/*
   * Linux driver for Disk-On-Chip Millennium
   * (c) 1999 Machine Vision Holdings, Inc.
   * (c) 1999, 2000 David Woodhouse <dwmw2@infradead.org>
   *

   * $Id: doc2001.c,v 1.49 2005/11/07 11:14:24 gleixner Exp $

   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <asm/errno.h>
  #include <asm/io.h>
  #include <asm/uaccess.h>
  #include <linux/miscdevice.h>

  #include <linux/delay.h>
  #include <linux/slab.h>

  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/bitops.h>
  
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/nand.h>
  #include <linux/mtd/doc2000.h>
  
  /* #define ECC_DEBUG */
  
  /* I have no idea why some DoC chips can not use memcop_form|to_io().
   * This may be due to the different revisions of the ASIC controller built-in or
   * simplily a QA/Bug issue. Who knows ?? If you have trouble, please uncomment
   * this:*/
  #undef USE_MEMCPY
  
  static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
  		    size_t *retlen, u_char *buf);
  static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
  		     size_t *retlen, const u_char *buf);

  static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
  			struct mtd_oob_ops *ops);
  static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
  			 struct mtd_oob_ops *ops);

  static int doc_erase (struct mtd_info *mtd, struct erase_info *instr);
  
  static struct mtd_info *docmillist = NULL;
  
  /* Perform the required delay cycles by reading from the NOP register */
  static void DoC_Delay(void __iomem * docptr, unsigned short cycles)
  {
  	volatile char dummy;
  	int i;
  
  	for (i = 0; i < cycles; i++)
  		dummy = ReadDOC(docptr, NOP);
  }
  
  /* DOC_WaitReady: Wait for RDY line to be asserted by the flash chip */
  static int _DoC_WaitReady(void __iomem * docptr)
  {
  	unsigned short c = 0xffff;
  
  	DEBUG(MTD_DEBUG_LEVEL3,
  	      "_DoC_WaitReady called for out-of-line wait
  ");
  
  	/* Out-of-line routine to wait for chip response */
  	while (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B) && --c)
  		;
  
  	if (c == 0)
  		DEBUG(MTD_DEBUG_LEVEL2, "_DoC_WaitReady timed out.
  ");
  
  	return (c == 0);
  }
  
  static inline int DoC_WaitReady(void __iomem * docptr)
  {
  	/* This is inline, to optimise the common case, where it's ready instantly */
  	int ret = 0;
  
  	/* 4 read form NOP register should be issued in prior to the read from CDSNControl
  	   see Software Requirement 11.4 item 2. */
  	DoC_Delay(docptr, 4);
  
  	if (!(ReadDOC(docptr, CDSNControl) & CDSN_CTRL_FR_B))
  		/* Call the out-of-line routine to wait */
  		ret = _DoC_WaitReady(docptr);
  
  	/* issue 2 read from NOP register after reading from CDSNControl register
  	   see Software Requirement 11.4 item 2. */
  	DoC_Delay(docptr, 2);
  
  	return ret;
  }
  
  /* DoC_Command: Send a flash command to the flash chip through the CDSN IO register
     with the internal pipeline. Each of 4 delay cycles (read from the NOP register) is
     required after writing to CDSN Control register, see Software Requirement 11.4 item 3. */

  static void DoC_Command(void __iomem * docptr, unsigned char command,

  			       unsigned char xtraflags)
  {
  	/* Assert the CLE (Command Latch Enable) line to the flash chip */
  	WriteDOC(xtraflags | CDSN_CTRL_CLE | CDSN_CTRL_CE, docptr, CDSNControl);
  	DoC_Delay(docptr, 4);
  
  	/* Send the command */
  	WriteDOC(command, docptr, Mil_CDSN_IO);
  	WriteDOC(0x00, docptr, WritePipeTerm);
  
  	/* Lower the CLE line */
  	WriteDOC(xtraflags | CDSN_CTRL_CE, docptr, CDSNControl);
  	DoC_Delay(docptr, 4);
  }
  
