drivers/block/blkmap.c - github/trini/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (c) 2023 Addiva Elektronik
  * Author: Tobias Waldekranz <tobias@waldekranz.com>
  */

 #include <common.h>
 #include <blk.h>
 #include <blkmap.h>
 #include <dm.h>
 #include <malloc.h>
 #include <mapmem.h>
 #include <part.h>
 #include <dm/device-internal.h>
 #include <dm/lists.h>
 #include <dm/root.h>

 struct blkmap;

 /**
  * struct blkmap_slice - Region mapped to a blkmap
  *
  * Common data for a region mapped to a blkmap, specialized by each
  * map type.
  *
  * @node: List node used to associate this slice with a blkmap
  * @blknr: Start block number of the mapping
  * @blkcnt: Number of blocks covered by this mapping
  */
 struct blkmap_slice {
 	struct list_head node;

 	lbaint_t blknr;
 	lbaint_t blkcnt;

 	/**
 	 * @read: - Read from slice
 	 *
 	 * @read.bm: Blkmap to which this slice belongs
 	 * @read.bms: This slice
 	 * @read.blknr: Start block number to read from
 	 * @read.blkcnt: Number of blocks to read
 	 * @read.buffer: Buffer to store read data to
 	 */
 	ulong (*read)(struct blkmap *bm, struct blkmap_slice *bms,
 		      lbaint_t blknr, lbaint_t blkcnt, void *buffer);

 	/**
 	 * @write: - Write to slice
 	 *
 	 * @write.bm: Blkmap to which this slice belongs
 	 * @write.bms: This slice
 	 * @write.blknr: Start block number to write to
 	 * @write.blkcnt: Number of blocks to write
 	 * @write.buffer: Data to be written
 	 */
 	ulong (*write)(struct blkmap *bm, struct blkmap_slice *bms,
 		       lbaint_t blknr, lbaint_t blkcnt, const void *buffer);

 	/**
 	 * @destroy: - Tear down slice
 	 *
 	 * @read.bm: Blkmap to which this slice belongs
 	 * @read.bms: This slice
 	 */
 	void (*destroy)(struct blkmap *bm, struct blkmap_slice *bms);
 };

 static bool blkmap_slice_contains(struct blkmap_slice *bms, lbaint_t blknr)
 {
 	return (blknr >= bms->blknr) && (blknr < (bms->blknr + bms->blkcnt));
 }

 static bool blkmap_slice_available(struct blkmap *bm, struct blkmap_slice *new)
 {
 	struct blkmap_slice *bms;
 	lbaint_t first, last;

 	first = new->blknr;
 	last = new->blknr + new->blkcnt - 1;

 	list_for_each_entry(bms, &bm->slices, node) {
 		if (blkmap_slice_contains(bms, first) ||
 		    blkmap_slice_contains(bms, last) ||
 		    blkmap_slice_contains(new, bms->blknr) ||
 		    blkmap_slice_contains(new, bms->blknr + bms->blkcnt - 1))
 			return false;
 	}

 	return true;
 }

 static int blkmap_slice_add(struct blkmap *bm, struct blkmap_slice *new)
 {
 	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
 	struct list_head *insert = &bm->slices;
 	struct blkmap_slice *bms;

 	if (!blkmap_slice_available(bm, new))
 		return -EBUSY;

 	list_for_each_entry(bms, &bm->slices, node) {
 		if (bms->blknr < new->blknr)
 			continue;

 		insert = &bms->node;
 		break;
 	}

 	list_add_tail(&new->node, insert);

 	/* Disk might have grown, update the size */
 	bms = list_last_entry(&bm->slices, struct blkmap_slice, node);
 	bd->lba = bms->blknr + bms->blkcnt;
 	return 0;
 }

