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 /** \addtogroup storage */
00018 /** @{*/
00019 
00020 #ifndef MBED_BLOCK_DEVICE_H
00021 #define MBED_BLOCK_DEVICE_H
00022 
00023 #include <stdint.h>
00024 
00025 namespace mbed {
00026 
00027 /** Enum of standard error codes
00028  *
00029  *  @enum bd_error
00030  */
00031 enum bd_error {
00032     BD_ERROR_OK                 = 0,     /*!< no error */
00033     BD_ERROR_DEVICE_ERROR       = -4001, /*!< device specific error */
00034 };
00035 
00036 /** Type representing the address of a specific block
00037  */
00038 typedef uint64_t bd_addr_t;
00039 
00040 /** Type representing a quantity of 8-bit bytes
00041  */
00042 typedef uint64_t bd_size_t;
00043 
00044 
00045 /** A hardware device capable of writing and reading blocks
00046  */
00047 class BlockDevice {
00048 public:
00049 
00050     /** Return the default block device
00051      *
00052      * Returns the default block device based on the configuration JSON.
00053      * Use the components in target.json or application config to change
00054      * the default block device.
00055      *
00056      * An application can override all target settings by implementing
00057      * BlockDevice::get_default_instance() - the default
00058      * definition is weak, and calls get_target_default_instance().
00059     */
00060     static BlockDevice *get_default_instance();
00061 
00062     /** Lifetime of a block device
00063      */
00064     virtual ~BlockDevice() {};
00065 
00066     /** Initialize a block device
00067      *
00068      *  @return         0 on success or a negative error code on failure
00069      */
00070     virtual int init() = 0;
00071 
00072     /** Deinitialize a block device
00073      *
00074      *  @return         0 on success or a negative error code on failure
00075      */
00076     virtual int deinit() = 0;
00077 
00078     /** Ensure data on storage is in sync with the driver
00079      *
00080      *  @return         0 on success or a negative error code on failure
00081      */
00082     virtual int sync()
00083     {
00084         return 0;
00085     }
00086 
00087     /** Read blocks from a block device
00088      *
00089      *  If a failure occurs, it is not possible to determine how many bytes succeeded
00090      *
00091      *  @param buffer   Buffer to write blocks to
00092      *  @param addr     Address of block to begin reading from
00093      *  @param size     Size to read in bytes, must be a multiple of the read block size
00094      *  @return         0 on success or a negative error code on failure
00095      */
00096     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size) = 0;
00097 
00098     /** Program blocks to a block device
00099      *
00100      *  The blocks must have been erased prior to being programmed
00101      *
00102      *  If a failure occurs, it is not possible to determine how many bytes succeeded
00103      *
00104      *  @param buffer   Buffer of data to write to blocks
00105      *  @param addr     Address of block to begin writing to
00106      *  @param size     Size to write in bytes, must be a multiple of the program block size
00107      *  @return         0 on success or a negative error code on failure
00108      */
00109     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size) = 0;
00110 
00111     /** Erase blocks on a block device
00112      *
00113      *  The state of an erased block is undefined until it has been programmed,
00114      *  unless get_erase_value returns a non-negative byte value
00115      *
00116      *  @param addr     Address of block to begin erasing
00117      *  @param size     Size to erase in bytes, must be a multiple of the erase block size
00118      *  @return         0 on success or a negative error code on failure
00119      */
00120     virtual int erase(bd_addr_t addr, bd_size_t size)
00121     {
00122         return 0;
00123     }
00124 
00125     /** Mark blocks as no longer in use
00126      *
00127      *  This function provides a hint to the underlying block device that a region of blocks
00128      *  is no longer in use and may be erased without side effects. Erase must still be called
00129      *  before programming, but trimming allows flash-translation-layers to schedule erases when
00130      *  the device is not busy.
