incubator-nuttx/drivers/mtd/skeleton.c

338 lines
11 KiB
C

/****************************************************************************
* drivers/mtd/skeleton.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 <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)
{
memset(geo, 0, sizeof(*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 BIOC_PARTINFO:
{
FAR struct partition_info_s *info =
(FAR struct partition_info_s *)arg;
if (info != NULL)
{
info->numsectors = 8192;
info->sectorsize = 512;
info->startsector = 0;
info->parent[0] = '\0';
ret = OK;
}
}
break;
case BIOC_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;
}