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/*

 * $Id: cmdlinepart.c,v 1.19 2005/11/07 11:14:19 gleixner Exp $

 *

 * Read flash partition table from command line

 *

 * Copyright 2002 SYSGO Real-Time Solutions GmbH

 *

 * The format for the command line is as follows:

 *

 * mtdparts=<mtddef>[;<mtddef]

 * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]

 * <partdef> := <size>[@offset][<name>][ro]

 * <mtd-id>  := unique name used in mapping driver/device (mtd->name)

 * <size>    := standard linux memsize OR "-" to denote all remaining space

 * <name>    := '(' NAME ')'

 *

 * 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/bootmem.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 UINT_MAX

#define OFFSET_CONTINUOUS UINT_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_setupd() */

static char *cmdline;

static int cmdline_parsed = 0;

/*

 * 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 size;

        unsigned long 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 (%lx)\n", size);

                        return NULL;

                }

        }

        /* 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;

                if ((p = strchr(name, delim)) == 0)

                {

                        printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);

                        return NULL;

                }

                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;

        }

        /* test if more partitions are following */

        if (*s == ',')

        {

                if (size == SIZE_REMAINING)

                {

                        printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");

                        return NULL;

                }

                /* more partitions follow, parse them */

                if ((parts = newpart(s + 1, &s, num_parts,

                                     this_part + 1, &extra_mem, extra_mem_size)) == 0)

                  return NULL;

        }

        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)

                {

                        printk(KERN_ERR ERRP "out of memory\n");

                        return NULL;

                }

                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 %x, size %x, mask flags %x\n",

             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;

                int num_parts;

                char *p, *mtd_id;

                mtd_id = s;

                /* fetch <mtd-id> */

                if (!(p = strchr(s, ':')))

                {

                        printk(KERN_ERR ERRP "no mtd-id\n");

                        return 0;

                }

                mtd_id_len = p - mtd_id;

                dbg(("parsing <%s>\n", 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(!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 0;

                 }

                /* 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>\n",

                     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)\n", *s);

                        return 0;

                }

                s++;

        }

        return 1;

}

/*

 * 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,

                             unsigned long origin)

{

        unsigned long offset;

        int i;

        struct cmdline_mtd_partition *part;

        char *mtd_id = master->name;

        if(!cmdline)

                return -EINVAL;

        /* parse command line */

        if (!cmdline_parsed)

                mtdpart_setup_real(cmdline);

        for(part = partitions; part; part = part->next)

        {

                if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))

                {

                        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\n",

                                               part->mtd_id);

                                        part->parts[i].size = master->size - offset;

                                        part->num_parts = i;

                                }

                                offset += part->parts[i].size;

                        }

                        *pparts = part->parts;

                        return part->num_parts;

                }

        }

        return -EINVAL;

}

/*

 * 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 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)

{

        return register_mtd_parser(&cmdline_parser);

}

module_init(cmdline_parser_init);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");

MODULE_DESCRIPTION("Command line configuration of MTD partitions");