  /* DoC_Address: Set the current address for the flash chip through the CDSN IO register
     with the internal pipeline. Each of 4 delay cycles (read from the NOP register) is
     required after writing to CDSN Control register, see Software Requirement 11.4 item 3. */
  
  static inline void DoC_Address(void __iomem * docptr, int numbytes, unsigned long ofs,
  			       unsigned char xtraflags1, unsigned char xtraflags2)
  {
  	/* Assert the ALE (Address Latch Enable) line to the flash chip */
  	WriteDOC(xtraflags1 | CDSN_CTRL_ALE | CDSN_CTRL_CE, docptr, CDSNControl);
  	DoC_Delay(docptr, 4);
  
  	/* Send the address */
  	switch (numbytes)
  	    {
  	    case 1:
  		    /* Send single byte, bits 0-7. */
  		    WriteDOC(ofs & 0xff, docptr, Mil_CDSN_IO);
  		    WriteDOC(0x00, docptr, WritePipeTerm);
  		    break;
  	    case 2:
  		    /* Send bits 9-16 followed by 17-23 */
  		    WriteDOC((ofs >> 9)  & 0xff, docptr, Mil_CDSN_IO);
  		    WriteDOC((ofs >> 17) & 0xff, docptr, Mil_CDSN_IO);
  		    WriteDOC(0x00, docptr, WritePipeTerm);
  		break;
  	    case 3:
  		    /* Send 0-7, 9-16, then 17-23 */
  		    WriteDOC(ofs & 0xff, docptr, Mil_CDSN_IO);
  		    WriteDOC((ofs >> 9)  & 0xff, docptr, Mil_CDSN_IO);
  		    WriteDOC((ofs >> 17) & 0xff, docptr, Mil_CDSN_IO);
  		    WriteDOC(0x00, docptr, WritePipeTerm);
  		break;
  	    default:
  		return;
  	    }
  
  	/* Lower the ALE line */
  	WriteDOC(xtraflags1 | xtraflags2 | CDSN_CTRL_CE, docptr, CDSNControl);
  	DoC_Delay(docptr, 4);
  }
  
  /* DoC_SelectChip: Select a given flash chip within the current floor */
  static int DoC_SelectChip(void __iomem * docptr, int chip)
  {
  	/* Select the individual flash chip requested */
  	WriteDOC(chip, docptr, CDSNDeviceSelect);
  	DoC_Delay(docptr, 4);
  
  	/* Wait for it to be ready */
  	return DoC_WaitReady(docptr);
  }
  
  /* DoC_SelectFloor: Select a given floor (bank of flash chips) */
  static int DoC_SelectFloor(void __iomem * docptr, int floor)
  {
  	/* Select the floor (bank) of chips required */
  	WriteDOC(floor, docptr, FloorSelect);
  
  	/* Wait for the chip to be ready */
  	return DoC_WaitReady(docptr);
  }
  
  /* DoC_IdentChip: Identify a given NAND chip given {floor,chip} */
  static int DoC_IdentChip(struct DiskOnChip *doc, int floor, int chip)
  {
  	int mfr, id, i, j;
  	volatile char dummy;
  
  	/* Page in the required floor/chip
  	   FIXME: is this supported by Millennium ?? */
  	DoC_SelectFloor(doc->virtadr, floor);
  	DoC_SelectChip(doc->virtadr, chip);
  
  	/* Reset the chip, see Software Requirement 11.4 item 1. */
  	DoC_Command(doc->virtadr, NAND_CMD_RESET, CDSN_CTRL_WP);
  	DoC_WaitReady(doc->virtadr);

  	/* Read the NAND chip ID: 1. Send ReadID command */

  	DoC_Command(doc->virtadr, NAND_CMD_READID, CDSN_CTRL_WP);

  	/* Read the NAND chip ID: 2. Send address byte zero */

  	DoC_Address(doc->virtadr, 1, 0x00, CDSN_CTRL_WP, 0x00);
  
  	/* Read the manufacturer and device id codes of the flash device through
  	   CDSN IO register see Software Requirement 11.4 item 5.*/
  	dummy = ReadDOC(doc->virtadr, ReadPipeInit);
  	DoC_Delay(doc->virtadr, 2);
  	mfr = ReadDOC(doc->virtadr, Mil_CDSN_IO);
  
  	DoC_Delay(doc->virtadr, 2);
  	id  = ReadDOC(doc->virtadr, Mil_CDSN_IO);
  	dummy = ReadDOC(doc->virtadr, LastDataRead);
  
  	/* No response - return failure */
  	if (mfr == 0xff || mfr == 0)
  		return 0;
  
