/****************************************************************************
 * drivers/mtd/mtd_rwbuffer.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * 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.
 *
 ****************************************************************************/

/* MTD driver that contains another MTD driver and provides read-ahead
 * and/or write buffering.
 */

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

#include <nuttx/config.h>

#include <sys/types.h>

#include <inttypes.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/kmalloc.h>
#include <nuttx/drivers/rwbuffer.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/mtd/mtd.h>

#if defined(CONFIG_DRVR_WRITEBUFFER) || defined(CONFIG_DRVR_READAHEAD)

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#ifndef CONFIG_DRVR_INVALIDATE
#  error This driver requires CONFIG_DRVR_INVALIDATE
#endif

#ifndef CONFIG_DRVR_READBYTES
#  error This driver requires CONFIG_DRVR_READBYTES
#endif

#ifndef CONFIG_MTD_NWRBLOCKS
#  define CONFIG_MTD_NWRBLOCKS 4
#endif

#ifndef CONFIG_MTD_NRDBLOCKS
#  define CONFIG_MTD_NRDBLOCKS 4
#endif

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

/* This type represents the state of the MTD device.
 * The struct mtd_dev_s must appear at the beginning of the definition so
 * that you can freely cast between  pointers to struct mtd_dev_s and struct
 * mtd_rwbuffer_s.
 */

struct mtd_rwbuffer_s
{
  struct mtd_dev_s       mtd;  /* Our exported MTD interface */
  FAR struct mtd_dev_s  *dev;  /* Saved lower level MTD interface instance */
  struct rwbuffer_s      rwb;  /* The rwbuffer state structure */
  uint16_t               spb;  /* Number of sectors per block */
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/* rwbuffer callouts */

static ssize_t mtd_reload(FAR void *dev,
                          FAR uint8_t *buffer,
                          off_t startblock,
                          size_t nblocks);
static ssize_t mtd_flush(FAR void *dev,
                         FAR const uint8_t *buffer,
                         off_t startblock,
                         size_t nblocks);

/* MTD driver methods */

static int mtd_erase(FAR struct mtd_dev_s *dev,
                     off_t block,
                     size_t nsectors);
static ssize_t mtd_bread(FAR struct mtd_dev_s *dev,
                         off_t block,
                         size_t nsectors,
                         FAR uint8_t *buf);
static ssize_t mtd_bwrite(FAR struct mtd_dev_s *dev,
                          off_t block,
                          size_t nsectors,
                          FAR const uint8_t *buf);
static ssize_t mtd_read(FAR struct mtd_dev_s *dev,
                        off_t offset,
                        size_t nbytes,
                        FAR uint8_t *buffer);
static int mtd_ioctl(FAR struct mtd_dev_s *dev,
                     int cmd,
                     unsigned long arg);

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

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: mtd_reload
 *
 * Description:
 *   Reload the read-ahead buffer
 *
 ****************************************************************************/

static ssize_t mtd_reload(FAR void *dev,
                          FAR uint8_t *buffer,
                          off_t startblock,
                          size_t nblocks)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;
  DEBUGASSERT(priv && priv->dev);

  /* This is just a pass-through to the contained MTD */

  return priv->dev->bread(priv->dev, startblock, nblocks, buffer);
}

/****************************************************************************
 * Name: mtd_flush
 *
 * Description:
 *   Flush the write buffer to hardware
 *
 ****************************************************************************/

static ssize_t mtd_flush(FAR void *dev,
                         FAR const uint8_t *buffer,
                         off_t startblock,
                         size_t nblocks)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;
  DEBUGASSERT(priv && priv->dev);

  /* This is just a pass-through to the contained MTD */

  return priv->dev->bwrite(priv->dev, startblock, nblocks, buffer);
}

/****************************************************************************
 * Name: mtd_erase
 ****************************************************************************/

static int mtd_erase(FAR struct mtd_dev_s *dev,
                     off_t block,
                     size_t nblocks)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;
  off_t sector;
  size_t nsectors;
  int ret;

  finfo("block: %08zx nsectors: %zu\n",
        (intmax_t)block, nsectors);

