/****************************************************************************
* drivers/mtd/skeleton.c
*
* Copyright (C) 2018 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <errno.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/mtd/mtd.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* 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 skel_dev_s.
*/
struct skel_dev_s
{
struct mtd_dev_s mtd;
/* Other implementation specific data may follow here */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* MTD driver methods */
static int skel_erase(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks);
static ssize_t skel_bread(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR uint8_t *buf);
static ssize_t skel_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR const uint8_t *buf);
static ssize_t skel_read(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR uint8_t *buffer);
#ifdef CONFIG_MTD_BYTE_WRITE
static ssize_t skel_write(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR const uint8_t *buffer);
#endif
static int skel_ioctl(FAR struct mtd_dev_s *dev, int cmd,
unsigned long arg);
/****************************************************************************
* Private Data
****************************************************************************/
/* This structure holds the state of the MTD driver */
static struct skel_dev_s g_skeldev =
{
{
skel_erase,
skel_bread,
skel_bwrite,
skel_read,
#ifdef CONFIG_MTD_BYTE_WRITE
skel_write, /* Should be NULL if the byte write method is not supported */
#endif
skel_ioctl
},
/* Initialization of any other implementation specific data goes here */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: skel_erase
*
* Description:
* Erase several blocks, each of the size previously reported.
*
****************************************************************************/
static int skel_erase(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks)
{
FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
/* The interface definition assumes that all erase blocks are the same
* size. If that is not true for this particular device, then transform
* the start block and nblocks as necessary.
*/
/* Erase the specified blocks and return status (OK or a negated errno) */
return OK;
}
/****************************************************************************
* Name: skel_bread
*
* Description:
* Read the specified number of blocks into the user provided buffer.
*
****************************************************************************/
static ssize_t skel_bread(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR uint8_t *buf)
{
FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
/* The interface definition assumes that all read/write blocks are the
* same size. If that is not true for this particular device, then
* transform the start block and nblocks as necessary.
*/
/* Read the specified blocks into the provided user buffer and return
* status (The positive, number of blocks actually read or a negated
* errno).
*/
return 0;
}
/****************************************************************************
* Name: skel_bwrite
*
* Description:
* Write the specified number of blocks from the user provided buffer.
*
****************************************************************************/
static ssize_t skel_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR const uint8_t *buf)
{
FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
/* The interface definition assumes that all read/write blocks are the
* same size. If that is not true for this particular device, then
* transform the start block and nblocks as necessary.
*/
/* Write the specified blocks from the provided user buffer and return
* status (The positive, number of blocks actually written or a negated
* errno)
*/
return 0;
}
/****************************************************************************
* Name: skel_read
*
* Description:
* Read the specified number of bytes to the user provided buffer.
*
****************************************************************************/
static ssize_t skel_read(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR uint8_t *buffer)
{
FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
/* Some devices may support byte oriented read (optional). Byte-oriented
* writing is inherently block oriented on most MTD devices and is not
* supported. It is recommended that low-level drivers not support read()
* if it requires buffering -- let the higher level logic handle that. If
* the read method is not implemented, just set the method pointer to NULL
* in the struct mtd_dev_s instance.
*/
/* The interface definition assumes that all read/write blocks are the
* same size. If that is not true for this particular device, then
* transform the start block and nblocks as necessary.
*/
/* Read the specified bytes into the provided user buffer and return
* status (The positive, number of bytes actually read or a negated
* errno)
*/
return 0;
}
/****************************************************************************
* Name: skel_write
*
* Description:
* Some FLASH parts have the ability to write an arbitrary number of
* bytes to an arbitrary offset on the device. This method should be
* implement only for devices that support such access.
*
****************************************************************************/
#ifdef CONFIG_MTD_BYTE_WRITE
static ssize_t skel_write(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR const uint8_t *buffer)
{
return -ENOSYS;
}
#endif
/****************************************************************************
* Name: skel_ioctl
****************************************************************************/
static int skel_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
{
FAR struct skel_dev_s *priv = (FAR struct skel_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 needed 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 = 512; /* Size of one read/write block */
geo->erasesize = 4096; /* Size of one erase block */
geo->neraseblocks = 1024; /* Number of erase blocks */
ret = OK;
}
}
break;
case MTDIOC_XIPBASE:
{
FAR void **ppv = (FAR void**)arg;
if (ppv)
{
/* If media is directly acccesible, return (void*) base address
* of device memory. NULL otherwise. It is acceptable to omit
* this case altogether and simply return -ENOTTY.
*/
*ppv = NULL;
ret = OK;
}
}
break;
case MTDIOC_BULKERASE:
{
/* Erase the entire device */
ret = OK;
}
break;
default:
ret = -ENOTTY; /* Bad command */
break;
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: skel_initialize
*
* Description:
* Create and initialize an MTD device instance. 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 *skel_initialize(void)
{
/* Allocate an instance of the private data structure -- OR, if there can
* only be a single instance of the driver, then use a shared, global
* device structure.
*/
/* Return the implementation-specific state structure as the MTD device */
return (FAR struct mtd_dev_s *)&g_skeldev;
}