nand.c

linux下的MTD设备驱动源代码,配合jffs2 yaffss2文件系统.

				goto out;
			page++;
		}

		this->data_poi = bufstart;
		ret = nand_verify_pages (mtd, this, startpage, numpages, oobbuf, oobsel, chipnr, 0);
		if (ret)
			goto out;
			
		written += mtd->oobblock * numpages;
		/* All done ? */
		if (!count)
			break;

		startpage = page & this->pagemask;
		/* Check, if we cross a chip boundary */
		if (!startpage) {
			chipnr++;
			this->select_chip(mtd, -1);
			this->select_chip(mtd, chipnr);
		}
	}
	ret = 0;
out:
	/* Deselect and wake up anyone waiting on the device */
	nand_release_chip(mtd);

	*retlen = written;
	return ret;
}

/*
 * NAND erase a block
 * 
 * @mtd:	MTD device structure
 * @instr:	erase instruction
 */
static int nand_erase (struct mtd_info *mtd, struct erase_info *instr)
{
	int page, len, status, pages_per_block, ret, chipnr;
	struct nand_chip *this = mtd->priv;

	DEBUG (MTD_DEBUG_LEVEL3,
	       "nand_erase: start = 0x%08x, len = %i\n", (unsigned int) instr->addr, (unsigned int) instr->len);

	/* Start address must align on block boundary */
	if (instr->addr & (mtd->erasesize - 1)) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_erase: Unaligned address\n");
		return -EINVAL;
	}

	/* Length must align on block boundary */
	if (instr->len & (mtd->erasesize - 1)) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_erase: Length not block aligned\n");
		return -EINVAL;
	}

	/* Do not allow erase past end of device */
	if ((instr->len + instr->addr) > mtd->size) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_erase: Erase past end of device\n");
		return -EINVAL;
	}

	/* Grab the lock and see if the device is available */
	nand_get_chip (this, mtd, FL_ERASING, NULL);

	/* Shift to get first page */
	page = (int) (instr->addr >> this->page_shift);
	chipnr = (int)((unsigned long)instr->addr / this->chipsize);

	/* Calculate pages in each block */
	pages_per_block = mtd->erasesize / mtd->oobblock;

	/* Select the NAND device */
	this->select_chip(mtd, chipnr);

	/* Check the WP bit */
	this->cmdfunc (mtd, NAND_CMD_STATUS, -1, -1);
	if (!(this->read_byte(mtd) & 0x80)) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_erase: Device is write protected!!!\n");
		instr->state = MTD_ERASE_FAILED;
		goto erase_exit;
	}

	/* Loop through the pages */
	len = instr->len;

	instr->state = MTD_ERASING;

	while (len) {
		/* Check if we have a bad block, we do not erase bad blocks ! */
		if (this->block_bad(mtd, (loff_t) page, 0)) {
			printk (KERN_WARNING "nand_erase: attempt to erase a bad block at page 0x%08x\n", page);
			instr->state = MTD_ERASE_FAILED;
			goto erase_exit;
		}
		
		/* Invalidate the page cache, if we erase the block which contains 
		   the current cached page */
		if (page >= this->pagebuf && this->pagebuf < (page + pages_per_block))  
			this->pagebuf = -1;

		/* Send commands to erase a page */
		this->cmdfunc (mtd, NAND_CMD_ERASE1, -1, page & this->pagemask);
		this->cmdfunc (mtd, NAND_CMD_ERASE2, -1, -1);

		status = this->waitfunc (mtd, this, FL_ERASING);

		/* See if block erase succeeded */
		if (status & 0x01) {
			DEBUG (MTD_DEBUG_LEVEL0, "nand_erase: " "Failed erase, page 0x%08x\n", page);
			instr->state = MTD_ERASE_FAILED;
			goto erase_exit;
		}
		
		/* Increment page address and decrement length */
		len -= mtd->erasesize;
		page += pages_per_block;

		/* Check, if we cross a chip boundary */
		if (len && !(page & this->pagemask)) {
			chipnr++;
			this->select_chip(mtd, -1);
			this->select_chip(mtd, chipnr);
		}
	}
	instr->state = MTD_ERASE_DONE;

erase_exit:

	ret = instr->state == MTD_ERASE_DONE ? 0 : -EIO;;
	/* Do call back function */
	if (!ret && instr->callback)
		instr->callback (instr);

	/* Deselect and wake up anyone waiting on the device */
	nand_release_chip(mtd);

