text: // SPDX-License-Identifier: GPL-2.0-or-later
  /*
   * Simple MTD partitioning layer
   *
   * Copyright © 2000 Nicolas Pitre <nico@fluxnic.net>
   * Copyright © 2002 Thomas Gleixner <gleixner@linutronix.de>
   * Copyright © 2000-2010 David Woodhouse <dwmw2@infradead.org>
   */
  
  #include <linux/module.h>
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/list.h>
  #include <linux/kmod.h>
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/partitions.h>
  #include <linux/err.h>
  #include <linux/of.h>
  
  #include "mtdcore.h"
  
  /*
   * MTD methods which simply translate the effective address and pass through
   * to the _real_ device.
   */
  
  static inline void free_partition(struct mtd_info *mtd)
  {
  	kfree(mtd->name);
  	kfree(mtd);
  }
  
  static struct mtd_info *allocate_partition(struct mtd_info *parent,
  					   const struct mtd_partition *part,
  					   int partno, uint64_t cur_offset)
  {
  	struct mtd_info *master = mtd_get_master(parent);
  	int wr_alignment = (parent->flags & MTD_NO_ERASE) ?
  			   master->writesize : master->erasesize;
  	u64 parent_size = mtd_is_partition(parent) ?
  			  parent->part.size : parent->size;
  	struct mtd_info *child;
  	u32 remainder;
  	char *name;
  	u64 tmp;
  
  	/* allocate the partition structure */
  	child = kzalloc(sizeof(*child), GFP_KERNEL);
  	name = kstrdup(part->name, GFP_KERNEL);
  	if (!name || !child) {
  		printk(KERN_ERR"memory allocation error while creating partitions for \"%s\"\n",
  		       parent->name);
  		kfree(name);
  		kfree(child);
  		return ERR_PTR(-ENOMEM);
  	}
  
  	/* set up the MTD object for this partition */
  	child->type = parent->type;
  	child->part.flags = parent->flags & ~part->mask_flags;
  	child->part.flags |= part->add_flags;
  	child->flags = child->part.flags;
  	child->part.size = part->size;
  	child->writesize = parent->writesize;
  	child->writebufsize = parent->writebufsize;
  	child->oobsize = parent->oobsize;
  	child->oobavail = parent->oobavail;
  	child->subpage_sft = parent->subpage_sft;
  
  	child->name = name;
  	child->owner = parent->owner;
  
  	/* NOTE: Historically, we didn't arrange MTDs as a tree out of
  	 * concern for showing the same data in multiple partitions.
  	 * However, it is very useful to have the master node present,
  	 * so the MTD_PARTITIONED_MASTER option allows that. The master
  	 * will have device nodes etc only if this is set, so make the
  	 * parent conditional on that option. Note, this is a way to
  	 * distinguish between the parent and its partitions in sysfs.
  	 */
  	child->dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || mtd_is_partition(parent) ?
  			    &parent->dev : parent->dev.parent;
  	child->dev.of_node = part->of_node;
  	child->parent = parent;
  	child->part.offset = part->offset;
  	INIT_LIST_HEAD(&child->partitions);
  
  	if (child->part.offset == MTDPART_OFS_APPEND)
  		child->part.offset = cur_offset;
  	if (child->part.offset == MTDPART_OFS_NXTBLK) {
  		tmp = cur_offset;
  		child->part.offset = cur_offset;
  		remainder = do_div(tmp, wr_alignment);
  		if (remainder) {
  			child->part.offset += wr_alignment - remainder;
  			printk(KERN_NOTICE "Moving partition %d: "
  			       "0x%012llx -> 0x%012llx\n", partno,
  			       (unsigned long long)cur_offset,
  			       child->part.offset);
  		}
  	}
  	if (child->part.offset == MTDPART_OFS_RETAIN) {
  		child->part.offset = cur_offset;
  		if (parent_size - child->part.offset >= child->part.size) {
  			child->part.size = parent_size - child->part.offset -
  					   child->part.size;
  		} else {
  			printk(KERN_ERR "mtd partition \"%s\" doesn't have enough space: %#llx < %#llx, disabled\n",
  				part->name, parent_size - child->part.offset,
  				child->part.size);
  			/* register to preserve ordering */
  			goto out_register;
  		}
  	}
  	if (child->part.size == MTDPART_SIZ_FULL)
  		child->part.size = parent_size - child->part.offset;
  