 /**
  * struct blkmap_linear - Linear mapping to other block device
  *
  * @slice: Common map data
  * @blk: Target block device of this mapping
  * @blknr: Start block number of the target device
  */
 struct blkmap_linear {
 	struct blkmap_slice slice;

 	struct udevice *blk;
 	lbaint_t blknr;
 };

 static ulong blkmap_linear_read(struct blkmap *bm, struct blkmap_slice *bms,
 				lbaint_t blknr, lbaint_t blkcnt, void *buffer)
 {
 	struct blkmap_linear *bml = container_of(bms, struct blkmap_linear, slice);

 	return blk_read(bml->blk, bml->blknr + blknr, blkcnt, buffer);
 }

 static ulong blkmap_linear_write(struct blkmap *bm, struct blkmap_slice *bms,
 				 lbaint_t blknr, lbaint_t blkcnt,
 				 const void *buffer)
 {
 	struct blkmap_linear *bml = container_of(bms, struct blkmap_linear, slice);

 	return blk_write(bml->blk, bml->blknr + blknr, blkcnt, buffer);
 }

 int blkmap_map_linear(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
 		      struct udevice *lblk, lbaint_t lblknr)
 {
 	struct blkmap *bm = dev_get_plat(dev);
 	struct blkmap_linear *linear;
 	struct blk_desc *bd, *lbd;
 	int err;

 	bd = dev_get_uclass_plat(bm->blk);
 	lbd = dev_get_uclass_plat(lblk);
 	if (lbd->blksz != bd->blksz) {
 		/* update to match the mapped device */
 		bd->blksz = lbd->blksz;
 		bd->log2blksz = LOG2(bd->blksz);
 	}

 	linear = malloc(sizeof(*linear));
 	if (!linear)
 		return -ENOMEM;

 	*linear = (struct blkmap_linear) {
 		.slice = {
 			.blknr = blknr,
 			.blkcnt = blkcnt,

 			.read = blkmap_linear_read,
 			.write = blkmap_linear_write,
 		},

 		.blk = lblk,
 		.blknr = lblknr,
 	};

 	err = blkmap_slice_add(bm, &linear->slice);
 	if (err)
 		free(linear);

 	return err;
 }

 /**
  * struct blkmap_mem - Memory mapping
  *
  * @slice: Common map data
  * @addr: Target memory region of this mapping
  * @remapped: True if @addr is backed by a physical to virtual memory
  * mapping that must be torn down at the end of this mapping's
  * lifetime.
  */
 struct blkmap_mem {
 	struct blkmap_slice slice;
 	void *addr;
 	bool remapped;
 };

 static ulong blkmap_mem_read(struct blkmap *bm, struct blkmap_slice *bms,
 			     lbaint_t blknr, lbaint_t blkcnt, void *buffer)
 {
 	struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice);
 	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
 	char *src;

 	src = bmm->addr + (blknr << bd->log2blksz);
 	memcpy(buffer, src, blkcnt << bd->log2blksz);
 	return blkcnt;
 }

 static ulong blkmap_mem_write(struct blkmap *bm, struct blkmap_slice *bms,
 			      lbaint_t blknr, lbaint_t blkcnt,
 			      const void *buffer)
 {
 	struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice);
 	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
 	char *dst;

 	dst = bmm->addr + (blknr << bd->log2blksz);
 	memcpy(dst, buffer, blkcnt << bd->log2blksz);
 	return blkcnt;
 }

 static void blkmap_mem_destroy(struct blkmap *bm, struct blkmap_slice *bms)
 {
 	struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice);

 	if (bmm->remapped)
 		unmap_sysmem(bmm->addr);
 }

 int __blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
 		     void *addr, bool remapped)
 {
 	struct blkmap *bm = dev_get_plat(dev);
 	struct blkmap_mem *bmm;
 	int err;

 	bmm = malloc(sizeof(*bmm));
 	if (!bmm)
 		return -ENOMEM;

 	*bmm = (struct blkmap_mem) {
 		.slice = {
 			.blknr = blknr,
 			.blkcnt = blkcnt,

 			.read = blkmap_mem_read,
 			.write = blkmap_mem_write,
 			.destroy = blkmap_mem_destroy,
 		},

