drivers/mtd/tests/mtd_speedtest.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * Copyright (C) 2007 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 read and write speed of a MTD device.
  *
  * Author: Adrian Hunter <adrian.hunter@nokia.com>
  */

 #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>
 #include <linux/random.h>

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

 static int count;
 module_param(count, int, S_IRUGO);
 MODULE_PARM_DESC(count, "Maximum number of eraseblocks to use "
 			"(0 means use all)");

 static struct mtd_info *mtd;
 static unsigned char *iobuf;
 static unsigned char *bbt;

 static int pgsize;
 static int ebcnt;
 static int pgcnt;
 static int goodebcnt;
 static struct timeval start, finish;


 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) {
 		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;
 }

 static int multiblock_erase(int ebnum, int blocks)
 {
 	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 * blocks;

 	err = mtd_erase(mtd, &ei);
 	if (err) {
 		pr_err("error %d while erasing EB %d, blocks %d\n",
 		       err, ebnum, blocks);
 		return err;
 	}

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

 	return 0;
 }

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

 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = erase_eraseblock(i);
 		if (err)
 			return err;
 		cond_resched();
 	}
 	return 0;
 }

 static int write_eraseblock(int ebnum)
 {
 	size_t written;
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;

 	err = mtd_write(mtd, addr, mtd->erasesize, &written, iobuf);
 	if (err || written != mtd->erasesize) {
 		pr_err("error: write failed at %#llx\n", addr);
 		if (!err)
 			err = -EINVAL;
 	}

 	return err;
 }

 static int write_eraseblock_by_page(int ebnum)
 {
 	size_t written;
 	int i, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;

 	for (i = 0; i < pgcnt; i++) {
 		err = mtd_write(mtd, addr, pgsize, &written, buf);
 		if (err || written != pgsize) {
 			pr_err("error: write failed at %#llx\n",
 			       addr);
 			if (!err)
 				err = -EINVAL;
 			break;
 		}
 		addr += pgsize;
 		buf += pgsize;
 	}

 	return err;
 }

 static int write_eraseblock_by_2pages(int ebnum)
 {
 	size_t written, sz = pgsize * 2;
 	int i, n = pgcnt / 2, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;

 	for (i = 0; i < n; i++) {
 		err = mtd_write(mtd, addr, sz, &written, buf);
 		if (err || written != sz) {
 			pr_err("error: write failed at %#llx\n",
 			       addr);
 			if (!err)
 				err = -EINVAL;
 			return err;
 		}
 		addr += sz;
 		buf += sz;
 	}
 	if (pgcnt % 2) {
 		err = mtd_write(mtd, addr, pgsize, &written, buf);
 		if (err || written != pgsize) {
 			pr_err("error: write failed at %#llx\n",
 			       addr);
 			if (!err)
 				err = -EINVAL;
 		}
 	}

 	return err;
 }

 static int read_eraseblock(int ebnum)
 {
 	size_t read;
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;

 	err = mtd_read(mtd, addr, mtd->erasesize, &read, iobuf);
 	/* Ignore corrected ECC errors */
 	if (mtd_is_bitflip(err))
 		err = 0;
 	if (err || read != mtd->erasesize) {
 		pr_err("error: read failed at %#llx\n", addr);
 		if (!err)
 			err = -EINVAL;
 	}

 	return err;
 }

 static int read_eraseblock_by_page(int ebnum)
 {
 	size_t read;
 	int i, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;

 	for (i = 0; i < pgcnt; i++) {
 		err = mtd_read(mtd, addr, pgsize, &read, buf);
 		/* Ignore corrected ECC errors */
 		if (mtd_is_bitflip(err))
 			err = 0;
 		if (err || read != pgsize) {
 			pr_err("error: read failed at %#llx\n",
 			       addr);
 			if (!err)
 				err = -EINVAL;
 			break;
 		}
 		addr += pgsize;
 		buf += pgsize;
 	}