  /* Convert to logical sectors and sector numbers */

  sector   = block * priv->spb;
  nsectors = nblocks * priv->spb;

  /* Then invalidate in cached data */

  ret = rwb_invalidate(&priv->rwb, sector, nsectors);
  if (ret < 0)
    {
      ferr("ERROR: rwb_invalidate failed: %d\n", ret);
      return ret;
    }

  /* Then let the lower level MTD driver do the real erase */

  return priv->dev->erase(priv->dev, block, nblocks);
}

/****************************************************************************
 * Name: mtd_bread
 ****************************************************************************/

static ssize_t mtd_bread(FAR struct mtd_dev_s *dev, off_t sector,
                          size_t nsectors, FAR uint8_t *buffer)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;

  /* Let the rwbuffer logic do it real work.
   * It will call out to mtd_reload if is needs to read any data.
   */

  return rwb_read(&priv->rwb, sector, nsectors, buffer);
}

/****************************************************************************
 * Name: mtd_bwrite
 ****************************************************************************/

static ssize_t mtd_bwrite(FAR struct mtd_dev_s *dev, off_t block,
                          size_t nsectors,
                          FAR const uint8_t *buffer)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;

  /* Let the rwbuffer logic do it real work.
   * It will call out to wrb_reload it is needs to read any data.
   */

  return rwb_write(&priv->rwb, block, nsectors, buffer);
}

/****************************************************************************
 * Name: mtd_read
 ****************************************************************************/

static ssize_t mtd_read(FAR struct mtd_dev_s *dev,
                        off_t offset,
                        size_t nbytes,
                        FAR uint8_t *buffer)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;

  /* Let the rwbuffer logic do it real work.
   * It will call out to mtd_reload it is needs to read any data.
   */

  return rwb_readbytes(&priv->rwb, offset, nbytes, buffer);
}

/****************************************************************************
 * Name: mtd_ioctl
 ****************************************************************************/

static int mtd_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
{
  FAR struct mtd_rwbuffer_s *priv = (FAR struct mtd_rwbuffer_s *)dev;
  int ret = -EINVAL; /* Assume good command with bad parameters */

  finfo("cmd: %d\n", cmd);

  switch (cmd)
    {
      case MTDIOC_GEOMETRY:
        {
          FAR struct mtd_geometry_s *geo = (FAR struct mtd_geometry_s *)
                                           ((uintptr_t)arg);
          if (geo)
            {
              memset(geo, 0, sizeof(*geo));

              /* Populate the geometry structure with information need to
               * know the capacity and how to access the device.
               *
               * NOTE:
               * that the device is treated as though it where just an array
               * of fixed size blocks. That is most likely not true, but the
               * client will expect the device logic to do whatever is
               * necessary to make it appear so.
               */

              geo->blocksize    = priv->rwb.blocksize;
              geo->erasesize    = priv->rwb.blocksize * priv->spb;
              geo->neraseblocks = priv->rwb.nblocks / priv->spb;
              ret               = OK;

              finfo("blocksize: %d erasesize: %d neraseblocks: %d\n",
                    geo->blocksize, geo->erasesize, geo->neraseblocks);
            }
        }
        break;

      case BIOC_PARTINFO:
        {
          FAR struct partition_info_s *info =
            (FAR struct partition_info_s *)arg;
          if (info != NULL)
            {
              info->numsectors  = priv->rwb.nblocks;
              info->sectorsize  = priv->rwb.blocksize;
              info->startsector = 0;
              info->parent[0]   = '\0';
              ret               = OK;
            }
        }
        break;

      case MTDIOC_BULKERASE:
        {
          /* Erase the entire device */

          ret = priv->dev->ioctl(priv->dev, MTDIOC_BULKERASE, 0);
          if (ret >= 0)
            {
              ferr("ERROR: Device ioctl failed: %d\n", ret);
              break;
            }