 		.addr = addr,
 		.remapped = remapped,
 	};

 	err = blkmap_slice_add(bm, &bmm->slice);
 	if (err)
 		free(bmm);

 	return err;
 }

 int blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
 		   void *addr)
 {
 	return __blkmap_map_mem(dev, blknr, blkcnt, addr, false);
 }

 int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
 		    phys_addr_t paddr)
 {
 	struct blkmap *bm = dev_get_plat(dev);
 	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
 	void *addr;
 	int err;

 	addr = map_sysmem(paddr, blkcnt << bd->log2blksz);
 	if (!addr)
 		return -ENOMEM;

 	err = __blkmap_map_mem(dev, blknr, blkcnt, addr, true);
 	if (err)
 		unmap_sysmem(addr);

 	return err;
 }

 static ulong blkmap_blk_read_slice(struct blkmap *bm, struct blkmap_slice *bms,
 				   lbaint_t blknr, lbaint_t blkcnt,
 				   void *buffer)
 {
 	lbaint_t nr, cnt;

 	nr = blknr - bms->blknr;
 	cnt = (blkcnt < bms->blkcnt) ? blkcnt : bms->blkcnt;
 	return bms->read(bm, bms, nr, cnt, buffer);
 }

 static ulong blkmap_blk_read(struct udevice *dev, lbaint_t blknr,
 			     lbaint_t blkcnt, void *buffer)
 {
 	struct blk_desc *bd = dev_get_uclass_plat(dev);
 	struct blkmap *bm = dev_get_plat(dev->parent);
 	struct blkmap_slice *bms;
 	lbaint_t cnt, total = 0;

 	list_for_each_entry(bms, &bm->slices, node) {
 		if (!blkmap_slice_contains(bms, blknr))
 			continue;

 		cnt = blkmap_blk_read_slice(bm, bms, blknr, blkcnt, buffer);
 		blknr += cnt;
 		blkcnt -= cnt;
 		buffer += cnt << bd->log2blksz;
 		total += cnt;
 	}

 	return total;
 }

 static ulong blkmap_blk_write_slice(struct blkmap *bm, struct blkmap_slice *bms,
 				    lbaint_t blknr, lbaint_t blkcnt,
 				    const void *buffer)
 {
 	lbaint_t nr, cnt;

 	nr = blknr - bms->blknr;
 	cnt = (blkcnt < bms->blkcnt) ? blkcnt : bms->blkcnt;
 	return bms->write(bm, bms, nr, cnt, buffer);
 }

 static ulong blkmap_blk_write(struct udevice *dev, lbaint_t blknr,
 			      lbaint_t blkcnt, const void *buffer)
 {
 	struct blk_desc *bd = dev_get_uclass_plat(dev);
 	struct blkmap *bm = dev_get_plat(dev->parent);
 	struct blkmap_slice *bms;
 	lbaint_t cnt, total = 0;

 	list_for_each_entry(bms, &bm->slices, node) {
 		if (!blkmap_slice_contains(bms, blknr))
 			continue;

 		cnt = blkmap_blk_write_slice(bm, bms, blknr, blkcnt, buffer);
 		blknr += cnt;
 		blkcnt -= cnt;
 		buffer += cnt << bd->log2blksz;
 		total += cnt;
 	}

 	return total;
 }

 static const struct blk_ops blkmap_blk_ops = {
 	.read	= blkmap_blk_read,
 	.write	= blkmap_blk_write,
 };

 U_BOOT_DRIVER(blkmap_blk) = {
 	.name		= "blkmap_blk",
 	.id		= UCLASS_BLK,
 	.ops		= &blkmap_blk_ops,
 };

 static int blkmap_dev_bind(struct udevice *dev)
 {
 	struct blkmap *bm = dev_get_plat(dev);
 	struct blk_desc *bd;
 	int err;

 	err = blk_create_devicef(dev, "blkmap_blk", "blk", UCLASS_BLKMAP,
 				 dev_seq(dev), DEFAULT_BLKSZ, 0, &bm->blk);
 	if (err)
 		return log_msg_ret("blk", err);

 	INIT_LIST_HEAD(&bm->slices);

 	bd = dev_get_uclass_plat(bm->blk);
 	snprintf(bd->vendor, BLK_VEN_SIZE, "U-Boot");
 	snprintf(bd->product, BLK_PRD_SIZE, "blkmap");
 	snprintf(bd->revision, BLK_REV_SIZE, "1.0");

