/*
 * =======================================================================================
 *
 *   Author:   Jan Eitzinger (je), jan.eitzinger@fau.de
 *   Copyright (c) 2020 RRZE, University Erlangen-Nuremberg
 *
 *   This file is part of MD-Bench.
 *
 *   MD-Bench is free software: you can redistribute it and/or modify it
 *   under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   MD-Bench is distributed in the hope that it will be useful, but WITHOUT ANY
 *   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 *   PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 *   details.
 *
 *   You should have received a copy of the GNU Lesser General Public License along
 *   with MD-Bench.  If not, see <https://www.gnu.org/licenses/>.
 * =======================================================================================
 */
#include <stdio.h>
#include <stdlib.h>
//---
#include <device.h>

#ifdef CUDA_TARGET
#include <cuda_runtime.h>

void cuda_assert(const char *label, cudaError_t err) {
    if (err != cudaSuccess) {
        printf("[CUDA Error]: %s: %s\r\n", label, cudaGetErrorString(err));
        exit(-1);
    }
}

void *allocateGPU(size_t bytesize) {
    void *ptr;
    #ifdef CUDA_HOST_MEMORY
    cuda_assert("allocateGPU", cudaMallocHost((void **) &ptr, bytesize));
    #else
    cuda_assert("allocateGPU", cudaMalloc((void **) &ptr, bytesize));
    #endif
    return ptr;
}

// Data is not preserved
void *reallocateGPU(void *ptr, size_t new_bytesize) {
    if(ptr != NULL) {
        #ifdef CUDA_HOST_MEMORY
        cudaFreeHost(ptr);
        #else
        cudaFree(ptr);
        #endif
    }

    return allocateGPU(new_bytesize);
}

void memcpyToGPU(void *d_ptr, void *h_ptr, size_t bytesize) {
    #ifndef CUDA_HOST_MEMORY
    cuda_assert("memcpyToGPU", cudaMemcpy(d_ptr, h_ptr, bytesize, cudaMemcpyHostToDevice));
    #endif
}

void memcpyFromGPU(void *h_ptr, void *d_ptr, size_t bytesize) {
    #ifndef CUDA_HOST_MEMORY
    cuda_assert("memcpyFromGPU", cudaMemcpy(h_ptr, d_ptr, bytesize, cudaMemcpyDeviceToHost));
    #endif
}

void memsetGPU(void *d_ptr, int value, size_t bytesize) {
    cuda_assert("memsetGPU", cudaMemset(d_ptr, value, bytesize));
}

void initDevice(Atom *atom, Neighbor *neighbor) {
    DeviceAtom *d_atom = &(atom->d_atom);
    DeviceNeighbor *d_neighbor = &(neighbor->d_neighbor);
    
    d_atom->epsilon         =   (MD_FLOAT *) allocateGPU(sizeof(MD_FLOAT) * atom->ntypes * atom->ntypes);
    d_atom->sigma6          =   (MD_FLOAT *) allocateGPU(sizeof(MD_FLOAT) * atom->ntypes * atom->ntypes);
    d_atom->cutforcesq      =   (MD_FLOAT *) allocateGPU(sizeof(MD_FLOAT) * atom->ntypes * atom->ntypes);
    d_neighbor->neighbors   =   (int *) allocateGPU(sizeof(int) * atom->Nmax * neighbor->maxneighs);
    d_neighbor->numneigh    =   (int *) allocateGPU(sizeof(int) * atom->Nmax);
    
    memcpyToGPU(d_atom->x,              atom->x,          sizeof(MD_FLOAT) * atom->Nmax * 3);
    memcpyToGPU(d_atom->vx,             atom->vx,         sizeof(MD_FLOAT) * atom->Nmax * 3);
    memcpyToGPU(d_atom->sigma6,         atom->sigma6,     sizeof(MD_FLOAT) * atom->ntypes * atom->ntypes);
    memcpyToGPU(d_atom->epsilon,        atom->epsilon,    sizeof(MD_FLOAT) * atom->ntypes * atom->ntypes);
    memcpyToGPU(d_atom->cutforcesq,     atom->cutforcesq, sizeof(MD_FLOAT) * atom->ntypes * atom->ntypes);
    memcpyToGPU(d_atom->type,           atom->type,       sizeof(int) * atom->Nmax);
}

#else
void initDevice(Atom *atom, Neighbor *neighbor) {}
void *allocateGPU(size_t bytesize) { return NULL; }
void *reallocateGPU(void *ptr, size_t new_bytesize) { return NULL; }
void memcpyToGPU(void *d_ptr, void *h_ptr, size_t bytesize) {}
void memcpyFromGPU(void *h_ptr, void *d_ptr, size_t bytesize) {}
void memsetGPU(void *d_ptr, int value, size_t bytesize) {}
#endif