/**************************************************************************** * drivers/mtd/rammtd.c * * Copyright (C) 2011-2012 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include /**************************************************************************** * 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 int ram_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg); /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * 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 if (newvalue != srcvalue) { dbg("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_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) { /* 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**)((uintptr_t)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; }