ChainingBlockDevice.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_CHAINING_BLOCK_DEVICE_H
00023 #define MBED_CHAINING_BLOCK_DEVICE_H
00024 
00025 #include "BlockDevice.h"
00026 #include "mbed.h"
00027 
00028 
00029 /** Block device for chaining multiple block devices
00030  *  with the similar block sizes at sequential addresses
00031  *
00032  *  @code
00033  *  #include "mbed.h"
00034  *  #include "HeapBlockDevice.h"
00035  *  #include "ChainingBlockDevice.h"
00036  *
00037  *  // Create two smaller block devices with
00038  *  // 64 and 32 blocks of size 512 bytes
00039  *  HeapBlockDevice mem1(64*512, 512);
00040  *  HeapBlockDevice mem2(32*512, 512);
00041  *
00042  *  // Create a block device backed by mem1 and mem2
00043  *  // contains 96 blocks of size 512 bytes
00044  *  BlockDevice *bds[] = {&mem1, &mem2};
00045  *  ChainingBlockDevice chainmem(bds);
00046  *  @endcode
00047  */
00048 class ChainingBlockDevice : public BlockDevice
00049 {
00050 public:
00051     /** Lifetime of the memory block device
00052      *
00053      *  @param bds         Array of block devices to chain with sequential block addresses
00054      *  @param bd_count    Number of block devices to chain
00055      *  @note All block devices must have the same block size
00056      */
00057     ChainingBlockDevice(BlockDevice **bds, size_t bd_count);
00058 
00059     /** Lifetime of the memory block device
00060      *
00061      *  @param bds          Array of block devices to chain with sequential block addresses
00062      *  @note All block devices must have the same block size
00063      */
00064     template <size_t Size>
00065     ChainingBlockDevice(BlockDevice *(&bds)[Size])
00066         : _bds(bds), _bd_count(sizeof(bds) / sizeof(bds[0]))
00067         , _read_size(0), _program_size(0), _erase_size(0), _size(0)
00068     {
00069     }
00070 
00071     /** Lifetime of the memory block device
00072      *
00073      */
00074     virtual ~ChainingBlockDevice() {}
00075 
00076     /** Initialize a block device
00077      *
00078      *  @return         0 on success or a negative error code on failure
00079      */
00080     virtual int init();
00081 
00082     /** Deinitialize a block device
00083      *
00084      *  @return         0 on success or a negative error code on failure
00085      */
00086     virtual int deinit();
00087 
00088     /** Ensure data on storage is in sync with the driver
00089      *
00090      *  @return         0 on success or a negative error code on failure
00091      */
00092     virtual int sync();
00093 
00094     /** Read blocks from a block device
00095      *
00096      *  @param buffer   Buffer to write blocks to
00097      *  @param addr     Address of block to begin reading from
00098      *  @param size     Size to read in bytes, must be a multiple of read block size
00099      *  @return         0 on success, negative error code on failure
00100      */
00101     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
00102 
00103     /** Program blocks to a block device
00104      *
00105      *  The blocks must have been erased prior to being programmed
00106      *
00107      *  @param buffer   Buffer of data to write to blocks
00108      *  @param addr     Address of block to begin writing to
00109      *  @param size     Size to write in bytes, must be a multiple of program block size
00110      *  @return         0 on success, negative error code on failure
00111      */
00112     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
00113 
00114     /** Erase blocks on a block device
00115      *
00116      *  The state of an erased block is undefined until it has been programmed,
00117      *  unless get_erase_value returns a non-negative byte value
00118      *
00119      *  @param addr     Address of block to begin erasing
00120      *  @param size     Size to erase in bytes, must be a multiple of erase block size
00121      *  @return         0 on success, negative error code on failure
00122      */
00123     virtual int erase(bd_addr_t addr, bd_size_t size);
00124 
00125     /** Get the size of a readable block
00126      *
00127      *  @return         Size of a readable block in bytes
00128      */
00129     virtual bd_size_t get_read_size() const;
00130 
00131     /** Get the size of a programable block
00132      *
00133      *  @return         Size of a programable block in bytes
00134      *  @note Must be a multiple of the read size
00135      */
00136     virtual bd_size_t get_program_size() const;
00137 
00138     /** Get the size of a eraseable block
00139      *
00140      *  @return         Size of a eraseable block in bytes
00141      *  @note Must be a multiple of the program size
00142      */
00143     virtual bd_size_t get_erase_size() const;
00144 
00145     /** Get the value of storage when erased
00146      *
00147      *  If get_erase_value returns a non-negative byte value, the underlying
00148      *  storage is set to that value when erased, and storage containing
00149      *  that value can be programmed without another erase.
00150      *
00151      *  @return         The value of storage when erased, or -1 if you can't
00152      *                  rely on the value of erased storage
00153      */
00154     virtual int get_erase_value() const;
00155 
00156     /** Get the total size of the underlying device
00157      *
00158      *  @return         Size of the underlying device in bytes
00159      */
00160     virtual bd_size_t size() const;
00161 
00162 protected:
00163     BlockDevice **_bds;
00164     size_t _bd_count;
00165     bd_size_t _read_size;
00166     bd_size_t _program_size;
00167     bd_size_t _erase_size;
00168     bd_size_t _size;
00169     int _erase_value;
00170 };
00171 
00172 
00173 #endif