linux/drivers/mtd/redboot.c
Brian Norris b9adf469f8 mtd: partitions: make parsers return 'const' partition arrays
We only want to modify these arrays inside the parser "drivers", so the
drivers should construct them however they like, then return them as
immutable arrays.

This will make other refactorings easier.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
2015-12-09 10:21:57 -08:00

303 lines
8.2 KiB
C

/*
* Parse RedBoot-style Flash Image System (FIS) tables and
* produce a Linux partition array to match.
*
* Copyright © 2001 Red Hat UK Limited
* Copyright © 2001-2010 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
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/module.h>
struct fis_image_desc {
unsigned char name[16]; // Null terminated name
uint32_t flash_base; // Address within FLASH of image
uint32_t mem_base; // Address in memory where it executes
uint32_t size; // Length of image
uint32_t entry_point; // Execution entry point
uint32_t data_length; // Length of actual data
unsigned char _pad[256-(16+7*sizeof(uint32_t))];
uint32_t desc_cksum; // Checksum over image descriptor
uint32_t file_cksum; // Checksum over image data
};
struct fis_list {
struct fis_image_desc *img;
struct fis_list *next;
};
static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
module_param(directory, int, 0);
static inline int redboot_checksum(struct fis_image_desc *img)
{
/* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
return 1;
}
static int parse_redboot_partitions(struct mtd_info *master,
const struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
{
int nrparts = 0;
struct fis_image_desc *buf;
struct mtd_partition *parts;
struct fis_list *fl = NULL, *tmp_fl;
int ret, i;
size_t retlen;
char *names;
char *nullname;
int namelen = 0;
int nulllen = 0;
int numslots;
unsigned long offset;
#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
static char nullstring[] = "unallocated";
#endif
if ( directory < 0 ) {
offset = master->size + directory * master->erasesize;
while (mtd_block_isbad(master, offset)) {
if (!offset) {
nogood:
printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
return -EIO;
}
offset -= master->erasesize;
}
} else {
offset = directory * master->erasesize;
while (mtd_block_isbad(master, offset)) {
offset += master->erasesize;
if (offset == master->size)
goto nogood;
}
}
buf = vmalloc(master->erasesize);
if (!buf)
return -ENOMEM;
printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
master->name, offset);
ret = mtd_read(master, offset, master->erasesize, &retlen,
(void *)buf);
if (ret)
goto out;
if (retlen != master->erasesize) {
ret = -EIO;
goto out;
}
numslots = (master->erasesize / sizeof(struct fis_image_desc));
for (i = 0; i < numslots; i++) {
if (!memcmp(buf[i].name, "FIS directory", 14)) {
/* This is apparently the FIS directory entry for the
* FIS directory itself. The FIS directory size is
* one erase block; if the buf[i].size field is
* swab32(erasesize) then we know we are looking at
* a byte swapped FIS directory - swap all the entries!
* (NOTE: this is 'size' not 'data_length'; size is
* the full size of the entry.)
*/
/* RedBoot can combine the FIS directory and
config partitions into a single eraseblock;
we assume wrong-endian if either the swapped
'size' matches the eraseblock size precisely,
or if the swapped size actually fits in an
eraseblock while the unswapped size doesn't. */
if (swab32(buf[i].size) == master->erasesize ||
(buf[i].size > master->erasesize
&& swab32(buf[i].size) < master->erasesize)) {
int j;
/* Update numslots based on actual FIS directory size */
numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
for (j = 0; j < numslots; ++j) {
/* A single 0xff denotes a deleted entry.
* Two of them in a row is the end of the table.
*/
if (buf[j].name[0] == 0xff) {
if (buf[j].name[1] == 0xff) {
break;
} else {
continue;
}
}
/* The unsigned long fields were written with the
* wrong byte sex, name and pad have no byte sex.
*/
swab32s(&buf[j].flash_base);
swab32s(&buf[j].mem_base);
swab32s(&buf[j].size);
swab32s(&buf[j].entry_point);
swab32s(&buf[j].data_length);
swab32s(&buf[j].desc_cksum);
swab32s(&buf[j].file_cksum);
}
} else if (buf[i].size < master->erasesize) {
/* Update numslots based on actual FIS directory size */
numslots = buf[i].size / sizeof(struct fis_image_desc);
}
break;
}
}
if (i == numslots) {
/* Didn't find it */
printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
master->name);
ret = 0;
goto out;
}
for (i = 0; i < numslots; i++) {
struct fis_list *new_fl, **prev;
if (buf[i].name[0] == 0xff) {
if (buf[i].name[1] == 0xff) {
break;
} else {
continue;
}
}
if (!redboot_checksum(&buf[i]))
break;
new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
namelen += strlen(buf[i].name)+1;
if (!new_fl) {
ret = -ENOMEM;
goto out;
}
new_fl->img = &buf[i];
if (data && data->origin)
buf[i].flash_base -= data->origin;
else
buf[i].flash_base &= master->size-1;
/* I'm sure the JFFS2 code has done me permanent damage.
* I now think the following is _normal_
*/
prev = &fl;
while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
prev = &(*prev)->next;
new_fl->next = *prev;
*prev = new_fl;
nrparts++;
}
#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
if (fl->img->flash_base) {
nrparts++;
nulllen = sizeof(nullstring);
}
for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
nrparts++;
nulllen = sizeof(nullstring);
}
}
#endif
parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
if (!parts) {
ret = -ENOMEM;
goto out;
}
nullname = (char *)&parts[nrparts];
#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
if (nulllen > 0) {
strcpy(nullname, nullstring);
}
#endif
names = nullname + nulllen;
i=0;
#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
if (fl->img->flash_base) {
parts[0].name = nullname;
parts[0].size = fl->img->flash_base;
parts[0].offset = 0;
i++;
}
#endif
for ( ; i<nrparts; i++) {
parts[i].size = fl->img->size;
parts[i].offset = fl->img->flash_base;
parts[i].name = names;
strcpy(names, fl->img->name);
#ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
if (!memcmp(names, "RedBoot", 8) ||
!memcmp(names, "RedBoot config", 15) ||
!memcmp(names, "FIS directory", 14)) {
parts[i].mask_flags = MTD_WRITEABLE;
}
#endif
names += strlen(names)+1;
#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
i++;
parts[i].offset = parts[i-1].size + parts[i-1].offset;
parts[i].size = fl->next->img->flash_base - parts[i].offset;
parts[i].name = nullname;
}
#endif
tmp_fl = fl;
fl = fl->next;
kfree(tmp_fl);
}
ret = nrparts;
*pparts = parts;
out:
while (fl) {
struct fis_list *old = fl;
fl = fl->next;
kfree(old);
}
vfree(buf);
return ret;
}
static struct mtd_part_parser redboot_parser = {
.parse_fn = parse_redboot_partitions,
.name = "RedBoot",
};
module_mtd_part_parser(redboot_parser);
/* mtd parsers will request the module by parser name */
MODULE_ALIAS("RedBoot");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");