/*
   * Read flash partition table from command line
   *
   * Copyright © 2002      SYSGO Real-Time Solutions GmbH
   * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
   *
   * 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.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * The format for the command line is as follows:
   *
   * mtdparts=<mtddef>[;<mtddef]
   * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
   * <partdef> := <size>[@<offset>][<name>][ro][lk]
   * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
   * <size>    := standard linux memsize OR "-" to denote all remaining space
   *              size is automatically truncated at end of device
   *              if specified or trucated size is 0 the part is skipped
   * <offset>  := standard linux memsize
   *              if omitted the part will immediately follow the previous part
   *              or 0 if the first part
   * <name>    := '(' NAME ')'
   *              NAME will appear in /proc/mtd
   *
   * <size> and <offset> can be specified such that the parts are out of order
   * in physical memory and may even overlap.
   *
   * The parts are assigned MTD numbers in the order they are specified in the
   * command line regardless of their order in physical memory.
   *
   * Examples:
   *
   * 1 NOR Flash, with 1 single writable partition:
   * edb7312-nor:-
   *
   * 1 NOR Flash with 2 partitions, 1 NAND with one
   * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
   */
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/mtd/mtd.h>
  #include <linux/mtd/partitions.h>
  #include <linux/module.h>
  #include <linux/err.h>
  
  /* error message prefix */
  #define ERRP "mtd: "
  
  /* debug macro */
  #if 0
  #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
  #else
  #define dbg(x)
  #endif
  
  
  /* special size referring to all the remaining space in a partition */
  #define SIZE_REMAINING ULLONG_MAX
  #define OFFSET_CONTINUOUS ULLONG_MAX
  
  struct cmdline_mtd_partition {
  	struct cmdline_mtd_partition *next;
  	char *mtd_id;
  	int num_parts;
  	struct mtd_partition *parts;
  };
  
  /* mtdpart_setup() parses into here */
  static struct cmdline_mtd_partition *partitions;
  
  /* the command line passed to mtdpart_setup() */
  static char *mtdparts;
  static char *cmdline;
  static int cmdline_parsed;
  
  /*
   * Parse one partition definition for an MTD. Since there can be many
   * comma separated partition definitions, this function calls itself
   * recursively until no more partition definitions are found. Nice side
   * effect: the memory to keep the mtd_partition structs and the names
   * is allocated upon the last definition being found. At that point the
   * syntax has been verified ok.
   */
  static struct mtd_partition * newpart(char *s,
  				      char **retptr,
  				      int *num_parts,
  				      int this_part,
  				      unsigned char **extra_mem_ptr,
  				      int extra_mem_size)
  {
  	struct mtd_partition *parts;
  	unsigned long long size, offset = OFFSET_CONTINUOUS;
  	char *name;
  	int name_len;
  	unsigned char *extra_mem;
  	char delim;
  	unsigned int mask_flags;
  
  	/* fetch the partition size */
  	if (*s == '-') {
  		/* assign all remaining space to this partition */
  		size = SIZE_REMAINING;
  		s++;
  	} else {
  		size = memparse(s, &s);
  		if (size < PAGE_SIZE) {
  			printk(KERN_ERR ERRP "partition size too small (%llx)
  ",
  			       size);
  			return ERR_PTR(-EINVAL);
  		}
  	}
  
  	/* fetch partition name and flags */
  	mask_flags = 0; /* this is going to be a regular partition */
  	delim = 0;
  
  	/* check for offset */
  	if (*s == '@') {
  		s++;
  		offset = memparse(s, &s);
  	}
  
  	/* now look for name */
  	if (*s == '(')
  		delim = ')';
  
  	if (delim) {
  		char *p;
  
  		name = ++s;
  		p = strchr(name, delim);
  		if (!p) {
  			printk(KERN_ERR ERRP "no closing %c found in partition name
  ", delim);
  			return ERR_PTR(-EINVAL);
  		}
  		name_len = p - name;
  		s = p + 1;
  	} else {
  		name = NULL;
  		name_len = 13; /* Partition_000 */
  	}
  
  	/* record name length for memory allocation later */
  	extra_mem_size += name_len + 1;
  
