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incubator-nuttx/drivers/mtd/nullmtd.c

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/****************************************************************************
* drivers/mtd/nullmtd.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 <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/mtd/mtd.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_NULLMTD_BLOCKSIZE
# define CONFIG_NULLMTD_BLOCKSIZE 512
#endif
#ifndef CONFIG_NULLMTD_ERASESIZE
# define CONFIG_NULLMTD_ERASESIZE 4096
#endif
#ifndef CONFIG_NULLMTD_ERASESTATE
# define CONFIG_NULLMTD_ERASESTATE 0xff
#endif
#if CONFIG_NULLMTD_ERASESTATE != 0xff && CONFIG_NULLMTD_ERASESTATE != 0x00
# error "Unsupported value for CONFIG_NULLMTD_ERASESTATE"
#endif
#if CONFIG_NULLMTD_BLOCKSIZE > CONFIG_NULLMTD_ERASESIZE
# error "Must have CONFIG_NULLMTD_BLOCKSIZE <= CONFIG_NULLMTD_ERASESIZE"
#endif
#undef NULLMTD_BLKPER
#define NULLMTD_BLKPER (CONFIG_NULLMTD_ERASESIZE/CONFIG_NULLMTD_BLOCKSIZE)
#if NULLMTD_BLKPER*CONFIG_NULLMTD_BLOCKSIZE != CONFIG_NULLMTD_ERASESIZE
# error "CONFIG_NULLMTD_ERASESIZE must be an even multiple of CONFIG_NULLMTD_BLOCKSIZE"
#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 null_dev_s.
*/
struct null_dev_s
{
struct mtd_dev_s mtd; /* MTD device */
size_t nblocks; /* Number of erase blocks */
size_t erasesize; /* Offset from start of file */
size_t blocksize; /* Offset from start of file */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
#define nullmtd_read(dest, len) memset(dest, CONFIG_NULLMTD_ERASESTATE, len)
/* MTD driver methods */
static int nullmtd_erase(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks);
static ssize_t nullmtd_bread(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR uint8_t *buf);
static ssize_t nullmtd_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR const uint8_t *buf);
static ssize_t nullmtd_byteread(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR uint8_t *buf);
#ifdef CONFIG_MTD_BYTE_WRITE
static ssize_t nullmtd_bytewrite(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR const uint8_t *buf);
#endif
static int nullmtd_ioctl(FAR struct mtd_dev_s *dev, int cmd,
unsigned long arg);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nullmtd_erase
****************************************************************************/
static int nullmtd_erase(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks)
{
FAR struct null_dev_s *priv = (FAR struct null_dev_s *)dev;
DEBUGASSERT(dev);
/* Don't let the erase exceed the configured size of the device */
if (startblock >= priv->nblocks)
{
return 0;
}
return OK;
}
/****************************************************************************
* Name: nullmtd_bread
****************************************************************************/
static ssize_t nullmtd_bread(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR uint8_t *buf)
{
FAR struct null_dev_s *priv = (FAR struct null_dev_s *)dev;
off_t maxblock;
size_t nbytes;
DEBUGASSERT(dev && buf);
/* Don't let the read exceed the configured size of the device */
maxblock = priv->nblocks * (priv->erasesize / priv->blocksize);
if (startblock >= maxblock)
{
return 0;
}
if (startblock + nblocks > maxblock)
{
nblocks = maxblock - startblock;
}
/* Get the size corresponding to the number of blocks.
