root/drivers/mtd/tests/oobtest.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2006-2008 Nokia Corporation
 *
 * Test OOB read and write on MTD device.
 *
 * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <asm/div64.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/err.h>
#include <linux/mtd/mtd.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/prandom.h>

#include "mtd_test.h"

static int dev = -EINVAL;
static int bitflip_limit;
module_param(dev, int, S_IRUGO);
MODULE_PARM_DESC(dev, "MTD device number to use");
module_param(bitflip_limit, int, S_IRUGO);
MODULE_PARM_DESC(bitflip_limit, "Max. allowed bitflips per page");

static struct mtd_info *mtd;
static unsigned char *readbuf;
static unsigned char *writebuf;
static unsigned char *bbt;

static int ebcnt;
static int pgcnt;
static int errcnt;
static int use_offset;
static int use_len;
static int use_len_max;
static int vary_offset;
static struct rnd_state rnd_state;

static void do_vary_offset(void)
{
        use_len -= 1;
        if (use_len < 1) {
                use_offset += 1;
                if (use_offset >= use_len_max)
                        use_offset = 0;
                use_len = use_len_max - use_offset;
        }
}

static int write_eraseblock(int ebnum)
{
        int i;
        struct mtd_oob_ops ops = { };
        int err = 0;
        loff_t addr = (loff_t)ebnum * mtd->erasesize;

        prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
        for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = use_len;
                ops.oobretlen = 0;
                ops.ooboffs   = use_offset;
                ops.datbuf    = NULL;
                ops.oobbuf    = writebuf + (use_len_max * i) + use_offset;
                err = mtd_write_oob(mtd, addr, &ops);
                if (err || ops.oobretlen != use_len) {
                        pr_err("error: writeoob failed at %#llx\n",
                               (long long)addr);
                        pr_err("error: use_len %d, use_offset %d\n",
                               use_len, use_offset);
                        errcnt += 1;
                        return err ? err : -1;
                }
                if (vary_offset)
                        do_vary_offset();
        }

        return err;
}

static int write_whole_device(void)
{
        int err;
        unsigned int i;

        pr_info("writing OOBs of whole device\n");
        for (i = 0; i < ebcnt; ++i) {
                if (bbt[i])
                        continue;
                err = write_eraseblock(i);
                if (err)
                        return err;
                if (i % 256 == 0)
                        pr_info("written up to eraseblock %u\n", i);

                err = mtdtest_relax();
                if (err)
                        return err;
        }
        pr_info("written %u eraseblocks\n", i);
        return 0;
}

/*
 * Display the address, offset and data bytes at comparison failure.
 * Return number of bitflips encountered.
 */
static size_t memcmpshowoffset(loff_t addr, loff_t offset, const void *cs,
                               const void *ct, size_t count)
{
        const unsigned char *su1, *su2;
        int res;
        size_t i = 0;
        size_t bitflips = 0;

        for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--, i++) {
                res = *su1 ^ *su2;
                if (res) {
                        pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0x%x diff 0x%x\n",
                                (unsigned long)addr, (unsigned long)offset + i,
                                *su1, *su2, res);
                        bitflips += hweight8(res);
                }
        }

        return bitflips;
}

#define memcmpshow(addr, cs, ct, count) memcmpshowoffset((addr), 0, (cs), (ct),\
                                                         (count))

/*
 * Compare with 0xff and show the address, offset and data bytes at
 * comparison failure. Return number of bitflips encountered.
 */
static size_t memffshow(loff_t addr, loff_t offset, const void *cs,
                        size_t count)
{
        const unsigned char *su1;
        int res;
        size_t i = 0;
        size_t bitflips = 0;

        for (su1 = cs; 0 < count; ++su1, count--, i++) {
                res = *su1 ^ 0xff;
                if (res) {
                        pr_info("error @addr[0x%lx:0x%lx] 0x%x -> 0xff diff 0x%x\n",
                                (unsigned long)addr, (unsigned long)offset + i,
                                *su1, res);
                        bitflips += hweight8(res);
                }
        }

        return bitflips;
}

static int verify_eraseblock(int ebnum)
{
        int i;
        struct mtd_oob_ops ops = { };
        int err = 0;
        loff_t addr = (loff_t)ebnum * mtd->erasesize;
        size_t bitflips;

