Partition API

const char *disk_partition_type_guid(const struct disk_partition *info): get partition type GUID

Parameters

const struct disk_partition *info: partition information

Description

By using this function to get the partition type GUID we can use ‘if (IS_ENABLED(CONFIG_PARTITION_TYPE_GUID))’ instead of ‘#ifdef CONFIG_PARTITION_TYPE_GUID’.

Return

partition type GUID

void disk_partition_set_type_guid(struct disk_partition *info, const char *val): set partition type GUID

Parameters

struct disk_partition *info: partition information
const char *val: partition type GUID as string

Description

By using this function to set the partition type GUID we can use ‘if (IS_ENABLED(CONFIG_PARTITION_TYPE_GUID))’ instead of ‘#ifdef CONFIG_PARTITION_TYPE_GUID’.

struct blk_desc *blk_get_dev(const char *ifname, int dev): get a pointer to a block device given its type and number

Parameters

const char *ifname: Interface name (e.g. “ide”, “scsi”)
int dev: Device number (0 for first device on that interface, 1 for second, etc.

Description

Each interface allocates its own devices and typically struct blk_desc is contained with the interface’s data structure. There is no global numbering for block devices, so the interface name must be provided.

Return

pointer to the block device, or NULL if not available, or an error occurred.

int part_get_info_by_type(struct blk_desc *desc, int part, int part_type, struct disk_partition *info): Get partitions from a block device using a specific partition driver

Parameters

struct blk_desc *desc: Block device descriptor
int part: Partition number to read
int part_type: Partition driver to use, or PART_TYPE_UNKNOWN to automatically choose a driver
struct disk_partition *info: Returned partition information

Description

Each interface allocates its own devices and typically struct blk_desc is contained with the interface’s data structure. There is no global numbering for block devices, so the interface name must be provided.

Return

0 on success, negative errno on failure

int part_get_info_whole_disk(struct blk_desc *desc, struct disk_partition *info): get partition info for the special case of a partition occupying the entire disk.

Parameters

struct blk_desc *desc: block device descriptor
struct disk_partition *info: returned partition information

Return

0 on success

int blk_get_device_by_str(const char *ifname, const char *dev_str, struct blk_desc **desc): Get a block device given its interface/hw partition

Parameters

const char *ifname: Interface name (e.g. “ide”, “scsi”)
const char *dev_str: Device and optional hw partition. This can either be a string containing the device number (e.g. “2”) or the device number and hardware partition number (e.g. “2.4”) for devices that support it (currently only MMC).
struct blk_desc **desc: Returns a pointer to the block device on success

Description

Each interface allocates its own devices and typically struct blk_desc is contained with the interface’s data structure. There is no global numbering for block devices, so the interface name must be provided.

The hardware parition is not related to the normal software partitioning of a device - each hardware partition is effectively a separately accessible block device. When a hardware parition is selected on MMC the other hardware partitions become inaccessible. The same block device is used to access all hardware partitions, but its capacity may change when a different hardware partition is selected.

When a hardware partition number is given, the block device switches to that hardware partition.

Return

block device number (local to the interface), or -1 on error

int blk_get_device_part_str(const char *ifname, const char *dev_part_str, struct blk_desc **desc, struct disk_partition *info, int allow_whole_dev): Get a block device and partition

Parameters

const char *ifname: Interface name (e.g. “ide”, “scsi”)
const char *dev_part_str: Device and partition string
struct blk_desc **desc: Returns a pointer to the block device on success
struct disk_partition *info: Returns partition information
int allow_whole_dev: true to allow the user to select partition 0 (which means the whole device), false to require a valid partition number >= 1

Description

This calls blk_get_device_by_str() to look up a device. It also looks up a partition and returns information about it.

dev_part_str is in the format <dev>.<hw_part>:<part> where

<dev> is the device number,
<hw_part> is the optional hardware partition number and
<part> is the partition number.

If ifname is “hostfs”, then this function returns the sandbox host block device.

If ifname is “ubi”, then this function returns 0, with info set to a special UBI device.

If dev_part_str is NULL or empty or “-”, then this function looks up the “bootdevice” environment variable and uses that string instead.

If the partition string is empty then the first partition is used. If the partition string is “auto” then the first bootable partition is used.