          /* Then invalidate in cached data */

         ret = rwb_invalidate(&priv->rwb, 0, priv->rwb.nblocks);
         if (ret < 0)
           {
              ferr("ERROR: rwb_invalidate failed: %d\n", ret);
           }
        }
        break;

      default:
        ret = -ENOTTY; /* Bad command */
        break;
    }

  finfo("return %d\n", ret);
  return ret;
}

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

/****************************************************************************
 * Name: mtd_rwb_initialize
 *
 * Description:
 *   Create an initialized MTD device instance.
 *   This MTD driver contains another MTD driver and converts a larger
 *   sector size to a standard 512 byte sector size.
 *
 *   MTD devices are not registered in the file system, but are created as
 *   instances that can be bound to other functions (such as a block or
 *   character driver front end).
 *
 ****************************************************************************/

FAR struct mtd_dev_s *mtd_rwb_initialize(FAR struct mtd_dev_s *mtd)
{
  FAR struct mtd_rwbuffer_s *priv;
  struct mtd_geometry_s geo;
  int ret;

  finfo("mtd: %p\n", mtd);
  DEBUGASSERT(mtd && mtd->ioctl);

  /* Get the device geometry */

  ret = mtd->ioctl(mtd, MTDIOC_GEOMETRY, (unsigned long)((uintptr_t)&geo));
  if (ret < 0)
    {
      ferr("ERROR: MTDIOC_GEOMETRY ioctl failed: %d\n", ret);
      return NULL;
    }

  /* Allocate a state structure (we allocate the structure instead of using
   * a fixed, static allocation so that we can handle multiple FLASH devices.
   * The current implementation would handle only one FLASH part per SPI
   * device (only because of the SPIDEV_FLASH(0) definition) and so would
   * have to be extended to handle multiple FLASH parts on the same SPI bus.
   */

  priv = (FAR struct mtd_rwbuffer_s *)
          kmm_zalloc(sizeof(struct mtd_rwbuffer_s));
  if (!priv)
    {
      ferr("ERROR: Failed to allocate mtd_rwbuffer\n");
      return NULL;
    }

  /* Initialize the allocated structure. (unsupported methods/fields
   * were already nullified by kmm_zalloc).
   */

  priv->mtd.erase    = mtd_erase;  /* Our MTD erase method */
  priv->mtd.bread    = mtd_bread;  /* Our MTD bread method */
  priv->mtd.bwrite   = mtd_bwrite; /* Our MTD bwrite method */
  priv->mtd.read     = mtd_read;   /* Our MTD read method */
  priv->mtd.ioctl    = mtd_ioctl;  /* Our MTD ioctl method */
  priv->mtd.name     = "rwbuffer";

  priv->dev          = mtd;        /* The contained MTD instance */

  /* Sectors per block.  The erase block size must be an even multiple
   * of the sector size.
   */

  priv->spb          = geo.erasesize / geo.blocksize;
  DEBUGASSERT((size_t)priv->spb * geo.blocksize == geo.erasesize);

  /* Values must be provided to rwb_initialize() */

  /* Supported geometry */

  priv->rwb.blocksize = geo.blocksize;
  priv->rwb.nblocks   = geo.neraseblocks * priv->spb;

  /* Buffer setup */

#ifdef CONFIG_DRVR_WRITEBUFFER
  priv->rwb.wrmaxblocks = CONFIG_MTD_NWRBLOCKS;
#endif
#ifdef CONFIG_DRVR_READAHEAD
  priv->rwb.rhmaxblocks = CONFIG_MTD_NRDBLOCKS;
#endif

  /* Callouts */

  priv->rwb.dev       = priv;             /* Device state passed to callouts */
  priv->rwb.wrflush   = mtd_flush;        /* Callout to flush buffer */
  priv->rwb.rhreload  = mtd_reload;       /* Callout to reload buffer */

  /* Initialize read-ahead/write buffering */

  ret = rwb_initialize(&priv->rwb);
  if (ret < 0)
    {
      ferr("ERROR: rwb_initialize failed: %d\n", ret);
      kmm_free(priv);
      return NULL;
    }

  /* Return the implementation-specific state structure as the MTD device */

  return &priv->mtd;
}

#endif /* CONFIG_DRVR_WRITEBUFFER || CONFIG_DRVR_READAHEAD */