MBRBlockDevice.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2017 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #ifndef MBED_MBR_BLOCK_DEVICE_H
00023 #define MBED_MBR_BLOCK_DEVICE_H
00024 
00025 #include "BlockDevice.h"
00026 #include "mbed.h"
00027 
00028 
00029 /** Additional error codes used for MBR records
00030  */
00031 enum {
00032     BD_ERROR_INVALID_MBR       = -3101,
00033     BD_ERROR_INVALID_PARTITION = -3102,
00034 };
00035 
00036 
00037 /** Block device for managing a Master Boot Record
00038  *  https://en.wikipedia.org/wiki/Master_boot_record
00039  *
00040  *  Here is an example of partitioning a heap backed block device
00041  *  @code
00042  *  #include "mbed.h"
00043  *  #include "HeapBlockDevice.h"
00044  *  #include "MBRBlockDevice.h"
00045  *
00046  *  // Create a block device with 64 blocks of size 512
00047  *  HeapBlockDevice mem(64*512, 512);
00048  *
00049  *  // Partition into two partitions with ~half the blocks
00050  *  MBRBlockDevice::partition(&mem, 1, 0x83, 0*512, 32*512);
00051  *  MBRBlockDevice::partition(&mem, 2, 0x83, 32*512);
00052  *
00053  *  // Create a block device that maps to the first 32 blocks (excluding MBR block)
00054  *  MBRBlockDevice part1(&mem, 1);
00055  *
00056  *  // Create a block device that maps to the last 32 blocks
00057  *  MBRBlockDevice part2(&mem, 2);
00058  *  @endcode
00059  *
00060  *  Here is a more realistic example where the MBRBlockDevice is used
00061  *  to partition a region of space on an SD card. When plugged into a computer,
00062  *  the partitions will be recognized appropriately.
00063  *  @code
00064  *  #include "mbed.h"
00065  *  #include "SDBlockDevice.h"
00066  *  #include "MBRBlockDevice.h"
00067  *  #include "FATFileSystem.h"
00068  *
00069  *  // Create an SD card
00070  *  SDBlockDevice sd(s0, s1, s2, s3);
00071  *
00072  *  // Create a partition with 1 GB of space
00073  *  MBRBlockDevice::partition(&sd, 1, 0x83, 0, 1024*1024);
00074  *
00075  *  // Create the block device that represents the partition
00076  *  MBRBlockDevice part1(&sd, 1);
00077  *
00078  *  // Format the partition with a FAT filesystem
00079  *  FATFileSystem::format(&part1);
00080  *
00081  *  // Create the FAT filesystem instance, files can now be written to
00082  *  // the FAT filesystem in partition 1
00083  *  FATFileSystem fat("fat", &part1);
00084  *  @endcode
00085  */
00086 class MBRBlockDevice : public BlockDevice
00087 {
00088 public:
00089     /** Format the MBR to contain the following partition
00090      *
00091      *  @param bd       Block device to partition
00092      *  @param part     Partition to use, 1-4
00093      *  @param type     8-bit partition type to identitfy partition's contents
00094      *  @param start    Start block address to map to block 0 of partition, 
00095      *                  negative addresses are calculated from the end of the
00096      *                  underlying block devices. Block 0 is implicitly ignored
00097      *                  from the range to store the MBR.
00098      *  @return         0 on success or a negative error code on failure
00099      *  @note This is the same as partition(bd, part, type, start, bd->size())
00100      */
00101     static int partition(BlockDevice *bd, int part, uint8_t type, bd_addr_t start);
00102 
00103     /** Format the MBR to contain the following partition
00104      *
00105      *  @param bd       Block device to partition
00106      *  @param part     Partition to use, 1-4
00107      *  @param type     8-bit partition type to identitfy partition's contents
00108      *  @param start    Start block address to map to block 0 of partition, 
00109      *                  negative addresses are calculated from the end of the
00110      *                  underlying block devices. Block 0 is implicitly ignored
00111      *                  from the range to store the MBR.
