nand.c

linux嵌入式课程实践中的一个关于声卡驱动程序 。

	this->state = FL_READY;
	wake_up (&this->wq);
	spin_unlock_bh (&this->chip_lock);

	return ret;
}

/*
 * NAND write with iovec
 */
static int nand_writev (struct mtd_info *mtd, const struct iovec *vecs, unsigned long count, loff_t to, size_t * retlen)
{
	int i, page, col, cnt, len, total_len, ret = 0;
	struct nand_chip *this = mtd->priv;

	/* Calculate total length of data */
	total_len = 0;
	for (i = 0; i < count; i++)
		total_len += (int) vecs[i].iov_len;

	DEBUG (MTD_DEBUG_LEVEL3,
	       "nand_writev: to = 0x%08x, len = %i, count = %ld\n", (unsigned int) to, (unsigned int) total_len, count);

	/* Do not allow write past end of page */
	if ((to + total_len) > mtd->size) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_writev: Attempted write past end of device\n");
		return -EINVAL;
	}

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

	/* Shift to get page */
	page = ((int) to) >> this->page_shift;

	/* Get the starting column */
	col = to & (mtd->oobblock - 1);

	/* Initialize return length value */
	*retlen = 0;

	/* Select the NAND device */
	nand_select ();

	/* Check the WP bit */
	this->cmdfunc (mtd, NAND_CMD_STATUS, -1, -1);
	if (!(readb (this->IO_ADDR_R) & 0x80)) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_writev: Device is write protected!!!\n");
		ret = -EIO;
		goto out;
	}

	/* Loop until all iovecs' data has been written */
	cnt = col;
	len = 0;
	while (count) {
		/* Invalidate cache, if we write to this page */
		if (this->cache_page == page)
			this->cache_page = -1;

		/* Do any need pre-fill for partial page programming */
		for (i = 0; i < cnt; i++)
			this->data_buf[i] = 0xff;

		/*
		 * Read data out of each tuple until we have a full page
		 * to write or we've read all the tuples.
		 */

		while ((cnt < mtd->oobblock) && count) {
			if (vecs->iov_base != NULL && vecs->iov_len) {
				this->data_buf[cnt++] = ((u_char *) vecs->iov_base)[len++];
			}
			if (len >= (int) vecs->iov_len) {
				vecs++;
				len = 0;
				count--;
			}
		}

		/* We use the same function for write and writev !) */
		ret = nand_write_page (mtd, this, page, col, cnt, this->ecc_code_buf);
		if (ret)
			goto out;

		/* Update written bytes count */
		*retlen += (cnt - col);

		/* Reset written byte counter and column */
		col = cnt = 0;

		/* Increment page address */
		page++;
	}

out:
	/* De-select the NAND device */
	nand_deselect ();

	/* Wake up anyone waiting on the device */
	spin_lock_bh (&this->chip_lock);
	this->state = FL_READY;
	wake_up (&this->wq);
	spin_unlock_bh (&this->chip_lock);

	/* Return happy */
	return ret;
}

/*
 * NAND erase a block
 */
static int nand_erase (struct mtd_info *mtd, struct erase_info *instr)
{
	int page, len, status, pages_per_block, ret;
	struct nand_chip *this = mtd->priv;
	DECLARE_WAITQUEUE (wait, current);

	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, FL_ERASING, NULL);

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

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

	/* Select the NAND device */
	nand_select ();

	/* Check the WP bit */
	this->cmdfunc (mtd, NAND_CMD_STATUS, -1, -1);
	if (!(readb (this->IO_ADDR_R) & 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) {
		if (oob_config.badblock_pos != -1) {
			/* Check if we have a bad block, we do not erase bad blocks ! */
			this->cmdfunc (mtd, NAND_CMD_READOOB, oob_config.badblock_pos, page);
			if (readb (this->IO_ADDR_R) != 0xff) {
				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;
			}
		}

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

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

		/* Get spinlock, in case we exit */
		spin_lock_bh (&this->chip_lock);
		/* 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;
		}
		
		/* Check, if we were interupted */
		if (this->state == FL_ERASING) {
			/* Invalidate cache, if last_page is inside erase-block */
			if (this->cache_page >= page && this->cache_page < (page + pages_per_block))
				this->cache_page = -1;