 	return err;
 }

 static int read_eraseblock_by_2pages(int ebnum)
 {
 	size_t read, sz = pgsize * 2;
 	int i, n = pgcnt / 2, err = 0;
 	loff_t addr = ebnum * mtd->erasesize;
 	void *buf = iobuf;

 	for (i = 0; i < n; i++) {
 		err = mtd_read(mtd, addr, sz, &read, buf);
 		/* Ignore corrected ECC errors */
 		if (mtd_is_bitflip(err))
 			err = 0;
 		if (err || read != sz) {
 			pr_err("error: read failed at %#llx\n",
 			       addr);
 			if (!err)
 				err = -EINVAL;
 			return err;
 		}
 		addr += sz;
 		buf += sz;
 	}
 	if (pgcnt % 2) {
 		err = mtd_read(mtd, addr, pgsize, &read, buf);
 		/* Ignore corrected ECC errors */
 		if (mtd_is_bitflip(err))
 			err = 0;
 		if (err || read != pgsize) {
 			pr_err("error: read failed at %#llx\n",
 			       addr);
 			if (!err)
 				err = -EINVAL;
 		}
 	}

 	return err;
 }

 static int is_block_bad(int ebnum)
 {
 	loff_t addr = ebnum * mtd->erasesize;
 	int ret;

 	ret = mtd_block_isbad(mtd, addr);
 	if (ret)
 		pr_info("block %d is bad\n", ebnum);
 	return ret;
 }

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

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

 static long calc_speed(void)
 {
 	uint64_t k;
 	long ms;

 	ms = (finish.tv_sec - start.tv_sec) * 1000 +
 	     (finish.tv_usec - start.tv_usec) / 1000;
 	if (ms == 0)
 		return 0;
 	k = goodebcnt * (mtd->erasesize / 1024) * 1000;
 	do_div(k, ms);
 	return k;
 }

 static int scan_for_bad_eraseblocks(void)
 {
 	int i, bad = 0;

 	bbt = kzalloc(ebcnt, GFP_KERNEL);
 	if (!bbt) {
 		pr_err("error: cannot allocate memory\n");
 		return -ENOMEM;
 	}

 	if (!mtd_can_have_bb(mtd))
 		goto out;

 	pr_info("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();
 	}
 	pr_info("scanned %d eraseblocks, %d are bad\n", i, bad);
 out:
 	goodebcnt = ebcnt - bad;
 	return 0;
 }

 static int __init mtd_speedtest_init(void)
 {
 	int err, i, blocks, j, k;
 	long speed;
 	uint64_t tmp;

 	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;
 	}

 	if (count)
 		pr_info("MTD device: %d    count: %d\n", dev, count);
 	else
 		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->writesize == 1) {
 		pr_info("not NAND flash, assume page size is 512 "
 		       "bytes.\n");
 		pgsize = 512;
 	} else
 		pgsize = mtd->writesize;

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

 	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,
 	       pgsize, ebcnt, pgcnt, mtd->oobsize);

 	if (count > 0 && count < ebcnt)
 		ebcnt = count;

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

 	prandom_bytes(iobuf, mtd->erasesize);

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

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

 	/* Write all eraseblocks, 1 eraseblock at a time */
 	pr_info("testing eraseblock write speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = write_eraseblock(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("eraseblock write speed is %ld KiB/s\n", speed);

 	/* Read all eraseblocks, 1 eraseblock at a time */
 	pr_info("testing eraseblock read speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = read_eraseblock(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("eraseblock read speed is %ld KiB/s\n", speed);

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

 	/* Write all eraseblocks, 1 page at a time */
 	pr_info("testing page write speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = write_eraseblock_by_page(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("page write speed is %ld KiB/s\n", speed);

 	/* Read all eraseblocks, 1 page at a time */
 	pr_info("testing page read speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = read_eraseblock_by_page(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("page read speed is %ld KiB/s\n", speed);