00112      *  @param stop     End block address to mark the end of the partition,
00113      *                  this block is not mapped, negative addresses are calculated
00114      *                  from the end of the underlying block device.
00115      *  @return         0 on success or a negative error code on failure
00116      */
00117     static int partition(BlockDevice *bd, int part, uint8_t type, bd_addr_t start, bd_addr_t stop);
00118 
00119     /** Lifetime of the block device
00120      *
00121      *  @param bd       Block device to back the MBRBlockDevice
00122      *  @param part     Partition to use, 1-4
00123      */
00124     MBRBlockDevice(BlockDevice *bd, int part);
00125 
00126     /** Lifetime of the block device
00127      */
00128     virtual ~MBRBlockDevice() {};
00129 
00130     /** Initialize a block device
00131      *
00132      *  @return         0 on success or a negative error code on failure
00133      */
00134     virtual int init();
00135 
00136     /** Deinitialize a block device
00137      *
00138      *  @return         0 on success or a negative error code on failure
00139      */
00140     virtual int deinit();
00141 
00142     /** Read blocks from a block device
00143      *
00144      *  @param buffer   Buffer to read blocks into
00145      *  @param addr     Address of block to begin reading from
00146      *  @param size     Size to read in bytes, must be a multiple of read block size
00147      *  @return         0 on success, negative error code on failure
00148      */
00149     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
00150 
00151     /** Program blocks to a block device
00152      *
00153      *  The blocks must have been erased prior to being programmed
00154      *
00155      *  @param buffer   Buffer of data to write to blocks
00156      *  @param addr     Address of block to begin writing to
00157      *  @param size     Size to write in bytes, must be a multiple of program block size
00158      *  @return         0 on success, negative error code on failure
00159      */
00160     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
00161 
00162     /** Erase blocks on a block device
00163      *
00164      *  The state of an erased block is undefined until it has been programmed
00165      *
00166      *  @param addr     Address of block to begin erasing
00167      *  @param size     Size to erase in bytes, must be a multiple of erase block size
00168      *  @return         0 on success, negative error code on failure
00169      */
00170     virtual int erase(bd_addr_t addr, bd_size_t size);
00171 
00172     /** Get the size of a readable block
00173      *
00174      *  @return         Size of a readable block in bytes
00175      */
00176     virtual bd_size_t get_read_size() const;
00177 
00178     /** Get the size of a programable block
00179      *
00180      *  @return         Size of a programable block in bytes
00181      *  @note Must be a multiple of the read size
00182      */
00183     virtual bd_size_t get_program_size() const;
00184 
00185     /** Get the size of a eraseable block
00186      *
00187      *  @return         Size of a eraseable block in bytes
00188      *  @note Must be a multiple of the program size
00189      */
00190     virtual bd_size_t get_erase_size() const;
00191 
00192     /** Get the total size of the underlying device
00193      *
00194      *  @return         Size of the underlying device in bytes
00195      */
00196     virtual bd_size_t size() const;
00197 
00198     /** Get the offset of the partition on the underlying block device
00199      *  @return         Offset of the partition on the underlying device
00200      */
00201     virtual bd_addr_t get_partition_start() const;
00202 
00203     /** Get size of partition on underlying block device
00204      *  @return         Size of the partition on the underlying device
00205      */
00206     virtual bd_addr_t get_partition_stop() const;
00207 
00208     /** Get 8-bit type of the partition
00209      *  @return         8-bit type of partition assigned during format
00210      */
00211     virtual uint8_t get_partition_type() const;
00212 
00213     /** Get the partition number
00214      *  @return         The partition number, 1-4
00215      */
00216     virtual int get_partition_number() const;
00217 
00218 protected:
00219     BlockDevice *_bd;
00220     bd_size_t _offset;
00221     bd_size_t _size;
00222     uint8_t _type;
00223     uint8_t _part;
00224 };
00225 
00226 
00227 #endif