  	/* test for options */
  	if (strncmp(s, "ro", 2) == 0) {
  		mask_flags |= MTD_WRITEABLE;
  		s += 2;
  	}
  
  	/* if lk is found do NOT unlock the MTD partition*/
  	if (strncmp(s, "lk", 2) == 0) {
  		mask_flags |= MTD_POWERUP_LOCK;
  		s += 2;
  	}
  
  	/* test if more partitions are following */
  	if (*s == ',') {
  		if (size == SIZE_REMAINING) {
  			printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition
  ");
  			return ERR_PTR(-EINVAL);
  		}
  		/* more partitions follow, parse them */
  		parts = newpart(s + 1, &s, num_parts, this_part + 1,
  				&extra_mem, extra_mem_size);
  		if (IS_ERR(parts))
  			return parts;
  	} else {
  		/* this is the last partition: allocate space for all */
  		int alloc_size;
  
  		*num_parts = this_part + 1;
  		alloc_size = *num_parts * sizeof(struct mtd_partition) +
  			     extra_mem_size;
  
  		parts = kzalloc(alloc_size, GFP_KERNEL);
  		if (!parts)
  			return ERR_PTR(-ENOMEM);
  		extra_mem = (unsigned char *)(parts + *num_parts);
  	}
  
  	/* enter this partition (offset will be calculated later if it is zero at this point) */
  	parts[this_part].size = size;
  	parts[this_part].offset = offset;
  	parts[this_part].mask_flags = mask_flags;
  	if (name)
  		strlcpy(extra_mem, name, name_len + 1);
  	else
  		sprintf(extra_mem, "Partition_%03d", this_part);
  	parts[this_part].name = extra_mem;
  	extra_mem += name_len + 1;
  
  	dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x
  ",
  	     this_part, parts[this_part].name, parts[this_part].offset,
  	     parts[this_part].size, parts[this_part].mask_flags));
  
  	/* return (updated) pointer to extra_mem memory */
  	if (extra_mem_ptr)
  		*extra_mem_ptr = extra_mem;
  
  	/* return (updated) pointer command line string */
  	*retptr = s;
  
  	/* return partition table */
  	return parts;
  }
  
  /*
   * Parse the command line.
   */
  static int mtdpart_setup_real(char *s)
  {
  	cmdline_parsed = 1;
  
  	for( ; s != NULL; )
  	{
  		struct cmdline_mtd_partition *this_mtd;
  		struct mtd_partition *parts;
  		int mtd_id_len, num_parts;
  		char *p, *mtd_id;
  
  		mtd_id = s;
  
  		/* fetch <mtd-id> */
  		p = strchr(s, ':');
  		if (!p) {
  			printk(KERN_ERR ERRP "no mtd-id
  ");
  			return -EINVAL;
  		}
  		mtd_id_len = p - mtd_id;
  
  		dbg(("parsing <%s>
  ", p+1));
  
  		/*
  		 * parse one mtd. have it reserve memory for the
  		 * struct cmdline_mtd_partition and the mtd-id string.
  		 */
  		parts = newpart(p + 1,		/* cmdline */
  				&s,		/* out: updated cmdline ptr */
  				&num_parts,	/* out: number of parts */
  				0,		/* first partition */
  				(unsigned char**)&this_mtd, /* out: extra mem */
  				mtd_id_len + 1 + sizeof(*this_mtd) +
  				sizeof(void*)-1 /*alignment*/);
  		if (IS_ERR(parts)) {
  			/*
  			 * An error occurred. We're either:
  			 * a) out of memory, or
  			 * b) in the middle of the partition spec
  			 * Either way, this mtd is hosed and we're
  			 * unlikely to succeed in parsing any more
  			 */
  			 return PTR_ERR(parts);
  		 }
  
  		/* align this_mtd */
  		this_mtd = (struct cmdline_mtd_partition *)
  				ALIGN((unsigned long)this_mtd, sizeof(void *));
  		/* enter results */
  		this_mtd->parts = parts;
  		this_mtd->num_parts = num_parts;
  		this_mtd->mtd_id = (char*)(this_mtd + 1);
  		strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
  
