drivers/mtd/tests/mtd_torturetest.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (C) 2006-2008 Artem Bityutskiy
  * Copyright (C) 2006-2008 Jarkko Lavinen
  * Copyright (C) 2006-2008 Adrian Hunter
  *
  * 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.
  *
  * Authors: Artem Bityutskiy, Jarkko Lavinen, Adria Hunter
  *
  * WARNING: this test program may kill your flash and your device. Do not
  * use it unless you know what you do. Authors are not responsible for any
  * damage caused by this program.
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #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>

 #define RETRIES 3

 static int eb = 8;
 module_param(eb, int, S_IRUGO);
 MODULE_PARM_DESC(eb, "eraseblock number within the selected MTD device");

 static int ebcnt = 32;
 module_param(ebcnt, int, S_IRUGO);
 MODULE_PARM_DESC(ebcnt, "number of consecutive eraseblocks to torture");

 static int pgcnt;
 module_param(pgcnt, int, S_IRUGO);
 MODULE_PARM_DESC(pgcnt, "number of pages per eraseblock to torture (0 => all)");

 static int dev = -EINVAL;
 module_param(dev, int, S_IRUGO);
 MODULE_PARM_DESC(dev, "MTD device number to use");

 static int gran = 512;
 module_param(gran, int, S_IRUGO);
 MODULE_PARM_DESC(gran, "how often the status information should be printed");

 static int check = 1;
 module_param(check, int, S_IRUGO);
 MODULE_PARM_DESC(check, "if the written data should be checked");

 static unsigned int cycles_count;
 module_param(cycles_count, uint, S_IRUGO);
 MODULE_PARM_DESC(cycles_count, "how many erase cycles to do "
 			       "(infinite by default)");

 static struct mtd_info *mtd;

 /* This buffer contains 0x555555...0xAAAAAA... pattern */
 static unsigned char *patt_5A5;
 /* This buffer contains 0xAAAAAA...0x555555... pattern */
 static unsigned char *patt_A5A;
 /* This buffer contains all 0xFF bytes */
 static unsigned char *patt_FF;
 /* This a temporary buffer is use when checking data */
 static unsigned char *check_buf;
 /* How many erase cycles were done */
 static unsigned int erase_cycles;

 static int pgsize;
 static struct timeval start, finish;

 static void report_corrupt(unsigned char *read, unsigned char *written);

 static inline void start_timing(void)
 {
 	do_gettimeofday(&start);
 }

 static inline void stop_timing(void)
 {
 	do_gettimeofday(&finish);
 }

 /*
  * Erase eraseblock number @ebnum.
  */
 static inline 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) {
 		pr_err("error %d while erasing EB %d\n", err, ebnum);
 		return err;
 	}

 	if (ei.state == MTD_ERASE_FAILED) {
 		pr_err("some erase error occurred at EB %d\n",
 		       ebnum);
 		return -EIO;
 	}

 	return 0;
 }

 /*
  * Check that the contents of eraseblock number @enbum is equivalent to the
  * @buf buffer.
  */
 static inline int check_eraseblock(int ebnum, unsigned char *buf)
 {
 	int err, retries = 0;
 	size_t read;
 	loff_t addr = ebnum * mtd->erasesize;
 	size_t len = mtd->erasesize;

 	if (pgcnt) {
 		addr = (ebnum + 1) * mtd->erasesize - pgcnt * pgsize;
 		len = pgcnt * pgsize;
 	}

 retry:
 	err = mtd_read(mtd, addr, len, &read, check_buf);
 	if (mtd_is_bitflip(err))
 		pr_err("single bit flip occurred at EB %d "
 		       "MTD reported that it was fixed.\n", ebnum);
 	else if (err) {
 		pr_err("error %d while reading EB %d, "
 		       "read %zd\n", err, ebnum, read);
 		return err;
 	}

 	if (read != len) {
 		pr_err("failed to read %zd bytes from EB %d, "
 		       "read only %zd, but no error reported\n",
 		       len, ebnum, read);
 		return -EIO;
 	}

 	if (memcmp(buf, check_buf, len)) {
 		pr_err("read wrong data from EB %d\n", ebnum);
 		report_corrupt(check_buf, buf);