 	/* EFI core isn't keen on zero-sized disks, so we lie. This is
 	 * updated with the correct size once the user adds a
 	 * mapping.
 	 */
 	bd->lba = 1;

 	return 0;
 }

 static int blkmap_dev_unbind(struct udevice *dev)
 {
 	struct blkmap *bm = dev_get_plat(dev);
 	struct blkmap_slice *bms, *tmp;
 	int err;

 	list_for_each_entry_safe(bms, tmp, &bm->slices, node) {
 		list_del(&bms->node);
 		free(bms);
 	}

 	err = device_remove(bm->blk, DM_REMOVE_NORMAL);
 	if (err)
 		return err;

 	return device_unbind(bm->blk);
 }

 U_BOOT_DRIVER(blkmap_root) = {
 	.name		= "blkmap_dev",
 	.id		= UCLASS_BLKMAP,
 	.bind		= blkmap_dev_bind,
 	.unbind		= blkmap_dev_unbind,
 	.plat_auto	= sizeof(struct blkmap),
 };

 struct udevice *blkmap_from_label(const char *label)
 {
 	struct udevice *dev;
 	struct uclass *uc;
 	struct blkmap *bm;

 	uclass_id_foreach_dev(UCLASS_BLKMAP, dev, uc) {
 		bm = dev_get_plat(dev);
 		if (bm->label && !strcmp(label, bm->label))
 			return dev;
 	}

 	return NULL;
 }

 int blkmap_create(const char *label, struct udevice **devp)
 {
 	char *hname, *hlabel;
 	struct udevice *dev;
 	struct blkmap *bm;
 	size_t namelen;
 	int err;

 	dev = blkmap_from_label(label);
 	if (dev) {
 		err = -EBUSY;
 		goto err;
 	}

 	hlabel = strdup(label);
 	if (!hlabel) {
 		err = -ENOMEM;
 		goto err;
 	}

 	namelen = strlen("blkmap-") + strlen(label) + 1;
 	hname = malloc(namelen);
 	if (!hname) {
 		err = -ENOMEM;
 		goto err_free_hlabel;
 	}

 	strlcpy(hname, "blkmap-", namelen);
 	strlcat(hname, label, namelen);

 	err = device_bind_driver(dm_root(), "blkmap_dev", hname, &dev);
 	if (err)
 		goto err_free_hname;

 	device_set_name_alloced(dev);
 	bm = dev_get_plat(dev);
 	bm->label = hlabel;

 	if (devp)
 		*devp = dev;

 	return 0;

 err_free_hname:
 	free(hname);
 err_free_hlabel:
 	free(hlabel);
 err:
 	return err;
 }

 int blkmap_destroy(struct udevice *dev)
 {
 	int err;

 	err = device_remove(dev, DM_REMOVE_NORMAL);
 	if (err)
 		return err;

 	return device_unbind(dev);
 }

 UCLASS_DRIVER(blkmap) = {
 	.id		= UCLASS_BLKMAP,
 	.name		= "blkmap",
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (c) 2023 Addiva Elektronik
	* Author: Tobias Waldekranz <tobias@waldekranz.com>
	*/

	#include <common.h>
	#include <blk.h>
	#include <blkmap.h>
	#include <dm.h>
	#include <malloc.h>
	#include <mapmem.h>
	#include <part.h>
	#include <dm/device-internal.h>
	#include <dm/lists.h>
	#include <dm/root.h>

	struct blkmap;

	/**
	* struct blkmap_slice - Region mapped to a blkmap
	*
	* Common data for a region mapped to a blkmap, specialized by each
	* map type.
	*
	* @node: List node used to associate this slice with a blkmap
	* @blknr: Start block number of the mapping
	* @blkcnt: Number of blocks covered by this mapping
	*/
	struct blkmap_slice {
	struct list_head node;

	lbaint_t blknr;
	lbaint_t blkcnt;

	/**
	* @read: - Read from slice
	*
	* @read.bm: Blkmap to which this slice belongs
	* @read.bms: This slice
	* @read.blknr: Start block number to read from
	* @read.blkcnt: Number of blocks to read
	* @read.buffer: Buffer to store read data to
	*/
	ulong (read)(struct blkmap bm, struct blkmap_slice *bms,
	lbaint_t blknr, lbaint_t blkcnt, void *buffer);

	/**
	* @write: - Write to slice
	*
	* @write.bm: Blkmap to which this slice belongs
	* @write.bms: This slice
	* @write.blknr: Start block number to write to
	* @write.blkcnt: Number of blocks to write
	* @write.buffer: Data to be written
	*/
	ulong (write)(struct blkmap bm, struct blkmap_slice *bms,
	lbaint_t blknr, lbaint_t blkcnt, const void *buffer);

