linux_dsm_epyc7002/include/linux/mtd/partitions.h
Miquel Raynal 46b5889cc2 mtd: implement proper partition handling
Instead of collecting partitions in a flat list, create a hierarchy
within the mtd_info structure: use a partitions list to keep track of
the partitions of an MTD device (which might be itself a partition of
another MTD device), a pointer to the parent device (NULL when the MTD
device is the root one, not a partition).

By also saving directly in mtd_info the offset of the partition, we
can get rid of the mtd_part structure.

While at it, be consistent in the naming of the mtd_info structures to
ease the understanding of the new hierarchy: these structures are
usually called 'mtd', unless there are multiple instances of the same
structure. In this case, there is usually a parent/child bound so we
will call them 'parent' and 'child'.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200114090952.11232-1-miquel.raynal@bootlin.com
2020-03-11 14:49:30 +01:00

114 lines
3.7 KiB
C

/*
* MTD partitioning layer definitions
*
* (C) 2000 Nicolas Pitre <nico@fluxnic.net>
*
* This code is GPL
*/
#ifndef MTD_PARTITIONS_H
#define MTD_PARTITIONS_H
#include <linux/types.h>
/*
* Partition definition structure:
*
* An array of struct partition is passed along with a MTD object to
* mtd_device_register() to create them.
*
* For each partition, these fields are available:
* name: string that will be used to label the partition's MTD device.
* types: some partitions can be containers using specific format to describe
* embedded subpartitions / volumes. E.g. many home routers use "firmware"
* partition that contains at least kernel and rootfs. In such case an
* extra parser is needed that will detect these dynamic partitions and
* report them to the MTD subsystem. If set this property stores an array
* of parser names to use when looking for subpartitions.
* size: the partition size; if defined as MTDPART_SIZ_FULL, the partition
* will extend to the end of the master MTD device.
* offset: absolute starting position within the master MTD device; if
* defined as MTDPART_OFS_APPEND, the partition will start where the
* previous one ended; if MTDPART_OFS_NXTBLK, at the next erase block;
* if MTDPART_OFS_RETAIN, consume as much as possible, leaving size
* after the end of partition.
* mask_flags: contains flags that have to be masked (removed) from the
* master MTD flag set for the corresponding MTD partition.
* For example, to force a read-only partition, simply adding
* MTD_WRITEABLE to the mask_flags will do the trick.
*
* Note: writeable partitions require their size and offset be
* erasesize aligned (e.g. use MTDPART_OFS_NEXTBLK).
*/
struct mtd_partition {
const char *name; /* identifier string */
const char *const *types; /* names of parsers to use if any */
uint64_t size; /* partition size */
uint64_t offset; /* offset within the master MTD space */
uint32_t mask_flags; /* master MTD flags to mask out for this partition */
struct device_node *of_node;
};
#define MTDPART_OFS_RETAIN (-3)
#define MTDPART_OFS_NXTBLK (-2)
#define MTDPART_OFS_APPEND (-1)
#define MTDPART_SIZ_FULL (0)
struct mtd_info;
struct device_node;
/**
* struct mtd_part_parser_data - used to pass data to MTD partition parsers.
* @origin: for RedBoot, start address of MTD device
*/
struct mtd_part_parser_data {
unsigned long origin;
};
/*
* Functions dealing with the various ways of partitioning the space
*/
struct mtd_part_parser {
struct list_head list;
struct module *owner;
const char *name;
const struct of_device_id *of_match_table;
int (*parse_fn)(struct mtd_info *, const struct mtd_partition **,
struct mtd_part_parser_data *);
void (*cleanup)(const struct mtd_partition *pparts, int nr_parts);
};
/* Container for passing around a set of parsed partitions */
struct mtd_partitions {
const struct mtd_partition *parts;
int nr_parts;
const struct mtd_part_parser *parser;
};
extern int __register_mtd_parser(struct mtd_part_parser *parser,
struct module *owner);
#define register_mtd_parser(parser) __register_mtd_parser(parser, THIS_MODULE)
extern void deregister_mtd_parser(struct mtd_part_parser *parser);
/*
* module_mtd_part_parser() - Helper macro for MTD partition parsers that don't
* do anything special in module init/exit. Each driver may only use this macro
* once, and calling it replaces module_init() and module_exit().
*/
#define module_mtd_part_parser(__mtd_part_parser) \
module_driver(__mtd_part_parser, register_mtd_parser, \
deregister_mtd_parser)
int mtd_add_partition(struct mtd_info *master, const char *name,
long long offset, long long length);
int mtd_del_partition(struct mtd_info *master, int partno);
uint64_t mtd_get_device_size(const struct mtd_info *mtd);
#endif