Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / mtd / tests / oobtest.c
diff --git a/kernel/drivers/mtd/tests/oobtest.c b/kernel/drivers/mtd/tests/oobtest.c
new file mode 100644 (file)
index 0000000..8e8525f
--- /dev/null
@@ -0,0 +1,724 @@
+/*
+ * 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>
+ */
+
+#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/random.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 memcmpshow(loff_t addr, 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%zx] 0x%x -> 0x%x diff 0x%x\n",
+                               (unsigned long)addr, i, *su1, *su2, res);
+                       bitflips += hweight8(res);
+               }
+       }
+
+       return bitflips;
+}
+
+/*
+ * 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 (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->ecclayout->oobavail) {
+                       int k;
+
+                       ops.mode      = MTD_OPS_AUTO_OOB;
+                       ops.len       = 0;
+                       ops.retlen    = 0;
+                       ops.ooblen    = mtd->ecclayout->oobavail;
+                       ops.oobretlen = 0;
+                       ops.ooboffs   = 0;
+                       ops.datbuf    = NULL;
+                       ops.oobbuf    = readbuf;
+                       err = mtd_read_oob(mtd, addr, &ops);
+                       if (err || ops.oobretlen != mtd->ecclayout->oobavail) {
+                               pr_err("error: readoob failed at %#llx\n",
+                                               (long long)addr);
+                               errcnt += 1;
+                               return err ? err : -1;
+                       }
+                       bitflips = memcmpshow(addr, 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->ecclayout->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->ecclayout->oobavail * pgcnt;
+       size_t oobavail = mtd->ecclayout->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 (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->ecclayout->oobavail;
+       use_len_max = mtd->ecclayout->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->ecclayout->oobavail;
+       use_len_max = mtd->ecclayout->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->ecclayout->oobavail;
+       use_len_max = mtd->ecclayout->oobavail;
+       vary_offset = 1;
+       prandom_seed_state(&rnd_state, 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 */
+       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->ecclayout->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");
+               err = 0;
+       } 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->ecclayout->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 (err) {
+               pr_info("error occurred as expected\n");
+               err = 0;
+       } 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->ecclayout->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");
+                       err = 0;
+               } 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->ecclayout->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 (err) {
+                       pr_info("error occurred as expected\n");
+                       err = 0;
+               } 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->ecclayout->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");
+                       err = 0;
+               } 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->ecclayout->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 (err) {
+                       pr_info("error occurred as expected\n");
+                       err = 0;
+               } 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->ecclayout->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->ecclayout->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->ecclayout->oobavail * 2;
+               ops.oobretlen = 0;
+               ops.ooboffs   = 0;
+               ops.datbuf    = NULL;
+               ops.oobbuf    = readbuf;
+               err = mtd_read_oob(mtd, addr, &ops);
+               if (err)
+                       goto out;
+               if (memcmpshow(addr, readbuf, writebuf,
+                              mtd->ecclayout->oobavail * 2)) {
+                       pr_err("error: verify failed at %#llx\n",
+                              (long long)addr);
+                       errcnt += 1;
+                       if (errcnt > 1000) {
+                               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");