  	printk(KERN_NOTICE "0x%012llx-0x%012llx : \"%s\"\n",
  	       child->part.offset, child->part.offset + child->part.size,
  	       child->name);
  
  	/* let's do some sanity checks */
  	if (child->part.offset >= parent_size) {
  		/* let's register it anyway to preserve ordering */
  		child->part.offset = 0;
  		child->part.size = 0;
  
  		/* Initialize ->erasesize to make add_mtd_device() happy. */
  		child->erasesize = parent->erasesize;
  		printk(KERN_ERR"mtd: partition \"%s\" is out of reach -- disabled\n",
  			part->name);
  		goto out_register;
  	}
  	if (child->part.offset + child->part.size > parent->size) {
  		child->part.size = parent_size - child->part.offset;
  		printk(KERN_WARNING"mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#llx\n",
  			part->name, parent->name, child->part.size);
  	}
  
  	if (parent->numeraseregions > 1) {
  		/* Deal with variable erase size stuff */
  		int i, max = parent->numeraseregions;
  		u64 end = child->part.offset + child->part.size;
  		struct mtd_erase_region_info *regions = parent->eraseregions;
  
  		/* Find the first erase regions which is part of this
  		 * partition. */
  		for (i = 0; i < max && regions[i].offset <= child->part.offset;
  		     i++)
  			;
  		/* The loop searched for the region _behind_ the first one */
  		if (i > 0)
  			i--;
  
  		/* Pick biggest erasesize */
  		for (; i < max && regions[i].offset < end; i++) {
  			if (child->erasesize < regions[i].erasesize)
  				child->erasesize = regions[i].erasesize;
  		}
  		BUG_ON(child->erasesize == 0);
  	} else {
  		/* Single erase size */
  		child->erasesize = master->erasesize;
  	}
  
  	/*
  	 * Child erasesize might differ from the parent one if the parent
  	 * exposes several regions with different erasesize. Adjust
  	 * wr_alignment accordingly.
  	 */
  	if (!(child->flags & MTD_NO_ERASE))
  		wr_alignment = child->erasesize;
  
  	tmp = mtd_get_master_ofs(child, 0);
  	remainder = do_div(tmp, wr_alignment);
  	if ((child->flags & MTD_WRITEABLE) && remainder) {
  		/* Doesn't start on a boundary of major erase size */
  		/* FIXME: Let it be writable if it is on a boundary of
  		 * _minor_ erase size though */
  		child->flags &= ~MTD_WRITEABLE;
  		printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase/write block boundary -- force read-only\n",
  			part->name);
  	}
  
  	tmp = mtd_get_master_ofs(child, 0) + child->part.size;
  	remainder = do_div(tmp, wr_alignment);
  	if ((child->flags & MTD_WRITEABLE) && remainder) {
  		child->flags &= ~MTD_WRITEABLE;
  		printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase/write block -- force read-only\n",
  			part->name);
  	}
  
  	child->size = child->part.size;
  	child->ecc_step_size = parent->ecc_step_size;
  	child->ecc_strength = parent->ecc_strength;
  	child->bitflip_threshold = parent->bitflip_threshold;
  
  	if (master->_block_isbad) {
  		uint64_t offs = 0;
  
  		while (offs < child->part.size) {
  			if (mtd_block_isreserved(child, offs))
  				child->ecc_stats.bbtblocks++;
  			else if (mtd_block_isbad(child, offs))
  				child->ecc_stats.badblocks++;
  			offs += child->erasesize;
  		}
  	}
  