			/* Increment page address and decrement length */
			len -= mtd->erasesize;
			page += pages_per_block;
		}
		/* Release the spin lock */
		spin_unlock_bh (&this->chip_lock);
erase_retry:
		spin_lock_bh (&this->chip_lock);
		/* Check the state and sleep if it changed */
		if (this->state == FL_ERASING || this->state == FL_READY) {
			/* Select the NAND device again, if we were interrupted */
			this->state = FL_ERASING;
			nand_select ();
			continue;
		} else {
			set_current_state (TASK_UNINTERRUPTIBLE);
			add_wait_queue (&this->wq, &wait);
			spin_unlock_bh (&this->chip_lock);
			schedule ();
			remove_wait_queue (&this->wq, &wait);
			goto erase_retry;
		}
	}
	instr->state = MTD_ERASE_DONE;

erase_exit:
	/* De-select the NAND device */
	nand_deselect ();
	spin_unlock_bh (&this->chip_lock);

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

	/* The device is ready */
	spin_lock_bh (&this->chip_lock);
	this->state = FL_READY;
	spin_unlock_bh (&this->chip_lock);

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

/*
 * NAND sync
 */
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);
}

/*
 * Scan for the NAND device
 */
int nand_scan (struct mtd_info *mtd)
{
	int i, nand_maf_id, nand_dev_id;
	struct nand_chip *this = mtd->priv;

	/* 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;

	/* Select the device */
	nand_select ();

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

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

	/* Print and store flash device information */
	for (i = 0; nand_flash_ids[i].name != NULL; i++) {
		if (nand_maf_id == nand_flash_ids[i].manufacture_id && nand_dev_id == nand_flash_ids[i].model_id) {
			if (!mtd->size) {
				mtd->name = nand_flash_ids[i].name;
				mtd->erasesize = nand_flash_ids[i].erasesize;
				mtd->size = (1 << nand_flash_ids[i].chipshift);
				mtd->eccsize = 256;
				if (nand_flash_ids[i].page256) {
					mtd->oobblock = 256;
					mtd->oobsize = 8;
					this->page_shift = 8;
				} else {
					mtd->oobblock = 512;
					mtd->oobsize = 16;
					this->page_shift = 9;
				}
			}
			printk (KERN_INFO "NAND device: Manufacture ID:"
				" 0x%02x, Chip ID: 0x%02x (%s)\n", nand_maf_id, nand_dev_id, mtd->name);
			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 */
	nand_deselect ();
	/* 
	 * Preset out of band configuration
	 */
#ifdef CONFIG_MTD_NAND_ECC_JFFS2
	oob_config.ecc_pos[0] = NAND_JFFS2_OOB_ECCPOS0;
	oob_config.ecc_pos[1] = NAND_JFFS2_OOB_ECCPOS1;
	oob_config.ecc_pos[2] = NAND_JFFS2_OOB_ECCPOS2;
	oob_config.ecc_pos[3] = NAND_JFFS2_OOB_ECCPOS3;
	oob_config.ecc_pos[4] = NAND_JFFS2_OOB_ECCPOS4;
	oob_config.ecc_pos[5] = NAND_JFFS2_OOB_ECCPOS5;
	oob_config.badblock_pos = 5;
	oob_config.eccvalid_pos = 4;
#else
	oob_config.ecc_pos[0] = NAND_NOOB_ECCPOS0;
	oob_config.ecc_pos[1] = NAND_NOOB_ECCPOS1;
	oob_config.ecc_pos[2] = NAND_NOOB_ECCPOS2;
	oob_config.ecc_pos[3] = NAND_NOOB_ECCPOS3;
	oob_config.ecc_pos[4] = NAND_NOOB_ECCPOS4;
	oob_config.ecc_pos[5] = NAND_NOOB_ECCPOS5;
	oob_config.badblock_pos = NAND_NOOB_BADBPOS;
	oob_config.eccvalid_pos = NAND_NOOB_ECCVPOS;
#endif

	/* Print warning message for no device */
	if (!mtd->size) {
		printk (KERN_WARNING "No NAND device found!!!\n");
		return 1;
	}

	/* Fill in remaining MTD driver data */
	mtd->type = MTD_NANDFLASH;
	mtd->flags = MTD_CAP_NANDFLASH | MTD_ECC;
	mtd->module = THIS_MODULE;
	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->sync = nand_sync;
	mtd->lock = NULL;
	mtd->unlock = NULL;
	mtd->suspend = NULL;
	mtd->resume = NULL;

	/* Return happy */
	return 0;
}

EXPORT_SYMBOL (nand_scan);

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