  	/* FIXME: to deal with multi-flash on multi-Millennium case more carefully */
  	for (i = 0; nand_flash_ids[i].name != NULL; i++) {
  		if ( id == nand_flash_ids[i].id) {
  			/* Try to identify manufacturer */
  			for (j = 0; nand_manuf_ids[j].id != 0x0; j++) {
  				if (nand_manuf_ids[j].id == mfr)
  					break;

  			}

  			printk(KERN_INFO "Flash chip found: Manufacturer ID: %2.2X, "
  			       "Chip ID: %2.2X (%s:%s)
  ",
  			       mfr, id, nand_manuf_ids[j].name, nand_flash_ids[i].name);
  			doc->mfr = mfr;
  			doc->id = id;
  			doc->chipshift = ffs((nand_flash_ids[i].chipsize << 20)) - 1;
  			break;
  		}
  	}
  
  	if (nand_flash_ids[i].name == NULL)
  		return 0;
  	else
  		return 1;
  }
  
  /* DoC_ScanChips: Find all NAND chips present in a DiskOnChip, and identify them */
  static void DoC_ScanChips(struct DiskOnChip *this)
  {
  	int floor, chip;
  	int numchips[MAX_FLOORS_MIL];
  	int ret;
  
  	this->numchips = 0;
  	this->mfr = 0;
  	this->id = 0;
  
  	/* For each floor, find the number of valid chips it contains */
  	for (floor = 0,ret = 1; floor < MAX_FLOORS_MIL; floor++) {
  		numchips[floor] = 0;
  		for (chip = 0; chip < MAX_CHIPS_MIL && ret != 0; chip++) {
  			ret = DoC_IdentChip(this, floor, chip);
  			if (ret) {
  				numchips[floor]++;
  				this->numchips++;
  			}
  		}
  	}
  	/* If there are none at all that we recognise, bail */
  	if (!this->numchips) {
  		printk("No flash chips recognised.
  ");
  		return;
  	}
  
  	/* Allocate an array to hold the information for each chip */
  	this->chips = kmalloc(sizeof(struct Nand) * this->numchips, GFP_KERNEL);
  	if (!this->chips){
  		printk("No memory for allocating chip info structures
  ");
  		return;
  	}

  	/* Fill out the chip array with {floor, chipno} for each

  	 * detected chip in the device. */
  	for (floor = 0, ret = 0; floor < MAX_FLOORS_MIL; floor++) {
  		for (chip = 0 ; chip < numchips[floor] ; chip++) {
  			this->chips[ret].floor = floor;
  			this->chips[ret].chip = chip;
  			this->chips[ret].curadr = 0;
  			this->chips[ret].curmode = 0x50;
  			ret++;
  		}
  	}
  
  	/* Calculate and print the total size of the device */
  	this->totlen = this->numchips * (1 << this->chipshift);
  	printk(KERN_INFO "%d flash chips found. Total DiskOnChip size: %ld MiB
  ",
  	       this->numchips ,this->totlen >> 20);
  }
  
  static int DoCMil_is_alias(struct DiskOnChip *doc1, struct DiskOnChip *doc2)
  {
  	int tmp1, tmp2, retval;
  
  	if (doc1->physadr == doc2->physadr)
  		return 1;
  
  	/* Use the alias resolution register which was set aside for this
  	 * purpose. If it's value is the same on both chips, they might
  	 * be the same chip, and we write to one and check for a change in
  	 * the other. It's unclear if this register is usuable in the
  	 * DoC 2000 (it's in the Millenium docs), but it seems to work. */
  	tmp1 = ReadDOC(doc1->virtadr, AliasResolution);
  	tmp2 = ReadDOC(doc2->virtadr, AliasResolution);
  	if (tmp1 != tmp2)
  		return 0;

  	WriteDOC((tmp1+1) % 0xff, doc1->virtadr, AliasResolution);
  	tmp2 = ReadDOC(doc2->virtadr, AliasResolution);
  	if (tmp2 == (tmp1+1) % 0xff)
  		retval = 1;
  	else
  		retval = 0;
  
  	/* Restore register contents.  May not be necessary, but do it just to
  	 * be safe. */
  	WriteDOC(tmp1, doc1->virtadr, AliasResolution);
  
  	return retval;
  }

  /* This routine is found from the docprobe code by symbol_get(),
   * which will bump the use count of this module. */
  void DoCMil_init(struct mtd_info *mtd)

