#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>

#include <mtd/mtd-user.h>
#include <sys/ioctl.h>

static int test_empty(const char *buf, size_t size)
{
    while(size--) {
        if (*buf++ != (char) 0xff)
            return 0;
    }
    return 1;
}

int nandread_main(int argc, char **argv)
{
    char *devname = NULL;
    char *filename = NULL;
    char *statusfilename = NULL;
    char *statusext = ".stat";
    int fd;
    int outfd = -1;
    FILE *statusfile = NULL;
    int ret;
    int verbose = 0;
    void *buffer;
    loff_t pos, opos, end, bpos;
    loff_t start = 0, len = 0;
    int c;
    int i;
    int empty_pages = 0;
    int page_count = 0;
    int bad_block;
    int rawmode = 0;
    uint32_t *oob_data;
    uint8_t *oob_fixed;
    size_t spare_size = 64;
    struct mtd_info_user mtdinfo;
    struct mtd_ecc_stats initial_ecc, last_ecc, ecc;
    struct mtd_oob_buf oobbuf;
    nand_ecclayout_t ecclayout;

    do {
        c = getopt(argc, argv, "d:f:s:S:L:Rhv");
        if (c == EOF)
            break;
        switch (c) {
        case 'd':
            devname = optarg;
            break;
        case 'f':
            filename = optarg;
            break;
        case 's':
            spare_size = atoi(optarg);
            break;
        case 'S':
            start = strtoll(optarg, NULL, 0);
            break;
        case 'L':
            len = strtoll(optarg, NULL, 0);
            break;
        case 'R':
            rawmode = 1;
            break;
        case 'v':
            verbose++;
            break;
        case 'h':
            fprintf(stderr, "%s [-d <dev>] [-f file] [-s sparesize] [-vh]\n"
                    "  -d <dev>   Read from <dev>\n"
                    "  -f <file>  Write to <file>\n"
                    "  -s <size>  Number of spare bytes in file (default 64)\n"
                    "  -R         Raw mode\n"
                    "  -S <start> Start offset (default 0)\n"
                    "  -L <len>   Length (default 0)\n"
                    "  -v         Print info\n"
                    "  -h         Print help\n", argv[0]);
            return -1;
        case '?':
            fprintf(stderr, "%s: invalid option -%c\n",
                argv[0], optopt);
            exit(1);
        }
    } while (1);

    if (optind < argc) {
        fprintf(stderr, "%s: extra arguments\n", argv[0]);
        return 1;
    }
    if (!devname) {
        fprintf(stderr, "%s: specify device name\n", argv[0]);
        return 1;
    }

    fd = open(devname, O_RDONLY);
    if (fd < 0) {
        fprintf(stderr, "cannot open %s, %s\n", devname, strerror(errno));
        return 1;
    }

    if (filename) {
        outfd = creat(filename, 0666);
        if (outfd < 0) {
            fprintf(stderr, "cannot open %s, %s\n", filename, strerror(errno));
            return 1;
        }
        statusfilename = malloc(strlen(filename) + strlen(statusext) + 1);
        strcpy(statusfilename, filename);
        strcat(statusfilename, statusext);
        statusfile = fopen(statusfilename, "w+");
        if (!statusfile) {
            fprintf(stderr, "cannot open %s, %s\n", statusfilename, strerror(errno));
            return 1;
        }
    }

    ret = ioctl(fd, MEMGETINFO, &mtdinfo);
    if (ret) {
        fprintf(stderr, "failed get mtd info for %s, %s\n",
                devname, strerror(errno));
        return 1;
    }

    if (verbose) {
        printf("size: %u\n", mtdinfo.size);
        printf("erase size: %u\n", mtdinfo.erasesize);
        printf("write size: %u\n", mtdinfo.writesize);
        printf("oob size: %u\n", mtdinfo.oobsize);
    }

    buffer = malloc(mtdinfo.writesize + mtdinfo.oobsize + spare_size);
    if (!buffer) {
        fprintf(stderr, "failed allocate readbuffer size %u\n",
                mtdinfo.writesize + mtdinfo.oobsize);
        return 1;
    }

    oobbuf.length = mtdinfo.oobsize;
    oob_data = (uint32_t *)((uint8_t *)buffer + mtdinfo.writesize);
    memset(oob_data, 0xff, mtdinfo.oobsize + spare_size);
    oobbuf.ptr = (uint8_t *)oob_data + spare_size;

    ret = ioctl(fd, ECCGETLAYOUT, &ecclayout);
    if (ret) {
        fprintf(stderr, "failed get ecc layout for %s, %s\n",
                devname, strerror(errno));
        return 1;
    }
    if (verbose) {
        printf("ecc bytes: %u\n", ecclayout.eccbytes);
        printf("oobavail: %u\n", ecclayout.oobavail);
    }
    if (ecclayout.oobavail > spare_size)
        printf("oobavail, %d > image spare size, %d\n", ecclayout.oobavail, spare_size);

    ret = ioctl(fd, ECCGETSTATS, &initial_ecc);
    if (ret) {
        fprintf(stderr, "failed get ecc stats for %s, %s\n",
                devname, strerror(errno));
        return 1;
    }
    last_ecc = initial_ecc;

    if (verbose) {
        printf("initial ecc corrected: %u\n", initial_ecc.corrected);
        printf("initial ecc failed: %u\n", initial_ecc.failed);
        printf("initial ecc badblocks: %u\n", initial_ecc.badblocks);
        printf("initial ecc bbtblocks: %u\n", initial_ecc.bbtblocks);
    }

