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nuttx-bb/nuttx/drivers/mtd/rammtd.c

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/****************************************************************************
* drivers/mtd/rammtd.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* 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/ioctl.h>
#include <nuttx/mtd.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#ifndef CONFIG_RAMMTD_BLOCKSIZE
# define CONFIG_RAMMTD_BLOCKSIZE 512
#endif
#ifndef CONFIG_RAMMTD_ERASESIZE
# define CONFIG_RAMMTD_ERASESIZE 4096
#endif
#ifndef CONFIG_RAMMTD_ERASESTATE
# define CONFIG_RAMMTD_ERASESTATE 0xff
#endif
#if CONFIG_RAMMTD_BLOCKSIZE > CONFIG_RAMMTD_ERASESIZE
# error "Must have CONFIG_RAMMTD_BLOCKSIZE <= CONFIG_RAMMTD_ERASESIZE"
#endif
#undef CONFIG_RAMMTD_BLKPER
#define CONFIG_RAMMTD_BLKPER (CONFIG_RAMMTD_ERASESIZE/CONFIG_RAMMTD_BLOCKSIZE)
#if CONFIG_RAMMTD_BLKPER*CONFIG_RAMMTD_BLOCKSIZE != CONFIG_RAMMTD_ERASESIZE
# error "CONFIG_RAMMTD_ERASESIZE must be an even multiple of CONFIG_RAMMTD_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 ram_dev_s.
*/
struct ram_dev_s
{
struct mtd_dev_s mtd; /* MTD device */
FAR uint8_t *start; /* Start of RAM */
size_t nblocks; /* Number of erase blocks */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* MTD driver methods */
static int ram_erase(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks);
static ssize_t ram_bread(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks,
FAR uint8_t *buf);
static ssize_t ram_bwrite(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks,
FAR const uint8_t *buf);
static int ram_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ram_erase
****************************************************************************/
static int ram_erase(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks)
{
FAR struct ram_dev_s *priv = (FAR struct ram_dev_s *)dev;
off_t offset;
size_t nbytes;
DEBUGASSERT(dev);
/* Convert the erase block to a logical block and the number of blocks
* in logical block numbers
*/
startblock *= CONFIG_RAMMTD_BLKPER;
nblocks *= CONFIG_RAMMTD_BLKPER;
/* Don't let the erase exceed the size of the ram buffer */
if (startblock >= priv->nblocks)
{
return 0;
}
if (startblock + nblocks >= priv->nblocks)
{
nblocks = priv->nblocks - nblocks;
}
/* Get the offset corresponding to the first block and the size
* corresponding to the number of blocks.
*/
offset = startblock * CONFIG_RAMMTD_BLOCKSIZE;
nbytes = nblocks * CONFIG_RAMMTD_BLOCKSIZE;
/* Then erase the data in RAM */
memset(&priv->start[offset], CONFIG_RAMMTD_ERASESTATE, nbytes);
return OK;
}
/****************************************************************************
* Name: ram_bread
****************************************************************************/
static ssize_t ram_bread(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks,
FAR uint8_t *buf)
{
FAR struct ram_dev_s *priv = (FAR struct ram_dev_s *)dev;
off_t offset;
size_t nbytes;
DEBUGASSERT(dev && buf);
/* Don't let the read exceed the size of the ram buffer */
if (startblock >= priv->nblocks)
{
return 0;
}
if (startblock + nblocks >= priv->nblocks)
{
nblocks = priv->nblocks - nblocks;
}
/* Get the offset corresponding to the first block and the size
* corresponding to the number of blocks.
*/
offset = startblock * CONFIG_RAMMTD_BLOCKSIZE;
nbytes = nblocks * CONFIG_RAMMTD_BLOCKSIZE;
/* Then read the data frp, RAM */
memcpy(buf, &priv->start[offset], nbytes);
return nblocks;
}
/****************************************************************************
* Name: ram_bwrite
****************************************************************************/
static ssize_t ram_bwrite(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks,
FAR const uint8_t *buf)
{
FAR struct ram_dev_s *priv = (FAR struct ram_dev_s *)dev;
off_t offset;
size_t nbytes;
DEBUGASSERT(dev && buf);
/* Don't let the write exceed the size of the ram buffer */
if (startblock >= priv->nblocks)
{
return 0;
}
if (startblock + nblocks >= priv->nblocks)
{
nblocks = priv->nblocks - nblocks;
}
/* Get the offset corresponding to the first block and the size
* corresponding to the number of blocks.
*/
offset = startblock * CONFIG_RAMMTD_BLOCKSIZE;
nbytes = nblocks * CONFIG_RAMMTD_BLOCKSIZE;
/* Then write the data to RAM */
memcpy(&priv->start[offset], buf, nbytes);
return nblocks;
}
/****************************************************************************
* Name: ram_ioctl
****************************************************************************/
static int ram_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
{
FAR struct ram_dev_s *priv = (FAR struct ram_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 *)arg;
if (geo)
{
/* Populate the geometry structure with information need to know
* the capacity and how to access the device.
*/
geo->blocksize = CONFIG_RAMMTD_BLOCKSIZE;
geo->erasesize = CONFIG_RAMMTD_ERASESIZE;
geo->neraseblocks = priv->nblocks;
ret = OK;
}
}
break;
case MTDIOC_XIPBASE:
{
FAR void **ppv = (FAR void**)arg;
if (ppv)
{
/* Return (void*) base address of device memory */
*ppv = (FAR void*)priv->start;
ret = OK;
}
}
break;
case MTDIOC_BULKERASE:
{
size_t size = priv->nblocks * CONFIG_RAMMTD_ERASESIZE;
/* Erase the entire device */
memset(priv->start, CONFIG_RAMMTD_ERASESTATE, size);
ret = OK;
}
break;
default:
ret = -ENOTTY; /* Bad command */
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: rammtd_initialize
*
* Description:
* Create and initialize a RAM MTD device instance.
*
* Input Parameters:
* start - Address of the beginning of the allocated RAM regions.
* size - The size in bytes of the allocated RAM region.
*
****************************************************************************/
FAR struct mtd_dev_s *rammtd_initialize(FAR uint8_t *start, size_t size)
{
FAR struct ram_dev_s *priv;
size_t nblocks;
/* Create an instance of the RAM MTD device state structure */
priv = (FAR struct ram_dev_s *)kmalloc(sizeof(struct ram_dev_s));
if (!priv)
{
fdbg("Failed to allocate the RAM MTD state structure\n");
return NULL;
}
/* Force the size to be an even number of the erase block size */
nblocks = size / CONFIG_RAMMTD_ERASESIZE;
if (nblocks <= 0)
{
fdbg("Need to provide at least one full erase block\n");
return NULL;
}
/* Perform initialization as necessary */
priv->mtd.erase = ram_erase;
priv->mtd.bread = ram_bread;
priv->mtd.bwrite = ram_bwrite;
priv->mtd.ioctl = ram_ioctl;
priv->mtd.erase = ram_erase;
priv->start = start;
priv->nblocks = nblocks;
return &priv->mtd;
}
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