  {
  	struct DiskOnChip *this = mtd->priv;
  	struct DiskOnChip *old = NULL;
  
  	/* We must avoid being called twice for the same device. */
  	if (docmillist)
  		old = docmillist->priv;
  
  	while (old) {
  		if (DoCMil_is_alias(this, old)) {
  			printk(KERN_NOTICE "Ignoring DiskOnChip Millennium at "
  			       "0x%lX - already configured
  ", this->physadr);
  			iounmap(this->virtadr);
  			kfree(mtd);
  			return;
  		}
  		if (old->nextdoc)
  			old = old->nextdoc->priv;
  		else
  			old = NULL;
  	}
  
  	mtd->name = "DiskOnChip Millennium";
  	printk(KERN_NOTICE "DiskOnChip Millennium found at address 0x%lX
  ",
  	       this->physadr);
  
  	mtd->type = MTD_NANDFLASH;
  	mtd->flags = MTD_CAP_NANDFLASH;

  	mtd->size = 0;
  
  	/* FIXME: erase size is not always 8KiB */
  	mtd->erasesize = 0x2000;

  	mtd->writesize = 512;

  	mtd->oobsize = 16;
  	mtd->owner = THIS_MODULE;
  	mtd->erase = doc_erase;
  	mtd->point = NULL;
  	mtd->unpoint = NULL;
  	mtd->read = doc_read;
  	mtd->write = doc_write;

  	mtd->read_oob = doc_read_oob;
  	mtd->write_oob = doc_write_oob;
  	mtd->sync = NULL;
  
  	this->totlen = 0;
  	this->numchips = 0;
  	this->curfloor = -1;
  	this->curchip = -1;
  
  	/* Ident all the chips present. */
  	DoC_ScanChips(this);
  
  	if (!this->totlen) {
  		kfree(mtd);
  		iounmap(this->virtadr);
  	} else {
  		this->nextdoc = docmillist;
  		docmillist = mtd;
  		mtd->size  = this->totlen;
  		add_mtd_device(mtd);
  		return;
  	}
  }

  EXPORT_SYMBOL_GPL(DoCMil_init);

  
  static int doc_read (struct mtd_info *mtd, loff_t from, size_t len,
  		     size_t *retlen, u_char *buf)
  {

  	int i, ret;
  	volatile char dummy;

  	unsigned char syndrome[6], eccbuf[6];

  	struct DiskOnChip *this = mtd->priv;
  	void __iomem *docptr = this->virtadr;
  	struct Nand *mychip = &this->chips[from >> (this->chipshift)];
  
  	/* Don't allow read past end of device */
  	if (from >= this->totlen)
  		return -EINVAL;
  
  	/* Don't allow a single read to cross a 512-byte block boundary */

  	if (from + len > ((from | 0x1ff) + 1))

  		len = ((from | 0x1ff) + 1) - from;
  
  	/* Find the chip which is to be used and select it */
  	if (this->curfloor != mychip->floor) {
  		DoC_SelectFloor(docptr, mychip->floor);
  		DoC_SelectChip(docptr, mychip->chip);
  	} else if (this->curchip != mychip->chip) {
  		DoC_SelectChip(docptr, mychip->chip);
  	}
  	this->curfloor = mychip->floor;
  	this->curchip = mychip->chip;
  
  	/* issue the Read0 or Read1 command depend on which half of the page
  	   we are accessing. Polling the Flash Ready bit after issue 3 bytes
  	   address in Sequence Read Mode, see Software Requirement 11.4 item 1.*/
  	DoC_Command(docptr, (from >> 8) & 1, CDSN_CTRL_WP);
  	DoC_Address(docptr, 3, from, CDSN_CTRL_WP, 0x00);
  	DoC_WaitReady(docptr);

  	/* init the ECC engine, see Reed-Solomon EDC/ECC 11.1 .*/
  	WriteDOC (DOC_ECC_RESET, docptr, ECCConf);
  	WriteDOC (DOC_ECC_EN, docptr, ECCConf);