        prandom_bytes_state(&rnd_state, writebuf, use_len_max * pgcnt);
        for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = use_len;
                ops.oobretlen = 0;
                ops.ooboffs   = use_offset;
                ops.datbuf    = NULL;
                ops.oobbuf    = readbuf;
                err = mtd_read_oob(mtd, addr, &ops);
                if (mtd_is_bitflip(err))
                        err = 0;

                if (err || ops.oobretlen != use_len) {
                        pr_err("error: readoob failed at %#llx\n",
                               (long long)addr);
                        errcnt += 1;
                        return err ? err : -1;
                }

                bitflips = memcmpshow(addr, readbuf,
                                      writebuf + (use_len_max * i) + use_offset,
                                      use_len);
                if (bitflips > bitflip_limit) {
                        pr_err("error: verify failed at %#llx\n",
                               (long long)addr);
                        errcnt += 1;
                        if (errcnt > 1000) {
                                pr_err("error: too many errors\n");
                                return -1;
                        }
                } else if (bitflips) {
                        pr_info("ignoring error as within bitflip_limit\n");
                }

                if (use_offset != 0 || use_len < mtd->oobavail) {
                        int k;

                        ops.mode      = MTD_OPS_AUTO_OOB;
                        ops.len       = 0;
                        ops.retlen    = 0;
                        ops.ooblen    = mtd->oobavail;
                        ops.oobretlen = 0;
                        ops.ooboffs   = 0;
                        ops.datbuf    = NULL;
                        ops.oobbuf    = readbuf;
                        err = mtd_read_oob(mtd, addr, &ops);
                        if (mtd_is_bitflip(err))
                                err = 0;

                        if (err || ops.oobretlen != mtd->oobavail) {
                                pr_err("error: readoob failed at %#llx\n",
                                                (long long)addr);
                                errcnt += 1;
                                return err ? err : -1;
                        }
                        bitflips = memcmpshowoffset(addr, use_offset,
                                                    readbuf + use_offset,
                                                    writebuf + (use_len_max * i) + use_offset,
                                                    use_len);

                        /* verify pre-offset area for 0xff */
                        bitflips += memffshow(addr, 0, readbuf, use_offset);

                        /* verify post-(use_offset + use_len) area for 0xff */
                        k = use_offset + use_len;
                        bitflips += memffshow(addr, k, readbuf + k,
                                              mtd->oobavail - k);

                        if (bitflips > bitflip_limit) {
                                pr_err("error: verify failed at %#llx\n",
                                                (long long)addr);
                                errcnt += 1;
                                if (errcnt > 1000) {
                                        pr_err("error: too many errors\n");
                                        return -1;
                                }
                        } else if (bitflips) {
                                pr_info("ignoring errors as within bitflip limit\n");
                        }
                }
                if (vary_offset)
                        do_vary_offset();
        }
        return err;
}

static int verify_eraseblock_in_one_go(int ebnum)
{
        struct mtd_oob_ops ops = { };
        int err = 0;
        loff_t addr = (loff_t)ebnum * mtd->erasesize;
        size_t len = mtd->oobavail * pgcnt;
        size_t oobavail = mtd->oobavail;
        size_t bitflips;
        int i;

        prandom_bytes_state(&rnd_state, writebuf, len);
        ops.mode      = MTD_OPS_AUTO_OOB;
        ops.len       = 0;
        ops.retlen    = 0;
        ops.ooblen    = len;
        ops.oobretlen = 0;
        ops.ooboffs   = 0;
        ops.datbuf    = NULL;
        ops.oobbuf    = readbuf;

        /* read entire block's OOB at one go */
        err = mtd_read_oob(mtd, addr, &ops);
        if (mtd_is_bitflip(err))
                err = 0;

        if (err || ops.oobretlen != len) {
                pr_err("error: readoob failed at %#llx\n",
                       (long long)addr);
                errcnt += 1;
                return err ? err : -1;
        }

