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nuttx/drivers/mtd/at24xx.c
patacongo 7c1d6619fa Use calculations on constants to (slightly) reduce code size 
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4077 42af7a65-404d-4744-a932-0658087f49c3
2011-11-01 16:48:21 +00:00

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/************************************************************************************
* drivers/mtd/at24xx.c
* Driver for I2C-based at24cxx EEPROM(at24c32,at24c64,at24c128,at24c256)
*
* Copyright (C) 2011 Li Zhuoyi. All rights reserved.
* Author: Li Zhuoyi <lzyy.cn@gmail.com>
* History: 0.1 2011-08-20 initial version
*
* 2011-11-1 Added support for larger MTD block sizes: Hal Glenn <hglenn@2g-eng.com>
*
* Derived from drivers/mtd/m25px.c
*
* Copyright (C) 2009-2011 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 <stdbool.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/ioctl.h>
#include <nuttx/i2c.h>
#include <nuttx/mtd.h>
#ifdef CONFIG_MTD_AT24XX
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
/* As a minimum, the size of the AT24 part and its 7-bit I2C address are required. */
#ifndef CONFIG_AT24XX_SIZE
# warning "Assuming AT24 size 64"
# define CONFIG_AT24XX_SIZE 64
#endif
#ifndef CONFIG_AT24XX_ADDR
# warning "Assuming AT24 address of 0x50"
# define CONFIG_AT24XX_ADDR 0x50
#endif
/* Get the part configuration based on the size configuration */
#if CONFIG_AT24XX_SIZE == 32
# define AT24XX_NPAGES 128
# define AT24XX_PAGESIZE 32
#elif CONFIG_AT24XX_SIZE == 48
# define AT24XX_NPAGES 192
# define AT24XX_PAGESIZE 32
#elif CONFIG_AT24XX_SIZE == 64
# define AT24XX_NPAGES 256
# define AT24XX_PAGESIZE 32
#elif CONFIG_AT24XX_SIZE == 128
# define AT24XX_NPAGES 256
# define AT24XX_PAGESIZE 64
#elif CONFIG_AT24XX_SIZE == 256
# define AT24XX_NPAGES 512
# define AT24XX_PAGESIZE 64
#endif
/* For applications where a file system is used on the AT24, the tiny page sizes
* will result in very inefficient FLASH usage. In such cases, it is better if
* blocks are comprised of "clusters" of pages so that the file system block
* size is, say, 256 or 512 bytes. In any event, the block size *must* be an
* even multiple of the pages.
*/
#ifndef CONFIG_AT24XX_MTD_BLOCKSIZE
# warning "Assuming driver block size is the same as the FLASH page size"
# define CONFIG_AT24XX_MTD_BLOCKSIZE AT24XX_PAGESIZE
#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 at24c_dev_s.
*/
struct at24c_dev_s
{
struct mtd_dev_s mtd; /* MTD interface */
FAR struct i2c_dev_s *dev; /* Saved I2C interface instance */
uint8_t addr; /* I2C address */
uint16_t pagesize; /* 32, 63 */
uint16_t npages; /* 128, 256, 512, 1024 */
};
/************************************************************************************
* Private Function Prototypes
************************************************************************************/
/* MTD driver methods */
static int at24c_erase(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks);
static ssize_t at24c_bread(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR uint8_t *buf);
static ssize_t at24c_bwrite(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR const uint8_t *buf);
static ssize_t at24c_read(FAR struct mtd_dev_s *dev, off_t offset,
size_t nbytes,FAR uint8_t *buffer);
static int at24c_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg);
/************************************************************************************
* Private Data
************************************************************************************/
/* At present, only a signal AT24 part is supported. In this case, a statically
* allocated state structure may be used.
*/
static struct at24c_dev_s g_at24c;
/************************************************************************************
* Private Functions
************************************************************************************/
static int at24c_eraseall(FAR struct at24c_dev_s *priv)
{
int startblock = 0;
uint8_t buf[AT24XX_PAGESIZE + 2];
memset(&buf[2],0xff,priv->pagesize);
I2C_SETADDRESS(priv->dev,priv->addr,7);
I2C_SETFREQUENCY(priv->dev,100000);
for (startblock = 0; startblock < priv->npages; startblock++)
{
uint16_t offset = startblock * priv->pagesize;
buf[1] = offset & 0xff;
buf[0] = (offset >> 8) & 0xff;
while (I2C_WRITE(priv->dev, buf, 2) < 0)
{
usleep(1000);
}
I2C_WRITE(priv->dev, buf, priv->pagesize + 2);
}
return OK;
}
/************************************************************************************
* Name: at24c_erase
************************************************************************************/
static int at24c_erase(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks)
{
/* EEprom need not erase */
return (int)nblocks;
}
/************************************************************************************
* Name: at24c_bread
************************************************************************************/
static ssize_t at24c_bread(FAR struct mtd_dev_s *dev, off_t startblock,
size_t nblocks, FAR uint8_t *buffer)
{
FAR struct at24c_dev_s *priv = (FAR struct at24c_dev_s *)dev;
size_t blocksleft;
#if CONFIG_AT24XX_MTD_BLOCKSIZE > AT24XX_PAGESIZE
startblock *= (CONFIG_AT24XX_MTD_BLOCKSIZE / AT24XX_PAGESIZE);
