mbed-os/features/storage/blockdevice/MBRBlockDevice.h

261 lines
9.3 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2017 ARM Limited
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef MBED_MBR_BLOCK_DEVICE_H
#define MBED_MBR_BLOCK_DEVICE_H
#include "BlockDevice.h"
#include "mbed.h"
/** Additional error codes used for MBR records
*/
enum {
BD_ERROR_INVALID_MBR = -3101,
BD_ERROR_INVALID_PARTITION = -3102,
};
/** 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
* @code
* #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);
* @endcode
*
* 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.
* @code
* #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);
* @endcode
*
* @note
* The MBR partition table is relatively limited:
* - At most 4 partitions are supported
* - Extended partitions are currently not supported and will error during init
*/
class MBRBlockDevice : public BlockDevice
{
public:
/** Format the MBR to contain the following partition
*
* @param bd Block device to partition
* @param part Partition to use, 1-4
* @param type 8-bit partition type to identitfy partition's contents
* @param 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.
* @return 0 on success or a negative error code on failure
* @note This is the same as partition(bd, part, type, start, bd->size())
*/
static int partition(BlockDevice *bd, int part, uint8_t type, bd_addr_t start);
/** Format the MBR to contain the following partition
*
* @param bd Block device to partition
* @param part Partition to use, 1-4
* @param type 8-bit partition type to identitfy partition's contents
* @param 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.
* @param 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.
* @return 0 on success or a negative error code on failure
*/
static int partition(BlockDevice *bd, int part, uint8_t type, bd_addr_t start, bd_addr_t stop);
/** Lifetime of the block device
*
* @param bd Block device to back the MBRBlockDevice
* @param part Partition to use, 1-4
*/
MBRBlockDevice(BlockDevice *bd, int part);
/** Lifetime of the block device
*/
virtual ~MBRBlockDevice() {};
/** Initialize a block device
*
* @return 0 on success or a negative error code on failure
*/
virtual int init();
/** Deinitialize a block device
*
* @return 0 on success or a negative error code on failure
*/
virtual int deinit();
/** Ensure data on storage is in sync with the driver
*
* @return 0 on success or a negative error code on failure
*/
virtual int sync();
/** Read blocks from a block device
*
* @param buffer Buffer to read blocks into
* @param addr Address of block to begin reading from
* @param size Size to read in bytes, must be a multiple of read block size
* @return 0 on success, negative error code on failure
*/
virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
/** Program blocks to a block device
*
* The blocks must have been erased prior to being programmed
*
* @param buffer Buffer of data to write to blocks
* @param addr Address of block to begin writing to
* @param size Size to write in bytes, must be a multiple of program block size
* @return 0 on success, negative error code on failure
*/
virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
/** Erase blocks on a block device
*
* The state of an erased block is undefined until it has been programmed,
* unless get_erase_value returns a non-negative byte value
*
* @param addr Address of block to begin erasing
* @param size Size to erase in bytes, must be a multiple of erase block size
* @return 0 on success, negative error code on failure
*/
virtual int erase(bd_addr_t addr, bd_size_t size);
/** Get the size of a readable block
*
* @return Size of a readable block in bytes
*/
virtual bd_size_t get_read_size() const;
/** Get the size of a programmable block
*
* @return Size of a programmable block in bytes
* @note Must be a multiple of the read size
*/
virtual bd_size_t get_program_size() const;
/** Get the size of an erasable block
*
* @return Size of an erasable block in bytes
* @note Must be a multiple of the program size
*/
virtual bd_size_t get_erase_size() const;
/** Get the size of an erasable block given address
*
* @param addr Address within the erasable block
* @return Size of an erasable block in bytes
* @note Must be a multiple of the program size
*/
virtual bd_size_t get_erase_size(bd_addr_t addr) const;
/** Get the value of storage when erased
*
* If get_erase_value returns a non-negative byte value, the underlying
* storage is set to that value when erased, and storage containing
* that value can be programmed without another erase.
*
* @return The value of storage when erased, or -1 if you can't
* rely on the value of erased storage
*/
virtual int get_erase_value() const;
/** Get the total size of the underlying device
*
* @return Size of the underlying device in bytes
*/
virtual bd_size_t size() const;
/** Get the offset of the partition on the underlying block device
* @return Offset of the partition on the underlying device
*/
virtual bd_addr_t get_partition_start() const;
/** Get size of partition on underlying block device
* @return Size of the partition on the underlying device
*/
virtual bd_addr_t get_partition_stop() const;
/** Get 8-bit type of the partition
* @return 8-bit type of partition assigned during format
*/
virtual uint8_t get_partition_type() const;
/** Get the partition number
* @return The partition number, 1-4
*/
virtual int get_partition_number() const;
protected:
BlockDevice *_bd;
bd_size_t _offset;
bd_size_t _size;
uint8_t _type;
uint8_t _part;
uint32_t _init_ref_count;
bool _is_initialized;
};
#endif