  out_register:
  	return child;
  }
  
  static ssize_t offset_show(struct device *dev,
  			   struct device_attribute *attr, char *buf)
  {
  	struct mtd_info *mtd = dev_get_drvdata(dev);
  
  	return sysfs_emit(buf, "%lld\n", mtd->part.offset);
  }
  static DEVICE_ATTR_RO(offset);	/* mtd partition offset */
  
  static const struct attribute *mtd_partition_attrs[] = {
  	&dev_attr_offset.attr,
  	NULL
  };
  
  static int mtd_add_partition_attrs(struct mtd_info *new)
  {
  	int ret = sysfs_create_files(&new->dev.kobj, mtd_partition_attrs);
  	if (ret)
  		printk(KERN_WARNING
  		       "mtd: failed to create partition attrs, err=%d\n", ret);
  	return ret;
  }
  
  int mtd_add_partition(struct mtd_info *parent, const char *name,
  		      long long offset, long long length)
  {
  	struct mtd_info *master = mtd_get_master(parent);
  	u64 parent_size = mtd_is_partition(parent) ?
  			  parent->part.size : parent->size;
  	struct mtd_partition part;
  	struct mtd_info *child;
  	int ret = 0;
  
  	/* the direct offset is expected */
  	if (offset == MTDPART_OFS_APPEND ||
  	    offset == MTDPART_OFS_NXTBLK)
  		return -EINVAL;
  
  	if (length == MTDPART_SIZ_FULL)
  		length = parent_size - offset;
  
  	if (length <= 0)
  		return -EINVAL;
  
  	memset(&part, 0, sizeof(part));
  	part.name = name;
  	part.size = length;
  	part.offset = offset;
  
  	child = allocate_partition(parent, &part, -1, offset);
  	if (IS_ERR(child))
  		return PTR_ERR(child);
  
  	mutex_lock(&master->master.partitions_lock);
  	list_add_tail(&child->part.node, &parent->partitions);
  	mutex_unlock(&master->master.partitions_lock);
  
  	ret = add_mtd_device(child);
  	if (ret)
  		goto err_remove_part;
  
  	mtd_add_partition_attrs(child);
  
  	return 0;
  
  err_remove_part:
  	mutex_lock(&master->master.partitions_lock);
  	list_del(&child->part.node);
  	mutex_unlock(&master->master.partitions_lock);
  
  	free_partition(child);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(mtd_add_partition);
  
  /**
   * __mtd_del_partition - delete MTD partition
   *
   * @mtd: MTD structure to be deleted
   *
   * This function must be called with the partitions mutex locked.
   */
  static int __mtd_del_partition(struct mtd_info *mtd)
  {
  	struct mtd_info *child, *next;
  	int err;
  
  	list_for_each_entry_safe(child, next, &mtd->partitions, part.node) {
  		err = __mtd_del_partition(child);
  		if (err)
  			return err;
  	}
  
  	sysfs_remove_files(&mtd->dev.kobj, mtd_partition_attrs);
  
  	err = del_mtd_device(mtd);
  	if (err)
  		return err;
  
  	list_del(&mtd->part.node);
  	free_partition(mtd);
  
  	return 0;
  }
  
  /*
   * This function unregisters and destroy all slave MTD objects which are
   * attached to the given MTD object, recursively.
   */
  static int __del_mtd_partitions(struct mtd_info *mtd)
  {
  	struct mtd_info *child, *next;
  	LIST_HEAD(tmp_list);
  	int ret, err = 0;
  
  	list_for_each_entry_safe(child, next, &mtd->partitions, part.node) {
  		if (mtd_has_partitions(child))
  			__del_mtd_partitions(child);
  
