MTD: tests: add mtd_oobtest

This test checks that OOB of a NAND MTD device works fine.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 742 insertions, 0 deletions

diff --git a/drivers/mtd/tests/mtd_oobtest.c b/drivers/mtd/tests/mtd_oobtest.c
new file mode 100644
index 000000000000..afbc3f8126db
--- /dev/null
+++ b/drivers/mtd/tests/mtd_oobtest.c
@@ -0,0 +1,742 @@
+/*
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program 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
+ * this program; see the file COPYING. If not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Test OOB read and write on MTD device.
+ *
+ * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
+ */
+
+#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/sched.h>
+
+#define PRINT_PREF KERN_INFO "mtd_oobtest: "
+
+static int dev;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+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 unsigned long next = 1;
+
+static inline unsigned int simple_rand(void)
+{
+        next = next * 1103515245 + 12345;
+        return (unsigned int)((next / 65536) % 32768);
+}
+
+static inline void simple_srand(unsigned long seed)
+{
+        next = seed;
+}
+
+static void set_random_data(unsigned char *buf, size_t len)
+{
+        size_t i;
+
+        for (i = 0; i < len; ++i)
+                buf[i] = simple_rand();
+}
+
+static int erase_eraseblock(int ebnum)
+{
+        int err;
+        struct erase_info ei;
+        loff_t addr = ebnum * mtd->erasesize;
+
+        memset(&ei, 0, sizeof(struct erase_info));
+        ei.mtd  = mtd;
+        ei.addr = addr;
+        ei.len  = mtd->erasesize;
+
+        err = mtd->erase(mtd, &ei);
+        if (err) {
+                printk(PRINT_PREF "error %d while erasing EB %d\n", err, ebnum);
+                return err;
+        }
+
+        if (ei.state == MTD_ERASE_FAILED) {
+                printk(PRINT_PREF "some erase error occurred at EB %d\n",
+                       ebnum);
+                return -EIO;
+        }
+
+        return 0;
+}
+
+static int erase_whole_device(void)
+{
+        int err;
+        unsigned int i;
+
+        printk(PRINT_PREF "erasing whole device\n");
+        for (i = 0; i < ebcnt; ++i) {
+                if (bbt[i])
+                        continue;
+                err = erase_eraseblock(i);
+                if (err)
+                        return err;
+                cond_resched();
+        }
+        printk(PRINT_PREF "erased %u eraseblocks\n", i);
+        return 0;
+}
+
+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 = ebnum * mtd->erasesize;
+
+        for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
+                set_random_data(writebuf, use_len);
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = use_len;
+                ops.oobretlen = 0;
+                ops.ooboffs   = use_offset;
+                ops.datbuf    = 0;
+                ops.oobbuf    = writebuf;
+                err = mtd->write_oob(mtd, addr, &ops);
+                if (err || ops.oobretlen != use_len) {
+                        printk(PRINT_PREF "error: writeoob failed at %#llx\n",
+                               (long long)addr);
+                        printk(PRINT_PREF "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;
+
+        printk(PRINT_PREF "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)
+                        printk(PRINT_PREF "written up to eraseblock %u\n", i);
+                cond_resched();
+        }
+        printk(PRINT_PREF "written %u eraseblocks\n", i);
+        return 0;
+}
+
+static int verify_eraseblock(int ebnum)
+{
+        int i;
+        struct mtd_oob_ops ops;
+        int err = 0;
+        loff_t addr = ebnum * mtd->erasesize;
+
+        for (i = 0; i < pgcnt; ++i, addr += mtd->writesize) {
+                set_random_data(writebuf, use_len);
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = use_len;
+                ops.oobretlen = 0;
+                ops.ooboffs   = use_offset;
+                ops.datbuf    = 0;
+                ops.oobbuf    = readbuf;
+                err = mtd->read_oob(mtd, addr, &ops);
+                if (err || ops.oobretlen != use_len) {
+                        printk(PRINT_PREF "error: readoob failed at %#llx\n",
+                               (long long)addr);