  		/* link into chain */
  		this_mtd->next = partitions;
  		partitions = this_mtd;
  
  		dbg(("mtdid=<%s> num_parts=<%d>
  ",
  		     this_mtd->mtd_id, this_mtd->num_parts));
  
  
  		/* EOS - we're done */
  		if (*s == 0)
  			break;
  
  		/* does another spec follow? */
  		if (*s != ';') {
  			printk(KERN_ERR ERRP "bad character after partition (%c)
  ", *s);
  			return -EINVAL;
  		}
  		s++;
  	}
  
  	return 0;
  }
  
  /*
   * Main function to be called from the MTD mapping driver/device to
   * obtain the partitioning information. At this point the command line
   * arguments will actually be parsed and turned to struct mtd_partition
   * information. It returns partitions for the requested mtd device, or
   * the first one in the chain if a NULL mtd_id is passed in.
   */
  static int parse_cmdline_partitions(struct mtd_info *master,
  				    struct mtd_partition **pparts,
  				    struct mtd_part_parser_data *data)
  {
  	unsigned long long offset;
  	int i, err;
  	struct cmdline_mtd_partition *part;
  	const char *mtd_id = master->name;
  
  	/* parse command line */
  	if (!cmdline_parsed) {
  		err = mtdpart_setup_real(cmdline);
  		if (err)
  			return err;
  	}
  
  	/*
  	 * Search for the partition definition matching master->name.
  	 * If master->name is not set, stop at first partition definition.
  	 */
  	for (part = partitions; part; part = part->next) {
  		if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
  			break;
  	}
  
  	if (!part)
  		return 0;
  
  	for (i = 0, offset = 0; i < part->num_parts; i++) {
  		if (part->parts[i].offset == OFFSET_CONTINUOUS)
  			part->parts[i].offset = offset;
  		else
  			offset = part->parts[i].offset;
  
  		if (part->parts[i].size == SIZE_REMAINING)
  			part->parts[i].size = master->size - offset;
  
  		if (offset + part->parts[i].size > master->size) {
  			printk(KERN_WARNING ERRP
  			       "%s: partitioning exceeds flash size, truncating
  ",
  			       part->mtd_id);
  			part->parts[i].size = master->size - offset;
  		}
  		offset += part->parts[i].size;
  
  		if (part->parts[i].size == 0) {
  			printk(KERN_WARNING ERRP
  			       "%s: skipping zero sized partition
  ",
  			       part->mtd_id);
  			part->num_parts--;
  			memmove(&part->parts[i], &part->parts[i + 1],
  				sizeof(*part->parts) * (part->num_parts - i));
  			i--;
  		}
  	}
  
  	*pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
  			  GFP_KERNEL);
  	if (!*pparts)
  		return -ENOMEM;
  
  	return part->num_parts;
  }
  
  
  /*
   * This is the handler for our kernel parameter, called from
   * main.c::checksetup(). Note that we can not yet kmalloc() anything,
   * so we only save the commandline for later processing.
   *
   * This function needs to be visible for bootloaders.
   */
  static int __init mtdpart_setup(char *s)
  {
  	cmdline = s;
  	return 1;
  }
  
  __setup("mtdparts=", mtdpart_setup);
  
  static struct mtd_part_parser cmdline_parser = {
  	.owner = THIS_MODULE,
  	.parse_fn = parse_cmdline_partitions,
  	.name = "cmdlinepart",
  };
  
  static int __init cmdline_parser_init(void)
  {
  	if (mtdparts)
  		mtdpart_setup(mtdparts);
  	register_mtd_parser(&cmdline_parser);
  	return 0;
  }
  
  static void __exit cmdline_parser_exit(void)
  {
  	deregister_mtd_parser(&cmdline_parser);
  }
  
  module_init(cmdline_parser_init);
  module_exit(cmdline_parser_exit);
  
  MODULE_PARM_DESC(mtdparts, "Partitioning specification");
  module_param(mtdparts, charp, 0);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
  MODULE_DESCRIPTION("Command line configuration of MTD partitions");