	/**
	* @destroy: - Tear down slice
	*
	* @read.bm: Blkmap to which this slice belongs
	* @read.bms: This slice
	*/
	void (destroy)(struct blkmap bm, struct blkmap_slice *bms);
	};

	static bool blkmap_slice_contains(struct blkmap_slice *bms, lbaint_t blknr)
	{
	return (blknr >= bms->blknr) && (blknr < (bms->blknr + bms->blkcnt));
	}

	static bool blkmap_slice_available(struct blkmap bm, struct blkmap_slice new)
	{
	struct blkmap_slice *bms;
	lbaint_t first, last;

	first = new->blknr;
	last = new->blknr + new->blkcnt - 1;

	list_for_each_entry(bms, &bm->slices, node) {
	if (blkmap_slice_contains(bms, first) \|\|
	blkmap_slice_contains(bms, last) \|\|
	blkmap_slice_contains(new, bms->blknr) \|\|
	blkmap_slice_contains(new, bms->blknr + bms->blkcnt - 1))
	return false;
	}

	return true;
	}

	static int blkmap_slice_add(struct blkmap bm, struct blkmap_slice new)
	{
	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
	struct list_head *insert = &bm->slices;
	struct blkmap_slice *bms;

	if (!blkmap_slice_available(bm, new))
	return -EBUSY;

	list_for_each_entry(bms, &bm->slices, node) {
	if (bms->blknr < new->blknr)
	continue;

	insert = &bms->node;
	break;
	}

	list_add_tail(&new->node, insert);

	/* Disk might have grown, update the size */
	bms = list_last_entry(&bm->slices, struct blkmap_slice, node);
	bd->lba = bms->blknr + bms->blkcnt;
	return 0;
	}

	/**
	* struct blkmap_linear - Linear mapping to other block device
	*
	* @slice: Common map data
	* @blk: Target block device of this mapping
	* @blknr: Start block number of the target device
	*/
	struct blkmap_linear {
	struct blkmap_slice slice;

	struct udevice *blk;
	lbaint_t blknr;
	};

	static ulong blkmap_linear_read(struct blkmap bm, struct blkmap_slice bms,
	lbaint_t blknr, lbaint_t blkcnt, void *buffer)
	{
	struct blkmap_linear *bml = container_of(bms, struct blkmap_linear, slice);

	return blk_read(bml->blk, bml->blknr + blknr, blkcnt, buffer);
	}

	static ulong blkmap_linear_write(struct blkmap bm, struct blkmap_slice bms,
	lbaint_t blknr, lbaint_t blkcnt,
	const void *buffer)
	{
	struct blkmap_linear *bml = container_of(bms, struct blkmap_linear, slice);

	return blk_write(bml->blk, bml->blknr + blknr, blkcnt, buffer);
	}

	int blkmap_map_linear(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
	struct udevice *lblk, lbaint_t lblknr)
	{
	struct blkmap *bm = dev_get_plat(dev);
	struct blkmap_linear *linear;
	struct blk_desc bd, lbd;
	int err;

	bd = dev_get_uclass_plat(bm->blk);
	lbd = dev_get_uclass_plat(lblk);
	if (lbd->blksz != bd->blksz) {
	/* update to match the mapped device */
	bd->blksz = lbd->blksz;
	bd->log2blksz = LOG2(bd->blksz);
	}

	linear = malloc(sizeof(*linear));
	if (!linear)
	return -ENOMEM;

	*linear = (struct blkmap_linear) {
	.slice = {
	.blknr = blknr,
	.blkcnt = blkcnt,

	.read = blkmap_linear_read,
	.write = blkmap_linear_write,
	},

	.blk = lblk,
	.blknr = lblknr,
	};

	err = blkmap_slice_add(bm, &linear->slice);
	if (err)
	free(linear);

	return err;
	}

	/**
	* struct blkmap_mem - Memory mapping
	*
	* @slice: Common map data
	* @addr: Target memory region of this mapping
	* @remapped: True if @addr is backed by a physical to virtual memory
	* mapping that must be torn down at the end of this mapping's
	* lifetime.
	*/
	struct blkmap_mem {
	struct blkmap_slice slice;
	void *addr;
	bool remapped;
	};

	static ulong blkmap_mem_read(struct blkmap bm, struct blkmap_slice bms,
	lbaint_t blknr, lbaint_t blkcnt, void *buffer)
	{
	struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice);
	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
	char *src;

