/*
   * Flash partitions described by the OF (or flattened) device tree
   *
   * Copyright © 2006 MontaVista Software Inc.
   * Author: Vitaly Wool <vwool@ru.mvista.com>
   *
   * Revised to handle newer style flash binding by:
   *   Copyright © 2007 David Gibson, IBM Corporation.
   *
   * This program is free software; you can redistribute  it and/or modify it
   * under  the terms of  the GNU General  Public License as published by the
   * Free Software Foundation;  either version 2 of the  License, or (at your
   * option) any later version.
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/of.h>
  #include <linux/mtd/mtd.h>
  #include <linux/slab.h>
  #include <linux/mtd/partitions.h>
  
  static bool node_has_compatible(struct device_node *pp)
  {
  	return of_get_property(pp, "compatible", NULL);
  }
  
  static int parse_ofpart_partitions(struct mtd_info *master,
  				   struct mtd_partition **pparts,
  				   struct mtd_part_parser_data *data)
  {
  	struct device_node *mtd_node;
  	struct device_node *ofpart_node;
  	const char *partname;
  	struct device_node *pp;
  	int nr_parts, i, ret = 0;
  	bool dedicated = true;
  
  
  	if (!data)
  		return 0;
  
  	mtd_node = data->of_node;
  	if (!mtd_node)
  		return 0;
  
  	ofpart_node = of_get_child_by_name(mtd_node, "partitions");
  	if (!ofpart_node) {
  		/*
  		 * We might get here even when ofpart isn't used at all (e.g.,
  		 * when using another parser), so don't be louder than
  		 * KERN_DEBUG
  		 */
  		pr_debug("%s: 'partitions' subnode not found on %s. Trying to parse direct subnodes as partitions.
  ",
  			 master->name, mtd_node->full_name);
  		ofpart_node = mtd_node;
  		dedicated = false;
  	} else if (!of_device_is_compatible(ofpart_node, "fixed-partitions")) {
  		/* The 'partitions' subnode might be used by another parser */
  		return 0;
  	}
  
  	/* First count the subnodes */
  	nr_parts = 0;
  	for_each_child_of_node(ofpart_node,  pp) {
  		if (!dedicated && node_has_compatible(pp))
  			continue;
  
  		nr_parts++;
  	}
  
  	if (nr_parts == 0)
  		return 0;
  
  	*pparts = kzalloc(nr_parts * sizeof(**pparts), GFP_KERNEL);
  	if (!*pparts)
  		return -ENOMEM;
  
  	i = 0;
  	for_each_child_of_node(ofpart_node,  pp) {
  		const __be32 *reg;
  		int len;
  		int a_cells, s_cells;
  
  		if (!dedicated && node_has_compatible(pp))
  			continue;
  
  		reg = of_get_property(pp, "reg", &len);
  		if (!reg) {
  			if (dedicated) {
  				pr_debug("%s: ofpart partition %s (%s) missing reg property.
  ",
  					 master->name, pp->full_name,
  					 mtd_node->full_name);
  				goto ofpart_fail;
  			} else {
  				nr_parts--;
  				continue;
  			}
  		}
  
  		a_cells = of_n_addr_cells(pp);
  		s_cells = of_n_size_cells(pp);
  		if (len / 4 != a_cells + s_cells) {
  			pr_debug("%s: ofpart partition %s (%s) error parsing reg property.
  ",
  				 master->name, pp->full_name,
  				 mtd_node->full_name);
  			goto ofpart_fail;
  		}
  
  		(*pparts)[i].offset = of_read_number(reg, a_cells);
  		(*pparts)[i].size = of_read_number(reg + a_cells, s_cells);
  
  		partname = of_get_property(pp, "label", &len);
  		if (!partname)
  			partname = of_get_property(pp, "name", &len);
  		(*pparts)[i].name = partname;
  
  		if (of_get_property(pp, "read-only", &len))
  			(*pparts)[i].mask_flags |= MTD_WRITEABLE;
  
  		if (of_get_property(pp, "lock", &len))
  			(*pparts)[i].mask_flags |= MTD_POWERUP_LOCK;
  
  		i++;
  	}
  
  	if (!nr_parts)
  		goto ofpart_none;
  
  	return nr_parts;
  
  ofpart_fail:
  	pr_err("%s: error parsing ofpart partition %s (%s)
  ",
  	       master->name, pp->full_name, mtd_node->full_name);
  	ret = -EINVAL;
  ofpart_none:
  	of_node_put(pp);
  	kfree(*pparts);
  	*pparts = NULL;
  	return ret;
  }
  
  static struct mtd_part_parser ofpart_parser = {
  	.owner = THIS_MODULE,
  	.parse_fn = parse_ofpart_partitions,
  	.name = "ofpart",
  };
  
  static int parse_ofoldpart_partitions(struct mtd_info *master,
  				      struct mtd_partition **pparts,
  				      struct mtd_part_parser_data *data)
  {
  	struct device_node *dp;
  	int i, plen, nr_parts;
  	const struct {
  		__be32 offset, len;
  	} *part;
  	const char *names;
  
  	if (!data)
  		return 0;
  
  	dp = data->of_node;
  	if (!dp)
  		return 0;
  
  	part = of_get_property(dp, "partitions", &plen);
  	if (!part)
  		return 0; /* No partitions found */
  
  	pr_warning("Device tree uses obsolete partition map binding: %s
  ",
  			dp->full_name);
  
  	nr_parts = plen / sizeof(part[0]);
  
  	*pparts = kzalloc(nr_parts * sizeof(*(*pparts)), GFP_KERNEL);
  	if (!*pparts)
  		return -ENOMEM;
  
  	names = of_get_property(dp, "partition-names", &plen);
  
  	for (i = 0; i < nr_parts; i++) {
  		(*pparts)[i].offset = be32_to_cpu(part->offset);
  		(*pparts)[i].size   = be32_to_cpu(part->len) & ~1;
  		/* bit 0 set signifies read only partition */
  		if (be32_to_cpu(part->len) & 1)
  			(*pparts)[i].mask_flags = MTD_WRITEABLE;
  
  		if (names && (plen > 0)) {
  			int len = strlen(names) + 1;
  
  			(*pparts)[i].name = names;
  			plen -= len;
  			names += len;
  		} else {
  			(*pparts)[i].name = "unnamed";
  		}
  
  		part++;
  	}
  
  	return nr_parts;
  }
  
  static struct mtd_part_parser ofoldpart_parser = {
  	.owner = THIS_MODULE,
  	.parse_fn = parse_ofoldpart_partitions,
  	.name = "ofoldpart",
  };
  
  static int __init ofpart_parser_init(void)
  {
  	register_mtd_parser(&ofpart_parser);
  	register_mtd_parser(&ofoldpart_parser);
  	return 0;
  }
  
  static void __exit ofpart_parser_exit(void)
  {
  	deregister_mtd_parser(&ofpart_parser);
  	deregister_mtd_parser(&ofoldpart_parser);
  }
  
  module_init(ofpart_parser_init);
  module_exit(ofpart_parser_exit);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
  MODULE_AUTHOR("Vitaly Wool, David Gibson");
  /*
   * When MTD core cannot find the requested parser, it tries to load the module
   * with the same name. Since we provide the ofoldpart parser, we should have
   * the corresponding alias.
   */
  MODULE_ALIAS("ofoldpart");