  		pr_info("Deleting %s MTD partition\n", child->name);
  		ret = del_mtd_device(child);
  		if (ret < 0) {
  			pr_err("Error when deleting partition \"%s\" (%d)\n",
  			       child->name, ret);
  			err = ret;
  			continue;
  		}
  
  		list_del(&child->part.node);
  		free_partition(child);
  	}
  
  	return err;
  }
  
  int del_mtd_partitions(struct mtd_info *mtd)
  {
  	struct mtd_info *master = mtd_get_master(mtd);
  	int ret;
  
  	pr_info("Deleting MTD partitions on \"%s\":\n", mtd->name);
  
  	mutex_lock(&master->master.partitions_lock);
  	ret = __del_mtd_partitions(mtd);
  	mutex_unlock(&master->master.partitions_lock);
  
  	return ret;
  }
  
  int mtd_del_partition(struct mtd_info *mtd, int partno)
  {
  	struct mtd_info *child, *master = mtd_get_master(mtd);
  	int ret = -EINVAL;
  
  	mutex_lock(&master->master.partitions_lock);
  	list_for_each_entry(child, &mtd->partitions, part.node) {
  		if (child->index == partno) {
  			ret = __mtd_del_partition(child);
  			break;
  		}
  	}
  	mutex_unlock(&master->master.partitions_lock);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(mtd_del_partition);
  
  /*
   * This function, given a parent MTD object and a partition table, creates
   * and registers the child MTD objects which are bound to the parent according
   * to the partition definitions.
   *
   * For historical reasons, this function's caller only registers the parent
   * if the MTD_PARTITIONED_MASTER config option is set.
   */
  
  int add_mtd_partitions(struct mtd_info *parent,
  		       const struct mtd_partition *parts,
  		       int nbparts)
  {
  	struct mtd_info *child, *master = mtd_get_master(parent);
  	uint64_t cur_offset = 0;
  	int i, ret;
  
  	printk(KERN_NOTICE "Creating %d MTD partitions on \"%s\":\n",
  	       nbparts, parent->name);
  
  	for (i = 0; i < nbparts; i++) {
  		child = allocate_partition(parent, parts + i, i, cur_offset);
  		if (IS_ERR(child)) {
  			ret = PTR_ERR(child);
  			goto err_del_partitions;
  		}
  
  		mutex_lock(&master->master.partitions_lock);
  		list_add_tail(&child->part.node, &parent->partitions);
  		mutex_unlock(&master->master.partitions_lock);
  
  		ret = add_mtd_device(child);
  		if (ret) {
  			mutex_lock(&master->master.partitions_lock);
  			list_del(&child->part.node);
  			mutex_unlock(&master->master.partitions_lock);
  
  			free_partition(child);
  			goto err_del_partitions;
  		}
  
  		mtd_add_partition_attrs(child);
  
  		/* Look for subpartitions */
  		parse_mtd_partitions(child, parts[i].types, NULL);
  
  		cur_offset = child->part.offset + child->part.size;
  	}
  
  	return 0;
  
  err_del_partitions:
  	del_mtd_partitions(master);
  
  	return ret;
  }
  
  static DEFINE_SPINLOCK(part_parser_lock);
  static LIST_HEAD(part_parsers);
  
  static struct mtd_part_parser *mtd_part_parser_get(const char *name)
  {
  	struct mtd_part_parser *p, *ret = NULL;
  
  	spin_lock(&part_parser_lock);
  
  	list_for_each_entry(p, &part_parsers, list)
  		if (!strcmp(p->name, name) && try_module_get(p->owner)) {
  			ret = p;
  			break;
  		}
  
  	spin_unlock(&part_parser_lock);
  
  	return ret;
  }
  
  static inline void mtd_part_parser_put(const struct mtd_part_parser *p)
  {
  	module_put(p->owner);
  }
  
