main.cpp

/* mbed Microcontroller Library
 * Copyright (c) 2018-2021 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.
 */
#include <stdio.h>
#include "blockdevice/BlockDevice.h"
#include "blockdevice/HeapBlockDevice.h"

// Entry point for the example
int main() {
    printf("--- Mbed OS block device example ---\n");

    // Emulate two 32-byte blocks.
    // Blocks are lazily allocated when used so it has very little
    // overhead if unused.
    HeapBlockDevice heap_bd(64, 32);

    BlockDevice *bd = BlockDevice::get_default_instance();
    if(!bd) {
        printf("No hardware BlockDevice found, using heap\n");
        bd = &heap_bd;
    }

    // Initialize the block device
    printf("bd->init()\n");
    int err = bd->init();
    printf("bd->init -> %d\n", err);

    // Get the block device type
    printf("bd->get_type()\n");
    const char *type = bd->get_type();
    printf("bd->get_type -> %s\n", type);

    // Get device geometry
    bd_size_t read_size    = bd->get_read_size();
    bd_size_t program_size = bd->get_program_size();
    bd_size_t erase_size   = bd->get_erase_size();
    bd_size_t size         = bd->size();

    printf("--- Block device geometry ---\n");
    printf("read_size:    %lld B\n", read_size);
    printf("program_size: %lld B\n", program_size);
    printf("erase_size:   %lld B\n", erase_size);
    printf("size:         %lld B\n", size);
    printf("---\n");

    // Allocate a block with enough space for our data, aligned to the
    // nearest program_size. This is the minimum size necessary to write
    // data to a block.
    size_t buffer_size = sizeof("Hello Storage!") + program_size-1;
    buffer_size = buffer_size - (buffer_size % program_size);
    char *buffer = new char[buffer_size];

    // Read what is currently stored on the block device. We haven't written
    // yet so this may be garbage
    printf("bd->read(%p, %d, %d)\n", buffer, 0, buffer_size);
    err = bd->read(buffer, 0, buffer_size);
    printf("bd->read -> %d\n", err);

    printf("--- Stored data ---\n");
    for (size_t i = 0; i < buffer_size; i += 16) {
        for (size_t j = 0; j < 16; j++) {
            if (i+j < buffer_size) {
                printf("%02x ", buffer[i+j]);
            } else {
                printf("   ");
            }
        }

        printf(" %.*s\n", buffer_size - i, &buffer[i]);
    }
    printf("---\n");

    // Update buffer with our string we want to store
    strncpy(buffer, "Hello Storage!", buffer_size);

    // Write data to first block, write occurs in two parts,
    // an erase followed by a program
    printf("bd->erase(%d, %lld)\n", 0, erase_size);
    err = bd->erase(0, erase_size);
    printf("bd->erase -> %d\n", err);

    printf("bd->program(%p, %d, %d)\n", buffer, 0, buffer_size);
    err = bd->program(buffer, 0, buffer_size);
    printf("bd->program -> %d\n", err);

    // Clobber the buffer so we don't get old data
    memset(buffer, 0xcc, buffer_size);

    // Read the data from the first block, note that the program_size must be
    // a multiple of the read_size, so we don't have to check for alignment
    printf("bd->read(%p, %d, %d)\n", buffer, 0, buffer_size);
    err = bd->read(buffer, 0, buffer_size);
    printf("bd->read -> %d\n", err);

    printf("--- Stored data ---\n");
    for (size_t i = 0; i < buffer_size; i += 16) {
        for (size_t j = 0; j < 16; j++) {
            if (i+j < buffer_size) {
                printf("%02x ", buffer[i+j]);
            } else {
                printf("   ");
            }
        }

        printf(" %.*s\n", buffer_size - i, &buffer[i]);
    }
    printf("---\n");

    // Deinitialize the block device
    printf("bd->deinit()\n");
    err = bd->deinit();
    printf("bd->deinit -> %d\n", err);

    printf("--- done! ---\n");
}