Mbed OS Reference | BufferedBlockDevice.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2018-2020 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * 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_BUFFERED_BLOCK_DEVICE_H
 #define MBED_BUFFERED_BLOCK_DEVICE_H
 
 #include "BlockDevice.h"
 
 namespace mbed {
 
 /** Block device for allowing minimal read and program sizes (of 1) for the underlying BD,
  *  using a buffer on the heap.
  */
 class BufferedBlockDevice : public BlockDevice {
 public:
     /** Lifetime of a memory-buffered block device wrapping an underlying block device
      *
      *  @param bd        Block device to back the BufferedBlockDevice
      */
     BufferedBlockDevice(BlockDevice *bd);
 
     /** Lifetime of the memory-buffered block device
      */
     virtual ~BufferedBlockDevice();
 
     /** Initialize a buffered-memory block device and its underlying block device
      *
      *  @return         0 on success or a negative error code on failure
      */
     virtual int init();
 
     /** Deinitialize the buffered-memory block device and its underlying block device
      *
      *  @return         0 on success or a negative error code on failure
      */
     virtual int deinit();
 
     /** Ensure that data on the underlying storage block device is in sync with the
      *  memory-buffered block device
      *
      *  @return         0 on success or a negative error code on failure
      */
     virtual int sync();
 
     /** Read blocks from the memory-buffered block device
      *
      *  @param buffer   Buffer to read blocks into
      *  @param addr     Address of block to begin reading from
      *  @param size     Size to read in bytes, must be a multiple of read block size
      *  @return         0 on success, negative error code on failure
      */
     virtual int read(void *buffer, bd_addr_t addr, bd_size_t size);
 
     /** Program data to the memory-buffered block device
      *
      *  The write address blocks must be erased prior to being programmed.
      *
      *  @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 program block size
      *  @return         0 on success, negative error code on failure
      */
     virtual int program(const void *buffer, bd_addr_t addr, bd_size_t size);
 
     /** Erase blocks from the memory-buffered 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 erase block size
      *  @return         0 on success, negative error code on failure
      */
     virtual int erase(bd_addr_t addr, bd_size_t size);
 
     /** 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 erase block size
      *  @return         0 on success, negative error code on failure
      */
     virtual int trim(bd_addr_t addr, bd_size_t size);
 
     /** Get the size of a readable block
      *
      *  @return         Size of a readable block in bytes
      */
     virtual bd_size_t get_read_size() const;
 
     /** 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;
 
     /** 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;
 
     /** Get the size of an erasable block of a 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;
 
     /** Get the value of storage data after being 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 erased storage
      */
     virtual int get_erase_value() const;
 
     /** Get the total size of the underlying device
      *
      *  @return         Size of the underlying device in bytes
      */
     virtual bd_size_t size() const;
 
     /** Get the underlying BlockDevice class type
      *
      *  @return         A string representing the underlying BlockDevice class type
      */
     virtual const char *get_type() const;
 
 protected:
     BlockDevice *_bd;
     bd_size_t _bd_program_size;
     bd_size_t _bd_read_size;
     bd_size_t _bd_size;
     bd_size_t _write_cache_addr;
     bool _write_cache_valid;
     uint8_t *_write_cache;
     uint8_t *_read_buf;
     uint32_t _init_ref_count;
     bool _is_initialized;
 
 #if !(DOXYGEN_ONLY)
     /** Flush data in cache
      *
      *  @return         0 on success or a negative error code on failure
      */
     int flush();
 
     /** Invalidate write cache
      *
      *  @return         none
      */
     void invalidate_write_cache();
 #endif //#if !(DOXYGEN_ONLY)
 };
 } // namespace mbed
 
 // Added "using" for backwards compatibility
 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
 using mbed::BufferedBlockDevice;
 #endif
 
 #endif
 
 /** @}*/
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