    if (rawmode) {
        rawmode = mtdinfo.oobsize;
#if !defined(MTD_STUPID_LOCK) /* using uapi kernel headers */
        ret = ioctl(fd, MTDFILEMODE, MTD_FILE_MODE_RAW);
#else /* still using old kernel headers */
        ret = ioctl(fd, MTDFILEMODE, MTD_MODE_RAW);
#endif
        if (ret) {
            fprintf(stderr, "failed set raw mode for %s, %s\n",
                    devname, strerror(errno));
            return 1;
        }
    }

    end = len ? (start + len) : mtdinfo.size;
    for (pos = start, opos = 0; pos < end; pos += mtdinfo.writesize) {
        bad_block = 0;
        if (verbose > 3)
            printf("reading at %llx\n", pos);
        lseek64(fd, pos, SEEK_SET);
        ret = read(fd, buffer, mtdinfo.writesize + rawmode);
        if (ret < (int)mtdinfo.writesize) {
            fprintf(stderr, "short read at %llx, %d\n", pos, ret);
            bad_block = 2;
        }
        if (!rawmode) {
            oobbuf.start = pos;
            ret = ioctl(fd, MEMREADOOB, &oobbuf);
            if (ret) {
                fprintf(stderr, "failed to read oob data at %llx, %d\n", pos, ret);
                bad_block = 2;
            }
        }
        ret = ioctl(fd, ECCGETSTATS, &ecc);
        if (ret) {
            fprintf(stderr, "failed get ecc stats for %s, %s\n",
                    devname, strerror(errno));
            return 1;
        }
        bpos = pos / mtdinfo.erasesize * mtdinfo.erasesize;
        ret = ioctl(fd, MEMGETBADBLOCK, &bpos);
        if (ret && errno != EOPNOTSUPP) {
            printf("badblock at %llx\n", pos);
            bad_block = 1;
        }
        if (ecc.corrected != last_ecc.corrected)
            printf("ecc corrected, %u, at %llx\n", ecc.corrected - last_ecc.corrected, pos);
        if (ecc.failed != last_ecc.failed)
            printf("ecc failed, %u, at %llx\n", ecc.failed - last_ecc.failed, pos);
        if (ecc.badblocks != last_ecc.badblocks)
            printf("ecc badblocks, %u, at %llx\n", ecc.badblocks - last_ecc.badblocks, pos);
        if (ecc.bbtblocks != last_ecc.bbtblocks)
            printf("ecc bbtblocks, %u, at %llx\n", ecc.bbtblocks - last_ecc.bbtblocks, pos);

        if (!rawmode) {
            oob_fixed = (uint8_t *)oob_data;
            for (i = 0; i < MTD_MAX_OOBFREE_ENTRIES; i++) {
                int len = ecclayout.oobfree[i].length;
                if (oob_fixed + len > oobbuf.ptr)
                    len = oobbuf.ptr - oob_fixed;
                if (len) {
                    memcpy(oob_fixed, oobbuf.ptr + ecclayout.oobfree[i].offset, len);
                    oob_fixed += len;
                }
            }
        }

        if (outfd >= 0) {
            ret = write(outfd, buffer, mtdinfo.writesize + spare_size);
            if (ret < (int)(mtdinfo.writesize + spare_size)) {
                fprintf(stderr, "short write at %llx, %d\n", pos, ret);
                close(outfd);
                outfd = -1;
            }
            if (ecc.corrected != last_ecc.corrected)
                fprintf(statusfile, "%08llx: ecc corrected\n", opos);
            if (ecc.failed != last_ecc.failed)
                fprintf(statusfile, "%08llx: ecc failed\n", opos);
            if (bad_block == 1)
                fprintf(statusfile, "%08llx: badblock\n", opos);
            if (bad_block == 2)
                fprintf(statusfile, "%08llx: read error\n", opos);
            opos += mtdinfo.writesize + spare_size;
        }

        last_ecc = ecc;
        page_count++;
        if (test_empty(buffer, mtdinfo.writesize + mtdinfo.oobsize + spare_size))
            empty_pages++;
        else if (verbose > 2 || (verbose > 1 && !(pos & (mtdinfo.erasesize - 1))))
            printf("page at %llx (%d oobbytes): %08x %08x %08x %08x "
                   "%08x %08x %08x %08x\n", pos, oobbuf.start,
                   oob_data[0], oob_data[1], oob_data[2], oob_data[3],
                   oob_data[4], oob_data[5], oob_data[6], oob_data[7]);
    }

    if (outfd >= 0) {
        fprintf(statusfile, "read %d pages, %d empty\n", page_count, empty_pages);
        fprintf(statusfile, "total ecc corrected, %u\n", ecc.corrected - initial_ecc.corrected);
        fprintf(statusfile, "total ecc failed, %u\n", ecc.failed - initial_ecc.failed);
        fprintf(statusfile, "total ecc badblocks, %u\n", ecc.badblocks - initial_ecc.badblocks);
        fprintf(statusfile, "total ecc bbtblocks, %u\n", ecc.bbtblocks - initial_ecc.bbtblocks);
    }
    if (verbose) {
        printf("total ecc corrected, %u\n", ecc.corrected - initial_ecc.corrected);
        printf("total ecc failed, %u\n", ecc.failed - initial_ecc.failed);
        printf("total ecc badblocks, %u\n", ecc.badblocks - initial_ecc.badblocks);
        printf("total ecc bbtblocks, %u\n", ecc.bbtblocks - initial_ecc.bbtblocks);
    }
    printf("read %d pages, %d empty\n", page_count, empty_pages);

    return 0;
}