	src = bmm->addr + (blknr << bd->log2blksz);
	memcpy(buffer, src, blkcnt << bd->log2blksz);
	return blkcnt;
	}

	static ulong blkmap_mem_write(struct blkmap bm, struct blkmap_slice bms,
	lbaint_t blknr, lbaint_t blkcnt,
	const void *buffer)
	{
	struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice);
	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
	char *dst;

	dst = bmm->addr + (blknr << bd->log2blksz);
	memcpy(dst, buffer, blkcnt << bd->log2blksz);
	return blkcnt;
	}

	static void blkmap_mem_destroy(struct blkmap bm, struct blkmap_slice bms)
	{
	struct blkmap_mem *bmm = container_of(bms, struct blkmap_mem, slice);

	if (bmm->remapped)
	unmap_sysmem(bmm->addr);
	}

	int __blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
	void *addr, bool remapped)
	{
	struct blkmap *bm = dev_get_plat(dev);
	struct blkmap_mem *bmm;
	int err;

	bmm = malloc(sizeof(*bmm));
	if (!bmm)
	return -ENOMEM;

	*bmm = (struct blkmap_mem) {
	.slice = {
	.blknr = blknr,
	.blkcnt = blkcnt,

	.read = blkmap_mem_read,
	.write = blkmap_mem_write,
	.destroy = blkmap_mem_destroy,
	},

	.addr = addr,
	.remapped = remapped,
	};

	err = blkmap_slice_add(bm, &bmm->slice);
	if (err)
	free(bmm);

	return err;
	}

	int blkmap_map_mem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
	void *addr)
	{
	return __blkmap_map_mem(dev, blknr, blkcnt, addr, false);
	}

	int blkmap_map_pmem(struct udevice *dev, lbaint_t blknr, lbaint_t blkcnt,
	phys_addr_t paddr)
	{
	struct blkmap *bm = dev_get_plat(dev);
	struct blk_desc *bd = dev_get_uclass_plat(bm->blk);
	void *addr;
	int err;

	addr = map_sysmem(paddr, blkcnt << bd->log2blksz);
	if (!addr)
	return -ENOMEM;

	err = __blkmap_map_mem(dev, blknr, blkcnt, addr, true);
	if (err)
	unmap_sysmem(addr);

	return err;
	}

	static ulong blkmap_blk_read_slice(struct blkmap bm, struct blkmap_slice bms,
	lbaint_t blknr, lbaint_t blkcnt,
	void *buffer)
	{
	lbaint_t nr, cnt;

	nr = blknr - bms->blknr;
	cnt = (blkcnt < bms->blkcnt) ? blkcnt : bms->blkcnt;
	return bms->read(bm, bms, nr, cnt, buffer);
	}

	static ulong blkmap_blk_read(struct udevice *dev, lbaint_t blknr,
	lbaint_t blkcnt, void *buffer)
	{
	struct blk_desc *bd = dev_get_uclass_plat(dev);
	struct blkmap *bm = dev_get_plat(dev->parent);
	struct blkmap_slice *bms;
	lbaint_t cnt, total = 0;

	list_for_each_entry(bms, &bm->slices, node) {
	if (!blkmap_slice_contains(bms, blknr))
	continue;

	cnt = blkmap_blk_read_slice(bm, bms, blknr, blkcnt, buffer);
	blknr += cnt;
	blkcnt -= cnt;
	buffer += cnt << bd->log2blksz;
	total += cnt;
	}

	return total;
	}

	static ulong blkmap_blk_write_slice(struct blkmap bm, struct blkmap_slice bms,
	lbaint_t blknr, lbaint_t blkcnt,
	const void *buffer)
	{
	lbaint_t nr, cnt;

	nr = blknr - bms->blknr;
	cnt = (blkcnt < bms->blkcnt) ? blkcnt : bms->blkcnt;
	return bms->write(bm, bms, nr, cnt, buffer);
	}

	static ulong blkmap_blk_write(struct udevice *dev, lbaint_t blknr,
	lbaint_t blkcnt, const void *buffer)
	{
	struct blk_desc *bd = dev_get_uclass_plat(dev);
	struct blkmap *bm = dev_get_plat(dev->parent);
	struct blkmap_slice *bms;
	lbaint_t cnt, total = 0;

	list_for_each_entry(bms, &bm->slices, node) {
	if (!blkmap_slice_contains(bms, blknr))
	continue;

	cnt = blkmap_blk_write_slice(bm, bms, blknr, blkcnt, buffer);
	blknr += cnt;
	blkcnt -= cnt;
	buffer += cnt << bd->log2blksz;
	total += cnt;
	}

	return total;
	}

	static const struct blk_ops blkmap_blk_ops = {
	.read = blkmap_blk_read,
	.write = blkmap_blk_write,
	};