  
  	/* Read the data via the internal pipeline through CDSN IO register,
  	   see Pipelined Read Operations 11.3 */
  	dummy = ReadDOC(docptr, ReadPipeInit);
  #ifndef USE_MEMCPY
  	for (i = 0; i < len-1; i++) {
  		/* N.B. you have to increase the source address in this way or the
  		   ECC logic will not work properly */
  		buf[i] = ReadDOC(docptr, Mil_CDSN_IO + (i & 0xff));
  	}
  #else
  	memcpy_fromio(buf, docptr + DoC_Mil_CDSN_IO, len - 1);
  #endif
  	buf[len - 1] = ReadDOC(docptr, LastDataRead);
  
  	/* Let the caller know we completed it */
  	*retlen = len;
          ret = 0;

  	/* Read the ECC data from Spare Data Area,
  	   see Reed-Solomon EDC/ECC 11.1 */
  	dummy = ReadDOC(docptr, ReadPipeInit);

  #ifndef USE_MEMCPY

  	for (i = 0; i < 5; i++) {
  		/* N.B. you have to increase the source address in this way or the
  		   ECC logic will not work properly */
  		eccbuf[i] = ReadDOC(docptr, Mil_CDSN_IO + i);
  	}

  #else

  	memcpy_fromio(eccbuf, docptr + DoC_Mil_CDSN_IO, 5);

  #endif

  	eccbuf[5] = ReadDOC(docptr, LastDataRead);

  	/* Flush the pipeline */
  	dummy = ReadDOC(docptr, ECCConf);
  	dummy = ReadDOC(docptr, ECCConf);

  	/* Check the ECC Status */
  	if (ReadDOC(docptr, ECCConf) & 0x80) {
  		int nb_errors;
  		/* There was an ECC error */

  #ifdef ECC_DEBUG

  		printk("DiskOnChip ECC Error: Read at %lx
  ", (long)from);

  #endif

  		/* Read the ECC syndrom through the DiskOnChip ECC logic.
  		   These syndrome will be all ZERO when there is no error */
  		for (i = 0; i < 6; i++) {
  			syndrome[i] = ReadDOC(docptr, ECCSyndrome0 + i);
  		}
  		nb_errors = doc_decode_ecc(buf, syndrome);

  #ifdef ECC_DEBUG

  		printk("ECC Errors corrected: %x
  ", nb_errors);

  #endif

  		if (nb_errors < 0) {
  			/* We return error, but have actually done the read. Not that
  			   this can be told to user-space, via sys_read(), but at least
  			   MTD-aware stuff can know about it by checking *retlen */
  			ret = -EIO;

  		}

  	}

  
  #ifdef PSYCHO_DEBUG

  	printk("ECC DATA at %lx: %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X
  ",
  	       (long)from, eccbuf[0], eccbuf[1], eccbuf[2], eccbuf[3],
  	       eccbuf[4], eccbuf[5]);

  #endif

  	/* disable the ECC engine */
  	WriteDOC(DOC_ECC_DIS, docptr , ECCConf);

  
  	return ret;
  }
  
  static int doc_write (struct mtd_info *mtd, loff_t to, size_t len,
  		      size_t *retlen, const u_char *buf)
  {

  	int i,ret = 0;

  	char eccbuf[6];

  	volatile char dummy;
  	struct DiskOnChip *this = mtd->priv;
  	void __iomem *docptr = this->virtadr;
  	struct Nand *mychip = &this->chips[to >> (this->chipshift)];
  
  	/* Don't allow write past end of device */
  	if (to >= this->totlen)
  		return -EINVAL;
  
  #if 0
  	/* Don't allow a single write to cross a 512-byte block boundary */

  	if (to + len > ( (to | 0x1ff) + 1))

  		len = ((to | 0x1ff) + 1) - to;
  #else
  	/* Don't allow writes which aren't exactly one block */
  	if (to & 0x1ff || len != 0x200)
  		return -EINVAL;
  #endif
  
  	/* Find the chip which is to be used and select it */
  	if (this->curfloor != mychip->floor) {
  		DoC_SelectFloor(docptr, mychip->floor);
  		DoC_SelectChip(docptr, mychip->chip);
  	} else if (this->curchip != mychip->chip) {
  		DoC_SelectChip(docptr, mychip->chip);
  	}
  	this->curfloor = mychip->floor;
  	this->curchip = mychip->chip;
  
  	/* Reset the chip, see Software Requirement 11.4 item 1. */
  	DoC_Command(docptr, NAND_CMD_RESET, 0x00);
  	DoC_WaitReady(docptr);
  	/* Set device to main plane of flash */
  	DoC_Command(docptr, NAND_CMD_READ0, 0x00);
  
