text: /*
   ***********************************************************************************************************************
   *
   *  Copyright (c) 2014-2018 Advanced Micro Devices, Inc. All Rights Reserved.
   *
   *  Permission is hereby granted, free of charge, to any person obtaining a copy
   *  of this software and associated documentation files (the "Software"), to deal
   *  in the Software without restriction, including without limitation the rights
   *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   *  copies of the Software, and to permit persons to whom the Software is
   *  furnished to do so, subject to the following conditions:
   *
   *  The above copyright notice and this permission notice shall be included in all
   *  copies or substantial portions of the Software.
   *
   *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   *  SOFTWARE.
   *
   **********************************************************************************************************************/
  
  #pragma once
  
  #include "core/queueSemaphore.h"
  #include "palDeque.h"
  #include "palMutex.h"
  
  namespace Pal
  {
  
  // Forward decl's
  class Platform;
  
  // =====================================================================================================================
  // Specialization of QueueSemaphore to handle Semaphores for single-GPU scenarios or the "master" Semaphore for multi-
  // GPU shared Semaphore objects.
  class MasterQueueSemaphore : public QueueSemaphore
  {
  public:
      explicit MasterQueueSemaphore(Device* pDevice);
      virtual ~MasterQueueSemaphore();
  
      virtual Result Init(const QueueSemaphoreCreateInfo& createInfo);
  
      // Master Queue Semaphores don't suppor the 'Open' operation!
      virtual Result Open(const QueueSemaphoreOpenInfo& openInfo) override { return Result::ErrorUnavailable; }
  
      // Instructs a Queue to signal this Semaphore.
      virtual Result Signal(
          Queue* pQueue,
          uint64 value) override { return SignalInternal(pQueue, this, value); }
  
      // Instructs a Queue to wait on this Semaphore.
      virtual Result Wait(
          Queue*         pQueue,
          uint64         value,
          volatile bool* pIsStalled) override { return WaitInternal(pQueue, this, value, pIsStalled); }
  
      // NOTE: Part of the public IQueueSemaphore interface.
      virtual bool HasStalledQueues() override;
  
      bool IsBlockedBySemaphore(const QueueSemaphore* pSemaphore);
      Result SignalInternal(
          Queue*          pQueue,
          QueueSemaphore* pSemaphore,
          uint64          value);
  
      Result WaitInternal(
          Queue*          pQueue,
          QueueSemaphore* pSemaphore,
          uint64          value,
          volatile bool*  pIsStalled);
  
      Result InitExternal();
  
      Result EarlySignal();
  
  private:
      Result AddBlockedQueue(
          Queue*          pQueue,
          QueueSemaphore* pSemaphore,
          uint64          value);
      Result ReleaseBlockedQueues();
  
      Util::Mutex  m_queuesLock;
  
      // Information associating a wait-count with the appropriate blocking Queue.
      struct BlockedInfo
      {
          Queue*           pQueue;        // The blocked Queue
          QueueSemaphore*  pSemaphore;    // The blocking Semaphore
          uint64           value;         // timeline semaphore point value
          uint64           waitCount;     // The wait-count before the Queue becomes unblocked
      };
  
      // Tracks the set of Queues blocked by this Semaphore, and their associated wait-counts.
      Util::Deque<BlockedInfo, Platform>  m_blockedQueues;
  
      // Tracks the total number of times this Semaphore has been waited-on and signaled. Includes the initial
      // count specified at creation-time.
      uint64  m_signalCount;
      uint64  m_waitCount;
  
      PAL_DISALLOW_DEFAULT_CTOR(MasterQueueSemaphore);
      PAL_DISALLOW_COPY_AND_ASSIGN(MasterQueueSemaphore);
  };
  
  } // Pal
  