Rtos API example
MBRBlockDevice Class Reference
Block device for managing a Master Boot Record https://en.wikipedia.org/wiki/Master_boot_record. More...
#include <MBRBlockDevice.h>
Inherits BlockDevice.
Public Member Functions | |
MBRBlockDevice (BlockDevice *bd, int part) | |
Lifetime of the block device. | |
virtual | ~MBRBlockDevice () |
Lifetime of the block device. | |
virtual int | init () |
Initialize a block device. | |
virtual int | deinit () |
Deinitialize a block device. | |
virtual int | read (void *buffer, bd_addr_t addr, bd_size_t size) |
Read blocks from a block device. | |
virtual int | program (const void *buffer, bd_addr_t addr, bd_size_t size) |
Program blocks to a block device. | |
virtual int | erase (bd_addr_t addr, bd_size_t size) |
Erase blocks on a block device. | |
virtual bd_size_t | get_read_size () const |
Get the size of a readable block. | |
virtual bd_size_t | get_program_size () const |
Get the size of a programable block. | |
virtual bd_size_t | get_erase_size () const |
Get the size of a eraseable block. | |
virtual bd_size_t | size () const |
Get the total size of the underlying device. | |
virtual bd_addr_t | get_partition_start () const |
Get the offset of the partition on the underlying block device. | |
virtual bd_addr_t | get_partition_stop () const |
Get size of partition on underlying block device. | |
virtual uint8_t | get_partition_type () const |
Get 8-bit type of the partition. | |
virtual int | get_partition_number () const |
Get the partition number. | |
virtual int | trim (bd_addr_t addr, bd_size_t size) |
Mark blocks as no longer in use. | |
bool | is_valid_read (bd_addr_t addr, bd_size_t size) const |
Convenience function for checking block read validity. | |
bool | is_valid_program (bd_addr_t addr, bd_size_t size) const |
Convenience function for checking block program validity. | |
bool | is_valid_erase (bd_addr_t addr, bd_size_t size) const |
Convenience function for checking block erase validity. | |
Static Public Member Functions | |
static int | partition (BlockDevice *bd, int part, uint8_t type, bd_addr_t start) |
Format the MBR to contain the following partition. | |
static int | partition (BlockDevice *bd, int part, uint8_t type, bd_addr_t start, bd_addr_t stop) |
Format the MBR to contain the following partition. |
Detailed Description
Block device for managing a Master Boot Record https://en.wikipedia.org/wiki/Master_boot_record.
Here is an example of partitioning a heap backed block device
#include "mbed.h" #include "HeapBlockDevice.h" #include "MBRBlockDevice.h" // Create a block device with 64 blocks of size 512 HeapBlockDevice mem(64*512, 512); // Partition into two partitions with ~half the blocks MBRBlockDevice::partition(&mem, 1, 0x83, 0*512, 32*512); MBRBlockDevice::partition(&mem, 2, 0x83, 32*512); // Create a block device that maps to the first 32 blocks (excluding MBR block) MBRBlockDevice part1(&mem, 1); // Create a block device that maps to the last 32 blocks MBRBlockDevice part2(&mem, 2);
Here is a more realistic example where the MBRBlockDevice is used to partition a region of space on an SD card. When plugged into a computer, the partitions will be recognized appropriately.
#include "mbed.h" #include "SDBlockDevice.h" #include "MBRBlockDevice.h" #include "FATFileSystem.h" // Create an SD card SDBlockDevice sd(s0, s1, s2, s3); // Create a partition with 1 GB of space MBRBlockDevice::partition(&sd, 1, 0x83, 0, 1024*1024); // Create the block device that represents the partition MBRBlockDevice part1(&sd, 1); // Format the partition with a FAT filesystem FATFileSystem::format(&part1); // Create the FAT filesystem instance, files can now be written to // the FAT filesystem in partition 1 FATFileSystem fat("fat", &part1);
Definition at line 86 of file MBRBlockDevice.h.
Constructor & Destructor Documentation
MBRBlockDevice | ( | BlockDevice * | bd, |
int | part | ||
) |
Lifetime of the block device.
- Parameters:
-
bd Block device to back the MBRBlockDevice part Partition to use, 1-4
Definition at line 182 of file MBRBlockDevice.cpp.
virtual ~MBRBlockDevice | ( | ) | [virtual] |
Lifetime of the block device.
Definition at line 128 of file MBRBlockDevice.h.
Member Function Documentation
int deinit | ( | ) | [virtual] |
Deinitialize a block device.
- Returns:
- 0 on success or a negative error code on failure
Implements BlockDevice.
Definition at line 232 of file MBRBlockDevice.cpp.
int erase | ( | bd_addr_t | addr, |
bd_size_t | size | ||
) | [virtual] |
Erase blocks on a block device.
The state of an erased block is undefined until it has been programmed
- Parameters:
-
addr Address of block to begin erasing size Size to erase in bytes, must be a multiple of erase block size
- Returns:
- 0 on success, negative error code on failure
Reimplemented from BlockDevice.
Definition at line 249 of file MBRBlockDevice.cpp.
bd_size_t get_erase_size | ( | ) | const [virtual] |
Get the size of a eraseable block.
- Returns:
- Size of a eraseable block in bytes
- Note:
- Must be a multiple of the program size
Reimplemented from BlockDevice.
Definition at line 265 of file MBRBlockDevice.cpp.
int get_partition_number | ( | ) | const [virtual] |
Get the partition number.