	U_BOOT_DRIVER(blkmap_blk) = {
	.name = "blkmap_blk",
	.id = UCLASS_BLK,
	.ops = &blkmap_blk_ops,
	};

	static int blkmap_dev_bind(struct udevice *dev)
	{
	struct blkmap *bm = dev_get_plat(dev);
	struct blk_desc *bd;
	int err;

	err = blk_create_devicef(dev, "blkmap_blk", "blk", UCLASS_BLKMAP,
	dev_seq(dev), DEFAULT_BLKSZ, 0, &bm->blk);
	if (err)
	return log_msg_ret("blk", err);

	INIT_LIST_HEAD(&bm->slices);

	bd = dev_get_uclass_plat(bm->blk);
	snprintf(bd->vendor, BLK_VEN_SIZE, "U-Boot");
	snprintf(bd->product, BLK_PRD_SIZE, "blkmap");
	snprintf(bd->revision, BLK_REV_SIZE, "1.0");

	/* EFI core isn't keen on zero-sized disks, so we lie. This is
	* updated with the correct size once the user adds a
	* mapping.
	*/
	bd->lba = 1;

	return 0;
	}

	static int blkmap_dev_unbind(struct udevice *dev)
	{
	struct blkmap *bm = dev_get_plat(dev);
	struct blkmap_slice bms, tmp;
	int err;

	list_for_each_entry_safe(bms, tmp, &bm->slices, node) {
	list_del(&bms->node);
	free(bms);
	}

	err = device_remove(bm->blk, DM_REMOVE_NORMAL);
	if (err)
	return err;

	return device_unbind(bm->blk);
	}

	U_BOOT_DRIVER(blkmap_root) = {
	.name = "blkmap_dev",
	.id = UCLASS_BLKMAP,
	.bind = blkmap_dev_bind,
	.unbind = blkmap_dev_unbind,
	.plat_auto = sizeof(struct blkmap),
	};

	struct udevice blkmap_from_label(const char label)
	{
	struct udevice *dev;
	struct uclass *uc;
	struct blkmap *bm;

	uclass_id_foreach_dev(UCLASS_BLKMAP, dev, uc) {
	bm = dev_get_plat(dev);
	if (bm->label && !strcmp(label, bm->label))
	return dev;
	}

	return NULL;
	}

	int blkmap_create(const char label, struct udevice *devp)
	{
	char hname, hlabel;
	struct udevice *dev;
	struct blkmap *bm;
	size_t namelen;
	int err;

	dev = blkmap_from_label(label);
	if (dev) {
	err = -EBUSY;
	goto err;
	}

	hlabel = strdup(label);
	if (!hlabel) {
	err = -ENOMEM;
	goto err;
	}

	namelen = strlen("blkmap-") + strlen(label) + 1;
	hname = malloc(namelen);
	if (!hname) {
	err = -ENOMEM;
	goto err_free_hlabel;
	}

	strlcpy(hname, "blkmap-", namelen);
	strlcat(hname, label, namelen);

	err = device_bind_driver(dm_root(), "blkmap_dev", hname, &dev);
	if (err)
	goto err_free_hname;

	device_set_name_alloced(dev);
	bm = dev_get_plat(dev);
	bm->label = hlabel;

	if (devp)
	*devp = dev;

	return 0;

	err_free_hname:
	free(hname);
	err_free_hlabel:
	free(hlabel);
	err:
	return err;
	}

	int blkmap_destroy(struct udevice *dev)
	{
	int err;

	err = device_remove(dev, DM_REMOVE_NORMAL);
	if (err)
	return err;

	return device_unbind(dev);
	}

	UCLASS_DRIVER(blkmap) = {
	.id = UCLASS_BLKMAP,
	.name = "blkmap",
	};