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

 	/* Write all eraseblocks, 2 pages at a time */
 	pr_info("testing 2 page write speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = write_eraseblock_by_2pages(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("2 page write speed is %ld KiB/s\n", speed);

 	/* Read all eraseblocks, 2 pages at a time */
 	pr_info("testing 2 page read speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = read_eraseblock_by_2pages(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("2 page read speed is %ld KiB/s\n", speed);

 	/* Erase all eraseblocks */
 	pr_info("Testing erase speed\n");
 	start_timing();
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = erase_eraseblock(i);
 		if (err)
 			goto out;
 		cond_resched();
 	}
 	stop_timing();
 	speed = calc_speed();
 	pr_info("erase speed is %ld KiB/s\n", speed);

 	/* Multi-block erase all eraseblocks */
 	for (k = 1; k < 7; k++) {
 		blocks = 1 << k;
 		pr_info("Testing %dx multi-block erase speed\n",
 		       blocks);
 		start_timing();
 		for (i = 0; i < ebcnt; ) {
 			for (j = 0; j < blocks && (i + j) < ebcnt; j++)
 				if (bbt[i + j])
 					break;
 			if (j < 1) {
 				i++;
 				continue;
 			}
 			err = multiblock_erase(i, j);
 			if (err)
 				goto out;
 			cond_resched();
 			i += j;
 		}
 		stop_timing();
 		speed = calc_speed();
 		pr_info("%dx multi-block erase speed is %ld KiB/s\n",
 		       blocks, speed);
 	}
 	pr_info("finished\n");
 out:
 	kfree(iobuf);
 	kfree(bbt);
 	put_mtd_device(mtd);
 	if (err)
 		pr_info("error %d occurred\n", err);
 	printk(KERN_INFO "=================================================\n");
 	return err;
 }
 module_init(mtd_speedtest_init);

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

 MODULE_DESCRIPTION("Speed test module");
 MODULE_AUTHOR("Adrian Hunter");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2007 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 read and write speed of a MTD device.
	*
	* Author: Adrian Hunter <adrian.hunter@nokia.com>
	*/

	#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>
	#include <linux/random.h>

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

	static int count;
	module_param(count, int, S_IRUGO);
	MODULE_PARM_DESC(count, "Maximum number of eraseblocks to use "
	"(0 means use all)");

	static struct mtd_info *mtd;
	static unsigned char *iobuf;
	static unsigned char *bbt;

	static int pgsize;
	static int ebcnt;
	static int pgcnt;
	static int goodebcnt;
	static struct timeval start, finish;


	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) {
	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;
	}

	static int multiblock_erase(int ebnum, int blocks)
	{
	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 * blocks;

	err = mtd_erase(mtd, &ei);
	if (err) {
	pr_err("error %d while erasing EB %d, blocks %d\n",
	err, ebnum, blocks);
	return err;
	}

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

	return 0;
	}

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

	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = erase_eraseblock(i);
	if (err)
	return err;
	cond_resched();
	}
	return 0;
	}

	static int write_eraseblock(int ebnum)
	{
	size_t written;
	int err = 0;
	loff_t addr = ebnum * mtd->erasesize;

	err = mtd_write(mtd, addr, mtd->erasesize, &written, iobuf);
	if (err \|\| written != mtd->erasesize) {
	pr_err("error: write failed at %#llx\n", addr);
	if (!err)
	err = -EINVAL;
	}

	return err;
	}

	static int write_eraseblock_by_page(int ebnum)
	{
	size_t written;
	int i, err = 0;
	loff_t addr = ebnum * mtd->erasesize;
	void *buf = iobuf;

	for (i = 0; i < pgcnt; i++) {
	err = mtd_write(mtd, addr, pgsize, &written, buf);
	if (err \|\| written != pgsize) {
	pr_err("error: write failed at %#llx\n",
	addr);
	if (!err)
	err = -EINVAL;
	break;
	}
	addr += pgsize;
	buf += pgsize;
	}

