342 lines
12 KiB
C
342 lines
12 KiB
C
/****************************************************************************
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* drivers/mtd/skeleton.c
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*
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* Copyright (C) 2015 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <errno.h>
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#include <nuttx/fs/ioctl.h>
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#include <nuttx/mtd/mtd.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* This type represents the state of the MTD device. The struct mtd_dev_s
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* must appear at the beginning of the definition so that you can freely
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* cast between pointers to struct mtd_dev_s and struct skel_dev_s.
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*/
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struct skel_dev_s
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{
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struct mtd_dev_s mtd;
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/* Other implementation specific data may follow here */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/* MTD driver methods */
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static int skel_erase(FAR struct mtd_dev_s *dev, off_t startblock,
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size_t nblocks);
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static ssize_t skel_bread(FAR struct mtd_dev_s *dev, off_t startblock,
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size_t nblocks, FAR uint8_t *buf);
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static ssize_t skel_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
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size_t nblocks, FAR const uint8_t *buf);
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static ssize_t skel_read(FAR struct mtd_dev_s *dev, off_t offset,
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size_t nbytes, FAR uint8_t *buffer);
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#ifdef CONFIG_MTD_BYTE_WRITE
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static ssize_t skel_write(FAR struct mtd_dev_s *dev, off_t offset,
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size_t nbytes, FAR const uint8_t *buffer);
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#endif
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static int skel_ioctl(FAR struct mtd_dev_s *dev, int cmd,
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unsigned long arg);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* This structure holds the state of the MTD driver */
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static struct skel_dev_s g_skeldev =
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{
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{
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skel_erase,
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skel_bread,
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skel_bwrite,
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skel_read,
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#ifdef CONFIG_MTD_BYTE_WRITE
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skel_write, /* Should be NULL if the byte write method is not supported */
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#endif
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skel_ioctl
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},
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/* Initialization of any other implementation specific data goes here */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: skel_erase
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*
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* Description:
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* Erase several blocks, each of the size previously reported.
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*
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****************************************************************************/
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static int skel_erase(FAR struct mtd_dev_s *dev, off_t startblock,
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size_t nblocks)
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{
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FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
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/* The interface definition assumes that all erase blocks are the same
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* size. If that is not true for this particular device, then transform
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* the start block and nblocks as necessary.
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*/
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/* Erase the specified blocks and return status (OK or a negated errno) */
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return OK;
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}
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/****************************************************************************
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* Name: skel_bread
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*
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* Description:
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* Read the specified number of blocks into the user provided buffer.
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*
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****************************************************************************/
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static ssize_t skel_bread(FAR struct mtd_dev_s *dev, off_t startblock,
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size_t nblocks, FAR uint8_t *buf)
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{
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FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
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/* The interface definition assumes that all read/write blocks are the
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* same size. If that is not true for this particular device, then
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* transform the start block and nblocks as necessary.
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*/
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/* Read the specified blocks into the provided user buffer and return
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* status (The positive, number of blocks actually read or a negated
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* errno).
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*/
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return 0;
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}
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/****************************************************************************
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* Name: skel_bwrite
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*
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* Description:
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* Write the specified number of blocks from the user provided buffer.
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*
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****************************************************************************/
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static ssize_t skel_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
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size_t nblocks, FAR const uint8_t *buf)
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{
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FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
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/* The interface definition assumes that all read/write blocks are the
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* same size. If that is not true for this particular device, then
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* transform the start block and nblocks as necessary.
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*/
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/* Write the specified blocks from the provided user buffer and return
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* status (The positive, number of blocks actually written or a negated
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* errno)
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*/
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return 0;
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}
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/****************************************************************************
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* Name: skel_read
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*
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* Description:
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* Read the specified number of bytes to the user provided buffer.
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*
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****************************************************************************/
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static ssize_t skel_read(FAR struct mtd_dev_s *dev, off_t offset,
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size_t nbytes, FAR uint8_t *buffer)
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{
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FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
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/* Some devices may support byte oriented read (optional). Byte-oriented
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* writing is inherently block oriented on most MTD devices and is not
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* supported. It is recommended that low-level drivers not support read()
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* if it requires buffering -- let the higher level logic handle that. If
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* the read method is not implemented, just set the method pointer to NULL
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* in the struct mtd_dev_s instance.
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*/
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/* The interface definition assumes that all read/write blocks are the
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* same size. If that is not true for this particular device, then
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* transform the start block and nblocks as necessary.
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*/
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/* Read the specified bytes into the provided user buffer and return
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* status (The positive, number of bytes actually read or a negated
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* errno)
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*/
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return 0;
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}
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/****************************************************************************
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* Name: skel_write
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*
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* Description:
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* Some FLASH parts have the ability to write an arbitrary number of
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* bytes to an arbitrary offset on the device. This method should be
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* implement only for devices that support such access.
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*
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****************************************************************************/
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#ifdef CONFIG_MTD_BYTE_WRITE
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static ssize_t skel_write(FAR struct mtd_dev_s *dev, off_t offset,
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size_t nbytes, FAR const uint8_t *buffer)
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{
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return -ENOSYS;
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}
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#endif
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/****************************************************************************
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* Name: skel_ioctl
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****************************************************************************/
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static int skel_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
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{
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FAR struct skel_dev_s *priv = (FAR struct skel_dev_s *)dev;
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int ret = -EINVAL; /* Assume good command with bad parameters */
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switch (cmd)
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{
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case MTDIOC_GEOMETRY:
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{
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FAR struct mtd_geometry_s *geo = (FAR struct mtd_geometry_s *)arg;
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if (geo)
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{
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/* Populate the geometry structure with information needed to know
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* the capacity and how to access the device.
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*
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* NOTE: that the device is treated as though it where just an array
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* of fixed size blocks. That is most likely not true, but the client
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* will expect the device logic to do whatever is necessary to make it
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* appear so.
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*/
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geo->blocksize = 512; /* Size of one read/write block */
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geo->erasesize = 4096; /* Size of one erase block */
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geo->neraseblocks = 1024; /* Number of erase blocks */
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ret = OK;
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}
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}
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break;
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case MTDIOC_XIPBASE:
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{
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FAR void **ppv = (FAR void**)arg;
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if (ppv)
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{
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/* If media is directly acccesible, return (void*) base address
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* of device memory. NULL otherwise. It is acceptable to omit
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* this case altogether and simply return -ENOTTY.
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*/
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*ppv = NULL;
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ret = OK;
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}
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}
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break;
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case MTDIOC_BULKERASE:
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{
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/* Erase the entire device */
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ret = OK;
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}
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break;
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default:
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ret = -ENOTTY; /* Bad command */
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break;
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}
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: skel_initialize
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*
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* Description:
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* Create and initialize an MTD device instance. MTD devices are not
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* registered in the file system, but are created as instances that can
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* be bound to other functions (such as a block or character driver front
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* end).
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*
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****************************************************************************/
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FAR struct mtd_dev_s *skel_initialize(void)
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{
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/* Allocate an instance of the private data structure -- OR, if there can
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* only be a single instance of the driver, then use a shared, global
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* device structure.
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*/
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/* Perform initialization as necessary */
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#ifdef CONFIG_MTD_REGISTRATION
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/* Register the MTD with the procfs system if enabled */
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mtd_register(&priv->mtd, "skeleton");
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#endif
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/* Return the implementation-specific state structure as the MTD device */
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return (FAR struct mtd_dev_s *)&g_skeldev;
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}
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