        /* verify one page OOB at a time for bitflip per page limit check */
        for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
                bitflips = memcmpshow(addr, readbuf + (i * oobavail),
                                      writebuf + (i * oobavail), oobavail);
                if (bitflips > bitflip_limit) {
                        pr_err("error: verify failed at %#llx\n",
                               (long long)addr);
                        errcnt += 1;
                        if (errcnt > 1000) {
                                pr_err("error: too many errors\n");
                                return -1;
                        }
                } else if (bitflips) {
                        pr_info("ignoring error as within bitflip_limit\n");
                }
        }

        return err;
}

static int verify_all_eraseblocks(void)
{
        int err;
        unsigned int i;

        pr_info("verifying all eraseblocks\n");
        for (i = 0; i < ebcnt; ++i) {
                if (bbt[i])
                        continue;
                err = verify_eraseblock(i);
                if (err)
                        return err;
                if (i % 256 == 0)
                        pr_info("verified up to eraseblock %u\n", i);

                err = mtdtest_relax();
                if (err)
                        return err;
        }
        pr_info("verified %u eraseblocks\n", i);
        return 0;
}

static int __init mtd_oobtest_init(void)
{
        int err = 0;
        unsigned int i;
        uint64_t tmp;
        struct mtd_oob_ops ops = { };
        loff_t addr = 0, addr0;

        printk(KERN_INFO "\n");
        printk(KERN_INFO "=================================================\n");

        if (dev < 0) {
                pr_info("Please specify a valid mtd-device via module parameter\n");
                pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
                return -EINVAL;
        }

        pr_info("MTD device: %d\n", dev);

        mtd = get_mtd_device(NULL, dev);
        if (IS_ERR(mtd)) {
                err = PTR_ERR(mtd);
                pr_err("error: cannot get MTD device\n");
                return err;
        }

        if (!mtd_type_is_nand(mtd)) {
                pr_info("this test requires NAND flash\n");
                goto out;
        }

        tmp = mtd->size;
        do_div(tmp, mtd->erasesize);
        ebcnt = tmp;
        pgcnt = mtd->erasesize / mtd->writesize;

        pr_info("MTD device size %llu, eraseblock size %u, "
               "page size %u, count of eraseblocks %u, pages per "
               "eraseblock %u, OOB size %u\n",
               (unsigned long long)mtd->size, mtd->erasesize,
               mtd->writesize, ebcnt, pgcnt, mtd->oobsize);

        err = -ENOMEM;
        readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
        if (!readbuf)
                goto out;
        writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
        if (!writebuf)
                goto out;
        bbt = kzalloc(ebcnt, GFP_KERNEL);
        if (!bbt)
                goto out;

        err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
        if (err)
                goto out;

        use_offset = 0;
        use_len = mtd->oobavail;
        use_len_max = mtd->oobavail;
        vary_offset = 0;

        /* First test: write all OOB, read it back and verify */
        pr_info("test 1 of 5\n");

        err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
        if (err)
                goto out;

        prandom_seed_state(&rnd_state, 1);
        err = write_whole_device();
        if (err)
                goto out;

        prandom_seed_state(&rnd_state, 1);
        err = verify_all_eraseblocks();
        if (err)
                goto out;

        /*
         * Second test: write all OOB, a block at a time, read it back and
         * verify.
         */
        pr_info("test 2 of 5\n");

        err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
        if (err)
                goto out;

        prandom_seed_state(&rnd_state, 3);
        err = write_whole_device();
        if (err)
                goto out;

        /* Check all eraseblocks */
        prandom_seed_state(&rnd_state, 3);
        pr_info("verifying all eraseblocks\n");
        for (i = 0; i < ebcnt; ++i) {
                if (bbt[i])
                        continue;
                err = verify_eraseblock_in_one_go(i);
                if (err)
                        goto out;
                if (i % 256 == 0)
                        pr_info("verified up to eraseblock %u\n", i);

                err = mtdtest_relax();
                if (err)
                        goto out;
        }
        pr_info("verified %u eraseblocks\n", i);

        /*
         * Third test: write OOB at varying offsets and lengths, read it back
         * and verify.
         */
        pr_info("test 3 of 5\n");

        err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
        if (err)
                goto out;

