//===--- amdgpu/impl/impl.cpp ------------------------------------- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "rt.h"
#include <memory>

/*
 * Data
 */

static hsa_status_t invoke_hsa_copy(hsa_signal_t sig, void *dest,
                                    const void *src, size_t size,
                                    hsa_agent_t agent) {
  const hsa_signal_value_t init = 1;
  const hsa_signal_value_t success = 0;
  hsa_signal_store_screlease(sig, init);

  hsa_status_t err =
      hsa_amd_memory_async_copy(dest, agent, src, agent, size, 0, NULL, sig);
  if (err != HSA_STATUS_SUCCESS) {
    return err;
  }

  // async_copy reports success by decrementing and failure by setting to < 0
  hsa_signal_value_t got = init;
  while (got == init) {
    got = hsa_signal_wait_scacquire(sig, HSA_SIGNAL_CONDITION_NE, init,
                                    UINT64_MAX, HSA_WAIT_STATE_BLOCKED);
  }

  if (got != success) {
    return HSA_STATUS_ERROR;
  }

  return err;
}

struct implFreePtrDeletor {
  void operator()(void *p) {
    core::Runtime::Memfree(p); // ignore failure to free
  }
};

hsa_status_t impl_memcpy_h2d(hsa_signal_t signal, void *deviceDest,
                             const void *hostSrc, size_t size,
                             hsa_agent_t agent,
                             hsa_amd_memory_pool_t MemoryPool) {
  hsa_status_t rc = hsa_memory_copy(deviceDest, hostSrc, size);

  // hsa_memory_copy sometimes fails in situations where
  // allocate + copy succeeds. Looks like it might be related to
  // locking part of a read only segment. Fall back for now.
  if (rc == HSA_STATUS_SUCCESS) {
    return HSA_STATUS_SUCCESS;
  }

  void *tempHostPtr;
  hsa_status_t ret = core::Runtime::HostMalloc(&tempHostPtr, size, MemoryPool);
  if (ret != HSA_STATUS_SUCCESS) {
    DP("HostMalloc: Unable to alloc %zu bytes for temp scratch\n", size);
    return ret;
  }
  std::unique_ptr<void, implFreePtrDeletor> del(tempHostPtr);
  memcpy(tempHostPtr, hostSrc, size);

  if (invoke_hsa_copy(signal, deviceDest, tempHostPtr, size, agent) !=
      HSA_STATUS_SUCCESS) {
    return HSA_STATUS_ERROR;
  }
  return HSA_STATUS_SUCCESS;
}

hsa_status_t impl_memcpy_d2h(hsa_signal_t signal, void *dest,
                             const void *deviceSrc, size_t size,
                             hsa_agent_t agent,
                             hsa_amd_memory_pool_t MemoryPool) {
  hsa_status_t rc = hsa_memory_copy(dest, deviceSrc, size);

  // hsa_memory_copy sometimes fails in situations where
  // allocate + copy succeeds. Looks like it might be related to
  // locking part of a read only segment. Fall back for now.
  if (rc == HSA_STATUS_SUCCESS) {
    return HSA_STATUS_SUCCESS;
  }

  void *tempHostPtr;
  hsa_status_t ret = core::Runtime::HostMalloc(&tempHostPtr, size, MemoryPool);
  if (ret != HSA_STATUS_SUCCESS) {
    DP("HostMalloc: Unable to alloc %zu bytes for temp scratch\n", size);
    return ret;
  }
  std::unique_ptr<void, implFreePtrDeletor> del(tempHostPtr);

  if (invoke_hsa_copy(signal, tempHostPtr, deviceSrc, size, agent) !=
      HSA_STATUS_SUCCESS) {
    return HSA_STATUS_ERROR;
  }

  memcpy(dest, tempHostPtr, size);
  return HSA_STATUS_SUCCESS;
}
