mtdconcat.c

基于linux-2.6.28的mtd驱动

	BUG_ON(i >= concat->num_subdev);

	/* now do the erase: */
	err = 0;
	for (; length > 0; i++) {
		/* loop for all subdevices affected by this request */
		subdev = concat->subdev[i];	/* get current subdevice */

		/* limit length to subdevice's size: */
		if (erase->addr + length > subdev->size)
			erase->len = subdev->size - erase->addr;
		else
			erase->len = length;

		if (!(subdev->flags & MTD_WRITEABLE)) {
			err = -EROFS;
			break;
		}
		length -= erase->len;
		if ((err = concat_dev_erase(subdev, erase))) {
			/* sanity check: should never happen since
			 * block alignment has been checked above */
			BUG_ON(err == -EINVAL);
			if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
				instr->fail_addr = erase->fail_addr + offset;
			break;
		}
		/*
		 * erase->addr specifies the offset of the area to be
		 * erased *within the current subdevice*. It can be
		 * non-zero only the first time through this loop, i.e.
		 * for the first subdevice where blocks need to be erased.
		 * All the following erases must begin at the start of the
		 * current subdevice, i.e. at offset zero.
		 */
		erase->addr = 0;
		offset += subdev->size;
	}
	instr->state = erase->state;
	kfree(erase);
	if (err)
		return err;

	if (instr->callback)
		instr->callback(instr);
	return 0;
}

static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i, err = -EINVAL;

	if ((len + ofs) > mtd->size)
		return -EINVAL;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];
		size_t size;

		if (ofs >= subdev->size) {
			size = 0;
			ofs -= subdev->size;
			continue;
		}
		if (ofs + len > subdev->size)
			size = subdev->size - ofs;
		else
			size = len;

		err = subdev->lock(subdev, ofs, size);

		if (err)
			break;

		len -= size;
		if (len == 0)
			break;

		err = -EINVAL;
		ofs = 0;
	}

	return err;
}

static int concat_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i, err = 0;

	if ((len + ofs) > mtd->size)
		return -EINVAL;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];
		size_t size;

		if (ofs >= subdev->size) {
			size = 0;
			ofs -= subdev->size;
			continue;
		}
		if (ofs + len > subdev->size)
			size = subdev->size - ofs;
		else
			size = len;

		err = subdev->unlock(subdev, ofs, size);

		if (err)
			break;

		len -= size;
		if (len == 0)
			break;

		err = -EINVAL;
		ofs = 0;
	}

	return err;
}

static void concat_sync(struct mtd_info *mtd)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];
		subdev->sync(subdev);
	}
}

static int concat_suspend(struct mtd_info *mtd)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i, rc = 0;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];
		if ((rc = subdev->suspend(subdev)) < 0)
			return rc;
	}
	return rc;
}

static void concat_resume(struct mtd_info *mtd)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];
		subdev->resume(subdev);
	}
}

static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i, res = 0;

	if (!concat->subdev[0]->block_isbad)
		return res;

	if (ofs > mtd->size)
		return -EINVAL;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];

		if (ofs >= subdev->size) {
			ofs -= subdev->size;
			continue;
		}

		res = subdev->block_isbad(subdev, ofs);
		break;
	}

	return res;
}

static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
	struct mtd_concat *concat = CONCAT(mtd);
	int i, err = -EINVAL;

	if (!concat->subdev[0]->block_markbad)
		return 0;

	if (ofs > mtd->size)
		return -EINVAL;

	for (i = 0; i < concat->num_subdev; i++) {
		struct mtd_info *subdev = concat->subdev[i];

		if (ofs >= subdev->size) {
			ofs -= subdev->size;
			continue;
		}

		err = subdev->block_markbad(subdev, ofs);
		if (!err)
			mtd->ecc_stats.badblocks++;
		break;
	}

	return err;
}

/*
 * This function constructs a virtual MTD device by concatenating
 * num_devs MTD devices. A pointer to the new device object is
 * stored to *new_dev upon success. This function does _not_
 * register any devices: this is the caller's responsibility.
 */
struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to concatenate */
				   int num_devs,	/* number of subdevices      */
				   char *name)
{				/* name for the new device   */
	int i;
	size_t size;
	struct mtd_concat *concat;
	u_int32_t max_erasesize, curr_erasesize;
	int num_erase_region;

	printk(KERN_NOTICE "Concatenating MTD devices:\n");
	for (i = 0; i < num_devs; i++)
		printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
	printk(KERN_NOTICE "into device \"%s\"\n", name);

