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bd: Added prototype block device api
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‎features/filesystem/bd/BlockDevice.cpp

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/* mbed Microcontroller Library
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* Copyright (c) 2016 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "BlockDevice.h"
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// Writes by default perform an erase + program
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bd_error_t BlockDevice::write(const void *buffer, bd_addr_t addr, bd_size_t size)
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{
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if (!is_valid_write(addr, size)) {
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return BD_ERROR_PARAMETER;
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}
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bd_error_t err = erase(addr, size);
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if (err) {
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return err;
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}
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return program(buffer, addr, size);
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}
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bd_size_t BlockDevice::write_size()
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{
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return erase_size();
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}
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bool BlockDevice::is_valid_write(bd_addr_t addr, bd_size_t size)
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{
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return is_valid_erase(addr, size);
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}
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// Convenience functions for checking block validity
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static bool is_aligned(uint64_t x, uint64_t alignment)
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{
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return (x / alignment) * alignment == x;
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}
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bool BlockDevice::is_valid_read(bd_addr_t addr, bd_size_t size)
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{
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return (
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is_aligned(addr, read_size()) &&
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is_aligned(size, read_size()) &&
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addr + size <= this->size());
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}
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bool BlockDevice::is_valid_erase(bd_addr_t addr, bd_size_t size)
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{
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return (
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is_aligned(addr, erase_size()) &&
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is_aligned(size, erase_size()) &&
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addr + size <= this->size());
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}
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bool BlockDevice::is_valid_program(bd_addr_t addr, bd_size_t size)
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{
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return (
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is_aligned(addr, program_size()) &&
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is_aligned(size, program_size()) &&
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addr + size <= this->size());
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}
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‎features/filesystem/bd/BlockDevice.h

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/* mbed Microcontroller Library
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* Copyright (c) 2016 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBED_BLOCK_DEVICE_H
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#define MBED_BLOCK_DEVICE_H
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#include <stdint.h>
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/** Enum of standard error codes
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*
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* @enum bd_error_t
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*/
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enum bd_error {
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BD_ERROR_OK = 0, /*!< no error */
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BD_ERROR_WOULD_BLOCK = -4001, /*!< operation would block */
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BD_ERROR_UNSUPPORTED = -4002, /*!< unsupported operation */
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BD_ERROR_PARAMETER = -4003, /*!< invalid parameter */
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BD_ERROR_NO_INIT = -4004, /*!< uninitialized */
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BD_ERROR_NO_DEVICE = -4005, /*!< device is missing or not connected */
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BD_ERROR_WRITE_PROTECTED = -4006, /*!< write protected */
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BD_ERROR_DEVICE_ERROR = -4007, /*!< device specific error */
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};
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/** Type representing either 0 or a negative error code
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*/
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typedef int32_t bd_error_t;
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/** Type representing the address of a specific block
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*/
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typedef uint64_t bd_addr_t;
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/** Type representing a quantity of 8-bit bytes
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*/
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typedef uint64_t bd_size_t;
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/** A hardware device capable of writing and reading blocks
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*/
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class BlockDevice {
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public:
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/** Lifetime of a block device
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*/
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virtual ~BlockDevice() {};
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/** Initialize a block device
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*
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* @return 0 on success or a negative error code on failure
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*/
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virtual bd_error_t init() = 0;
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/** Deinitialize a block device
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*
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* @return 0 on success or a negative error code on failure
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*/
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virtual bd_error_t deinit() = 0;
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/** Read blocks from a block device
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*
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* @param buffer Buffer to write blocks to
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* @param addr Address of block to begin reading from
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* @param size Size to read in bytes, must be a multiple of read block size
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* @return 0 on success, negative error code on failure
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*/
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virtual bd_error_t read(void *buffer, bd_addr_t addr, bd_size_t size) = 0;
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/** Write blocks to a block device
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*
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* A write is equivalent to an erase followed by a program
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*
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* @param buffer Buffer of data to write to blocks
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* @param addr Address of block to begin writing to
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* @param size Size to write in bytes, must be a multiple of write block size
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* @return 0 on success, negative error code on failure
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*/
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virtual bd_error_t write(const void *buffer, bd_addr_t addr, bd_size_t size);
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/** Program blocks to a block device
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*
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* The blocks must have been erased prior to being programmed
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*
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* @param buffer Buffer of data to write to blocks
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* @param addr Address of block to begin writing to
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* @param size Size to write in bytes, must be a multiple of program block size
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* @return 0 on success, negative error code on failure
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*/
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virtual bd_error_t program(const void *buffer, bd_addr_t addr, bd_size_t size) = 0;
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/** Erase blocks on a block device
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*
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* The state of an erased block is undefined until it has been programmed
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*
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* @param addr Address of block to begin erasing
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* @param size Size to erase in bytes, must be a multiple of erase block size
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* @return 0 on success, negative error code on failure
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*/
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virtual bd_error_t erase(bd_addr_t addr, bd_size_t size) = 0;
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/** Get the size of a readable block
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*
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* @return Size of a readable block in bytes
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*/
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virtual bd_size_t read_size() = 0;
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/** Get the size of a writeable block
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*
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* @return Size of a writeable block in bytes
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* @note Must be a multiple of the read size, this is
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* equivalent to the erase size of the device
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*/
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virtual bd_size_t write_size();
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/** Get the size of a programable block
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*
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* @return Size of a programable block in bytes
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* @note Must be a multiple of the read size
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*/
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virtual bd_size_t program_size() = 0;
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/** Get the size of a eraseable block
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*
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* @return Size of a eraseable block in bytes
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* @note Must be a multiple of the program size
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*/
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virtual bd_size_t erase_size() = 0;
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/** Get the total size of the underlying device
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*
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* @return Size of the underlying device in bytes
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*/
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virtual bd_size_t size() = 0;
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/** Convenience function for checking block read validity
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*
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* @param addr Address of block to begin reading from
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* @param size Size to read in bytes
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* @return True if read is valid for underlying block device
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*/
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bool is_valid_read(bd_addr_t addr, bd_size_t size);
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/** Convenience function for checking block write validity
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*
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* @param addr Address of block to begin writing to
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* @param size Size to write in bytes
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* @return True if write is valid for underlying block device
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*/
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bool is_valid_write(bd_addr_t addr, bd_size_t size);
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/** Convenience function for checking block program validity
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*
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* @param addr Address of block to begin writing to
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* @param size Size to write in bytes
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* @return True if program is valid for underlying block device
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*/
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bool is_valid_program(bd_addr_t addr, bd_size_t size);
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/** Convenience function for checking block erase validity
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*
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* @param addr Address of block to begin erasing
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* @param size Size to erase in bytes
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* @return True if erase is valid for underlying block device
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*/
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bool is_valid_erase(bd_addr_t addr, bd_size_t size);
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};
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#endif

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