	/* Return more or less happy */
	return ret;
}

/*
 * NAND sync
 *
 * @mtd:	MTD device structure
 */
static void nand_sync (struct mtd_info *mtd)
{
	struct nand_chip *this = mtd->priv;
	DECLARE_WAITQUEUE (wait, current);

	DEBUG (MTD_DEBUG_LEVEL3, "nand_sync: called\n");

retry:
	/* Grab the spinlock */
	spin_lock_bh (&this->chip_lock);

	/* See what's going on */
	switch (this->state) {
	case FL_READY:
	case FL_SYNCING:
		this->state = FL_SYNCING;
		spin_unlock_bh (&this->chip_lock);
		break;

	default:
		/* Not an idle state */
		add_wait_queue (&this->wq, &wait);
		spin_unlock_bh (&this->chip_lock);
		schedule ();

		remove_wait_queue (&this->wq, &wait);
		goto retry;
	}

	/* Lock the device */
	spin_lock_bh (&this->chip_lock);

	/* Set the device to be ready again */
	if (this->state == FL_SYNCING) {
		this->state = FL_READY;
		wake_up (&this->wq);
	}

	/* Unlock the device */
	spin_unlock_bh (&this->chip_lock);
}

/*
 * Check whether the block at the given offset is bad
 *
 * @mtd:	MTD device structure
 * @ofs:	offset relative to mtd start
 */
static int nand_block_isbad (struct mtd_info *mtd, loff_t ofs)
{
	struct nand_chip *this = mtd->priv;
	
	/* Check for invalid offset */
	if (ofs > mtd->size) 
		return -EINVAL;

	return this->block_bad(mtd, ofs, 1);
}

/*
 * Mark the block at the given offset as bad
 *
 * @mtd:	MTD device structure
 * @ofs:	offset relative to mtd start
 */
static int nand_block_markbad (struct mtd_info *mtd, loff_t ofs)
{
	struct nand_chip *this = mtd->priv;
		
	/* Check for invalid offset */
	if (ofs > mtd->size) 
		return -EINVAL;

	return this->block_markbad(mtd, ofs);
}

/*
 * Scan for the NAND device
 *
 * This fills out all the not initialized function pointers
 * with the defaults.
 * The flash ID is read and the mtd/chip structures are
 * filled with the appropriate values.
 *
 * @mtd:	MTD device structure
 * @maxchips:	Number of chips to scan for
 */
int nand_scan (struct mtd_info *mtd, int maxchips)
{
	int i, nand_maf_id, nand_dev_id, busw;
	struct nand_chip *this = mtd->priv;

	/* Get buswidth to select the correct functions*/
	busw = this->options & NAND_BUSWIDTH_16;

	/* check for proper chip_delay setup, set 20us if not */
	if (!this->chip_delay)
		this->chip_delay = 20;

	/* check, if a user supplied command function given */
	if (this->cmdfunc == NULL)
		this->cmdfunc = nand_command;

	/* check, if a user supplied wait function given */
	if (this->waitfunc == NULL)
		this->waitfunc = nand_wait;

	if (!this->select_chip)
		this->select_chip = nand_select_chip;
	if (!this->write_byte)
		this->write_byte = busw ? nand_write_byte16 : nand_write_byte;
	if (!this->read_byte)
		this->read_byte = busw ? nand_read_byte16 : nand_read_byte;
	if (!this->write_word)
		this->write_word = nand_write_word;
	if (!this->read_word)
		this->read_word = nand_read_word;
	if (!this->block_bad)
		this->block_bad = nand_block_bad;
	if (!this->block_markbad)
		this->block_markbad = nand_default_block_markbad;
	if (!this->write_buf)
		this->write_buf = busw ? nand_write_buf16 : nand_write_buf;
	if (!this->read_buf)
		this->read_buf = busw ? nand_read_buf16 : nand_read_buf;
	if (!this->verify_buf)
		this->verify_buf = busw ? nand_verify_buf16 : nand_verify_buf;

	/* Select the device */
	this->select_chip(mtd, 0);

	/* Send the command for reading device ID */
	this->cmdfunc (mtd, NAND_CMD_READID, 0x00, -1);

	/* Read manufacturer and device IDs */
	nand_maf_id = this->read_byte(mtd);
	nand_dev_id = this->read_byte(mtd);

	/* Print and store flash device information */
	for (i = 0; nand_flash_ids[i].name != NULL; i++) {
				
		if (nand_dev_id != nand_flash_ids[i].id) 
			continue;
			
		mtd->name = nand_flash_ids[i].name;
		this->chipsize = nand_flash_ids[i].chipsize << 20;
		