	/* allocate the device structure */
	size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
	concat = kzalloc(size, GFP_KERNEL);
	if (!concat) {
		printk
		    ("memory allocation error while creating concatenated device \"%s\"\n",
		     name);
		return NULL;
	}
	concat->subdev = (struct mtd_info **) (concat + 1);

	/*
	 * Set up the new "super" device's MTD object structure, check for
	 * incompatibilites between the subdevices.
	 */
	concat->mtd.type = subdev[0]->type;
	concat->mtd.flags = subdev[0]->flags;
	concat->mtd.size = subdev[0]->size;
	concat->mtd.erasesize = subdev[0]->erasesize;
	concat->mtd.writesize = subdev[0]->writesize;
	concat->mtd.subpage_sft = subdev[0]->subpage_sft;
	concat->mtd.oobsize = subdev[0]->oobsize;
	concat->mtd.oobavail = subdev[0]->oobavail;
	if (subdev[0]->writev)
		concat->mtd.writev = concat_writev;
	if (subdev[0]->read_oob)
		concat->mtd.read_oob = concat_read_oob;
	if (subdev[0]->write_oob)
		concat->mtd.write_oob = concat_write_oob;
	if (subdev[0]->block_isbad)
		concat->mtd.block_isbad = concat_block_isbad;
	if (subdev[0]->block_markbad)
		concat->mtd.block_markbad = concat_block_markbad;

	concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;

	concat->subdev[0] = subdev[0];

	for (i = 1; i < num_devs; i++) {
		if (concat->mtd.type != subdev[i]->type) {
			kfree(concat);
			printk("Incompatible device type on \"%s\"\n",
			       subdev[i]->name);
			return NULL;
		}
		if (concat->mtd.flags != subdev[i]->flags) {
			/*
			 * Expect all flags except MTD_WRITEABLE to be
			 * equal on all subdevices.
			 */
			if ((concat->mtd.flags ^ subdev[i]->
			     flags) & ~MTD_WRITEABLE) {
				kfree(concat);
				printk("Incompatible device flags on \"%s\"\n",
				       subdev[i]->name);
				return NULL;
			} else
				/* if writeable attribute differs,
				   make super device writeable */
				concat->mtd.flags |=
				    subdev[i]->flags & MTD_WRITEABLE;
		}
		concat->mtd.size += subdev[i]->size;
		concat->mtd.ecc_stats.badblocks +=
			subdev[i]->ecc_stats.badblocks;
		if (concat->mtd.writesize   !=  subdev[i]->writesize ||
		    concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
		    concat->mtd.oobsize    !=  subdev[i]->oobsize ||
		    !concat->mtd.read_oob  != !subdev[i]->read_oob ||
		    !concat->mtd.write_oob != !subdev[i]->write_oob) {
			kfree(concat);
			printk("Incompatible OOB or ECC data on \"%s\"\n",
			       subdev[i]->name);
			return NULL;
		}
		concat->subdev[i] = subdev[i];

	}

	concat->mtd.ecclayout = subdev[0]->ecclayout;

	concat->num_subdev = num_devs;
	concat->mtd.name = name;

	concat->mtd.erase = concat_erase;
	concat->mtd.read = concat_read;
	concat->mtd.write = concat_write;
	concat->mtd.sync = concat_sync;
	concat->mtd.lock = concat_lock;
	concat->mtd.unlock = concat_unlock;
	concat->mtd.suspend = concat_suspend;
	concat->mtd.resume = concat_resume;