- Returns:
- The partition number, 1-4
Definition at line 290 of file MBRBlockDevice.cpp.
bd_size_t get_partition_start | ( | ) | const [virtual] |
Get the offset of the partition on the underlying block device.
- Returns:
- Offset of the partition on the underlying device
Definition at line 275 of file MBRBlockDevice.cpp.
bd_size_t get_partition_stop | ( | ) | const [virtual] |
Get size of partition on underlying block device.
- Returns:
- Size of the partition on the underlying device
Definition at line 280 of file MBRBlockDevice.cpp.
uint8_t get_partition_type | ( | ) | const [virtual] |
Get 8-bit type of the partition.
- Returns:
- 8-bit type of partition assigned during format
Definition at line 285 of file MBRBlockDevice.cpp.
bd_size_t get_program_size | ( | ) | const [virtual] |
Get the size of a programable block.
- Returns:
- Size of a programable block in bytes
- Note:
- Must be a multiple of the read size
Implements BlockDevice.
Definition at line 260 of file MBRBlockDevice.cpp.
bd_size_t get_read_size | ( | ) | const [virtual] |
Get the size of a readable block.
- Returns:
- Size of a readable block in bytes
Implements BlockDevice.
Definition at line 255 of file MBRBlockDevice.cpp.
int init | ( | ) | [virtual] |
Initialize a block device.
- Returns:
- 0 on success or a negative error code on failure
Implements BlockDevice.
Definition at line 188 of file MBRBlockDevice.cpp.
bool is_valid_erase | ( | bd_addr_t | addr, |
bd_size_t | size | ||
) | const [inherited] |
Convenience function for checking block erase validity.
- Parameters:
-
addr Address of block to begin erasing size Size to erase in bytes
- Returns:
- True if erase is valid for underlying block device
Definition at line 178 of file BlockDevice.h.
bool is_valid_program | ( | bd_addr_t | addr, |
bd_size_t | size | ||
) | const [inherited] |
Convenience function for checking block program validity.
- Parameters:
-
addr Address of block to begin writing to size Size to write in bytes
- Returns:
- True if program is valid for underlying block device
Definition at line 164 of file BlockDevice.h.
bool is_valid_read | ( | bd_addr_t | addr, |
bd_size_t | size | ||
) | const [inherited] |
Convenience function for checking block read validity.
- Parameters:
-
addr Address of block to begin reading from size Size to read in bytes
- Returns:
- True if read is valid for underlying block device
Definition at line 150 of file BlockDevice.h.
int partition | ( | BlockDevice * | bd, |
int | part, | ||
uint8_t | type, | ||
bd_addr_t | start | ||
) | [static] |
Format the MBR to contain the following partition.
- Parameters:
-
bd Block device to partition part Partition to use, 1-4 type 8-bit partition type to identitfy partition's contents start Start block address to map to block 0 of partition, negative addresses are calculated from the end of the underlying block devices. Block 0 is implicitly ignored from the range to store the MBR.
- Returns:
- 0 on success or a negative error code on failure
- Note:
- This is the same as partition(bd, part, type, start, bd->size())
Definition at line 121 of file MBRBlockDevice.cpp.
int partition | ( | BlockDevice * | bd, |
int | part, | ||
uint8_t | type, | ||
bd_addr_t | start, | ||
bd_addr_t | stop | ||
) | [static] |
Format the MBR to contain the following partition.
- Parameters:
-
bd Block device to partition part Partition to use, 1-4 type 8-bit partition type to identitfy partition's contents start Start block address to map to block 0 of partition, negative addresses are calculated from the end of the underlying block devices. Block 0 is implicitly ignored from the range to store the MBR. stop End block address to mark the end of the partition, this block is not mapped, negative addresses are calculated from the end of the underlying block device.
- Returns:
- 0 on success or a negative error code on failure
Definition at line 151 of file MBRBlockDevice.cpp.
int program | ( | const void * | buffer, |
bd_addr_t | addr, | ||
bd_size_t | size | ||
) | [virtual] |
Program blocks to a block device.
The blocks must have been erased prior to being programmed
- Parameters:
-
buffer Buffer of data to write to blocks addr Address of block to begin writing to size Size to write in bytes, must be a multiple of program block size
- Returns:
- 0 on success, negative error code on failure
Implements BlockDevice.
Definition at line 243 of file MBRBlockDevice.cpp.
int read | ( | void * | buffer, |
bd_addr_t | addr, | ||
bd_size_t | size | ||
) | [virtual] |
Read blocks from a block device.
- Parameters:
-
buffer Buffer to read blocks into addr Address of block to begin reading from size Size to read in bytes, must be a multiple of read block size
- Returns:
- 0 on success, negative error code on failure
Implements BlockDevice.
Definition at line 237 of file MBRBlockDevice.cpp.
bd_size_t size | ( | ) | const [virtual] |
Get the total size of the underlying device.
- Returns:
- Size of the underlying device in bytes
Implements BlockDevice.
Definition at line 270 of file MBRBlockDevice.cpp.
virtual int trim | ( | bd_addr_t | addr, |
bd_size_t | size | ||
) | [virtual, inherited] |
Mark blocks as no longer in use.
This function provides a hint to the underlying block device that a region of blocks is no longer in use and may be erased without side effects. Erase must still be called before programming, but trimming allows flash-translation-layers to schedule erases when the device is not busy.
- Parameters:
-
addr Address of block to mark as unused size Size to mark as unused in bytes, must be a multiple of erase block size
- Returns:
- 0 on success, negative error code on failure
Definition at line 110 of file BlockDevice.h.
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