+                        errcnt += 1;
+                        return err ? err : -1;
+                }
+                if (memcmp(readbuf, writebuf, use_len)) {
+                        printk(PRINT_PREF "error: verify failed at %#llx\n",
+                               (long long)addr);
+                        errcnt += 1;
+                        if (errcnt > 1000) {
+                                printk(PRINT_PREF "error: too many errors\n");
+                                return -1;
+                        }
+                }
+                if (use_offset != 0 || use_len < mtd->ecclayout->oobavail) {
+                        int k;
+
+                        ops.mode      = MTD_OOB_AUTO;
+                        ops.len       = 0;
+                        ops.retlen    = 0;
+                        ops.ooblen    = mtd->ecclayout->oobavail;
+                        ops.oobretlen = 0;
+                        ops.ooboffs   = 0;
+                        ops.datbuf    = 0;
+                        ops.oobbuf    = readbuf;
+                        err = mtd->read_oob(mtd, addr, &ops);
+                        if (err || ops.oobretlen != mtd->ecclayout->oobavail) {
+                                printk(PRINT_PREF "error: readoob failed at "
+                                       "%#llx\n", (long long)addr);
+                                errcnt += 1;
+                                return err ? err : -1;
+                        }
+                        if (memcmp(readbuf + use_offset, writebuf, use_len)) {
+                                printk(PRINT_PREF "error: verify failed at "
+                                       "%#llx\n", (long long)addr);
+                                errcnt += 1;
+                                if (errcnt > 1000) {
+                                        printk(PRINT_PREF "error: too many "
+                                               "errors\n");
+                                        return -1;
+                                }
+                        }
+                        for (k = 0; k < use_offset; ++k)
+                                if (readbuf[k] != 0xff) {
+                                        printk(PRINT_PREF "error: verify 0xff "
+                                               "failed at %#llx\n",
+                                               (long long)addr);
+                                        errcnt += 1;
+                                        if (errcnt > 1000) {
+                                                printk(PRINT_PREF "error: too "
+                                                       "many errors\n");
+                                                return -1;
+                                        }
+                                }
+                        for (k = use_offset + use_len;
+                             k < mtd->ecclayout->oobavail; ++k)
+                                if (readbuf[k] != 0xff) {
+                                        printk(PRINT_PREF "error: verify 0xff "
+                                               "failed at %#llx\n",
+                                               (long long)addr);
+                                        errcnt += 1;
+                                        if (errcnt > 1000) {
+                                                printk(PRINT_PREF "error: too "
+                                                       "many errors\n");
+                                                return -1;
+                                        }
+                                }
+                }
+                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 = ebnum * mtd->erasesize;
+        size_t len = mtd->ecclayout->oobavail * pgcnt;
+
+        set_random_data(writebuf, len);
+        ops.mode      = MTD_OOB_AUTO;
+        ops.len       = 0;
+        ops.retlen    = 0;
+        ops.ooblen    = len;
+        ops.oobretlen = 0;
+        ops.ooboffs   = 0;
+        ops.datbuf    = 0;
+        ops.oobbuf    = readbuf;
+        err = mtd->read_oob(mtd, addr, &ops);
+        if (err || ops.oobretlen != len) {
+                printk(PRINT_PREF "error: readoob failed at %#llx\n",
+                       (long long)addr);
+                errcnt += 1;