	/*
	 * Combine the erase block size info of the subdevices:
	 *
	 * first, walk the map of the new device and see how
	 * many changes in erase size we have
	 */
	max_erasesize = curr_erasesize = subdev[0]->erasesize;
	num_erase_region = 1;
	for (i = 0; i < num_devs; i++) {
		if (subdev[i]->numeraseregions == 0) {
			/* current subdevice has uniform erase size */
			if (subdev[i]->erasesize != curr_erasesize) {
				/* if it differs from the last subdevice's erase size, count it */
				++num_erase_region;
				curr_erasesize = subdev[i]->erasesize;
				if (curr_erasesize > max_erasesize)
					max_erasesize = curr_erasesize;
			}
		} else {
			/* current subdevice has variable erase size */
			int j;
			for (j = 0; j < subdev[i]->numeraseregions; j++) {

				/* walk the list of erase regions, count any changes */
				if (subdev[i]->eraseregions[j].erasesize !=
				    curr_erasesize) {
					++num_erase_region;
					curr_erasesize =
					    subdev[i]->eraseregions[j].
					    erasesize;
					if (curr_erasesize > max_erasesize)
						max_erasesize = curr_erasesize;
				}
			}
		}
	}

	if (num_erase_region == 1) {
		/*
		 * All subdevices have the same uniform erase size.
		 * This is easy:
		 */
		concat->mtd.erasesize = curr_erasesize;
		concat->mtd.numeraseregions = 0;
	} else {
		/*
		 * erase block size varies across the subdevices: allocate
		 * space to store the data describing the variable erase regions
		 */
		struct mtd_erase_region_info *erase_region_p;
		u_int32_t begin, position;

		concat->mtd.erasesize = max_erasesize;
		concat->mtd.numeraseregions = num_erase_region;
		concat->mtd.eraseregions = erase_region_p =
		    kmalloc(num_erase_region *
			    sizeof (struct mtd_erase_region_info), GFP_KERNEL);
		if (!erase_region_p) {
			kfree(concat);
			printk
			    ("memory allocation error while creating erase region list"
			     " for device \"%s\"\n", name);
			return NULL;
		}

		/*
		 * walk the map of the new device once more and fill in
		 * in erase region info:
		 */
		curr_erasesize = subdev[0]->erasesize;
		begin = position = 0;
		for (i = 0; i < num_devs; i++) {
			if (subdev[i]->numeraseregions == 0) {
				/* current subdevice has uniform erase size */
				if (subdev[i]->erasesize != curr_erasesize) {
					/*
					 *  fill in an mtd_erase_region_info structure for the area
					 *  we have walked so far:
					 */
					erase_region_p->offset = begin;
					erase_region_p->erasesize =
					    curr_erasesize;
					erase_region_p->numblocks =
					    (position - begin) / curr_erasesize;
					begin = position;

					curr_erasesize = subdev[i]->erasesize;
					++erase_region_p;
				}
				position += subdev[i]->size;
			} else {
				/* current subdevice has variable erase size */
				int j;
				for (j = 0; j < subdev[i]->numeraseregions; j++) {
					/* walk the list of erase regions, count any changes */
					if (subdev[i]->eraseregions[j].
					    erasesize != curr_erasesize) {
						erase_region_p->offset = begin;
						erase_region_p->erasesize =
						    curr_erasesize;
						erase_region_p->numblocks =
						    (position -
						     begin) / curr_erasesize;
						begin = position;

						curr_erasesize =
						    subdev[i]->eraseregions[j].
						    erasesize;
						++erase_region_p;
					}
					position +=
					    subdev[i]->eraseregions[j].
					    numblocks * curr_erasesize;
				}
			}
		}
		/* Now write the final entry */
		erase_region_p->offset = begin;
		erase_region_p->erasesize = curr_erasesize;
		erase_region_p->numblocks = (position - begin) / curr_erasesize;
	}

	return &concat->mtd;
}

/*
 * This function destroys an MTD object obtained from concat_mtd_devs()
 */

void mtd_concat_destroy(struct mtd_info *mtd)
{
	struct mtd_concat *concat = CONCAT(mtd);
	if (concat->mtd.numeraseregions)
		kfree(concat->mtd.eraseregions);
	kfree(concat);
}

EXPORT_SYMBOL(mtd_concat_create);
EXPORT_SYMBOL(mtd_concat_destroy);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Robert Kaiser <[e-mail]>");
MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");