        /* Write all eraseblocks */
        use_offset = 0;
        use_len = mtd->oobavail;
        use_len_max = mtd->oobavail;
        vary_offset = 1;
        prandom_seed_state(&rnd_state, 5);

        err = write_whole_device();
        if (err)
                goto out;

        /* Check all eraseblocks */
        use_offset = 0;
        use_len = mtd->oobavail;
        use_len_max = mtd->oobavail;
        vary_offset = 1;
        prandom_seed_state(&rnd_state, 5);
        err = verify_all_eraseblocks();
        if (err)
                goto out;

        use_offset = 0;
        use_len = mtd->oobavail;
        use_len_max = mtd->oobavail;
        vary_offset = 0;

        /* Fourth test: try to write off end of device */
        pr_info("test 4 of 5\n");

        err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
        if (err)
                goto out;

        addr0 = 0;
        for (i = 0; i < ebcnt && bbt[i]; ++i)
                addr0 += mtd->erasesize;

        /* Attempt to write off end of OOB */
        ops.mode      = MTD_OPS_AUTO_OOB;
        ops.len       = 0;
        ops.retlen    = 0;
        ops.ooblen    = 1;
        ops.oobretlen = 0;
        ops.ooboffs   = mtd->oobavail;
        ops.datbuf    = NULL;
        ops.oobbuf    = writebuf;
        pr_info("attempting to start write past end of OOB\n");
        pr_info("an error is expected...\n");
        err = mtd_write_oob(mtd, addr0, &ops);
        if (err) {
                pr_info("error occurred as expected\n");
        } else {
                pr_err("error: can write past end of OOB\n");
                errcnt += 1;
        }

        /* Attempt to read off end of OOB */
        ops.mode      = MTD_OPS_AUTO_OOB;
        ops.len       = 0;
        ops.retlen    = 0;
        ops.ooblen    = 1;
        ops.oobretlen = 0;
        ops.ooboffs   = mtd->oobavail;
        ops.datbuf    = NULL;
        ops.oobbuf    = readbuf;
        pr_info("attempting to start read past end of OOB\n");
        pr_info("an error is expected...\n");
        err = mtd_read_oob(mtd, addr0, &ops);
        if (mtd_is_bitflip(err))
                err = 0;

        if (err) {
                pr_info("error occurred as expected\n");
        } else {
                pr_err("error: can read past end of OOB\n");
                errcnt += 1;
        }

        if (bbt[ebcnt - 1])
                pr_info("skipping end of device tests because last "
                       "block is bad\n");
        else {
                /* Attempt to write off end of device */
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = mtd->oobavail + 1;
                ops.oobretlen = 0;
                ops.ooboffs   = 0;
                ops.datbuf    = NULL;
                ops.oobbuf    = writebuf;
                pr_info("attempting to write past end of device\n");
                pr_info("an error is expected...\n");
                err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
                if (err) {
                        pr_info("error occurred as expected\n");
                } else {
                        pr_err("error: wrote past end of device\n");
                        errcnt += 1;
                }

                /* Attempt to read off end of device */
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = mtd->oobavail + 1;
                ops.oobretlen = 0;
                ops.ooboffs   = 0;
                ops.datbuf    = NULL;
                ops.oobbuf    = readbuf;
                pr_info("attempting to read past end of device\n");
                pr_info("an error is expected...\n");
                err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
                if (mtd_is_bitflip(err))
                        err = 0;

                if (err) {
                        pr_info("error occurred as expected\n");
                } else {
                        pr_err("error: read past end of device\n");
                        errcnt += 1;
                }

                err = mtdtest_erase_eraseblock(mtd, ebcnt - 1);
                if (err)
                        goto out;

                /* Attempt to write off end of device */
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = mtd->oobavail;
                ops.oobretlen = 0;
                ops.ooboffs   = 1;
                ops.datbuf    = NULL;
                ops.oobbuf    = writebuf;
                pr_info("attempting to write past end of device\n");
                pr_info("an error is expected...\n");
                err = mtd_write_oob(mtd, mtd->size - mtd->writesize, &ops);
                if (err) {
                        pr_info("error occurred as expected\n");
                } else {
                        pr_err("error: wrote past end of device\n");
                        errcnt += 1;
                }

