Mbed OS Reference | BlockDevice.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2017 ARM Limited
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 /** \addtogroup storage */
 /** @{*/
 
 #ifndef MBED_BLOCK_DEVICE_H
 #define MBED_BLOCK_DEVICE_H
 
 #include <stdint.h>
 
 namespace mbed {
 
 /** Enum of standard error codes
  *
  *  @enum bd_error
  */
 enum bd_error {
     BD_ERROR_OK                 = 0,     /*!< no error */
     BD_ERROR_DEVICE_ERROR       = -4001, /*!< device specific error */
 };
 
 /** Type representing the address of a specific block
  */
 typedef uint64_t bd_addr_t;
 
 /** Type representing a quantity of 8-bit bytes
  */
 typedef uint64_t bd_size_t;
 
 
 /** A hardware device capable of writing and reading blocks
  */
 class BlockDevice {
 public:
 
     /** Return the default block device
      *
      * Returns the default block device based on the configuration JSON.
      * Use the components in target.json or application config to change
      * the default block device.
      *
      * An application can override all target settings by implementing
      * BlockDevice::get_default_instance() - the default
      * definition is weak, and calls get_target_default_instance().
     */
     static BlockDevice *get_default_instance();
 
     /** Lifetime of a block device
      */
     virtual ~BlockDevice() {};
 
     /** Initialize a block device
      *
      *  @return         0 on success or a negative error code on failure
      */
     virtual int init() = 0;
 
     /** Deinitialize a block device
      *
      *  @return         0 on success or a negative error code on failure
      */
     virtual int deinit() = 0;
 
     /** Ensure data on storage is in sync with the driver
      *
      *  @return         0 on success or a negative error code on failure
      */
     virtual int sync()
     {
         return 0;
     }
 
     /** Read blocks from a block device
      *
      *  If a failure occurs, it is not possible to determine how many bytes succeeded
      *
      *  @param buffer   Buffer to write blocks to
      *  @param addr     Address of block to begin reading from
      *  @param size     Size to read in bytes, must be a multiple of the read block size
      *  @return         0 on success or a negative error code on failure
      */
     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size) = 0;
 
     /** Program blocks to a block device
      *
      *  The blocks must have been erased prior to being programmed
      *
      *  If a failure occurs, it is not possible to determine how many bytes succeeded
      *
      *  @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 the program block size
      *  @return         0 on success or a negative error code on failure
      */
     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size) = 0;
 
     /** 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 the erase block size
      *  @return         0 on success or a negative error code on failure
      */
     virtual int erase(bd_addr_t addr, bd_size_t size)
     {
         return 0;
     }
 
     /** Mark blocks as no longer in use
      *
      *  This function provides a hint to the underlying block device that a region of blocks
      *  is no longer in use and may be erased without side effects. Erase must still be called
      *  before programming, but trimming allows flash-translation-layers to schedule erases when
      *  the device is not busy.
      *
      *  @param addr     Address of block to mark as unused
      *  @param size     Size to mark as unused in bytes, must be a multiple of the erase block size
      *  @return         0 on success or a negative error code on failure
      */
     virtual int trim(bd_addr_t addr, bd_size_t size)
     {
         return 0;
     }
 
     /** Get the size of a readable block
      *
      *  @return         Size of a readable block in bytes
      */
     virtual bd_size_t get_read_size() const = 0;
 
     /** 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 = 0;
 
     /** 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
     {
         return get_program_size();
     }
 
     /** 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
     {
         return get_erase_size();
     }
 
     /** 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 the erased storage
      */
     virtual int get_erase_value() const
     {
         return -1;
     }
 
     /** Get the total size of the underlying device
      *
      *  @return         Size of the underlying device in bytes
      */
     virtual bd_size_t size() const = 0;
 
     /** Convenience function for checking block read validity
      *
      *  @param addr     Address of block to begin reading from
      *  @param size     Size to read in bytes
      *  @return         True if read is valid for underlying block device
      */
     virtual bool is_valid_read(bd_addr_t addr, bd_size_t size) const
     {
         return (
                    addr % get_read_size() == 0 &&
                    size % get_read_size() == 0 &&
                    addr + size <= this->size());
     }
 
     /** Convenience function for checking block program validity
      *
      *  @param addr     Address of block to begin writing to
      *  @param size     Size to write in bytes
      *  @return         True if program is valid for underlying block device
      */
     virtual bool is_valid_program(bd_addr_t addr, bd_size_t size) const
     {
         return (
                    addr % get_program_size() == 0 &&
                    size % get_program_size() == 0 &&
                    addr + size <= this->size());
     }
 
     /** Convenience function for checking block erase validity
      *
      *  @param addr     Address of block to begin erasing
      *  @param size     Size to erase in bytes
      *  @return         True if erase is valid for underlying block device
      */
     virtual bool is_valid_erase(bd_addr_t addr, bd_size_t size) const
     {
         return (
                    addr % get_erase_size(addr) == 0 &&
                    (addr + size) % get_erase_size(addr + size - 1) == 0 &&
                    addr + size <= this->size());
     }
 
     /** Get the BlockDevice class type.
      *
      *  @return         A string represent the BlockDevice class type.
      */
     virtual const char *get_type() const = 0;
 };
 
 } // namespace mbed
 
 // Added "using" for backwards compatibility
 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
 using mbed::BlockDevice;
 using mbed::bd_addr_t;
 using mbed::bd_size_t;
 using mbed::BD_ERROR_OK;
 using mbed::BD_ERROR_DEVICE_ERROR;
 #endif
 
 #endif
 
 /** @}*/
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