Return

partition number, or -1 on error

int part_get_info_by_name(struct blk_desc *desc, const char *name, struct disk_partition *info): Search for a partition by name among all available registered partitions

Parameters

struct blk_desc *desc: block device descriptor
const char *name: the specified table entry name
struct disk_partition *info: returns the disk partition info

Return

the partition number on match (starting on 1), -1 on no match, otherwise error

int part_get_info_by_dev_and_name_or_num(const char *dev_iface, const char *dev_part_str, struct blk_desc **desc, struct disk_partition *part_info, int allow_whole_dev): Get partition info from dev number and part name, or dev number and part number.

Parameters

const char *dev_iface: Device interface
const char *dev_part_str: Input partition description, like “0#misc” or “0:1”
struct blk_desc **desc: Place to store the device description pointer
struct disk_partition *part_info: Place to store the partition information
int allow_whole_dev: true to allow the user to select partition 0 (which means the whole device), false to require a valid partition number >= 1

Description

Parse a device number and partition description (either name or number) in the form of device number plus partition name separated by a “#” (like “device_num#partition_name”) or a device number plus a partition number separated by a “:”. For example both “0#misc” and “0:1” can be valid partition descriptions for a given interface. If the partition is found, sets desc and part_info accordingly with the information of the partition.

Return

the partition number on success, or negative errno on error

void part_set_generic_name(const struct blk_desc *desc, int part_num, char *name): create generic partition like hda1 or sdb2

Parameters

const struct blk_desc *desc: pointer to the block device
int part_num: partition number for which the name is generated
char *name: buffer where the name is written

Description

Helper function for partition tables, which don’t hold partition names (DOS, ISO). Generates partition name out of the device type and partition number.

ulong disk_blk_read(struct udevice *dev, lbaint_t start, lbaint_t blkcnt, void *buffer): read blocks from a disk partition

Parameters

struct udevice *dev: Device to read from (UCLASS_PARTITION)
lbaint_t start: Start block number to read in the partition (0=first)
lbaint_t blkcnt: Number of blocks to read
void *buffer: Destination buffer for data read

Return

number of blocks read, or -ve error number (see the IS_ERR_VALUE() macro

ulong disk_blk_write(struct udevice *dev, lbaint_t start, lbaint_t blkcnt, const void *buffer): write to a disk partition

Parameters

struct udevice *dev: Device to write to (UCLASS_PARTITION)
lbaint_t start: Start block number to write in the partition (0=first)
lbaint_t blkcnt: Number of blocks to write
const void *buffer: Source buffer for data to write

Return

number of blocks written, or -ve error number (see the IS_ERR_VALUE() macro

ulong disk_blk_erase(struct udevice *dev, lbaint_t start, lbaint_t blkcnt): erase a section of a disk partition

Parameters

struct udevice *dev: Device to (partially) erase (UCLASS_PARTITION)
lbaint_t start: Start block number to erase in the partition (0=first)
lbaint_t blkcnt: Number of blocks to erase

Return

number of blocks erased, or -ve error number (see the IS_ERR_VALUE() macro

struct part_driver: partition driver

Definition

struct part_driver {
  const char *name;
  int part_type;
  const int max_entries;
  int (*get_info)(struct blk_desc *desc, int part, struct disk_partition *info);
  void (*print)(struct blk_desc *desc);
  int (*test)(struct blk_desc *desc);
};

Members

name

partition name

part_type

(MBR) partition type

max_entries

maximum number of partition table entries

get_info

Get information about a partition

get_info.desc: Block device descriptor get_info.part: Partition number (1 = first) get_info.info: Returns partition information

print

Print partition information

print.desc: Block device descriptor

test

Test if a device contains this partition type

test.desc: Block device descriptor test.Return: 0 if the block device appears to contain this partition type, -ve if not

int write_gpt_table(struct blk_desc *desc, gpt_header *gpt_h, gpt_entry *gpt_e): Write the GUID Partition Table to disk

Parameters

struct blk_desc *desc: block device descriptor
gpt_header *gpt_h: pointer to GPT header representation
gpt_entry *gpt_e: pointer to GPT partition table entries

Return

zero on success, otherwise error

int gpt_fill_pte(struct blk_desc *desc, gpt_header *gpt_h, gpt_entry *gpt_e, struct disk_partition *partitions, int parts): Fill the GPT partition table entry