+                return err ? err : -1;
+        }
+        if (memcmp(readbuf, writebuf, len)) {
+                printk(PRINT_PREF "error: verify failed at %#llx\n",
+                       (long long)addr);
+                errcnt += 1;
+                if (errcnt > 1000) {
+                        printk(PRINT_PREF "error: too many errors\n");
+                        return -1;
+                }
+        }
+
+        return err;
+}
+
+static int verify_all_eraseblocks(void)
+{
+        int err;
+        unsigned int i;
+
+        printk(PRINT_PREF "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)
+                        printk(PRINT_PREF "verified up to eraseblock %u\n", i);
+                cond_resched();
+        }
+        printk(PRINT_PREF "verified %u eraseblocks\n", i);
+        return 0;
+}
+
+static int is_block_bad(int ebnum)
+{
+        int ret;
+        loff_t addr = ebnum * mtd->erasesize;
+
+        ret = mtd->block_isbad(mtd, addr);
+        if (ret)
+                printk(PRINT_PREF "block %d is bad\n", ebnum);
+        return ret;
+}
+
+static int scan_for_bad_eraseblocks(void)
+{
+        int i, bad = 0;
+
+        bbt = kmalloc(ebcnt, GFP_KERNEL);
+        if (!bbt) {
+                printk(PRINT_PREF "error: cannot allocate memory\n");
+                return -ENOMEM;
+        }
+        memset(bbt, 0 , ebcnt);
+
+        printk(PRINT_PREF "scanning for bad eraseblocks\n");
+        for (i = 0; i < ebcnt; ++i) {
+                bbt[i] = is_block_bad(i) ? 1 : 0;
+                if (bbt[i])
+                        bad += 1;
+                cond_resched();
+        }
+        printk(PRINT_PREF "scanned %d eraseblocks, %d are bad\n", i, bad);
+        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");
+        printk(PRINT_PREF "MTD device: %d\n", dev);
+
+        mtd = get_mtd_device(NULL, dev);
+        if (IS_ERR(mtd)) {
+                err = PTR_ERR(mtd);
+                printk(PRINT_PREF "error: cannot get MTD device\n");
+                return err;
+        }
+
+        if (mtd->type != MTD_NANDFLASH) {
+                printk(PRINT_PREF "this test requires NAND flash\n");
+                goto out;
+        }
+
+        tmp = mtd->size;
+        do_div(tmp, mtd->erasesize);
+        ebcnt = tmp;
+        pgcnt = mtd->erasesize / mtd->writesize;
+
+        printk(PRINT_PREF "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;
+        mtd->erasesize = mtd->erasesize;
+        readbuf = kmalloc(mtd->erasesize, GFP_KERNEL);
+        if (!readbuf) {
+                printk(PRINT_PREF "error: cannot allocate memory\n");
+                goto out;
+        }
+        writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
+        if (!writebuf) {
+                printk(PRINT_PREF "error: cannot allocate memory\n");
+                goto out;
+        }
+
+        err = scan_for_bad_eraseblocks();
+        if (err)
+                goto out;
+
+        use_offset = 0;
+        use_len = mtd->ecclayout->oobavail;
+        use_len_max = mtd->ecclayout->oobavail;
+        vary_offset = 0;
+
+        /* First test: write all OOB, read it back and verify */
+        printk(PRINT_PREF "test 1 of 5\n");
+
+        err = erase_whole_device();
+        if (err)
+                goto out;
+
+        simple_srand(1);
+        err = write_whole_device();
+        if (err)
+                goto out;
+
+        simple_srand(1);
+        err = verify_all_eraseblocks();
+        if (err)
+                goto out;
+
+        /*
+         * Second test: write all OOB, a block at a time, read it back and
+         * verify.
+         */
+        printk(PRINT_PREF "test 2 of 5\n");
+
+        err = erase_whole_device();
+        if (err)
+                goto out;
+
+        simple_srand(3);
+        err = write_whole_device();
+        if (err)
+                goto out;
+
+        /* Check all eraseblocks */
+        simple_srand(3);
+        printk(PRINT_PREF "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)
+                        printk(PRINT_PREF "verified up to eraseblock %u\n", i);
+                cond_resched();
+        }
+        printk(PRINT_PREF "verified %u eraseblocks\n", i);
+
+        /*
+         * Third test: write OOB at varying offsets and lengths, read it back
+         * and verify.