  	/* issue the Serial Data In command to initial the Page Program process */
  	DoC_Command(docptr, NAND_CMD_SEQIN, 0x00);
  	DoC_Address(docptr, 3, to, 0x00, 0x00);
  	DoC_WaitReady(docptr);

  	/* init the ECC engine, see Reed-Solomon EDC/ECC 11.1 .*/
  	WriteDOC (DOC_ECC_RESET, docptr, ECCConf);
  	WriteDOC (DOC_ECC_EN | DOC_ECC_RW, docptr, ECCConf);

  
  	/* Write the data via the internal pipeline through CDSN IO register,
  	   see Pipelined Write Operations 11.2 */
  #ifndef USE_MEMCPY
  	for (i = 0; i < len; i++) {
  		/* N.B. you have to increase the source address in this way or the
  		   ECC logic will not work properly */
  		WriteDOC(buf[i], docptr, Mil_CDSN_IO + i);
  	}
  #else
  	memcpy_toio(docptr + DoC_Mil_CDSN_IO, buf, len);
  #endif
  	WriteDOC(0x00, docptr, WritePipeTerm);

  	/* Write ECC data to flash, the ECC info is generated by the DiskOnChip ECC logic
  	   see Reed-Solomon EDC/ECC 11.1 */
  	WriteDOC(0, docptr, NOP);
  	WriteDOC(0, docptr, NOP);
  	WriteDOC(0, docptr, NOP);

  	/* Read the ECC data through the DiskOnChip ECC logic */
  	for (i = 0; i < 6; i++) {
  		eccbuf[i] = ReadDOC(docptr, ECCSyndrome0 + i);
  	}

  	/* ignore the ECC engine */
  	WriteDOC(DOC_ECC_DIS, docptr , ECCConf);

  
  #ifndef USE_MEMCPY

  	/* Write the ECC data to flash */
  	for (i = 0; i < 6; i++) {
  		/* N.B. you have to increase the source address in this way or the
  		   ECC logic will not work properly */
  		WriteDOC(eccbuf[i], docptr, Mil_CDSN_IO + i);
  	}

  #else

  	memcpy_toio(docptr + DoC_Mil_CDSN_IO, eccbuf, 6);

  #endif

  	/* write the block status BLOCK_USED (0x5555) at the end of ECC data
  	   FIXME: this is only a hack for programming the IPL area for LinuxBIOS
  	   and should be replace with proper codes in user space utilities */
  	WriteDOC(0x55, docptr, Mil_CDSN_IO);
  	WriteDOC(0x55, docptr, Mil_CDSN_IO + 1);

  	WriteDOC(0x00, docptr, WritePipeTerm);

  
  #ifdef PSYCHO_DEBUG

  	printk("OOB data at %lx is %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X
  ",
  	       (long) to, eccbuf[0], eccbuf[1], eccbuf[2], eccbuf[3],
  	       eccbuf[4], eccbuf[5]);

  #endif

  
  	/* Commit the Page Program command and wait for ready
  	   see Software Requirement 11.4 item 1.*/
  	DoC_Command(docptr, NAND_CMD_PAGEPROG, 0x00);
  	DoC_WaitReady(docptr);
  
  	/* Read the status of the flash device through CDSN IO register
  	   see Software Requirement 11.4 item 5.*/
  	DoC_Command(docptr, NAND_CMD_STATUS, CDSN_CTRL_WP);
  	dummy = ReadDOC(docptr, ReadPipeInit);
  	DoC_Delay(docptr, 2);
  	if (ReadDOC(docptr, Mil_CDSN_IO) & 1) {
  		printk("Error programming flash
  ");
  		/* Error in programming
  		   FIXME: implement Bad Block Replacement (in nftl.c ??) */
  		*retlen = 0;
  		ret = -EIO;
  	}
  	dummy = ReadDOC(docptr, LastDataRead);
  
  	/* Let the caller know we completed it */
  	*retlen = len;
  
  	return ret;
  }

  static int doc_read_oob(struct mtd_info *mtd, loff_t ofs,
  			struct mtd_oob_ops *ops)

  {
  #ifndef USE_MEMCPY
  	int i;
  #endif
  	volatile char dummy;
  	struct DiskOnChip *this = mtd->priv;
  	void __iomem *docptr = this->virtadr;
  	struct Nand *mychip = &this->chips[ofs >> this->chipshift];

  	uint8_t *buf = ops->oobbuf;
  	size_t len = ops->len;
  