	return err;
	}

	static int write_eraseblock_by_2pages(int ebnum)
	{
	size_t written, sz = pgsize * 2;
	int i, n = pgcnt / 2, err = 0;
	loff_t addr = ebnum * mtd->erasesize;
	void *buf = iobuf;

	for (i = 0; i < n; i++) {
	err = mtd_write(mtd, addr, sz, &written, buf);
	if (err \|\| written != sz) {
	pr_err("error: write failed at %#llx\n",
	addr);
	if (!err)
	err = -EINVAL;
	return err;
	}
	addr += sz;
	buf += sz;
	}
	if (pgcnt % 2) {
	err = mtd_write(mtd, addr, pgsize, &written, buf);
	if (err \|\| written != pgsize) {
	pr_err("error: write failed at %#llx\n",
	addr);
	if (!err)
	err = -EINVAL;
	}
	}

	return err;
	}

	static int read_eraseblock(int ebnum)
	{
	size_t read;
	int err = 0;
	loff_t addr = ebnum * mtd->erasesize;

	err = mtd_read(mtd, addr, mtd->erasesize, &read, iobuf);
	/* Ignore corrected ECC errors */
	if (mtd_is_bitflip(err))
	err = 0;
	if (err \|\| read != mtd->erasesize) {
	pr_err("error: read failed at %#llx\n", addr);
	if (!err)
	err = -EINVAL;
	}

	return err;
	}

	static int read_eraseblock_by_page(int ebnum)
	{
	size_t read;
	int i, err = 0;
	loff_t addr = ebnum * mtd->erasesize;
	void *buf = iobuf;

	for (i = 0; i < pgcnt; i++) {
	err = mtd_read(mtd, addr, pgsize, &read, buf);
	/* Ignore corrected ECC errors */
	if (mtd_is_bitflip(err))
	err = 0;
	if (err \|\| read != pgsize) {
	pr_err("error: read failed at %#llx\n",
	addr);
	if (!err)
	err = -EINVAL;
	break;
	}
	addr += pgsize;
	buf += pgsize;
	}

	return err;
	}

	static int read_eraseblock_by_2pages(int ebnum)
	{
	size_t read, sz = pgsize * 2;
	int i, n = pgcnt / 2, err = 0;
	loff_t addr = ebnum * mtd->erasesize;
	void *buf = iobuf;

	for (i = 0; i < n; i++) {
	err = mtd_read(mtd, addr, sz, &read, buf);
	/* Ignore corrected ECC errors */
	if (mtd_is_bitflip(err))
	err = 0;
	if (err \|\| read != sz) {
	pr_err("error: read failed at %#llx\n",
	addr);
	if (!err)
	err = -EINVAL;
	return err;
	}
	addr += sz;
	buf += sz;
	}
	if (pgcnt % 2) {
	err = mtd_read(mtd, addr, pgsize, &read, buf);
	/* Ignore corrected ECC errors */
	if (mtd_is_bitflip(err))
	err = 0;
	if (err \|\| read != pgsize) {
	pr_err("error: read failed at %#llx\n",
	addr);
	if (!err)
	err = -EINVAL;
	}
	}

	return err;
	}

	static int is_block_bad(int ebnum)
	{
	loff_t addr = ebnum * mtd->erasesize;
	int ret;

	ret = mtd_block_isbad(mtd, addr);
	if (ret)
	pr_info("block %d is bad\n", ebnum);
	return ret;
	}