nblocks *= (CONFIG_AT24XX_MTD_BLOCKSIZE / AT24XX_PAGESIZE);
#endif
blocksleft = nblocks;
fvdbg("startblock: %08lx nblocks: %d\n", (long)startblock, (int)nblocks);
if (startblock >= priv->npages)
{
return 0;
}
if (startblock + nblocks > priv->npages)
{
nblocks = priv->npages - startblock;
}
I2C_SETADDRESS(priv->dev,priv->addr,7);
I2C_SETFREQUENCY(priv->dev,100000);
while (blocksleft-- > 0)
{
uint16_t offset = startblock * priv->pagesize;
uint8_t buf[2];
buf[1] = offset & 0xff;
buf[0] = (offset >> 8) & 0xff;
while (I2C_WRITE(priv->dev, buf, 2) < 0)
{
fvdbg("wait\n");
usleep(1000);
}
I2C_READ(priv->dev, buffer, priv->pagesize);
startblock++;
buffer += priv->pagesize;
}
#if CONFIG_AT24XX_MTD_BLOCKSIZE > AT24XX_PAGESIZE
return nblocks / (CONFIG_AT24XX_MTD_BLOCKSIZE / AT24XX_PAGESIZE);
#else
return nblocks;
#endif
}
/************************************************************************************
* Name: at24c_bwrite
*
* Operates on MTD block's and translates to FLASH pages
*
************************************************************************************/
static ssize_t at24c_bwrite(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks,
FAR const uint8_t *buffer)
{
FAR struct at24c_dev_s *priv = (FAR struct at24c_dev_s *)dev;
size_t blocksleft;
uint8_t buf[AT24XX_PAGESIZE+2];
#if CONFIG_AT24XX_MTD_BLOCKSIZE > AT24XX_PAGESIZE
startblock *= (CONFIG_AT24XX_MTD_BLOCKSIZE / AT24XX_PAGESIZE);
nblocks *= (CONFIG_AT24XX_MTD_BLOCKSIZE / AT24XX_PAGESIZE);
#endif
blocksleft = nblocks;
if (startblock >= priv->npages)
{
return 0;
}
if (startblock + nblocks > priv->npages)
{
nblocks = priv->npages - startblock;
}
fvdbg("startblock: %08lx nblocks: %d\n", (long)startblock, (int)nblocks);
I2C_SETADDRESS(priv->dev, priv->addr, 7);
I2C_SETFREQUENCY(priv->dev, 100000);
while (blocksleft-- > 0)
{
uint16_t offset = startblock * priv->pagesize;
while (I2C_WRITE(priv->dev, (uint8_t *)&offset, 2) < 0)
{
fvdbg("wait\n");
usleep(1000);
}
buf[1] = offset & 0xff;
buf[0] = (offset >> 8) & 0xff;
memcpy(&buf[2], buffer, priv->pagesize);
I2C_WRITE(priv->dev, buf, priv->pagesize + 2);
startblock++;
buffer += priv->pagesize;
}
#if CONFIG_AT24XX_MTD_BLOCKSIZE > AT24XX_PAGESIZE
return nblocks / (CONFIG_AT24XX_MTD_BLOCKSIZE / AT24XX_PAGESIZE);
#else
return nblocks;
#endif
}
/************************************************************************************
* Name: at24c_ioctl
************************************************************************************/
static int at24c_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
{
FAR struct at24c_dev_s *priv = (FAR struct at24c_dev_s *)dev;
int ret = -EINVAL; /* Assume good command with bad parameters */
fvdbg("cmd: %d \n", cmd);
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.
*
* 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.
*
* blocksize:
* May be user defined. The block size for the at24XX devices may be
* larger than the page size in order to better support file systems.
* The read and write functions translate BLOCKS to pages for the
* small flash devices
* erasesize:
* It has to be at least as big as the blocksize, bigger serves no
* purpose.
* neraseblocks
* Note that the device size is in kilobits and must be scaled by
* 1024 / 8
*/
#if CONFIG_AT24XX_MTD_BLOCKSIZE > AT24XX_PAGESIZE
geo->blocksize = CONFIG_AT24XX_MTD_BLOCKSIZE;
geo->erasesize = CONFIG_AT24XX_MTD_BLOCKSIZE;
geo->neraseblocks = (CONFIG_AT24XX_SIZE * 1024 / 8) / CONFIG_AT24XX_MTD_BLOCKSIZE;
#else
geo->blocksize = priv->pagesize;
geo->erasesize = priv->pagesize;
geo->neraseblocks = priv->npages;
#endif
ret = OK;
fvdbg("blocksize: %d erasesize: %d neraseblocks: %d\n",
geo->blocksize, geo->erasesize, geo->neraseblocks);
}
}
break;
case MTDIOC_BULKERASE:
ret=at24c_eraseall(priv);
break;
case MTDIOC_XIPBASE:
default:
ret = -ENOTTY; /* Bad command */
break;
}
return ret;
}
/************************************************************************************
* Public Functions
************************************************************************************/
/************************************************************************************
* Name: at24c_initialize
*
* Description:
* Create an initialize 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 *at24c_initialize(FAR struct i2c_dev_s *dev)
{
FAR struct at24c_dev_s *priv;
fvdbg("dev: %p\n", dev);
/* Allocate a state structure (we allocate the structure instead of using
* a fixed, static allocation so that we can handle multiple FLASH devices.
* The current implementation would handle only one FLASH part per I2C
* device (only because of the SPIDEV_FLASH definition) and so would have
* to be extended to handle multiple FLASH parts on the same I2C bus.
*/
priv = &g_at24c;
if (priv)
{
/* Initialize the allocated structure */
priv->addr = CONFIG_AT24XX_ADDR;
priv->pagesize = AT24XX_PAGESIZE;
priv->npages = AT24XX_NPAGES;
priv->mtd.erase = at24c_erase;
priv->mtd.bread = at24c_bread;
priv->mtd.bwrite = at24c_bwrite;
priv->mtd.ioctl = at24c_ioctl;
priv->dev = dev;
}
/* Return the implementation-specific state structure as the MTD device */
fvdbg("Return %p\n", priv);
return (FAR struct mtd_dev_s *)priv;
}
#endif
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