doc2000.c

基于linux-2.6.28的mtd驱动

				doc->pageadrlen = doc->chipshift > 25 ? 3 : 2;
				doc->erasesize =
				    nand_flash_ids[i].erasesize;
				return 1;
			}
			return 0;
		}
	}


	/* We haven't fully identified the chip. Print as much as we know. */
	printk(KERN_WARNING "Unknown flash chip found: %2.2X %2.2X\n",
	       id, mfr);

	printk(KERN_WARNING "Please report to [e-mail]\n");
	return 0;
}

/* DoC_ScanChips: Find all NAND chips present in a DiskOnChip, and identify them */

static void DoC_ScanChips(struct DiskOnChip *this, int maxchips)
{
	int floor, chip;
	int numchips[MAX_FLOORS];
	int ret = 1;

	this->numchips = 0;
	this->mfr = 0;
	this->id = 0;

	/* For each floor, find the number of valid chips it contains */
	for (floor = 0; floor < MAX_FLOORS; floor++) {
		ret = 1;
		numchips[floor] = 0;
		for (chip = 0; chip < maxchips && 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(KERN_NOTICE "No flash chips recognised.\n");
		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(KERN_NOTICE "No memory for allocating chip info structures\n");
		return;
	}

	ret = 0;

	/* Fill out the chip array with {floor, chipno} for each
	 * detected chip in the device. */
	for (floor = 0; floor < MAX_FLOORS; 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\n",
	       this->numchips, this->totlen >> 20);
}

static int DoC2k_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 Millennium 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 DoC2k_init(struct mtd_info *mtd)
{
	struct DiskOnChip *this = mtd->priv;
	struct DiskOnChip *old = NULL;
	int maxchips;

	/* We must avoid being called twice for the same device. */

	if (doc2klist)
		old = doc2klist->priv;

	while (old) {
		if (DoC2k_is_alias(old, this)) {
			printk(KERN_NOTICE
			       "Ignoring DiskOnChip 2000 at 0x%lX - already configured\n",
			       this->physadr);
			iounmap(this->virtadr);
			kfree(mtd);
			return;
		}
		if (old->nextdoc)
			old = old->nextdoc->priv;
		else
			old = NULL;
	}


	switch (this->ChipID) {
	case DOC_ChipID_Doc2kTSOP:
		mtd->name = "DiskOnChip 2000 TSOP";
		this->ioreg = DoC_Mil_CDSN_IO;
		/* Pretend it's a Millennium */
		this->ChipID = DOC_ChipID_DocMil;
		maxchips = MAX_CHIPS;
		break;
	case DOC_ChipID_Doc2k:
		mtd->name = "DiskOnChip 2000";
		this->ioreg = DoC_2k_CDSN_IO;
		maxchips = MAX_CHIPS;
		break;
	case DOC_ChipID_DocMil:
		mtd->name = "DiskOnChip Millennium";
		this->ioreg = DoC_Mil_CDSN_IO;
		maxchips = MAX_CHIPS_MIL;
		break;
	default:
		printk("Unknown ChipID 0x%02x\n", this->ChipID);
		kfree(mtd);
		iounmap(this->virtadr);
		return;
	}

	printk(KERN_NOTICE "%s found at address 0x%lX\n", mtd->name,
	       this->physadr);

	mtd->type = MTD_NANDFLASH;
	mtd->flags = MTD_CAP_NANDFLASH;
	mtd->size = 0;
	mtd->erasesize = 0;
	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;
	mutex_init(&this->lock);

	/* Ident all the chips present. */
	DoC_ScanChips(this, maxchips);

	if (!this->totlen) {
		kfree(mtd);
		iounmap(this->virtadr);
	} else {
		this->nextdoc = doc2klist;
		doc2klist = mtd;
		mtd->size = this->totlen;
		mtd->erasesize = this->erasesize;
		add_mtd_device(mtd);
		return;
	}
}
EXPORT_SYMBOL_GPL(DoC2k_init);

static int doc_read(struct mtd_info *mtd, loff_t from, size_t len,
		    size_t * retlen, u_char * buf)
{
	struct DiskOnChip *this = mtd->priv;
	void __iomem *docptr = this->virtadr;
	struct Nand *mychip;
	unsigned char syndrome[6], eccbuf[6];
	volatile char dummy;
	int i, len256 = 0, ret=0;
	size_t left = len;

	/* Don't allow read past end of device */
	if (from >= this->totlen)
		return -EINVAL;

	mutex_lock(&this->lock);

	*retlen = 0;
	while (left) {
		len = left;

		/* Don't allow a single read to cross a 512-byte block boundary */
		if (from + len > ((from | 0x1ff) + 1))
			len = ((from | 0x1ff) + 1) - from;

		/* The ECC will not be calculated correctly if less than 512 is read */
		if (len != 0x200)
			printk(KERN_WARNING
			       "ECC needs a full sector read (adr: %lx size %lx)\n",
			       (long) from, (long) len);