*/
nbytes = nblocks * priv->blocksize;
/* Then read the data from the file */
nullmtd_read(buf, nbytes);
return nblocks;
}
/****************************************************************************
* Name: nullmtd_bwrite
****************************************************************************/
static ssize_t nullmtd_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR const uint8_t *buf)
{
FAR struct null_dev_s *priv = (FAR struct null_dev_s *)dev;
off_t maxblock;
DEBUGASSERT(dev && buf);
/* Don't let the write exceed the configured size of the device */
maxblock = priv->nblocks * (priv->erasesize / priv->blocksize);
if (startblock >= maxblock)
{
return 0;
}
if (startblock + nblocks > maxblock)
{
nblocks = maxblock - startblock;
}
return nblocks;
}
/****************************************************************************
* Name: nullmtd_byteread
****************************************************************************/
static ssize_t nullmtd_byteread(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR uint8_t *buf)
{
FAR struct null_dev_s *priv = (FAR struct null_dev_s *)dev;
off_t maxoffset;
DEBUGASSERT(dev && buf);
/* Don't let the read exceed the configured size of the device */
maxoffset = priv->nblocks * priv->erasesize;
if (offset >= maxoffset)
{
return 0;
}
if (offset + nbytes > maxoffset)
{
nbytes = maxoffset - offset;
}
nullmtd_read(buf, nbytes);
return nbytes;
}
/****************************************************************************
* Name: nullmtd_bytewrite
****************************************************************************/
#ifdef CONFIG_MTD_BYTE_WRITE
static ssize_t nullmtd_bytewrite(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR const uint8_t *buf)
{
FAR struct null_dev_s *priv = (FAR struct null_dev_s *)dev;
off_t maxoffset;
DEBUGASSERT(dev && buf);
/* Don't let the write exceed the configured size of the device */
maxoffset = priv->nblocks * priv->erasesize;
if (offset >= maxoffset)
{
return 0;
}
if (offset + nbytes > maxoffset)
{
nbytes = maxoffset - offset;
}
return nbytes;
}
#endif
/****************************************************************************
* Name: nullmtd_ioctl
****************************************************************************/
static int nullmtd_ioctl(FAR struct mtd_dev_s *dev, int cmd,
unsigned long arg)
{
FAR struct null_dev_s *priv = (FAR struct null_dev_s *)dev;
int ret = -EINVAL; /* Assume good command with bad parameters */
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.
*/
geo->blocksize = priv->blocksize;
geo->erasesize = priv->erasesize;
geo->neraseblocks = priv->nblocks;
ret = OK;
}
}
break;
case BIOC_PARTINFO:
{
FAR struct partition_info_s *info =
(FAR struct partition_info_s *)arg;
if (info != NULL)
{
info->numsectors = priv->nblocks *
priv->erasesize / priv->blocksize;
info->sectorsize = priv->blocksize;
info->startsector = 0;
info->parent[0] = '\0';
ret = OK;
}
}
break;
case MTDIOC_BULKERASE:
{
/* Erase the entire device */
ret = nullmtd_erase(dev, 0, priv->nblocks);
}
break;
case MTDIOC_ERASESTATE:
{
FAR uint8_t *result = (FAR uint8_t *)arg;
*result = CONFIG_NULLMTD_ERASESTATE;
ret = OK;
}
break;
default:
ret = -ENOTTY; /* Bad command */
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nullmtd_initialize
*
* Description:
* Create and initialize a MTD null device instance.
*
* Input Parameters:
* mtdlen - total size of MTD device
* sectsize
*
****************************************************************************/
FAR struct mtd_dev_s *nullmtd_initialize(size_t mtdlen, int16_t sectsize,
int32_t erasesize)
{
FAR struct null_dev_s *priv;
size_t nblocks;
/* Create an instance of the RAM MTD device state structure */
priv = kmm_zalloc(sizeof(struct null_dev_s));
if (!priv)
{
ferr("ERROR: Failed to allocate the RAM MTD state structure\n");
return NULL;
}
/* Set the block size based on the provided sectsize parameter */
if (sectsize <= 0)
{
priv->blocksize = CONFIG_NULLMTD_BLOCKSIZE;
}
else
{
priv->blocksize = sectsize;
}
/* Set the erase size based on the provided erasesize parameter */
if (erasesize <= 0)
{
priv->erasesize = CONFIG_NULLMTD_ERASESIZE;
}
else
{
priv->erasesize = erasesize;
}
/* Force the size to be an even number of the erase block size */
nblocks = mtdlen / priv->erasesize;
if (nblocks < 1)
{
ferr("ERROR: Need to provide at least one full erase block\n");
kmm_free(priv);
return NULL;
}
/* Perform initialization as necessary. (unsupported methods were
* nullified by kmm_zalloc).
*/
priv->mtd.erase = nullmtd_erase;
priv->mtd.bread = nullmtd_bread;
priv->mtd.bwrite = nullmtd_bwrite;
priv->mtd.read = nullmtd_byteread;
#ifdef CONFIG_MTD_BYTE_WRITE
priv->mtd.write = nullmtd_bytewrite;
#endif
priv->mtd.ioctl = nullmtd_ioctl;
priv->mtd.name = "nullmtd";
priv->nblocks = nblocks;
return &priv->mtd;
}
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