path: root/nuttx/drivers/mtd/at24xx.c

/************************************************************************************
 * 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, 2013 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/fs/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;
      uint8_t tries = 100;

      while (I2C_WRITE(priv->dev, buf, 2) < 0 && tries-- > 0)
        {
          fvdbg("wait\n");
          usleep(1000);
        }
      if (tries == 0) {
          fdbg("timed out reading at offset %u\n", (unsigned)offset);
          return 0;
      }

      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;
      uint8_t tries = 100;

      while (I2C_WRITE(priv->dev, (uint8_t *)&offset, 2) < 0 && tries-- > 0)
        {
          fvdbg("wait\n");
          usleep(1000);
        }
      if (tries == 0) {
          fdbg("timed out writing at offset %u\n", (unsigned)offset);
          return 0;
      }

      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;

      /* NOTE since the pre-allocated device structure lies in .bss, any
       * unsupported methods should have been nullified.
       */

      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