 		if (retries++ < RETRIES) {
 			/* Try read again */
 			yield();
 			pr_info("re-try reading data from EB %d\n",
 			       ebnum);
 			goto retry;
 		} else {
 			pr_info("retried %d times, still errors, "
 			       "give-up\n", RETRIES);
 			return -EINVAL;
 		}
 	}

 	if (retries != 0)
 		pr_info("only attempt number %d was OK (!!!)\n",
 		       retries);

 	return 0;
 }

 static inline int write_pattern(int ebnum, void *buf)
 {
 	int err;
 	size_t written;
 	loff_t addr = ebnum * mtd->erasesize;
 	size_t len = mtd->erasesize;

 	if (pgcnt) {
 		addr = (ebnum + 1) * mtd->erasesize - pgcnt * pgsize;
 		len = pgcnt * pgsize;
 	}
 	err = mtd_write(mtd, addr, len, &written, buf);
 	if (err) {
 		pr_err("error %d while writing EB %d, written %zd"
 		      " bytes\n", err, ebnum, written);
 		return err;
 	}
 	if (written != len) {
 		pr_info("written only %zd bytes of %zd, but no error"
 		       " reported\n", written, len);
 		return -EIO;
 	}

 	return 0;
 }

 static int __init tort_init(void)
 {
 	int err = 0, i, infinite = !cycles_count;
 	int bad_ebs[ebcnt];

 	printk(KERN_INFO "\n");
 	printk(KERN_INFO "=================================================\n");
 	pr_info("Warning: this program is trying to wear out your "
 	       "flash, stop it if this is not wanted.\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);
 	pr_info("torture %d eraseblocks (%d-%d) of mtd%d\n",
 	       ebcnt, eb, eb + ebcnt - 1, dev);
 	if (pgcnt)
 		pr_info("torturing just %d pages per eraseblock\n",
 			pgcnt);
 	pr_info("write verify %s\n", check ? "enabled" : "disabled");

 	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->writesize == 1) {
 		pr_info("not NAND flash, assume page size is 512 "
 		       "bytes.\n");
 		pgsize = 512;
 	} else
 		pgsize = mtd->writesize;

 	if (pgcnt && (pgcnt > mtd->erasesize / pgsize || pgcnt < 0)) {
 		pr_err("error: invalid pgcnt value %d\n", pgcnt);
 		goto out_mtd;
 	}

 	err = -ENOMEM;
 	patt_5A5 = kmalloc(mtd->erasesize, GFP_KERNEL);
 	if (!patt_5A5) {
 		pr_err("error: cannot allocate memory\n");
 		goto out_mtd;
 	}

 	patt_A5A = kmalloc(mtd->erasesize, GFP_KERNEL);
 	if (!patt_A5A) {
 		pr_err("error: cannot allocate memory\n");
 		goto out_patt_5A5;
 	}

 	patt_FF = kmalloc(mtd->erasesize, GFP_KERNEL);
 	if (!patt_FF) {
 		pr_err("error: cannot allocate memory\n");
 		goto out_patt_A5A;
 	}

 	check_buf = kmalloc(mtd->erasesize, GFP_KERNEL);
 	if (!check_buf) {
 		pr_err("error: cannot allocate memory\n");
 		goto out_patt_FF;
 	}

 	err = 0;

 	/* Initialize patterns */
 	memset(patt_FF, 0xFF, mtd->erasesize);
 	for (i = 0; i < mtd->erasesize / pgsize; i++) {
 		if (!(i & 1)) {
 			memset(patt_5A5 + i * pgsize, 0x55, pgsize);
 			memset(patt_A5A + i * pgsize, 0xAA, pgsize);
 		} else {
 			memset(patt_5A5 + i * pgsize, 0xAA, pgsize);
 			memset(patt_A5A + i * pgsize, 0x55, pgsize);
 		}
 	}

 	/*
 	 * Check if there is a bad eraseblock among those we are going to test.
 	 */
 	memset(&bad_ebs[0], 0, sizeof(int) * ebcnt);
 	if (mtd_can_have_bb(mtd)) {
 		for (i = eb; i < eb + ebcnt; i++) {
 			err = mtd_block_isbad(mtd, (loff_t)i * mtd->erasesize);

 			if (err < 0) {
 				pr_info("block_isbad() returned %d "
 				       "for EB %d\n", err, i);
 				goto out;
 			}

 			if (err) {
 				pr_err("EB %d is bad. Skip it.\n", i);
 				bad_ebs[i - eb] = 1;
 			}
 		}
 	}

 	start_timing();
 	while (1) {
 		int i;
 		void *patt;

