konkers@android.com>
[jstultz: Add commit message, whitespace fixes and move to
staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index c95aede..cc406cc 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -81,6 +81,24 @@
 	  drivers.  Sync implementations can take advantage of hardware
 	  synchronization built into devices like GPUs.
 
+config SW_SYNC
+	bool "Software synchronization objects"
+	default n
+	depends on SYNC
+	help
+	  A sync object driver that uses a 32bit counter to coordinate
+	  syncrhronization.  Useful when there is no hardware primitive backing
+	  the synchronization.
+
+config SW_SYNC_USER
+	bool "Userspace API for SW_SYNC"
+	default n
+	depends on SW_SYNC
+	help
+	  Provides a user space API to the sw sync object.
+	  *WARNING* improper use of this can result in deadlocking kernel
+	  drivers from userspace.
+
 endif # if ANDROID
 
 endmenu