		/* New devices have all the information in additional id bytes */
		if (!nand_flash_ids[i].pagesize) {
			int extid;
			/* The 3rd id byte contains non relevant data ATM */
			extid = this->read_byte(mtd);
			/* The 4th id byte is the important one */
			extid = this->read_byte(mtd);
			/* Calc pagesize */
			mtd->oobblock = 1024 << (extid & 0x3);
			extid >>= 2;
			/* Calc oobsize */
			mtd->oobsize = (8 << (extid & 0x03)) * (mtd->oobblock / 512);
			extid >>= 2;
			/* Calc blocksize. Blocksize is multiples of 64KiB */
			mtd->erasesize = (64 * 1024)  << (extid & 0x03);
			extid >>= 2;
			/* Get buswidth information */
			busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
		
			/* Do not replace user supplied command function ! */
			if (this->cmdfunc == nand_command)
				this->cmdfunc = nand_command_lp;
		} else {
			/* Old devices have this data hardcoded in the
			 * device id table */
			mtd->erasesize = nand_flash_ids[i].erasesize;
			mtd->oobblock = nand_flash_ids[i].pagesize;
			mtd->oobsize = mtd->oobblock / 32;
			busw = nand_flash_ids[i].options & NAND_BUSWIDTH_16;
		}

		/* Check, if buswidth is correct. Hardware drivers should set
		 * this correct ! */
		if (busw != (this->options & NAND_BUSWIDTH_16)) {
			printk (KERN_INFO "NAND device: Manufacturer ID:"
				" 0x%02x, Chip ID: 0x%02x (%s %s)\n", nand_maf_id, nand_dev_id, 
				nand_manuf_ids[i].name , mtd->name);
			printk (KERN_WARNING 
				"NAND bus width %d instead %d bit\n", 
					(this->options & NAND_BUSWIDTH_16) ? 16 : 8,
					busw ? 16 : 8);
			this->select_chip(mtd, -1);
			return 1;	
		}
		
		/* Calculate the address shift from the page size */	
		this->page_shift = ffs(mtd->oobblock) - 1;

		/* Set the bad block position */
		this->badblockpos = mtd->oobblock > 512 ? 
			NAND_LARGE_BADBLOCK_POS : NAND_SMALL_BADBLOCK_POS;

		/* Get chip options */
		this->options = nand_flash_ids[i].options;
		/* Check if this is a not a samsung device */	
		if (nand_maf_id != NAND_MFR_SAMSUNG)
			this->options &= ~NAND_SAMSUNG_LP_OPTIONS;
		
		/* Try to identify manufacturer */
		for (i = 0; nand_manuf_ids[i].id != 0x0; i++) {
			if (nand_manuf_ids[i].id == nand_maf_id)
				break;
		}
		printk (KERN_INFO "NAND device: Manufacturer ID:"
			" 0x%02x, Chip ID: 0x%02x (%s %s)\n", nand_maf_id, nand_dev_id, 
			nand_manuf_ids[i].name , mtd->name);
		break;
	}

	if (!mtd->name) {
		printk (KERN_WARNING "No NAND device found!!!\n");
		this->select_chip(mtd, -1);
		return 1;
	}

	for (i=1; i < maxchips; i++) {
		this->select_chip(mtd, i);

		/* Send the command for reading device ID */
		this->cmdfunc (mtd, NAND_CMD_READID, 0x00, -1);

		/* Read manufacturer and device IDs */
		if (nand_maf_id != this->read_byte(mtd) ||
		    nand_dev_id != this->read_byte(mtd))
			break;
	}
	if (i > 1)
		printk(KERN_INFO "%d NAND chips detected\n", i);
	
	if (!this->oob_buf || !this->data_buf) {
		printk (KERN_WARNING "nand_scan(): Buffers not set. Scan aborted\n"); 
		return 1;
	}

	/* Store the number of chips and calc total size for mtd */
	this->numchips = i;
	mtd->size = i * this->chipsize;
	/* Convert chipsize to number of pages per chip -1. */
	this->pagemask = (this->chipsize >> this->page_shift) - 1;
	/* Preset the internal oob buffer */
	memset(this->oob_buf, 0xff, mtd->oobsize * (mtd->erasesize / mtd->oobblock));	