  /*
   * Many partition parsers just expected the core to kfree() all their data in
   * one chunk. Do that by default.
   */
  static void mtd_part_parser_cleanup_default(const struct mtd_partition *pparts,
  					    int nr_parts)
  {
  	kfree(pparts);
  }
  
  int __register_mtd_parser(struct mtd_part_parser *p, struct module *owner)
  {
  	p->owner = owner;
  
  	if (!p->cleanup)
  		p->cleanup = &mtd_part_parser_cleanup_default;
  
  	spin_lock(&part_parser_lock);
  	list_add(&p->list, &part_parsers);
  	spin_unlock(&part_parser_lock);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(__register_mtd_parser);
  
  void deregister_mtd_parser(struct mtd_part_parser *p)
  {
  	spin_lock(&part_parser_lock);
  	list_del(&p->list);
  	spin_unlock(&part_parser_lock);
  }
  EXPORT_SYMBOL_GPL(deregister_mtd_parser);
  
  /*
   * Do not forget to update 'parse_mtd_partitions()' kerneldoc comment if you
   * are changing this array!
   */
  static const char * const default_mtd_part_types[] = {
  	"cmdlinepart",
  	"ofpart",
  	NULL
  };
  
  /* Check DT only when looking for subpartitions. */
  static const char * const default_subpartition_types[] = {
  	"ofpart",
  	NULL
  };
  
  static int mtd_part_do_parse(struct mtd_part_parser *parser,
  			     struct mtd_info *master,
  			     struct mtd_partitions *pparts,
  			     struct mtd_part_parser_data *data)
  {
  	int ret;
  
  	ret = (*parser->parse_fn)(master, &pparts->parts, data);
  	pr_debug("%s: parser %s: %i\n", master->name, parser->name, ret);
  	if (ret <= 0)
  		return ret;
  
  	pr_notice("%d %s partitions found on MTD device %s\n", ret,
  		  parser->name, master->name);
  
  	pparts->nr_parts = ret;
  	pparts->parser = parser;
  
  	return ret;
  }
  
  /**
   * mtd_part_get_compatible_parser - find MTD parser by a compatible string
   *
   * @compat: compatible string describing partitions in a device tree
   *
   * MTD parsers can specify supported partitions by providing a table of
   * compatibility strings. This function finds a parser that advertises support
   * for a passed value of "compatible".
   */
  static struct mtd_part_parser *mtd_part_get_compatible_parser(const char *compat)
  {
  	struct mtd_part_parser *p, *ret = NULL;
  
  	spin_lock(&part_parser_lock);
  
  	list_for_each_entry(p, &part_parsers, list) {
  		const struct of_device_id *matches;
  
  		matches = p->of_match_table;
  		if (!matches)
  			continue;
  
  		for (; matches->compatible[0]; matches++) {
  			if (!strcmp(matches->compatible, compat) &&
  			    try_module_get(p->owner)) {
  				ret = p;
  				break;
  			}
  		}
  
  		if (ret)
  			break;
  	}
  
  	spin_unlock(&part_parser_lock);
  
  	return ret;
  }
  
  static int mtd_part_of_parse(struct mtd_info *master,
  			     struct mtd_partitions *pparts)
  {
  	struct mtd_part_parser *parser;
  	struct device_node *np;
  	struct property *prop;
  	const char *compat;
  	const char *fixed = "fixed-partitions";
  	int ret, err = 0;
  
  	np = mtd_get_of_node(master);
  	if (mtd_is_partition(master))
  		of_node_get(np);
  	else
  		np = of_get_child_by_name(np, "partitions");
  
  	of_property_for_each_string(np, "compatible", prop, compat) {
  		parser = mtd_part_get_compatible_parser(compat);
  		if (!parser)
  			continue;
  		ret = mtd_part_do_parse(parser, master, pparts, NULL);
  		if (ret > 0) {
  			of_node_put(np);
  			return ret;
  		}
  		mtd_part_parser_put(parser);
  		if (ret < 0 && !err)
  			err = ret;
  	}
  	of_node_put(np);
  
