/****************************************************************************
 * drivers/virtio/virtio.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <debug.h>

#include <nuttx/mutex.h>
#include <nuttx/kmalloc.h>
#include <nuttx/virtio/virtio.h>

#include "virtio-blk.h"
#include "virtio-gpu.h"
#include "virtio-net.h"
#include "virtio-rng.h"
#include "virtio-serial.h"

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct virtio_bus_s
{
  mutex_t lock;                /* Lock for the list */
  struct list_node device;     /* Wait match virtio device list */
  struct list_node driver;     /* Virtio driver list */
};
struct virtio_device_item_s
{
  struct list_node      node;    /* list node */
  struct virtio_device *device;  /* Pointer to the virtio device */
  struct virtio_driver *driver;  /* Pointer to the virtio driver that
                                  * matched with current virtio device
                                  */
};

/****************************************************************************
 * Private Data
 ****************************************************************************/

static struct virtio_bus_s g_virtio_bus =
{
  NXMUTEX_INITIALIZER,
  LIST_INITIAL_VALUE(g_virtio_bus.device),
  LIST_INITIAL_VALUE(g_virtio_bus.driver),
};

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: virtio_alloc_buf
 ****************************************************************************/

FAR void *virtio_alloc_buf(FAR struct virtio_device *vdev,
                           size_t size, size_t align)
{
  if (align == 0)
    {
      return kmm_malloc(size);
    }
  else
    {
      return kmm_memalign(align, size);
    }
}

/****************************************************************************
 * Name: virtio_zalloc_buf
 ****************************************************************************/

FAR void *virtio_zalloc_buf(FAR struct virtio_device *vdev,
                            size_t size, size_t align)
{
  FAR void *ptr = virtio_alloc_buf(vdev, size, align);
  if (ptr != NULL)
    {
      memset(ptr, 0, size);
    }

  return ptr;
}

/****************************************************************************
 * Name: virtio_mmio_free_buf
 ****************************************************************************/

void virtio_free_buf(FAR struct virtio_device *vdev, FAR void *buf)
{
  kmm_free(buf);
}

/****************************************************************************
 * Name: virtio_register_drivers
 ****************************************************************************/

void virtio_register_drivers(void)
{
  int ret = OK;

#ifdef CONFIG_DRIVERS_VIRTIO_BLK
  ret = virtio_register_blk_driver();
  if (ret < 0)
    {
      vrterr("virtio_register_blk_driver failed, ret=%d\n", ret);
    }
#endif

#ifdef CONFIG_DRIVERS_VIRTIO_GPU
  ret = virtio_register_gpu_driver();
  if (ret < 0)
    {
      vrterr("virtio_register_gpu_driver failed, ret=%d\n", ret);
    }
#endif

#ifdef CONFIG_DRIVERS_VIRTIO_NET
  ret = virtio_register_net_driver();
  if (ret < 0)
    {
      vrterr("virtio_register_net_driver failed, ret=%d\n", ret);
    }
#endif

#ifdef CONFIG_DRIVERS_VIRTIO_RNG
  ret = virtio_register_rng_driver();
  if (ret < 0)
    {
      vrterr("virtio_register_rng_driver failed, ret=%d\n", ret);
    }
#endif

#ifdef CONFIG_DRIVERS_VIRTIO_SERIAL
  ret = virtio_register_serial_driver();
  if (ret < 0)
    {
      vrterr("virtio_serial_driver_init failed, ret=%d\n", ret);
    }
#endif

  UNUSED(ret);
}

/****************************************************************************
 * Name: virtio_register_driver
 ****************************************************************************/

int virtio_register_driver(FAR struct virtio_driver *driver)
{
  FAR struct list_node *node;
  int ret;

  DEBUGASSERT(driver != NULL && driver->probe != NULL &&
              driver->remove != NULL);

  ret = nxmutex_lock(&g_virtio_bus.lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Add the driver to the virtio_bus driver list */

  list_add_tail(&g_virtio_bus.driver, &driver->node);

  /* Match all the devices has registered in the virtio_bus */

  list_for_every(&g_virtio_bus.device, node)
    {
      FAR struct virtio_device_item_s *item =
        container_of(node, struct virtio_device_item_s, node);
      FAR struct virtio_device *device = item->device;
      if (driver->device == device->id.device)
        {
          /* If found the device in the device list, call driver probe,
           * if probe success, assign item->driver to indicate the device
           * matched.
           */

          if (driver->probe(device) >= 0)
            {
              item->driver = driver;
            }
        }
    }

  nxmutex_unlock(&g_virtio_bus.lock);
  return ret;
}

/****************************************************************************
 * Name: virtio_unregister_driver
 ****************************************************************************/

int virtio_unregister_driver(FAR struct virtio_driver *driver)
{
  FAR struct list_node *node;
  int ret;

  DEBUGASSERT(driver != NULL);

  ret = nxmutex_lock(&g_virtio_bus.lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Find all the devices matched with driver in device list */

  list_for_every(&g_virtio_bus.device, node)
    {
      FAR struct virtio_device_item_s *item =
        container_of(node, struct virtio_device_item_s, node);
      if (item->driver == driver)
        {
          /* 1. Call driver remove function;
           * 2. Mark item->driver NULL to indicate the device unmatched;
           */

          driver->remove(item->device);
          item->driver = NULL;
        }
    }

  /* Remove the driver from the driver list */

  list_delete(&driver->node);

  nxmutex_unlock(&g_virtio_bus.lock);
  return ret;
}

/****************************************************************************
 * Name: virtio_register_device
 ****************************************************************************/

int virtio_register_device(FAR struct virtio_device *device)
{
  FAR struct virtio_device_item_s *item;
  FAR struct list_node *node;
  int ret;

  item = kmm_zalloc(sizeof(*item));
  if (item == NULL)
    {
      return -ENOMEM;
    }

  item->device = device;

  ret = nxmutex_lock(&g_virtio_bus.lock);
  if (ret < 0)
    {
      kmm_free(item);
      return ret;
    }

  /* Add the device to the virtio_bus device list */

  list_add_tail(&g_virtio_bus.device, &item->node);

  /* Match the driver has registered in the virtio_bus */

  list_for_every(&g_virtio_bus.driver, node)
    {
      FAR struct virtio_driver *driver =
        container_of(node, struct virtio_driver, node);
      if (driver->device == device->id.device)
        {
          /* If found the driver in the driver list, call driver probe,
           * if probe success, assign item->driver to indicate the device
           * matched.
           */

          if (driver->probe(device) >= 0)
            {
              item->driver = driver;
            }

          break;
        }
    }

  nxmutex_unlock(&g_virtio_bus.lock);
  return ret;
}

/****************************************************************************
 * Name: virtio_unregister_device
 ****************************************************************************/

int virtio_unregister_device(FAR struct virtio_device *device)
{
  FAR struct list_node *node;
  int ret;

  ret = nxmutex_lock(&g_virtio_bus.lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Find the device in device list */

  list_for_every(&g_virtio_bus.device, node)
    {
      FAR struct virtio_device_item_s *item =
        container_of(node, struct virtio_device_item_s, node);
      if (item->device == device)
        {
          /* Call driver remove and mark item->driver NULL to indicate
           * the device unmatched
           */

          item->driver->remove(device);
          item->driver = NULL;

          /* Remove the device from the device list and free memory */

          list_delete(&item->node);
          kmm_free(item);
          break;
        }
    }

  nxmutex_unlock(&g_virtio_bus.lock);
  return ret;
}