SlicingBlockDevice.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_SLICING_BLOCK_DEVICE_H
00023 #define MBED_SLICING_BLOCK_DEVICE_H
00024 
00025 #include "BlockDevice.h"
00026 #include "platform/mbed_assert.h"
00027 
00028 /** Block device for mapping to a slice of another block device
00029  *
00030  *  @code
00031  *  #include "mbed.h"
00032  *  #include "HeapBlockDevice.h"
00033  *  #include "SlicingBlockDevice.h"
00034  *
00035  *  // Create a block device with 64 blocks of size 512
00036  *  HeapBlockDevice mem(64*512, 512);
00037  *
00038  *  // Create a block device that maps to the first 32 blocks
00039  *  SlicingBlockDevice slice1(&mem, 0*512, 32*512);
00040  *
00041  *  // Create a block device that maps to the last 32 blocks
00042  *  SlicingBlockDevice slice2(&mem, 32*512);
00043  *
00044  *  // Create a block device that maps to the middle 32 blocks
00045  *  SlicingBlockDevice slice3(&mem, 16*512, -16*512);
00046  * @endcode
00047  */
00048 class SlicingBlockDevice : public BlockDevice
00049 {
00050 public:
00051     /** Lifetime of the memory block device
00052      *
00053      *  @param bd       Block device to back the SlicingBlockDevice
00054      *  @param start    Start block address to map to block 0, negative addresses
00055      *                  are calculated from the end of the underlying block device
00056      *  @param end      End block address to mark the end of the block device,
00057      *                  this block is not mapped, negative addresses are
00058      *                  calculated from the end of the underlying block device.
00059      *                  The default stops at end of the underlying block device.
00060      */
00061     SlicingBlockDevice(BlockDevice *bd, bd_addr_t start, bd_addr_t end = 0);
00062 
00063     /** Lifetime of a block device
00064      */
00065     virtual ~SlicingBlockDevice() {};
00066 
00067     /** Initialize a block device
00068      *
00069      *  @return         0 on success or a negative error code on failure
00070      */
00071     virtual int init();
00072 
00073     /** Deinitialize a block device
00074      *
00075      *  @return         0 on success or a negative error code on failure
00076      */
00077     virtual int deinit();
00078 
00079     /** Ensure data on storage is in sync with the driver
00080      *
00081      *  @return         0 on success or a negative error code on failure
00082      */
00083     virtual int sync();
00084 
00085     /** Read blocks from a block device
00086      *
00087      *  @param buffer   Buffer to read blocks into
00088      *  @param addr     Address of block to begin reading from
00089      *  @param size     Size to read in bytes, must be a multiple of read block size
00090      *  @return         0 on success, negative error code on failure
00091      */
00092     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
00093 
00094     /** Program blocks to a block device
00095      *
00096      *  The blocks must have been erased prior to being programmed
00097      *
00098      *  @param buffer   Buffer of data to write to blocks
00099      *  @param addr     Address of block to begin writing to
00100      *  @param size     Size to write in bytes, must be a multiple of program block size
00101      *  @return         0 on success, negative error code on failure
00102      */
00103     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
00104 
00105     /** Erase blocks on a block device
00106      *
00107      *  The state of an erased block is undefined until it has been programmed,
00108      *  unless get_erase_value returns a non-negative byte value
00109      *
00110      *  @param addr     Address of block to begin erasing
00111      *  @param size     Size to erase in bytes, must be a multiple of erase block size
00112      *  @return         0 on success, negative error code on failure
00113      */
00114     virtual int erase(bd_addr_t addr, bd_size_t size);
00115 
00116     /** Get the size of a readable block
00117      *
00118      *  @return         Size of a readable block in bytes
00119      */
00120     virtual bd_size_t get_read_size() const;
00121 
00122     /** Get the size of a programmable block
00123      *
00124      *  @return         Size of a programmable block in bytes
00125      *  @note Must be a multiple of the read size
00126      */
00127     virtual bd_size_t get_program_size() const;
00128 
00129     /** Get the size of an erasable block
00130      *
00131      *  @return         Size of an erasable block in bytes
00132      *  @note Must be a multiple of the program size
00133      */
00134     virtual bd_size_t get_erase_size() const;
00135 
00136     /** Get the size of an erasable block given address
00137      *
00138      *  @param addr     Address within the erasable block
00139      *  @return         Size of an erasable block in bytes
00140      *  @note Must be a multiple of the program size
00141      */
00142     virtual bd_size_t get_erase_size(bd_addr_t addr) const;
00143 
00144     /** Get the value of storage when erased
00145      *
00146      *  If get_erase_value returns a non-negative byte value, the underlying
00147      *  storage is set to that value when erased, and storage containing
00148      *  that value can be programmed without another erase.
00149      *
00150      *  @return         The value of storage when erased, or -1 if you can't
00151      *                  rely on the value of erased storage
00152      */
00153     virtual int get_erase_value() const;
00154 
00155     /** Get the total size of the underlying device
00156      *
00157      *  @return         Size of the underlying device in bytes
00158      */
00159     virtual bd_size_t size() const;
00160 
00161 protected:
00162     BlockDevice *_bd;
00163     bool _start_from_end;
00164     bd_size_t _start;
00165     bool _stop_from_end;
00166     bd_size_t _stop;
00167 };
00168 
00169 
00170 #endif