BlockDevice.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2017 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef MBED_BLOCK_DEVICE_H
00018 #define MBED_BLOCK_DEVICE_H
00019 
00020 #include <stdint.h>
00021 
00022 
00023 /** Enum of standard error codes
00024  *
00025  *  @enum bd_error
00026  */
00027 enum bd_error {
00028     BD_ERROR_OK                 = 0,     /*!< no error */
00029     BD_ERROR_DEVICE_ERROR       = -4001, /*!< device specific error */
00030 };
00031 
00032 /** Type representing the address of a specific block
00033  */
00034 typedef uint64_t bd_addr_t;
00035 
00036 /** Type representing a quantity of 8-bit bytes
00037  */
00038 typedef uint64_t bd_size_t;
00039 
00040 
00041 /** A hardware device capable of writing and reading blocks
00042  */
00043 class BlockDevice
00044 {
00045 public:
00046     /** Lifetime of a block device
00047      */
00048     virtual ~BlockDevice() {};
00049 
00050     /** Initialize a block device
00051      *
00052      *  @return         0 on success or a negative error code on failure
00053      */
00054     virtual int init() = 0;
00055 
00056     /** Deinitialize a block device
00057      *
00058      *  @return         0 on success or a negative error code on failure
00059      */
00060     virtual int deinit() = 0;
00061 
00062     /** Read blocks from a block device
00063      *
00064      *  If a failure occurs, it is not possible to determine how many bytes succeeded
00065      *
00066      *  @param buffer   Buffer to write blocks to
00067      *  @param addr     Address of block to begin reading from
00068      *  @param size     Size to read in bytes, must be a multiple of read block size
00069      *  @return         0 on success, negative error code on failure
00070      */
00071     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size) = 0;
00072 
00073     /** Program blocks to a block device
00074      *
00075      *  The blocks must have been erased prior to being programmed
00076      *
00077      *  If a failure occurs, it is not possible to determine how many bytes succeeded
00078      *
00079      *  @param buffer   Buffer of data to write to blocks
00080      *  @param addr     Address of block to begin writing to
00081      *  @param size     Size to write in bytes, must be a multiple of program block size
00082      *  @return         0 on success, negative error code on failure
00083      */
00084     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size) = 0;
00085 
00086     /** Erase blocks on a block device
00087      *
00088      *  The state of an erased block is undefined until it has been programmed
00089      *
00090      *  @param addr     Address of block to begin erasing
00091      *  @param size     Size to erase in bytes, must be a multiple of erase block size
00092      *  @return         0 on success, negative error code on failure
00093      */
00094     virtual int erase(bd_addr_t addr, bd_size_t size)
00095     {
00096         return 0;
00097     }
00098 
00099     /** Mark blocks as no longer in use
00100      *
00101      *  This function provides a hint to the underlying block device that a region of blocks
00102      *  is no longer in use and may be erased without side effects. Erase must still be called
00103      *  before programming, but trimming allows flash-translation-layers to schedule erases when
00104      *  the device is not busy.
00105      *
00106      *  @param addr     Address of block to mark as unused
00107      *  @param size     Size to mark as unused in bytes, must be a multiple of erase block size
00108      *  @return         0 on success, negative error code on failure
00109      */
00110     virtual int trim(bd_addr_t addr, bd_size_t size)
00111     {
00112         return 0;
00113     }
00114 
00115     /** Get the size of a readable block
00116      *
00117      *  @return         Size of a readable block in bytes
00118      */
00119     virtual bd_size_t get_read_size() const = 0;
00120 
00121     /** Get the size of a programable block
00122      *
00123      *  @return         Size of a programable block in bytes
00124      *  @note Must be a multiple of the read size
00125      */
00126     virtual bd_size_t get_program_size() const = 0;
00127 
00128     /** Get the size of a eraseable block
00129      *
00130      *  @return         Size of a eraseable block in bytes
00131      *  @note Must be a multiple of the program size
00132      */
00133     virtual bd_size_t get_erase_size() const
00134     {
00135         return get_program_size();
00136     }
00137 
00138     /** Get the total size of the underlying device
00139      *
00140      *  @return         Size of the underlying device in bytes
00141      */
00142     virtual bd_size_t size() const = 0;
00143 
00144     /** Convenience function for checking block read validity
00145      *
00146      *  @param addr     Address of block to begin reading from
00147      *  @param size     Size to read in bytes
00148      *  @return         True if read is valid for underlying block device
00149      */
00150     bool is_valid_read(bd_addr_t addr, bd_size_t size) const
00151     {
00152         return (
00153             addr % get_read_size() == 0 &&
00154             size % get_read_size() == 0 &&
00155             addr + size <= this->size());
00156     }
00157 
00158     /** Convenience function for checking block program validity
00159      *
00160      *  @param addr     Address of block to begin writing to
00161      *  @param size     Size to write in bytes
00162      *  @return         True if program is valid for underlying block device
00163      */
00164     bool is_valid_program(bd_addr_t addr, bd_size_t size) const
00165     {
00166         return (
00167             addr % get_program_size() == 0 &&
00168             size % get_program_size() == 0 &&
00169             addr + size <= this->size());
00170     }
00171 
00172     /** Convenience function for checking block erase validity
00173      *
00174      *  @param addr     Address of block to begin erasing
00175      *  @param size     Size to erase in bytes
00176      *  @return         True if erase is valid for underlying block device
00177      */
00178     bool is_valid_erase(bd_addr_t addr, bd_size_t size) const
00179     {
00180         return (
00181             addr % get_erase_size() == 0 &&
00182             size % get_erase_size() == 0 &&
00183             addr + size <= this->size());
00184     }
00185 };
00186 
00187 
00188 #endif