                /* Attempt to read off end of device */
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = mtd->oobavail;
                ops.oobretlen = 0;
                ops.ooboffs   = 1;
                ops.datbuf    = NULL;
                ops.oobbuf    = readbuf;
                pr_info("attempting to read past end of device\n");
                pr_info("an error is expected...\n");
                err = mtd_read_oob(mtd, mtd->size - mtd->writesize, &ops);
                if (mtd_is_bitflip(err))
                        err = 0;

                if (err) {
                        pr_info("error occurred as expected\n");
                } else {
                        pr_err("error: read past end of device\n");
                        errcnt += 1;
                }
        }

        /* Fifth test: write / read across block boundaries */
        pr_info("test 5 of 5\n");

        /* Erase all eraseblocks */
        err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
        if (err)
                goto out;

        /* Write all eraseblocks */
        prandom_seed_state(&rnd_state, 11);
        pr_info("writing OOBs of whole device\n");
        for (i = 0; i < ebcnt - 1; ++i) {
                int cnt = 2;
                int pg;
                size_t sz = mtd->oobavail;
                if (bbt[i] || bbt[i + 1])
                        continue;
                addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
                prandom_bytes_state(&rnd_state, writebuf, sz * cnt);
                for (pg = 0; pg < cnt; ++pg) {
                        ops.mode      = MTD_OPS_AUTO_OOB;
                        ops.len       = 0;
                        ops.retlen    = 0;
                        ops.ooblen    = sz;
                        ops.oobretlen = 0;
                        ops.ooboffs   = 0;
                        ops.datbuf    = NULL;
                        ops.oobbuf    = writebuf + pg * sz;
                        err = mtd_write_oob(mtd, addr, &ops);
                        if (err)
                                goto out;
                        if (i % 256 == 0)
                                pr_info("written up to eraseblock %u\n", i);

                        err = mtdtest_relax();
                        if (err)
                                goto out;

                        addr += mtd->writesize;
                }
        }
        pr_info("written %u eraseblocks\n", i);

        /* Check all eraseblocks */
        prandom_seed_state(&rnd_state, 11);
        pr_info("verifying all eraseblocks\n");
        for (i = 0; i < ebcnt - 1; ++i) {
                if (bbt[i] || bbt[i + 1])
                        continue;
                prandom_bytes_state(&rnd_state, writebuf, mtd->oobavail * 2);
                addr = (loff_t)(i + 1) * mtd->erasesize - mtd->writesize;
                ops.mode      = MTD_OPS_AUTO_OOB;
                ops.len       = 0;
                ops.retlen    = 0;
                ops.ooblen    = mtd->oobavail * 2;
                ops.oobretlen = 0;
                ops.ooboffs   = 0;
                ops.datbuf    = NULL;
                ops.oobbuf    = readbuf;
                err = mtd_read_oob(mtd, addr, &ops);
                if (mtd_is_bitflip(err))
                        err = 0;

                if (err)
                        goto out;
                if (memcmpshow(addr, readbuf, writebuf,
                               mtd->oobavail * 2)) {
                        pr_err("error: verify failed at %#llx\n",
                               (long long)addr);
                        errcnt += 1;
                        if (errcnt > 1000) {
                                err = -EINVAL;
                                pr_err("error: too many errors\n");
                                goto out;
                        }
                }
                if (i % 256 == 0)
                        pr_info("verified up to eraseblock %u\n", i);

                err = mtdtest_relax();
                if (err)
                        goto out;
        }
        pr_info("verified %u eraseblocks\n", i);

        pr_info("finished with %d errors\n", errcnt);
out:
        kfree(bbt);
        kfree(writebuf);
        kfree(readbuf);
        put_mtd_device(mtd);
        if (err)
                pr_info("error %d occurred\n", err);
        printk(KERN_INFO "=================================================\n");
        return err;
}
module_init(mtd_oobtest_init);

static void __exit mtd_oobtest_exit(void)
{
        return;
}
module_exit(mtd_oobtest_exit);

MODULE_DESCRIPTION("Out-of-band test module");
MODULE_AUTHOR("Adrian Hunter");
MODULE_LICENSE("GPL");