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

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

	static long calc_speed(void)
	{
	uint64_t k;
	long ms;

	ms = (finish.tv_sec - start.tv_sec) * 1000 +
	(finish.tv_usec - start.tv_usec) / 1000;
	if (ms == 0)
	return 0;
	k = goodebcnt * (mtd->erasesize / 1024) * 1000;
	do_div(k, ms);
	return k;
	}

	static int scan_for_bad_eraseblocks(void)
	{
	int i, bad = 0;

	bbt = kzalloc(ebcnt, GFP_KERNEL);
	if (!bbt) {
	pr_err("error: cannot allocate memory\n");
	return -ENOMEM;
	}

	if (!mtd_can_have_bb(mtd))
	goto out;

	pr_info("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();
	}
	pr_info("scanned %d eraseblocks, %d are bad\n", i, bad);
	out:
	goodebcnt = ebcnt - bad;
	return 0;
	}

	static int __init mtd_speedtest_init(void)
	{
	int err, i, blocks, j, k;
	long speed;
	uint64_t tmp;

	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;
	}

	if (count)
	pr_info("MTD device: %d count: %d\n", dev, count);
	else
	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->writesize == 1) {
	pr_info("not NAND flash, assume page size is 512 "
	"bytes.\n");
	pgsize = 512;
	} else
	pgsize = mtd->writesize;

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

	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,
	pgsize, ebcnt, pgcnt, mtd->oobsize);

	if (count > 0 && count < ebcnt)
	ebcnt = count;

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

	prandom_bytes(iobuf, mtd->erasesize);

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

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

	/* Write all eraseblocks, 1 eraseblock at a time */
	pr_info("testing eraseblock write speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = write_eraseblock(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("eraseblock write speed is %ld KiB/s\n", speed);

	/* Read all eraseblocks, 1 eraseblock at a time */
	pr_info("testing eraseblock read speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = read_eraseblock(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("eraseblock read speed is %ld KiB/s\n", speed);

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

	/* Write all eraseblocks, 1 page at a time */
	pr_info("testing page write speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = write_eraseblock_by_page(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("page write speed is %ld KiB/s\n", speed);

	/* Read all eraseblocks, 1 page at a time */
	pr_info("testing page read speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = read_eraseblock_by_page(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("page read speed is %ld KiB/s\n", speed);

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

	/* Write all eraseblocks, 2 pages at a time */
	pr_info("testing 2 page write speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = write_eraseblock_by_2pages(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("2 page write speed is %ld KiB/s\n", speed);

	/* Read all eraseblocks, 2 pages at a time */
	pr_info("testing 2 page read speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = read_eraseblock_by_2pages(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("2 page read speed is %ld KiB/s\n", speed);

	/* Erase all eraseblocks */
	pr_info("Testing erase speed\n");
	start_timing();
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = erase_eraseblock(i);
	if (err)
	goto out;
	cond_resched();
	}
	stop_timing();
	speed = calc_speed();
	pr_info("erase speed is %ld KiB/s\n", speed);

	/* Multi-block erase all eraseblocks */
	for (k = 1; k < 7; k++) {
	blocks = 1 << k;
	pr_info("Testing %dx multi-block erase speed\n",
	blocks);
	start_timing();
	for (i = 0; i < ebcnt; ) {
	for (j = 0; j < blocks && (i + j) < ebcnt; j++)
	if (bbt[i + j])
	break;
	if (j < 1) {
	i++;
	continue;
	}
	err = multiblock_erase(i, j);
	if (err)
	goto out;
	cond_resched();
	i += j;
	}
	stop_timing();
	speed = calc_speed();
	pr_info("%dx multi-block erase speed is %ld KiB/s\n",
	blocks, speed);
	}
	pr_info("finished\n");
	out:
	kfree(iobuf);
	kfree(bbt);
	put_mtd_device(mtd);
	if (err)
	pr_info("error %d occurred\n", err);
	printk(KERN_INFO "=================================================\n");
	return err;
	}
	module_init(mtd_speedtest_init);

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

	MODULE_DESCRIPTION("Speed test module");
	MODULE_AUTHOR("Adrian Hunter");
	MODULE_LICENSE("GPL");