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cmdlinepart.c 9.96 KiB
/*
* 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>]
* where <mtd-id> is the name from the "cat /proc/mtd" command
* <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
* <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;
p = strchr(name, delim);
if (!p)
{
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;
}
/* 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\n");
return NULL;
}
/* more partitions follow, parse them */
parts = newpart(s + 1, &s, num_parts, this_part + 1,
&extra_mem, extra_mem_size);
if (!parts)
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 %llx, size %llx, 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;
const char *mtd_id = master->name;
/* 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 = kmemdup(part->parts,
sizeof(*part->parts) * part->num_parts,
GFP_KERNEL);
if (!*pparts)
return -ENOMEM;
return part->num_parts;
}
}
return 0;
}
/*
* 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");