/*
 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "runtime/gpu.hpp"
#include "utilities/ostream.hpp"

void gpu::probe_gpu() {
  set_available(gpu::Linux::probe_gpu());
  if (TraceGPUInteraction) {
    tty->print_cr("gpu_linux::probe_gpu(): %d", gpu::is_available());
  }
}

/*
 * Probe for CUDA device on PCI bus using /proc/bus/pci/devices. Do
 * not rely on CUDA tool kit being installed. We will check if CUDA
 * library is installed later.
 */

static unsigned int nvidia_vendor_id = 0x10de;
static unsigned int nvidia_gk110_dev_id = 0x1005;

bool gpu::Linux::probe_gpu() {
  /* 
     Open /proc/bus/pci/devices to look for the first CUDA enabled
     device. For now, finding the first CUDA device. Will need to
     revisit this wo support execution on multiple CUDA devices if
     they exist.
  */
  FILE *pci_devices = fopen("/proc/bus/pci/devices", "r");
  char contents[4096];
  unsigned int bus_num_devfn_ign;
  unsigned int vendor;
  unsigned int device;
  bool cuda_device_exists = false;
  if (pci_devices == NULL) {
    tty->print_cr("*** Failed to open /proc/bus/pci/devices");
    return cuda_device_exists;
  }

  while (fgets(contents, sizeof(contents)-1, pci_devices)) {
    sscanf(contents, "%04x%04x%04x", &bus_num_devfn_ign, &vendor, &device);
    /* Break after finding the first CUDA device. */
    if ((vendor == nvidia_vendor_id) && (device = nvidia_gk110_dev_id)) {
      cuda_device_exists = true;
      if (TraceGPUInteraction) {
        tty->print_cr("Found supported nVidia CUDA device vendor : 0x%04x device 0x%04x", vendor, device);
      }
      break;
    }
  }

  // Close file pointer.
  fclose(pci_devices);

  return cuda_device_exists;
}