00131      *
00132      *  @param addr     Address of block to mark as unused
00133      *  @param size     Size to mark as unused in bytes, must be a multiple of the erase block size
00134      *  @return         0 on success or a negative error code on failure
00135      */
00136     virtual int trim(bd_addr_t addr, bd_size_t size)
00137     {
00138         return 0;
00139     }
00140 
00141     /** Get the size of a readable block
00142      *
00143      *  @return         Size of a readable block in bytes
00144      */
00145     virtual bd_size_t get_read_size() const = 0;
00146 
00147     /** Get the size of a programmable block
00148      *
00149      *  @return         Size of a programmable block in bytes
00150      *  @note Must be a multiple of the read size
00151      */
00152     virtual bd_size_t get_program_size() const = 0;
00153 
00154     /** Get the size of an erasable block
00155      *
00156      *  @return         Size of an erasable block in bytes
00157      *  @note Must be a multiple of the program size
00158      */
00159     virtual bd_size_t get_erase_size() const
00160     {
00161         return get_program_size();
00162     }
00163 
00164     /** Get the size of an erasable block given address
00165      *
00166      *  @param addr     Address within the erasable block
00167      *  @return         Size of an erasable block in bytes
00168      *  @note Must be a multiple of the program size
00169      */
00170     virtual bd_size_t get_erase_size(bd_addr_t addr) const
00171     {
00172         return get_erase_size();
00173     }
00174 
00175     /** Get the value of storage when erased
00176      *
00177      *  If get_erase_value returns a non-negative byte value, the underlying
00178      *  storage is set to that value when erased, and storage containing
00179      *  that value can be programmed without another erase.
00180      *
00181      *  @return         The value of storage when erased, or -1 if you can't
00182      *                  rely on the value of the erased storage
00183      */
00184     virtual int get_erase_value() const
00185     {
00186         return -1;
00187     }
00188 
00189     /** Get the total size of the underlying device
00190      *
00191      *  @return         Size of the underlying device in bytes
00192      */
00193     virtual bd_size_t size() const = 0;
00194 
00195     /** Convenience function for checking block read validity
00196      *
00197      *  @param addr     Address of block to begin reading from
00198      *  @param size     Size to read in bytes
00199      *  @return         True if read is valid for underlying block device
00200      */
00201     virtual bool is_valid_read(bd_addr_t addr, bd_size_t size) const
00202     {
00203         return (
00204                    addr % get_read_size() == 0 &&
00205                    size % get_read_size() == 0 &&
00206                    addr + size <= this->size());
00207     }
00208 
00209     /** Convenience function for checking block program validity
00210      *
00211      *  @param addr     Address of block to begin writing to
00212      *  @param size     Size to write in bytes
00213      *  @return         True if program is valid for underlying block device
00214      */
00215     virtual bool is_valid_program(bd_addr_t addr, bd_size_t size) const
00216     {
00217         return (
00218                    addr % get_program_size() == 0 &&
00219                    size % get_program_size() == 0 &&
00220                    addr + size <= this->size());
00221     }
00222 
00223     /** Convenience function for checking block erase validity
00224      *
00225      *  @param addr     Address of block to begin erasing
00226      *  @param size     Size to erase in bytes
00227      *  @return         True if erase is valid for underlying block device
00228      */
00229     virtual bool is_valid_erase(bd_addr_t addr, bd_size_t size) const
00230     {
00231         return (
00232                    addr % get_erase_size(addr) == 0 &&
00233                    (addr + size) % get_erase_size(addr + size - 1) == 0 &&
00234                    addr + size <= this->size());
00235     }
00236 
00237     /** Get the BlockDevice class type.
00238      *
00239      *  @return         A string represent the BlockDevice class type.
00240      */
00241     virtual const char *get_type() const = 0;
00242 };
00243 
00244 } // namespace mbed
00245 
00246 // Added "using" for backwards compatibility
00247 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
00248 using mbed::BlockDevice;
00249 using mbed::bd_addr_t;
00250 using mbed::bd_size_t;
00251 using mbed::BD_ERROR_OK;
00252 using mbed::BD_ERROR_DEVICE_ERROR;
00253 #endif
00254 
00255 #endif
00256 
00257 /** @}*/