 		/* Erase all eraseblocks */
 		for (i = eb; i < eb + ebcnt; i++) {
 			if (bad_ebs[i - eb])
 				continue;
 			err = erase_eraseblock(i);
 			if (err)
 				goto out;
 			cond_resched();
 		}

 		/* Check if the eraseblocks contain only 0xFF bytes */
 		if (check) {
 			for (i = eb; i < eb + ebcnt; i++) {
 				if (bad_ebs[i - eb])
 					continue;
 				err = check_eraseblock(i, patt_FF);
 				if (err) {
 					pr_info("verify failed"
 					       " for 0xFF... pattern\n");
 					goto out;
 				}
 				cond_resched();
 			}
 		}

 		/* Write the pattern */
 		for (i = eb; i < eb + ebcnt; i++) {
 			if (bad_ebs[i - eb])
 				continue;
 			if ((eb + erase_cycles) & 1)
 				patt = patt_5A5;
 			else
 				patt = patt_A5A;
 			err = write_pattern(i, patt);
 			if (err)
 				goto out;
 			cond_resched();
 		}

 		/* Verify what we wrote */
 		if (check) {
 			for (i = eb; i < eb + ebcnt; i++) {
 				if (bad_ebs[i - eb])
 					continue;
 				if ((eb + erase_cycles) & 1)
 					patt = patt_5A5;
 				else
 					patt = patt_A5A;
 				err = check_eraseblock(i, patt);
 				if (err) {
 					pr_info("verify failed for %s"
 					       " pattern\n",
 					       ((eb + erase_cycles) & 1) ?
 					       "0x55AA55..." : "0xAA55AA...");
 					goto out;
 				}
 				cond_resched();
 			}
 		}

 		erase_cycles += 1;

 		if (erase_cycles % gran == 0) {
 			long ms;

 			stop_timing();
 			ms = (finish.tv_sec - start.tv_sec) * 1000 +
 			     (finish.tv_usec - start.tv_usec) / 1000;
 			pr_info("%08u erase cycles done, took %lu "
 			       "milliseconds (%lu seconds)\n",
 			       erase_cycles, ms, ms / 1000);
 			start_timing();
 		}

 		if (!infinite && --cycles_count == 0)
 			break;
 	}
 out:

 	pr_info("finished after %u erase cycles\n",
 	       erase_cycles);
 	kfree(check_buf);
 out_patt_FF:
 	kfree(patt_FF);
 out_patt_A5A:
 	kfree(patt_A5A);
 out_patt_5A5:
 	kfree(patt_5A5);
 out_mtd:
 	put_mtd_device(mtd);
 	if (err)
 		pr_info("error %d occurred during torturing\n", err);
 	printk(KERN_INFO "=================================================\n");
 	return err;
 }
 module_init(tort_init);

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

 static int countdiffs(unsigned char *buf, unsigned char *check_buf,
 		      unsigned offset, unsigned len, unsigned *bytesp,
 		      unsigned *bitsp);
 static void print_bufs(unsigned char *read, unsigned char *written, int start,
 		       int len);

 /*
  * Report the detailed information about how the read EB differs from what was
  * written.
  */
 static void report_corrupt(unsigned char *read, unsigned char *written)
 {
 	int i;
 	int bytes, bits, pages, first;
 	int offset, len;
 	size_t check_len = mtd->erasesize;

 	if (pgcnt)
 		check_len = pgcnt * pgsize;

 	bytes = bits = pages = 0;
 	for (i = 0; i < check_len; i += pgsize)
 		if (countdiffs(written, read, i, pgsize, &bytes,
 			       &bits) >= 0)
 			pages++;

 	pr_info("verify fails on %d pages, %d bytes/%d bits\n",
 	       pages, bytes, bits);
 	pr_info("The following is a list of all differences between"
 	       " what was read from flash and what was expected\n");