Parameters

struct blk_desc *desc: block device descriptor
gpt_header *gpt_h: GPT header representation
gpt_entry *gpt_e: GPT partition table entries
struct disk_partition *partitions: list of partitions
int parts: number of partitions

Return

zero on success

int gpt_fill_header(struct blk_desc *desc, gpt_header *gpt_h, char *str_guid, int parts_count): Fill the GPT header

Parameters

struct blk_desc *desc: block device descriptor
gpt_header *gpt_h: GPT header representation
char *str_guid: disk guid string representation
int parts_count: number of partitions

Return

error on str_guid conversion error

int gpt_restore(struct blk_desc *desc, char *str_disk_guid, struct disk_partition *partitions, const int parts_count): Restore GPT partition table

Parameters

struct blk_desc *desc: block device descriptor
char *str_disk_guid: disk GUID
struct disk_partition *partitions: list of partitions
const int parts_count: number of partitions

Return

0 on success

int is_valid_gpt_buf(struct blk_desc *desc, void *buf): Ensure that the Primary GPT information is valid

Parameters

struct blk_desc *desc: block device descriptor
void *buf: buffer which contains the MBR and Primary GPT info

Return

0 on success, otherwise error

int write_mbr_and_gpt_partitions(struct blk_desc *desc, void *buf): write MBR, Primary GPT and Backup GPT

Parameters

struct blk_desc *desc: block device descriptor
void *buf: buffer which contains the MBR and Primary GPT info

Return

0 on success, otherwise error

int gpt_verify_headers(struct blk_desc *desc, gpt_header *gpt_head, gpt_entry **gpt_pte): Read and check CRC32 of the GPT’s header and partition table entries (PTE)

Parameters

struct blk_desc *desc: block device descriptor
gpt_header *gpt_head: pointer to GPT header data read from medium
gpt_entry **gpt_pte: pointer to GPT partition table enties read from medium

Description

As a side effect if sets gpt_head and gpt_pte so they point to GPT data.

Return

0 on success, otherwise error

int gpt_repair_headers(struct blk_desc *desc): Function to repair the GPT’s header and partition table entries (PTE)

Parameters

struct blk_desc *desc: block device descriptor

Return

0 on success, otherwise error

int gpt_verify_partitions(struct blk_desc *desc, struct disk_partition *partitions, int parts, gpt_header *gpt_head, gpt_entry **gpt_pte): Function to check if partitions’ name, start and size correspond to ‘$partitions’ env variable

Parameters

struct blk_desc *desc: block device descriptor
struct disk_partition *partitions: partition data read from ‘$partitions’ env variable
int parts: number of partitions read from ‘$partitions’ env variable
gpt_header *gpt_head: pointer to GPT header data read from medium
gpt_entry **gpt_pte: pointer to GPT partition table enties read from medium

Description

This function checks if on medium stored GPT data is in sync with information provided in ‘$partitions’ environment variable. Specificially, name, start and size of the partition is checked.

Return

0 on success, otherwise error

int get_disk_guid(struct blk_desc *desc, char *guid): Read the GUID string from a device’s GPT

Parameters

struct blk_desc *desc: block device descriptor
char *guid: pre-allocated string in which to return the GUID

Description

This function reads the GUID string from a block device whose descriptor is provided.

Return

0 on success, otherwise error

int is_valid_dos_buf(void *buf): Ensure that a DOS MBR image is valid

Parameters

void *buf: buffer which contains the MBR

Return

0 on success, otherwise error

int write_mbr_sector(struct blk_desc *desc, void *buf): write DOS MBR

Parameters

struct blk_desc *desc: block device descriptor
void *buf: buffer which contains the MBR

Return

0 on success, otherwise error

int part_driver_get_count(void): get partition driver count

Parameters

void: no arguments

Return

number of partition drivers

struct part_driver *part_driver_get_first(void): get first partition driver

Parameters

void: no arguments

Return

pointer to first partition driver on success, otherwise NULL

int part_get_type_by_name(const char *name): Get partition type by name

Parameters

const char *name: Name of partition type to look up (not case-sensitive)

Return

Corresponding partition type (PART_TYPE_…) or PART_TYPE_UNKNOWN

int part_get_bootable(struct blk_desc *desc): Find the first bootable partition

Parameters

struct blk_desc *desc: Block-device descriptor

Return

first bootable partition, or 0 if there is none