src/udev/mtd_probe/probe_smartmedia.c

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Copyright (C) 2010 - Maxim Levitsky
 *
 * mtd_probe is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mtd_probe is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with mtd_probe; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

#include <fcntl.h>
#include <mtd/mtd-user.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "mtd_probe.h"

static const uint8_t cis_signature[] = {
        0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
};


void probe_smart_media(int mtd_fd, mtd_info_t* info)
{
        int sector_size;
        int block_size;
        int size_in_megs;
        int spare_count;
        char* cis_buffer = malloc(SM_SECTOR_SIZE);
        int offset;
        int cis_found = 0;

        if (!cis_buffer)
                return;

        if (info->type != MTD_NANDFLASH)
                goto exit;

        sector_size = info->writesize;
        block_size = info->erasesize;
        size_in_megs = info->size / (1024 * 1024);

        if (!IN_SET(sector_size, SM_SECTOR_SIZE, SM_SMALL_PAGE))
                goto exit;

        switch(size_in_megs) {
        case 1:
        case 2:
                spare_count = 6;
                break;
        case 4:
                spare_count = 12;
                break;
        default:
                spare_count = 24;
                break;
        }

        for (offset = 0 ; offset < block_size * spare_count ;
                                                offset += sector_size) {
                lseek(mtd_fd, SEEK_SET, offset);
                if (read(mtd_fd, cis_buffer, SM_SECTOR_SIZE) == SM_SECTOR_SIZE) {
                        cis_found = 1;
                        break;
                }
        }

        if (!cis_found)
                goto exit;

        if (memcmp(cis_buffer, cis_signature, sizeof(cis_signature)) != 0 &&
                (memcmp(cis_buffer + SM_SMALL_PAGE, cis_signature,
                        sizeof(cis_signature)) != 0))
                goto exit;

        printf("MTD_FTL=smartmedia\n");
        free(cis_buffer);
        exit(0);
exit:
        free(cis_buffer);
        return;
}