 	for (i = 0; i < check_len; i += pgsize) {
 		cond_resched();
 		bytes = bits = 0;
 		first = countdiffs(written, read, i, pgsize, &bytes,
 				   &bits);
 		if (first < 0)
 			continue;

 		printk("-------------------------------------------------------"
 		       "----------------------------------\n");

 		pr_info("Page %zd has %d bytes/%d bits failing verify,"
 		       " starting at offset 0x%x\n",
 		       (mtd->erasesize - check_len + i) / pgsize,
 		       bytes, bits, first);

 		offset = first & ~0x7;
 		len = ((first + bytes) | 0x7) + 1 - offset;

 		print_bufs(read, written, offset, len);
 	}
 }

 static void print_bufs(unsigned char *read, unsigned char *written, int start,
 		       int len)
 {
 	int i = 0, j1, j2;
 	char *diff;

 	printk("Offset       Read                          Written\n");
 	while (i < len) {
 		printk("0x%08x: ", start + i);
 		diff = "   ";
 		for (j1 = 0; j1 < 8 && i + j1 < len; j1++) {
 			printk(" %02x", read[start + i + j1]);
 			if (read[start + i + j1] != written[start + i + j1])
 				diff = "***";
 		}

 		while (j1 < 8) {
 			printk(" ");
 			j1 += 1;
 		}

 		printk("  %s ", diff);

 		for (j2 = 0; j2 < 8 && i + j2 < len; j2++)
 			printk(" %02x", written[start + i + j2]);
 		printk("\n");
 		i += 8;
 	}
 }

 /*
  * Count the number of differing bytes and bits and return the first differing
  * offset.
  */
 static int countdiffs(unsigned char *buf, unsigned char *check_buf,
 		      unsigned offset, unsigned len, unsigned *bytesp,
 		      unsigned *bitsp)
 {
 	unsigned i, bit;
 	int first = -1;

 	for (i = offset; i < offset + len; i++)
 		if (buf[i] != check_buf[i]) {
 			first = i;
 			break;
 		}

 	while (i < offset + len) {
 		if (buf[i] != check_buf[i]) {
 			(*bytesp)++;
 			bit = 1;
 			while (bit < 256) {
 				if ((buf[i] & bit) != (check_buf[i] & bit))
 					(*bitsp)++;
 				bit <<= 1;
 			}
 		}
 		i++;
 	}

 	return first;
 }

 MODULE_DESCRIPTION("Eraseblock torturing module");
 MODULE_AUTHOR("Artem Bityutskiy, Jarkko Lavinen, Adrian Hunter");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2006-2008 Artem Bityutskiy
	* Copyright (C) 2006-2008 Jarkko Lavinen
	* Copyright (C) 2006-2008 Adrian Hunter
	*
	* 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.
	*
	* Authors: Artem Bityutskiy, Jarkko Lavinen, Adria Hunter
	*
	* WARNING: this test program may kill your flash and your device. Do not
	* use it unless you know what you do. Authors are not responsible for any
	* damage caused by this program.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#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>

	#define RETRIES 3

	static int eb = 8;
	module_param(eb, int, S_IRUGO);
	MODULE_PARM_DESC(eb, "eraseblock number within the selected MTD device");

	static int ebcnt = 32;
	module_param(ebcnt, int, S_IRUGO);
	MODULE_PARM_DESC(ebcnt, "number of consecutive eraseblocks to torture");

	static int pgcnt;
	module_param(pgcnt, int, S_IRUGO);
	MODULE_PARM_DESC(pgcnt, "number of pages per eraseblock to torture (0 => all)");

	static int dev = -EINVAL;
	module_param(dev, int, S_IRUGO);
	MODULE_PARM_DESC(dev, "MTD device number to use");

	static int gran = 512;
	module_param(gran, int, S_IRUGO);
	MODULE_PARM_DESC(gran, "how often the status information should be printed");

	static int check = 1;
	module_param(check, int, S_IRUGO);
	MODULE_PARM_DESC(check, "if the written data should be checked");

	static unsigned int cycles_count;
	module_param(cycles_count, uint, S_IRUGO);
	MODULE_PARM_DESC(cycles_count, "how many erase cycles to do "
	"(infinite by default)");

	static struct mtd_info *mtd;