+         */
+        printk(PRINT_PREF "test 3 of 5\n");
+
+        err = erase_whole_device();
+        if (err)
+                goto out;
+
+        /* Write all eraseblocks */
+        use_offset = 0;
+        use_len = mtd->ecclayout->oobavail;
+        use_len_max = mtd->ecclayout->oobavail;
+        vary_offset = 1;
+        simple_srand(5);
+        printk(PRINT_PREF "writing OOBs of whole device\n");
+        for (i = 0; i < ebcnt; ++i) {
+                if (bbt[i])
+                        continue;
+                err = write_eraseblock(i);
+                if (err)
+                        goto out;
+                if (i % 256 == 0)
+                        printk(PRINT_PREF "written up to eraseblock %u\n", i);
+                cond_resched();
+        }
+        printk(PRINT_PREF "written %u eraseblocks\n", i);
+
+        /* Check all eraseblocks */
+        use_offset = 0;
+        use_len = mtd->ecclayout->oobavail;
+        use_len_max = mtd->ecclayout->oobavail;
+        vary_offset = 1;
+        simple_srand(5);
+        err = verify_all_eraseblocks();
+        if (err)
+                goto out;
+
+        use_offset = 0;
+        use_len = mtd->ecclayout->oobavail;
+        use_len_max = mtd->ecclayout->oobavail;
+        vary_offset = 0;
+
+        /* Fourth test: try to write off end of device */
+        printk(PRINT_PREF "test 4 of 5\n");
+
+        err = erase_whole_device();
+        if (err)
+                goto out;
+
+        addr0 = 0;
+        for (i = 0; bbt[i] && i < ebcnt; ++i)
+                addr0 += mtd->erasesize;
+
+        /* Attempt to write off end of OOB */
+        ops.mode      = MTD_OOB_AUTO;
+        ops.len       = 0;
+        ops.retlen    = 0;
+        ops.ooblen    = 1;
+        ops.oobretlen = 0;
+        ops.ooboffs   = mtd->ecclayout->oobavail;
+        ops.datbuf    = 0;
+        ops.oobbuf    = writebuf;
+        printk(PRINT_PREF "attempting to start write past end of OOB\n");
+        printk(PRINT_PREF "an error is expected...\n");
+        err = mtd->write_oob(mtd, addr0, &ops);
+        if (err) {
+                printk(PRINT_PREF "error occurred as expected\n");
+                err = 0;
+        } else {
+                printk(PRINT_PREF "error: can write past end of OOB\n");
+                errcnt += 1;
+        }
+
+        /* Attempt to read off end of OOB */
+        ops.mode      = MTD_OOB_AUTO;
+        ops.len       = 0;
+        ops.retlen    = 0;
+        ops.ooblen    = 1;
+        ops.oobretlen = 0;
+        ops.ooboffs   = mtd->ecclayout->oobavail;
+        ops.datbuf    = 0;
+        ops.oobbuf    = readbuf;
+        printk(PRINT_PREF "attempting to start read past end of OOB\n");
+        printk(PRINT_PREF "an error is expected...\n");
+        err = mtd->read_oob(mtd, addr0, &ops);
+        if (err) {
+                printk(PRINT_PREF "error occurred as expected\n");
+                err = 0;
+        } else {
+                printk(PRINT_PREF "error: can read past end of OOB\n");
+                errcnt += 1;
+        }
+
+        if (bbt[ebcnt - 1])
+                printk(PRINT_PREF "skipping end of device tests because last "
+                       "block is bad\n");
+        else {
+                /* Attempt to write off end of device */
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = mtd->ecclayout->oobavail + 1;
+                ops.oobretlen = 0;
+                ops.ooboffs   = 0;
+                ops.datbuf    = 0;
+                ops.oobbuf    = writebuf;
+                printk(PRINT_PREF "attempting to write past end of device\n");
+                printk(PRINT_PREF "an error is expected...\n");
+                err = mtd->write_oob(mtd, mtd->size - mtd->writesize, &ops);
+                if (err) {
+                        printk(PRINT_PREF "error occurred as expected\n");
+                        err = 0;
+                } else {
+                        printk(PRINT_PREF "error: wrote past end of device\n");
+                        errcnt += 1;
+                }
+
+                /* Attempt to read off end of device */
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = mtd->ecclayout->oobavail + 1;
+                ops.oobretlen = 0;
+                ops.ooboffs   = 0;
+                ops.datbuf    = 0;
+                ops.oobbuf    = readbuf;
+                printk(PRINT_PREF "attempting to read past end of device\n");
+                printk(PRINT_PREF "an error is expected...\n");
+                err = mtd->read_oob(mtd, mtd->size - mtd->writesize, &ops);
+                if (err) {
+                        printk(PRINT_PREF "error occurred as expected\n");
+                        err = 0;
+                } else {
+                        printk(PRINT_PREF "error: read past end of device\n");
+                        errcnt += 1;
+                }
+
+                err = erase_eraseblock(ebcnt - 1);
+                if (err)
+                        goto out;
+
+                /* Attempt to write off end of device */