  	/*
  	 * For backward compatibility we have to try the "fixed-partitions"
  	 * parser. It supports old DT format with partitions specified as a
  	 * direct subnodes of a flash device DT node without any compatibility
  	 * specified we could match.
  	 */
  	parser = mtd_part_parser_get(fixed);
  	if (!parser && !request_module("%s", fixed))
  		parser = mtd_part_parser_get(fixed);
  	if (parser) {
  		ret = mtd_part_do_parse(parser, master, pparts, NULL);
  		if (ret > 0)
  			return ret;
  		mtd_part_parser_put(parser);
  		if (ret < 0 && !err)
  			err = ret;
  	}
  
  	return err;
  }
  
  /**
   * parse_mtd_partitions - parse and register MTD partitions
   *
   * @master: the master partition (describes whole MTD device)
   * @types: names of partition parsers to try or %NULL
   * @data: MTD partition parser-specific data
   *
   * This function tries to find & register partitions on MTD device @master. It
   * uses MTD partition parsers, specified in @types. However, if @types is %NULL,
   * then the default list of parsers is used. The default list contains only the
   * "cmdlinepart" and "ofpart" parsers ATM.
   * Note: If there are more then one parser in @types, the kernel only takes the
   * partitions parsed out by the first parser.
   *
   * This function may return:
   * o a negative error code in case of failure
   * o number of found partitions otherwise
   */
  int parse_mtd_partitions(struct mtd_info *master, const char *const *types,
  			 struct mtd_part_parser_data *data)
  {
  	struct mtd_partitions pparts = { };
  	struct mtd_part_parser *parser;
  	int ret, err = 0;
  
  	if (!types)
  		types = mtd_is_partition(master) ? default_subpartition_types :
  			default_mtd_part_types;
  
  	for ( ; *types; types++) {
  		/*
  		 * ofpart is a special type that means OF partitioning info
  		 * should be used. It requires a bit different logic so it is
  		 * handled in a separated function.
  		 */
  		if (!strcmp(*types, "ofpart")) {
  			ret = mtd_part_of_parse(master, &pparts);
  		} else {
  			pr_debug("%s: parsing partitions %s\n", master->name,
  				 *types);
  			parser = mtd_part_parser_get(*types);
  			if (!parser && !request_module("%s", *types))
  				parser = mtd_part_parser_get(*types);
  			pr_debug("%s: got parser %s\n", master->name,
  				parser ? parser->name : NULL);
  			if (!parser)
  				continue;
  			ret = mtd_part_do_parse(parser, master, &pparts, data);
  			if (ret <= 0)
  				mtd_part_parser_put(parser);
  		}
  		/* Found partitions! */
  		if (ret > 0) {
  			err = add_mtd_partitions(master, pparts.parts,
  						 pparts.nr_parts);
  			mtd_part_parser_cleanup(&pparts);
  			return err ? err : pparts.nr_parts;
  		}
  		/*
  		 * Stash the first error we see; only report it if no parser
  		 * succeeds
  		 */
  		if (ret < 0 && !err)
  			err = ret;
  	}
  	return err;
  }
  
  void mtd_part_parser_cleanup(struct mtd_partitions *parts)
  {
  	const struct mtd_part_parser *parser;
  
  	if (!parts)
  		return;
  
  	parser = parts->parser;
  	if (parser) {
  		if (parser->cleanup)
  			parser->cleanup(parts->parts, parts->nr_parts);
  
  		mtd_part_parser_put(parser);
  	}
  }
  
  /* Returns the size of the entire flash chip */
  uint64_t mtd_get_device_size(const struct mtd_info *mtd)
  {
  	struct mtd_info *master = mtd_get_master((struct mtd_info *)mtd);
  
  	return master->size;
  }
  EXPORT_SYMBOL_GPL(mtd_get_device_size);
  