	/* This buffer contains 0x555555...0xAAAAAA... pattern */
	static unsigned char *patt_5A5;
	/* This buffer contains 0xAAAAAA...0x555555... pattern */
	static unsigned char *patt_A5A;
	/* This buffer contains all 0xFF bytes */
	static unsigned char *patt_FF;
	/* This a temporary buffer is use when checking data */
	static unsigned char *check_buf;
	/* How many erase cycles were done */
	static unsigned int erase_cycles;

	static int pgsize;
	static struct timeval start, finish;

	static void report_corrupt(unsigned char read, unsigned char written);

	static inline void start_timing(void)
	{
	do_gettimeofday(&start);
	}

	static inline void stop_timing(void)
	{
	do_gettimeofday(&finish);
	}

	/*
	* Erase eraseblock number @ebnum.
	*/
	static inline 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) {
	pr_err("error %d while erasing EB %d\n", err, ebnum);
	return err;
	}

	if (ei.state == MTD_ERASE_FAILED) {
	pr_err("some erase error occurred at EB %d\n",
	ebnum);
	return -EIO;
	}

	return 0;
	}

	/*
	* Check that the contents of eraseblock number @enbum is equivalent to the
	* @buf buffer.
	*/
	static inline int check_eraseblock(int ebnum, unsigned char *buf)
	{
	int err, retries = 0;
	size_t read;
	loff_t addr = ebnum * mtd->erasesize;
	size_t len = mtd->erasesize;

	if (pgcnt) {
	addr = (ebnum + 1) * mtd->erasesize - pgcnt * pgsize;
	len = pgcnt * pgsize;
	}

	retry:
	err = mtd_read(mtd, addr, len, &read, check_buf);
	if (mtd_is_bitflip(err))
	pr_err("single bit flip occurred at EB %d "
	"MTD reported that it was fixed.\n", ebnum);
	else if (err) {
	pr_err("error %d while reading EB %d, "
	"read %zd\n", err, ebnum, read);
	return err;
	}

	if (read != len) {
	pr_err("failed to read %zd bytes from EB %d, "
	"read only %zd, but no error reported\n",
	len, ebnum, read);
	return -EIO;
	}

	if (memcmp(buf, check_buf, len)) {
	pr_err("read wrong data from EB %d\n", ebnum);
	report_corrupt(check_buf, buf);

	if (retries++ < RETRIES) {
	/* Try read again */
	yield();
	pr_info("re-try reading data from EB %d\n",
	ebnum);
	goto retry;
	} else {
	pr_info("retried %d times, still errors, "
	"give-up\n", RETRIES);
	return -EINVAL;
	}
	}

	if (retries != 0)
	pr_info("only attempt number %d was OK (!!!)\n",
	retries);

	return 0;
	}

	static inline int write_pattern(int ebnum, void *buf)
	{
	int err;
	size_t written;
	loff_t addr = ebnum * mtd->erasesize;
	size_t len = mtd->erasesize;

	if (pgcnt) {
	addr = (ebnum + 1) * mtd->erasesize - pgcnt * pgsize;
	len = pgcnt * pgsize;
	}
	err = mtd_write(mtd, addr, len, &written, buf);
	if (err) {
	pr_err("error %d while writing EB %d, written %zd"
	" bytes\n", err, ebnum, written);
	return err;
	}
	if (written != len) {
	pr_info("written only %zd bytes of %zd, but no error"
	" reported\n", written, len);
	return -EIO;
	}

	return 0;
	}

	static int __init tort_init(void)
	{
	int err = 0, i, infinite = !cycles_count;
	int bad_ebs[ebcnt];

	printk(KERN_INFO "\n");
	printk(KERN_INFO "=================================================\n");
	pr_info("Warning: this program is trying to wear out your "
	"flash, stop it if this is not wanted.\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);
	pr_info("torture %d eraseblocks (%d-%d) of mtd%d\n",
	ebcnt, eb, eb + ebcnt - 1, dev);
	if (pgcnt)
	pr_info("torturing just %d pages per eraseblock\n",
	pgcnt);
	pr_info("write verify %s\n", check ? "enabled" : "disabled");

