sdm: Add support for CPU hint

- Set the hint when there is only one updating layer, which helps
  in reducing CPU clock and thus power.
- This feature is enabled with the property sdm.perf_hint_window,
  which is set to a positive value, which will be the window of frames
  to skip before the hint is set.

CRs-fixed: 853602
Change-Id: I1af21551510f99752c0b6bbfec3e5c75880c3ab2
diff --git a/sdm/libs/hwc/cpuhint.h b/sdm/libs/hwc/cpuhint.h
new file mode 100644
index 0000000..2165c99
--- /dev/null
+++ b/sdm/libs/hwc/cpuhint.h
@@ -0,0 +1,62 @@
+/* Copyright (c) 2015, The Linux Foundataion. All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are
+* met:
+*     * Redistributions of source code must retain the above copyright
+*       notice, this list of conditions and the following disclaimer.
+*     * Redistributions in binary form must reproduce the above
+*       copyright notice, this list of conditions and the following
+*       disclaimer in the documentation and/or other materials provided
+*       with the distribution.
+*     * Neither the name of The Linux Foundation nor the names of its
+*       contributors may be used to endorse or promote products derived
+*       from this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+* ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*
+*/
+
+#ifndef __CPUHINT_H__
+#define __CPUHINT_H__
+
+#include <core/sdm_types.h>
+
+namespace sdm {
+
+class HWCDebugHandler;
+
+class CPUHint {
+ public:
+  CPUHint();
+  ~CPUHint();
+  DisplayError Init(HWCDebugHandler *debug_handler);
+  void Set();
+  void Reset();
+
+ private:
+  enum { HINT =  0x4701 /* 47-display layer hint, 01-Enable */ };
+  bool enabled_;
+  // frames to wait before setting this hint
+  int pre_enable_window_;
+  int frame_countdown_;
+  int lock_handle_;
+  bool lock_acquired_;
+  void *lib_handle_;
+  int (*fn_lock_acquire_)(int handle, int duration, int *hints, int num_args);
+  int (*fn_lock_release_)(int value);
+};
+
+}  // namespace sdm
+
+#endif  // __CPUHINT_H__