Diff: mbed-os/features/filesystem/bd/MBRBlockDevice.h

Revision:

0:6ad07c9019fd

diff -r 000000000000 -r 6ad07c9019fd mbed-os/features/filesystem/bd/MBRBlockDevice.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/features/filesystem/bd/MBRBlockDevice.h	Wed May 30 00:01:50 2018 +0000
@@ -0,0 +1,258 @@
+/* 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;
+};
+
+
+#endif