	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->writesize == 1) {
	pr_info("not NAND flash, assume page size is 512 "
	"bytes.\n");
	pgsize = 512;
	} else
	pgsize = mtd->writesize;

	if (pgcnt && (pgcnt > mtd->erasesize / pgsize \|\| pgcnt < 0)) {
	pr_err("error: invalid pgcnt value %d\n", pgcnt);
	goto out_mtd;
	}

	err = -ENOMEM;
	patt_5A5 = kmalloc(mtd->erasesize, GFP_KERNEL);
	if (!patt_5A5) {
	pr_err("error: cannot allocate memory\n");
	goto out_mtd;
	}

	patt_A5A = kmalloc(mtd->erasesize, GFP_KERNEL);
	if (!patt_A5A) {
	pr_err("error: cannot allocate memory\n");
	goto out_patt_5A5;
	}

	patt_FF = kmalloc(mtd->erasesize, GFP_KERNEL);
	if (!patt_FF) {
	pr_err("error: cannot allocate memory\n");
	goto out_patt_A5A;
	}

	check_buf = kmalloc(mtd->erasesize, GFP_KERNEL);
	if (!check_buf) {
	pr_err("error: cannot allocate memory\n");
	goto out_patt_FF;
	}

	err = 0;

	/* Initialize patterns */
	memset(patt_FF, 0xFF, mtd->erasesize);
	for (i = 0; i < mtd->erasesize / pgsize; i++) {
	if (!(i & 1)) {
	memset(patt_5A5 + i * pgsize, 0x55, pgsize);
	memset(patt_A5A + i * pgsize, 0xAA, pgsize);
	} else {
	memset(patt_5A5 + i * pgsize, 0xAA, pgsize);
	memset(patt_A5A + i * pgsize, 0x55, pgsize);
	}
	}

	/*
	* Check if there is a bad eraseblock among those we are going to test.
	*/
	memset(&bad_ebs[0], 0, sizeof(int) * ebcnt);
	if (mtd_can_have_bb(mtd)) {
	for (i = eb; i < eb + ebcnt; i++) {
	err = mtd_block_isbad(mtd, (loff_t)i * mtd->erasesize);

	if (err < 0) {
	pr_info("block_isbad() returned %d "
	"for EB %d\n", err, i);
	goto out;
	}

	if (err) {
	pr_err("EB %d is bad. Skip it.\n", i);
	bad_ebs[i - eb] = 1;
	}
	}
	}

	start_timing();
	while (1) {
	int i;
	void *patt;

	/* Erase all eraseblocks */
	for (i = eb; i < eb + ebcnt; i++) {
	if (bad_ebs[i - eb])
	continue;
	err = erase_eraseblock(i);
	if (err)
	goto out;
	cond_resched();
	}

	/* Check if the eraseblocks contain only 0xFF bytes */
	if (check) {
	for (i = eb; i < eb + ebcnt; i++) {
	if (bad_ebs[i - eb])
	continue;
	err = check_eraseblock(i, patt_FF);
	if (err) {
	pr_info("verify failed"
	" for 0xFF... pattern\n");
	goto out;
	}
	cond_resched();
	}
	}

	/* Write the pattern */
	for (i = eb; i < eb + ebcnt; i++) {
	if (bad_ebs[i - eb])
	continue;
	if ((eb + erase_cycles) & 1)
	patt = patt_5A5;
	else
	patt = patt_A5A;
	err = write_pattern(i, patt);
	if (err)
	goto out;
	cond_resched();
	}

	/* Verify what we wrote */
	if (check) {
	for (i = eb; i < eb + ebcnt; i++) {
	if (bad_ebs[i - eb])
	continue;
	if ((eb + erase_cycles) & 1)
	patt = patt_5A5;
	else
	patt = patt_A5A;
	err = check_eraseblock(i, patt);
	if (err) {
	pr_info("verify failed for %s"
	" pattern\n",
	((eb + erase_cycles) & 1) ?
	"0x55AA55..." : "0xAA55AA...");
	goto out;
	}
	cond_resched();
	}
	}

	erase_cycles += 1;

	if (erase_cycles % gran == 0) {
	long ms;