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = mtd->ecclayout->oobavail;
+                ops.oobretlen = 0;
+                ops.ooboffs   = 1;
+                ops.datbuf    = 0;
+                ops.oobbuf    = writebuf;
+                printk(PRINT_PREF "attempting to write past end of device\n");
+                printk(PRINT_PREF "an error is expected...\n");
+                err = mtd->write_oob(mtd, mtd->size - mtd->writesize, &ops);
+                if (err) {
+                        printk(PRINT_PREF "error occurred as expected\n");
+                        err = 0;
+                } else {
+                        printk(PRINT_PREF "error: wrote past end of device\n");
+                        errcnt += 1;
+                }
+
+                /* Attempt to read off end of device */
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = mtd->ecclayout->oobavail;
+                ops.oobretlen = 0;
+                ops.ooboffs   = 1;
+                ops.datbuf    = 0;
+                ops.oobbuf    = readbuf;
+                printk(PRINT_PREF "attempting to read past end of device\n");
+                printk(PRINT_PREF "an error is expected...\n");
+                err = mtd->read_oob(mtd, mtd->size - mtd->writesize, &ops);
+                if (err) {
+                        printk(PRINT_PREF "error occurred as expected\n");
+                        err = 0;
+                } else {
+                        printk(PRINT_PREF "error: read past end of device\n");
+                        errcnt += 1;
+                }
+        }
+
+        /* Fifth test: write / read across block boundaries */
+        printk(PRINT_PREF "test 5 of 5\n");
+
+        /* Erase all eraseblocks */
+        err = erase_whole_device();
+        if (err)
+                goto out;
+
+        /* Write all eraseblocks */
+        simple_srand(11);
+        printk(PRINT_PREF "writing OOBs of whole device\n");
+        for (i = 0; i < ebcnt - 1; ++i) {
+                int cnt = 2;
+                int pg;
+                size_t sz = mtd->ecclayout->oobavail;
+                if (bbt[i] || bbt[i + 1])
+                        continue;
+                addr = (i + 1) * mtd->erasesize - mtd->writesize;
+                for (pg = 0; pg < cnt; ++pg) {
+                        set_random_data(writebuf, sz);
+                        ops.mode      = MTD_OOB_AUTO;
+                        ops.len       = 0;
+                        ops.retlen    = 0;
+                        ops.ooblen    = sz;
+                        ops.oobretlen = 0;
+                        ops.ooboffs   = 0;
+                        ops.datbuf    = 0;
+                        ops.oobbuf    = writebuf;
+                        err = mtd->write_oob(mtd, addr, &ops);
+                        if (err)
+                                goto out;
+                        if (i % 256 == 0)
+                                printk(PRINT_PREF "written up to eraseblock "
+                                       "%u\n", i);
+                        cond_resched();
+                        addr += mtd->writesize;
+                }
+        }
+        printk(PRINT_PREF "written %u eraseblocks\n", i);
+
+        /* Check all eraseblocks */
+        simple_srand(11);
+        printk(PRINT_PREF "verifying all eraseblocks\n");
+        for (i = 0; i < ebcnt - 1; ++i) {
+                if (bbt[i] || bbt[i + 1])
+                        continue;
+                set_random_data(writebuf, mtd->ecclayout->oobavail * 2);
+                addr = (i + 1) * mtd->erasesize - mtd->writesize;
+                ops.mode      = MTD_OOB_AUTO;
+                ops.len       = 0;
+                ops.retlen    = 0;
+                ops.ooblen    = mtd->ecclayout->oobavail * 2;
+                ops.oobretlen = 0;
+                ops.ooboffs   = 0;
+                ops.datbuf    = 0;
+                ops.oobbuf    = readbuf;
+                err = mtd->read_oob(mtd, addr, &ops);
+                if (err)
+                        goto out;
+                if (memcmp(readbuf, writebuf, mtd->ecclayout->oobavail * 2)) {
+                        printk(PRINT_PREF "error: verify failed at %#llx\n",
+                               (long long)addr);
+                        errcnt += 1;
+                        if (errcnt > 1000) {
+                                printk(PRINT_PREF "error: too many errors\n");
+                                goto out;
+                        }
+                }
+                if (i % 256 == 0)
+                        printk(PRINT_PREF "verified up to eraseblock %u\n", i);
+                cond_resched();
+        }
+        printk(PRINT_PREF "verified %u eraseblocks\n", i);
+
+        printk(PRINT_PREF "finished with %d errors\n", errcnt);
+out:
+        kfree(bbt);
+        kfree(writebuf);
+        kfree(readbuf);
+        put_mtd_device(mtd);
+        if (err)
+                printk(PRINT_PREF "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");