include/linux/mtd/ubi.h

Source file repositories/reference/linux-study-clean/include/linux/mtd/ubi.h

File Facts

System
Linux kernel
Corpus path
include/linux/mtd/ubi.h
Extension
.h
Size
9977 bytes
Lines
274
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ubi_volume_info {
	int ubi_num;
	int vol_id;
	int size;
	long long used_bytes;
	int used_ebs;
	int vol_type;
	int corrupted;
	int upd_marker;
	int alignment;
	int usable_leb_size;
	int name_len;
	const char *name;
	dev_t cdev;
	struct device *dev;
};

/**
 * struct ubi_sgl - UBI scatter gather list data structure.
 * @list_pos: current position in @sg[]
 * @page_pos: current position in @sg[@list_pos]
 * @sg: the scatter gather list itself
 *
 * ubi_sgl is a wrapper around a scatter list which keeps track of the
 * current position in the list and the current list item such that
 * it can be used across multiple ubi_leb_read_sg() calls.
 */
struct ubi_sgl {
	int list_pos;
	int page_pos;
	struct scatterlist sg[UBI_MAX_SG_COUNT];
};

/**
 * ubi_sgl_init - initialize an UBI scatter gather list data structure.
 * @usgl: the UBI scatter gather struct itself
 *
 * Please note that you still have to use sg_init_table() or any adequate
 * function to initialize the unterlaying struct scatterlist.
 */
static inline void ubi_sgl_init(struct ubi_sgl *usgl)
{
	usgl->list_pos = 0;
	usgl->page_pos = 0;
}

/**
 * struct ubi_device_info - UBI device description data structure.
 * @ubi_num: ubi device number
 * @leb_size: logical eraseblock size on this UBI device
 * @leb_start: starting offset of logical eraseblocks within physical
 *             eraseblocks
 * @min_io_size: minimal I/O unit size
 * @max_write_size: maximum amount of bytes the underlying flash can write at a
 *                  time (MTD write buffer size)
 * @ro_mode: if this device is in read-only mode
 * @cdev: UBI character device major and minor numbers
 *
 * Note, @leb_size is the logical eraseblock size offered by the UBI device.
 * Volumes of this UBI device may have smaller logical eraseblock size if their
 * alignment is not equivalent to %1.
 *
 * The @max_write_size field describes flash write maximum write unit. For
 * example, NOR flash allows for changing individual bytes, so @min_io_size is
 * %1. However, it does not mean than NOR flash has to write data byte-by-byte.
 * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
 * writing large chunks of data, they write 64-bytes at a time. Obviously, this
 * improves write throughput.
 *
 * Also, the MTD device may have N interleaved (striped) flash chips
 * underneath, in which case @min_io_size can be physical min. I/O size of
 * single flash chip, while @max_write_size can be N * @min_io_size.
 *
 * The @max_write_size field is always greater or equivalent to @min_io_size.
 * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
 * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
 * page size.
 */
struct ubi_device_info {
	int ubi_num;
	int leb_size;
	int leb_start;
	int min_io_size;
	int max_write_size;
	int ro_mode;
	dev_t cdev;
};

/*
 * Volume notification types.

Annotation

Implementation Notes