	stop_timing();
	ms = (finish.tv_sec - start.tv_sec) * 1000 +
	(finish.tv_usec - start.tv_usec) / 1000;
	pr_info("%08u erase cycles done, took %lu "
	"milliseconds (%lu seconds)\n",
	erase_cycles, ms, ms / 1000);
	start_timing();
	}

	if (!infinite && --cycles_count == 0)
	break;
	}
	out:

	pr_info("finished after %u erase cycles\n",
	erase_cycles);
	kfree(check_buf);
	out_patt_FF:
	kfree(patt_FF);
	out_patt_A5A:
	kfree(patt_A5A);
	out_patt_5A5:
	kfree(patt_5A5);
	out_mtd:
	put_mtd_device(mtd);
	if (err)
	pr_info("error %d occurred during torturing\n", err);
	printk(KERN_INFO "=================================================\n");
	return err;
	}
	module_init(tort_init);

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

	static int countdiffs(unsigned char buf, unsigned char check_buf,
	unsigned offset, unsigned len, unsigned *bytesp,
	unsigned *bitsp);
	static void print_bufs(unsigned char read, unsigned char written, int start,
	int len);

	/*
	* Report the detailed information about how the read EB differs from what was
	* written.
	*/
	static void report_corrupt(unsigned char read, unsigned char written)
	{
	int i;
	int bytes, bits, pages, first;
	int offset, len;
	size_t check_len = mtd->erasesize;

	if (pgcnt)
	check_len = pgcnt * pgsize;

	bytes = bits = pages = 0;
	for (i = 0; i < check_len; i += pgsize)
	if (countdiffs(written, read, i, pgsize, &bytes,
	&bits) >= 0)
	pages++;

	pr_info("verify fails on %d pages, %d bytes/%d bits\n",
	pages, bytes, bits);
	pr_info("The following is a list of all differences between"
	" what was read from flash and what was expected\n");

	for (i = 0; i < check_len; i += pgsize) {
	cond_resched();
	bytes = bits = 0;
	first = countdiffs(written, read, i, pgsize, &bytes,
	&bits);
	if (first < 0)
	continue;

	printk("-------------------------------------------------------"
	"----------------------------------\n");

	pr_info("Page %zd has %d bytes/%d bits failing verify,"
	" starting at offset 0x%x\n",
	(mtd->erasesize - check_len + i) / pgsize,
	bytes, bits, first);

	offset = first & ~0x7;
	len = ((first + bytes) \| 0x7) + 1 - offset;

	print_bufs(read, written, offset, len);
	}
	}

	static void print_bufs(unsigned char read, unsigned char written, int start,
	int len)
	{
	int i = 0, j1, j2;
	char *diff;

	printk("Offset Read Written\n");
	while (i < len) {
	printk("0x%08x: ", start + i);
	diff = " ";
	for (j1 = 0; j1 < 8 && i + j1 < len; j1++) {
	printk(" %02x", read[start + i + j1]);
	if (read[start + i + j1] != written[start + i + j1])
	diff = "***";
	}

	while (j1 < 8) {
	printk(" ");
	j1 += 1;
	}

	printk(" %s ", diff);

	for (j2 = 0; j2 < 8 && i + j2 < len; j2++)
	printk(" %02x", written[start + i + j2]);
	printk("\n");
	i += 8;
	}
	}

	/*
	* Count the number of differing bytes and bits and return the first differing
	* offset.
	*/
	static int countdiffs(unsigned char buf, unsigned char check_buf,
	unsigned offset, unsigned len, unsigned *bytesp,
	unsigned *bitsp)
	{
	unsigned i, bit;
	int first = -1;

	for (i = offset; i < offset + len; i++)
	if (buf[i] != check_buf[i]) {
	first = i;
	break;
	}

	while (i < offset + len) {
	if (buf[i] != check_buf[i]) {
	(*bytesp)++;
	bit = 1;
	while (bit < 256) {
	if ((buf[i] & bit) != (check_buf[i] & bit))
	(*bitsp)++;
	bit <<= 1;
	}
	}
	i++;
	}

	return first;
	}

	MODULE_DESCRIPTION("Eraseblock torturing module");
	MODULE_AUTHOR("Artem Bityutskiy, Jarkko Lavinen, Adrian Hunter");
	MODULE_LICENSE("GPL");