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incubator-nuttx/drivers/mtd/rammtd.c

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/****************************************************************************
* drivers/mtd/rammtd.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_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_ERASESTATE != 0xff && CONFIG_RAMMTD_ERASESTATE != 0x00
# error "Unsupported value for CONFIG_RAMMTD_ERASESTATE"
#endif
#if CONFIG_RAMMTD_BLOCKSIZE > CONFIG_RAMMTD_ERASESIZE
# error "Must have CONFIG_RAMMTD_BLOCKSIZE <= CONFIG_RAMMTD_ERASESIZE"
#endif
#undef RAMMTD_BLKPER
#define RAMMTD_BLKPER (CONFIG_RAMMTD_ERASESIZE/CONFIG_RAMMTD_BLOCKSIZE)
#if 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
****************************************************************************/
/* The RAM MTD driver may be useful just as it is, but another good use of
* the RAM MTD driver is as a FLASH simulation -- to support testing of FLASH
* based logic without having FLASH. CONFIG_RAMMTD_FLASHSIM will add some
* extra logic to improve the level of FLASH simulation.
*/
#define ram_read(dest, src, len) memcpy(dest, src, len)
#ifdef CONFIG_RAMMTD_FLASHSIM
static void *ram_write(FAR void *dest, FAR const void *src, size_t len);
#else
# define ram_write(dest, src, len) memcpy(dest, src, len)
#endif
/* 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 ssize_t ram_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 ram_bytewrite(FAR struct mtd_dev_s *dev,
off_t offset,
size_t nbytes,
FAR const uint8_t *buf);
#endif
static int ram_ioctl(FAR struct mtd_dev_s *dev,
int cmd,
unsigned long arg);
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ram_write
****************************************************************************/
#ifdef CONFIG_RAMMTD_FLASHSIM
static void *ram_write(FAR void *dest, FAR const void *src, size_t len)
{
FAR uint8_t *pout = (FAR uint8_t *)dest;
FAR const uint8_t *pin = (FAR const uint8_t *)src;
while (len-- > 0)
{
/* Get the source and destination values */
uint8_t oldvalue = *pout;
uint8_t srcvalue = *pin++;
uint8_t newvalue;
/* Get the new destination value, accounting for bits that cannot be
* changes because they are not in the erased state.
*/
#if CONFIG_RAMMTD_ERASESTATE == 0xff
newvalue = oldvalue & srcvalue; /* We can only clear bits */
#else /* CONFIG_RAMMTD_ERASESTATE == 0x00 */
newvalue = oldvalue | srcvalue; /* We can only set bits */
#endif
/* Report any attempt to change the value of bits that are not in the
* erased state.
*/
#ifdef CONFIG_DEBUG_FEATURES
if (newvalue != srcvalue)
{
_err("ERROR: Bad write: source=%02x dest=%02x result=%02x\n",
srcvalue, oldvalue, newvalue);
}
#endif
/* Write the modified value to simulated FLASH */
*pout++ = newvalue;
}
return dest;
}
#endif
/****************************************************************************
* 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);
/* 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 - startblock;
}
/* Convert the erase block to a logical block and the number of blocks
* in logical block numbers
*/
startblock *= RAMMTD_BLKPER;
nblocks *= RAMMTD_BLKPER;
/* 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;
off_t maxblock;
size_t nbytes;
DEBUGASSERT(dev && buf);
/* Don't let the read exceed the size of the ram buffer */
maxblock = priv->nblocks * RAMMTD_BLKPER;
if (startblock >= maxblock)
{
return 0;
}
if (startblock + nblocks > maxblock)
{
nblocks = maxblock - startblock;
}
/* 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 */
ram_read(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;
off_t maxblock;
size_t nbytes;
DEBUGASSERT(dev && buf);
/* Don't let the write exceed the size of the ram buffer */
maxblock = priv->nblocks * RAMMTD_BLKPER;
if (startblock >= maxblock)
{
return 0;
}
if (startblock + nblocks > maxblock)
{
nblocks = maxblock - startblock;
}
/* 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 */
ram_write(&priv->start[offset], buf, nbytes);
return nblocks;
}
/****************************************************************************
* Name: ram_byteread
****************************************************************************/
static ssize_t ram_byteread(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR uint8_t *buf)
{
FAR struct ram_dev_s *priv = (FAR struct ram_dev_s *)dev;
off_t maxoffset;
DEBUGASSERT(dev && buf);
/* Don't let the read exceed the size of the ram buffer */
maxoffset = priv->nblocks * CONFIG_RAMMTD_ERASESIZE;
if (offset >= maxoffset)
{
return 0;
}
if (offset + nbytes > maxoffset)
{
nbytes = maxoffset - offset;
}
ram_read(buf, &priv->start[offset], nbytes);
return nbytes;
}
/****************************************************************************
* Name: ram_bytewrite
****************************************************************************/
#ifdef CONFIG_MTD_BYTE_WRITE
static ssize_t ram_bytewrite(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes, FAR const uint8_t *buf)
{
FAR struct ram_dev_s *priv = (FAR struct ram_dev_s *)dev;
off_t maxoffset;
DEBUGASSERT(dev && buf);
/* Don't let the write exceed the size of the ram buffer */
maxoffset = priv->nblocks * CONFIG_RAMMTD_ERASESIZE;
if (offset >= maxoffset)
{
return 0;
}
if (offset + nbytes > maxoffset)
{
nbytes = maxoffset - offset;
}
/* Then write the data to RAM */
ram_write(&priv->start[offset], buf, nbytes);
return nbytes;
}
#endif
/****************************************************************************
* 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 *)((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 = CONFIG_RAMMTD_BLOCKSIZE;
geo->erasesize = CONFIG_RAMMTD_ERASESIZE;
geo->neraseblocks = priv->nblocks;
ret = OK;
}
}
break;
case BIOC_XIPBASE:
{
FAR void **ppv = (FAR void**)((uintptr_t)arg);
if (ppv)
{
/* Return (void*) base address of device memory */
*ppv = (FAR void *)priv->start;
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 *
CONFIG_RAMMTD_ERASESIZE /
CONFIG_RAMMTD_BLOCKSIZE;
info->sectorsize = CONFIG_RAMMTD_BLOCKSIZE;
info->startsector = 0;
info->parent[0] = '\0';
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;
case MTDIOC_ERASESTATE:
{
FAR uint8_t *result = (FAR uint8_t *)arg;
*result = CONFIG_RAMMTD_ERASESTATE;
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 *)kmm_zalloc(sizeof(struct ram_dev_s));
if (!priv)
{
ferr("ERROR: 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 < 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 = ram_erase;
priv->mtd.bread = ram_bread;
priv->mtd.bwrite = ram_bwrite;
priv->mtd.read = ram_byteread;
#ifdef CONFIG_MTD_BYTE_WRITE
priv->mtd.write = ram_bytewrite;
#endif
priv->mtd.ioctl = ram_ioctl;
priv->mtd.name = "rammtd";
priv->start = start;
priv->nblocks = nblocks;
return &priv->mtd;
}
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