  	BUG_ON(ops->mode != MTD_OOB_PLACE);
  
  	ofs += ops->ooboffs;

  
  	/* Find the chip which is to be used and select it */
  	if (this->curfloor != mychip->floor) {
  		DoC_SelectFloor(docptr, mychip->floor);
  		DoC_SelectChip(docptr, mychip->chip);
  	} else if (this->curchip != mychip->chip) {
  		DoC_SelectChip(docptr, mychip->chip);
  	}
  	this->curfloor = mychip->floor;
  	this->curchip = mychip->chip;
  
  	/* disable the ECC engine */
  	WriteDOC (DOC_ECC_RESET, docptr, ECCConf);
  	WriteDOC (DOC_ECC_DIS, docptr, ECCConf);
  
  	/* issue the Read2 command to set the pointer to the Spare Data Area.
  	   Polling the Flash Ready bit after issue 3 bytes address in
  	   Sequence Read Mode, see Software Requirement 11.4 item 1.*/
  	DoC_Command(docptr, NAND_CMD_READOOB, CDSN_CTRL_WP);
  	DoC_Address(docptr, 3, ofs, CDSN_CTRL_WP, 0x00);
  	DoC_WaitReady(docptr);
  
  	/* Read the data out via the internal pipeline through CDSN IO register,
  	   see Pipelined Read Operations 11.3 */
  	dummy = ReadDOC(docptr, ReadPipeInit);
  #ifndef USE_MEMCPY
  	for (i = 0; i < len-1; i++) {
  		/* N.B. you have to increase the source address in this way or the
  		   ECC logic will not work properly */
  		buf[i] = ReadDOC(docptr, Mil_CDSN_IO + i);
  	}
  #else
  	memcpy_fromio(buf, docptr + DoC_Mil_CDSN_IO, len - 1);
  #endif
  	buf[len - 1] = ReadDOC(docptr, LastDataRead);

  	ops->retlen = len;

  
  	return 0;
  }

  static int doc_write_oob(struct mtd_info *mtd, loff_t ofs,
  			 struct mtd_oob_ops *ops)

  {
  #ifndef USE_MEMCPY
  	int i;
  #endif
  	volatile char dummy;
  	int ret = 0;
  	struct DiskOnChip *this = mtd->priv;
  	void __iomem *docptr = this->virtadr;
  	struct Nand *mychip = &this->chips[ofs >> this->chipshift];

  	uint8_t *buf = ops->oobbuf;
  	size_t len = ops->len;
  
  	BUG_ON(ops->mode != MTD_OOB_PLACE);
  
  	ofs += ops->ooboffs;

  
  	/* Find the chip which is to be used and select it */
  	if (this->curfloor != mychip->floor) {
  		DoC_SelectFloor(docptr, mychip->floor);
  		DoC_SelectChip(docptr, mychip->chip);
  	} else if (this->curchip != mychip->chip) {
  		DoC_SelectChip(docptr, mychip->chip);
  	}
  	this->curfloor = mychip->floor;
  	this->curchip = mychip->chip;
  
  	/* disable the ECC engine */
  	WriteDOC (DOC_ECC_RESET, docptr, ECCConf);
  	WriteDOC (DOC_ECC_DIS, docptr, ECCConf);
  
  	/* Reset the chip, see Software Requirement 11.4 item 1. */
  	DoC_Command(docptr, NAND_CMD_RESET, CDSN_CTRL_WP);
  	DoC_WaitReady(docptr);
  	/* issue the Read2 command to set the pointer to the Spare Data Area. */
  	DoC_Command(docptr, NAND_CMD_READOOB, CDSN_CTRL_WP);
  
  	/* issue the Serial Data In command to initial the Page Program process */
  	DoC_Command(docptr, NAND_CMD_SEQIN, 0x00);
  	DoC_Address(docptr, 3, ofs, 0x00, 0x00);
  