		/* printk("DoC_Read (adr: %lx size %lx)\n", (long) from, (long) len); */


		/* Find the chip which is to be used and select it */
		mychip = &this->chips[from >> (this->chipshift)];

		if (this->curfloor != mychip->floor) {
			DoC_SelectFloor(this, mychip->floor);
			DoC_SelectChip(this, mychip->chip);
		} else if (this->curchip != mychip->chip) {
			DoC_SelectChip(this, mychip->chip);
		}

		this->curfloor = mychip->floor;
		this->curchip = mychip->chip;

		DoC_Command(this,
			    (!this->page256
			     && (from & 0x100)) ? NAND_CMD_READ1 : NAND_CMD_READ0,
			    CDSN_CTRL_WP);
		DoC_Address(this, ADDR_COLUMN_PAGE, from, CDSN_CTRL_WP,
			    CDSN_CTRL_ECC_IO);

		/* Prime the ECC engine */
		WriteDOC(DOC_ECC_RESET, docptr, ECCConf);
		WriteDOC(DOC_ECC_EN, docptr, ECCConf);

		/* treat crossing 256-byte sector for 2M x 8bits devices */
		if (this->page256 && from + len > (from | 0xff) + 1) {
			len256 = (from | 0xff) + 1 - from;
			DoC_ReadBuf(this, buf, len256);

			DoC_Command(this, NAND_CMD_READ0, CDSN_CTRL_WP);
			DoC_Address(this, ADDR_COLUMN_PAGE, from + len256,
				    CDSN_CTRL_WP, CDSN_CTRL_ECC_IO);
		}

		DoC_ReadBuf(this, &buf[len256], len - len256);

		/* Let the caller know we completed it */
		*retlen += len;

		/* Read the ECC data through the DiskOnChip ECC logic */
		/* Note: this will work even with 2M x 8bit devices as   */
		/*       they have 8 bytes of OOB per 256 page. mf.      */
		DoC_ReadBuf(this, eccbuf, 6);

		/* Flush the pipeline */
		if (DoC_is_Millennium(this)) {
			dummy = ReadDOC(docptr, ECCConf);
			dummy = ReadDOC(docptr, ECCConf);
			i = ReadDOC(docptr, ECCConf);
		} else {
			dummy = ReadDOC(docptr, 2k_ECCStatus);
			dummy = ReadDOC(docptr, 2k_ECCStatus);
			i = ReadDOC(docptr, 2k_ECCStatus);
		}

		/* Check the ECC Status */
		if (i & 0x80) {
			int nb_errors;
			/* There was an ECC error */
#ifdef ECC_DEBUG
			printk(KERN_ERR "DiskOnChip ECC Error: Read at %lx\n", (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(KERN_ERR "Errors corrected: %x\n", 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(KERN_DEBUG "ECC DATA at %lxB: %2.2X %2.2X %2.2X %2.2X %2.2X %2.2X\n",
		       (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);

		/* according to 11.4.1, we need to wait for the busy line
	         * drop if we read to the end of the page.  */
		if(0 == ((from + len) & 0x1ff))
		{
		    DoC_WaitReady(this);
		}

		from += len;
		left -= len;
		buf += len;
	}

	mutex_unlock(&this->lock);

	return ret;
}

static int doc_write(struct mtd_info *mtd, loff_t to, size_t len,
		     size_t * retlen, const u_char * buf)
{
	struct DiskOnChip *this = mtd->priv;
	int di; /* Yes, DI is a hangover from when I was disassembling the binary driver */
	void __iomem *docptr = this->virtadr;
	unsigned char eccbuf[6];
	volatile char dummy;
	int len256 = 0;
	struct Nand *mychip;
	size_t left = len;
	int status;

	/* Don't allow write past end of device */
	if (to >= this->totlen)
		return -EINVAL;

	mutex_lock(&this->lock);

	*retlen = 0;
	while (left) {
		len = left;

		/* Don't allow a single write to cross a 512-byte block boundary */
		if (to + len > ((to | 0x1ff) + 1))
			len = ((to | 0x1ff) + 1) - to;

		/* The ECC will not be calculated correctly if less than 512 is written */
/* DBB-
		if (len != 0x200 && eccbuf)
			printk(KERN_WARNING
			       "ECC needs a full sector write (adr: %lx size %lx)\n",
			       (long) to, (long) len);
   -DBB */

		/* printk("DoC_Write (adr: %lx size %lx)\n", (long) to, (long) len); */

		/* Find the chip which is to be used and select it */
		mychip = &this->chips[to >> (this->chipshift)];

		if (this->curfloor != mychip->floor) {
			DoC_SelectFloor(this, mychip->floor);
			DoC_SelectChip(this, mychip->chip);
		} else if (this->curchip != mychip->chip) {
			DoC_SelectChip(this, mychip->chip);
		}

		this->curfloor = mychip->floor;
		this->curchip = mychip->chip;

		/* Set device to main plane of flash */
		DoC_Command(this, NAND_CMD_RESET, CDSN_CTRL_WP);