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1a0915be19
Some devices have partitions that are kind of containers with extra
subpartitions / volumes instead of e.g. a simple filesystem data. To
support such cases we need to first create normal flash device
partitions and then take care of these special ones.
It's very common case for home routers. Depending on the vendor there
are formats like TRX, Seama, TP-Link, WRGG & more. All of them are used
to embed few partitions into a single one / single firmware file.
Ideally all vendors would use some well documented / standardized format
like UBI (and some probably start doing so), but there are still
countless devices on the market using these poor vendor specific
formats.
This patch extends MTD subsystem by allowing to specify list of parsers
that should be tried for a given partition. Supporting such poor formats
is highly unlikely to be the top priority so these changes try to
minimize maintenance cost to the minimum. It reuses existing code for
these new parsers and just adds a one property and one new function.
This implementation requires setting partition parsers in a flash
parser. A proper change of bcm47xxpart will follow and in the future we
will hopefully also find a solution for doing it with ofpart
("fixed-partitions").
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
114 lines
3.7 KiB
C
114 lines
3.7 KiB
C
/*
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* MTD partitioning layer definitions
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*
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* (C) 2000 Nicolas Pitre <nico@fluxnic.net>
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*
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* This code is GPL
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*/
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#ifndef MTD_PARTITIONS_H
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#define MTD_PARTITIONS_H
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#include <linux/types.h>
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/*
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* Partition definition structure:
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*
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* An array of struct partition is passed along with a MTD object to
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* mtd_device_register() to create them.
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*
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* For each partition, these fields are available:
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* name: string that will be used to label the partition's MTD device.
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* types: some partitions can be containers using specific format to describe
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* embedded subpartitions / volumes. E.g. many home routers use "firmware"
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* partition that contains at least kernel and rootfs. In such case an
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* extra parser is needed that will detect these dynamic partitions and
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* report them to the MTD subsystem. If set this property stores an array
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* of parser names to use when looking for subpartitions.
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* size: the partition size; if defined as MTDPART_SIZ_FULL, the partition
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* will extend to the end of the master MTD device.
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* offset: absolute starting position within the master MTD device; if
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* defined as MTDPART_OFS_APPEND, the partition will start where the
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* previous one ended; if MTDPART_OFS_NXTBLK, at the next erase block;
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* if MTDPART_OFS_RETAIN, consume as much as possible, leaving size
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* after the end of partition.
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* mask_flags: contains flags that have to be masked (removed) from the
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* master MTD flag set for the corresponding MTD partition.
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* For example, to force a read-only partition, simply adding
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* MTD_WRITEABLE to the mask_flags will do the trick.
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*
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* Note: writeable partitions require their size and offset be
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* erasesize aligned (e.g. use MTDPART_OFS_NEXTBLK).
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*/
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struct mtd_partition {
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const char *name; /* identifier string */
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const char *const *types; /* names of parsers to use if any */
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uint64_t size; /* partition size */
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uint64_t offset; /* offset within the master MTD space */
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uint32_t mask_flags; /* master MTD flags to mask out for this partition */
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struct device_node *of_node;
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};
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#define MTDPART_OFS_RETAIN (-3)
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#define MTDPART_OFS_NXTBLK (-2)
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#define MTDPART_OFS_APPEND (-1)
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#define MTDPART_SIZ_FULL (0)
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struct mtd_info;
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struct device_node;
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/**
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* struct mtd_part_parser_data - used to pass data to MTD partition parsers.
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* @origin: for RedBoot, start address of MTD device
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*/
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struct mtd_part_parser_data {
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unsigned long origin;
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};
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/*
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* Functions dealing with the various ways of partitioning the space
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*/
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struct mtd_part_parser {
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struct list_head list;
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struct module *owner;
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const char *name;
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int (*parse_fn)(struct mtd_info *, const struct mtd_partition **,
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struct mtd_part_parser_data *);
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void (*cleanup)(const struct mtd_partition *pparts, int nr_parts);
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};
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/* Container for passing around a set of parsed partitions */
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struct mtd_partitions {
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const struct mtd_partition *parts;
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int nr_parts;
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const struct mtd_part_parser *parser;
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};
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extern int __register_mtd_parser(struct mtd_part_parser *parser,
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struct module *owner);
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#define register_mtd_parser(parser) __register_mtd_parser(parser, THIS_MODULE)
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extern void deregister_mtd_parser(struct mtd_part_parser *parser);
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/*
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* module_mtd_part_parser() - Helper macro for MTD partition parsers that don't
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* do anything special in module init/exit. Each driver may only use this macro
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* once, and calling it replaces module_init() and module_exit().
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*/
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#define module_mtd_part_parser(__mtd_part_parser) \
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module_driver(__mtd_part_parser, register_mtd_parser, \
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deregister_mtd_parser)
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int mtd_is_partition(const struct mtd_info *mtd);
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int mtd_add_partition(struct mtd_info *master, const char *name,
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long long offset, long long length);
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int mtd_del_partition(struct mtd_info *master, int partno);
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uint64_t mtd_get_device_size(const struct mtd_info *mtd);
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#endif
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