	/* If no default placement scheme is given, select an
	 * appropriate one */
	if (!this->autooob) {
		/* Select the appropriate default oob placement scheme for
		 * placement agnostic filesystems */
		switch (mtd->oobsize) { 
		case 8:
			this->autooob = &nand_oob_8;
			break;
		case 16:
			this->autooob = &nand_oob_16;
			break;
		case 64:
			this->autooob = &nand_oob_64;
			break;
		default:
			printk (KERN_WARNING "No oob scheme defined for oobsize %d\n",
				mtd->oobsize);
			BUG();
		}
	}
	
	/* The number of bytes available for the filesystem to place fs dependend
	 * oob data */
	if (this->options & NAND_BUSWIDTH_16) {
		mtd->oobavail = mtd->oobsize - (this->autooob->eccbytes + 2);
		if (this->autooob->eccbytes & 0x01)
			mtd->oobavail--;
	} else
		mtd->oobavail = mtd->oobsize - (this->autooob->eccbytes + 1);

	/* 
	 * check ECC mode, default to software
	 * if 3byte/512byte hardware ECC is selected and we have 256 byte pagesize
	 * fallback to software ECC 
	*/
	this->eccsize = 256;	/* set default eccsize */	

	switch (this->eccmode) {

	case NAND_ECC_HW3_512: 
	case NAND_ECC_HW6_512: 
		if (mtd->oobblock == 256) {
			printk (KERN_WARNING "512 byte HW ECC not possible on 256 Byte pagesize, fallback to SW ECC \n");
			this->eccmode = NAND_ECC_SOFT;
			this->calculate_ecc = nand_calculate_ecc;
			this->correct_data = nand_correct_data;
			break;		
		} else 
			this->eccsize = 512; /* set eccsize to 512 and fall through for function check */

	case NAND_ECC_HW3_256:
		if (this->calculate_ecc && this->correct_data && this->enable_hwecc)
			break;
		printk (KERN_WARNING "No ECC functions supplied, Hardware ECC not possible\n");
		BUG();	

	case NAND_ECC_NONE: 
		printk (KERN_WARNING "NAND_ECC_NONE selected by board driver. This is not recommended !!\n");
		this->eccmode = NAND_ECC_NONE;
		break;

	case NAND_ECC_SOFT:	
		this->calculate_ecc = nand_calculate_ecc;
		this->correct_data = nand_correct_data;
		break;

	default:
		printk (KERN_WARNING "Invalid NAND_ECC_MODE %d\n", this->eccmode);
		BUG();	
	}	
	
	mtd->eccsize = this->eccsize;
	
	/* Set the number of read / write steps for one page to ensure ECC generation */
	switch (this->eccmode) {
	case NAND_ECC_HW3_512:
	case NAND_ECC_HW6_512:
		this->eccsteps = mtd->oobblock / 512;
		break;
	case NAND_ECC_HW3_256:
	case NAND_ECC_SOFT:	
		this->eccsteps = mtd->oobblock / 256;
		break;
		
	case NAND_ECC_NONE: 
		this->eccsteps = 1;
		break;
	}
	
	/* Initialize state, waitqueue and spinlock */
	this->state = FL_READY;
	init_waitqueue_head (&this->wq);
	spin_lock_init (&this->chip_lock);

	/* De-select the device */
	this->select_chip(mtd, -1);

	/* Invalidate the pagebuffer reference */
	this->pagebuf = -1;

	/* Fill in remaining MTD driver data */
	mtd->type = MTD_NANDFLASH;
	mtd->flags = MTD_CAP_NANDFLASH | MTD_ECC;
	mtd->ecctype = MTD_ECC_SW;
	mtd->erase = nand_erase;
	mtd->point = NULL;
	mtd->unpoint = NULL;
	mtd->read = nand_read;
	mtd->write = nand_write;
	mtd->read_ecc = nand_read_ecc;
	mtd->write_ecc = nand_write_ecc;
	mtd->read_oob = nand_read_oob;
	mtd->write_oob = nand_write_oob;
	mtd->readv = NULL;
	mtd->writev = nand_writev;
	mtd->writev_ecc = nand_writev_ecc;
	mtd->sync = nand_sync;
	mtd->lock = NULL;
	mtd->unlock = NULL;
	mtd->suspend = NULL;
	mtd->resume = NULL;
	mtd->block_isbad = nand_block_isbad;
	mtd->block_markbad = nand_block_markbad;
	mtd->owner = THIS_MODULE;

	/* Return happy */
	return 0;
}

EXPORT_SYMBOL (nand_scan);

MODULE_LICENSE ("GPL");
MODULE_AUTHOR ("Steven J. Hill <[e-mail]>, Thomas Gleixner <[e-mail]>");
MODULE_DESCRIPTION ("Generic NAND flash driver code");