  	/* Write the data via the internal pipeline through CDSN IO register,
  	   see Pipelined Write Operations 11.2 */
  #ifndef USE_MEMCPY
  	for (i = 0; i < len; i++) {
  		/* N.B. you have to increase the source address in this way or the
  		   ECC logic will not work properly */
  		WriteDOC(buf[i], docptr, Mil_CDSN_IO + i);
  	}
  #else
  	memcpy_toio(docptr + DoC_Mil_CDSN_IO, buf, len);
  #endif
  	WriteDOC(0x00, docptr, WritePipeTerm);
  
  	/* Commit the Page Program command and wait for ready
  	   see Software Requirement 11.4 item 1.*/
  	DoC_Command(docptr, NAND_CMD_PAGEPROG, 0x00);
  	DoC_WaitReady(docptr);
  
  	/* Read the status of the flash device through CDSN IO register
  	   see Software Requirement 11.4 item 5.*/
  	DoC_Command(docptr, NAND_CMD_STATUS, 0x00);
  	dummy = ReadDOC(docptr, ReadPipeInit);
  	DoC_Delay(docptr, 2);
  	if (ReadDOC(docptr, Mil_CDSN_IO) & 1) {
  		printk("Error programming oob data
  ");
  		/* FIXME: implement Bad Block Replacement (in nftl.c ??) */

  		ops->retlen = 0;

  		ret = -EIO;
  	}
  	dummy = ReadDOC(docptr, LastDataRead);

  	ops->retlen = len;

  
  	return ret;
  }
  
  int doc_erase (struct mtd_info *mtd, struct erase_info *instr)
  {
  	volatile char dummy;
  	struct DiskOnChip *this = mtd->priv;
  	__u32 ofs = instr->addr;
  	__u32 len = instr->len;
  	void __iomem *docptr = this->virtadr;
  	struct Nand *mychip = &this->chips[ofs >> this->chipshift];

  	if (len != mtd->erasesize)

  		printk(KERN_WARNING "Erase not right size (%x != %x)n",
  		       len, mtd->erasesize);
  
  	/* Find the chip which is to be used and select it */
  	if (this->curfloor != mychip->floor) {
  		DoC_SelectFloor(docptr, mychip->floor);
  		DoC_SelectChip(docptr, mychip->chip);
  	} else if (this->curchip != mychip->chip) {
  		DoC_SelectChip(docptr, mychip->chip);
  	}
  	this->curfloor = mychip->floor;
  	this->curchip = mychip->chip;
  
  	instr->state = MTD_ERASE_PENDING;
  
  	/* issue the Erase Setup command */
  	DoC_Command(docptr, NAND_CMD_ERASE1, 0x00);
  	DoC_Address(docptr, 2, ofs, 0x00, 0x00);
  
  	/* Commit the Erase Start command and wait for ready
  	   see Software Requirement 11.4 item 1.*/
  	DoC_Command(docptr, NAND_CMD_ERASE2, 0x00);
  	DoC_WaitReady(docptr);
  
  	instr->state = MTD_ERASING;
  
  	/* Read the status of the flash device through CDSN IO register
  	   see Software Requirement 11.4 item 5.
  	   FIXME: it seems that we are not wait long enough, some blocks are not
  	   erased fully */
  	DoC_Command(docptr, NAND_CMD_STATUS, CDSN_CTRL_WP);
  	dummy = ReadDOC(docptr, ReadPipeInit);
  	DoC_Delay(docptr, 2);
  	if (ReadDOC(docptr, Mil_CDSN_IO) & 1) {
  		printk("Error Erasing at 0x%x
  ", ofs);
  		/* There was an error
  		   FIXME: implement Bad Block Replacement (in nftl.c ??) */
  		instr->state = MTD_ERASE_FAILED;
  	} else
  		instr->state = MTD_ERASE_DONE;
  	dummy = ReadDOC(docptr, LastDataRead);
  
  	mtd_erase_callback(instr);
  
  	return 0;
  }
  
  /****************************************************************************
   *
   * Module stuff
   *
   ****************************************************************************/

  static void __exit cleanup_doc2001(void)
  {
  	struct mtd_info *mtd;
  	struct DiskOnChip *this;
  
  	while ((mtd=docmillist)) {
  		this = mtd->priv;
  		docmillist = this->nextdoc;

  		del_mtd_device(mtd);

  		iounmap(this->virtadr);
  		kfree(this->chips);
  		kfree(mtd);
  	}

  }
  
  module_exit(cleanup_doc2001);

  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org> et al.");
  MODULE_DESCRIPTION("Alternative driver for DiskOnChip Millennium");