drivers/mtd/tests/mtd_subpagetest.c - LeafOS-Devices/android_kernel_realme_mt6785 - Gitiles

 /*
  * Copyright (C) 2006-2007 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 sub-page read and write on MTD device.
  * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
  *
  */

 #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 PRINT_PREF KERN_INFO "mtd_subpagetest: "

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

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

 static int subpgsize;
 static int bufsize;
 static int ebcnt;
 static int pgcnt;
 static int errcnt;
 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 inline void clear_data(unsigned char *buf, size_t len)
 {
 	memset(buf, 0, len);
 }

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

 	set_random_data(writebuf, subpgsize);
 	err = mtd->write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
 		       (long long)addr);
 		if (written != subpgsize) {
 			printk(PRINT_PREF "  write size: %#x\n", subpgsize);
 			printk(PRINT_PREF "  written: %#zx\n", written);
 		}
 		return err ? err : -1;
 	}

 	addr += subpgsize;

 	set_random_data(writebuf, subpgsize);
 	err = mtd->write(mtd, addr, subpgsize, &written, writebuf);
 	if (unlikely(err || written != subpgsize)) {
 		printk(PRINT_PREF "error: write failed at %#llx\n",
 		       (long long)addr);
 		if (written != subpgsize) {
 			printk(PRINT_PREF "  write size: %#x\n", subpgsize);
 			printk(PRINT_PREF "  written: %#zx\n", written);
 		}
 		return err ? err : -1;
 	}

 	return err;
 }

 static int write_eraseblock2(int ebnum)
 {
 	size_t written = 0;
 	int err = 0, k;
 	loff_t addr = ebnum * mtd->erasesize;

 	for (k = 1; k < 33; ++k) {
 		if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
 			break;
 		set_random_data(writebuf, subpgsize * k);
 		err = mtd->write(mtd, addr, subpgsize * k, &written, writebuf);
 		if (unlikely(err || written != subpgsize * k)) {
 			printk(PRINT_PREF "error: write failed at %#llx\n",
 			       (long long)addr);
 			if (written != subpgsize) {
 				printk(PRINT_PREF "  write size: %#x\n",
 				       subpgsize * k);
 				printk(PRINT_PREF "  written: %#08zx\n",
 				       written);
 			}
 			return err ? err : -1;
 		}
 		addr += subpgsize * k;
 	}

 	return err;
 }

 static void print_subpage(unsigned char *p)
 {
 	int i, j;

 	for (i = 0; i < subpgsize; ) {
 		for (j = 0; i < subpgsize && j < 32; ++i, ++j)
 			printk("%02x", *p++);
 		printk("\n");
 	}
 }

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

 	set_random_data(writebuf, subpgsize);
 	clear_data(readbuf, subpgsize);
 	read = 0;
 	err = mtd->read(mtd, addr, subpgsize, &read, readbuf);
 	if (unlikely(err || read != subpgsize)) {
 		if (mtd_is_bitflip(err) && read == subpgsize) {
 			printk(PRINT_PREF "ECC correction at %#llx\n",
 			       (long long)addr);
 			err = 0;
 		} else {
 			printk(PRINT_PREF "error: read failed at %#llx\n",
 			       (long long)addr);
 			return err ? err : -1;
 		}
 	}
 	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
 		printk(PRINT_PREF "error: verify failed at %#llx\n",
 		       (long long)addr);
 		printk(PRINT_PREF "------------- written----------------\n");
 		print_subpage(writebuf);
 		printk(PRINT_PREF "------------- read ------------------\n");
 		print_subpage(readbuf);
 		printk(PRINT_PREF "-------------------------------------\n");
 		errcnt += 1;
 	}

 	addr += subpgsize;

 	set_random_data(writebuf, subpgsize);
 	clear_data(readbuf, subpgsize);
 	read = 0;
 	err = mtd->read(mtd, addr, subpgsize, &read, readbuf);
 	if (unlikely(err || read != subpgsize)) {
 		if (mtd_is_bitflip(err) && read == subpgsize) {
 			printk(PRINT_PREF "ECC correction at %#llx\n",
 			       (long long)addr);
 			err = 0;
 		} else {
 			printk(PRINT_PREF "error: read failed at %#llx\n",
 			       (long long)addr);
 			return err ? err : -1;
 		}
 	}
 	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
 		printk(PRINT_PREF "error: verify failed at %#llx\n",
 		       (long long)addr);
 		printk(PRINT_PREF "------------- written----------------\n");
 		print_subpage(writebuf);
 		printk(PRINT_PREF "------------- read ------------------\n");
 		print_subpage(readbuf);
 		printk(PRINT_PREF "-------------------------------------\n");
 		errcnt += 1;
 	}

 	return err;
 }

 static int verify_eraseblock2(int ebnum)
 {
 	size_t read = 0;
 	int err = 0, k;
 	loff_t addr = ebnum * mtd->erasesize;

 	for (k = 1; k < 33; ++k) {
 		if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
 			break;
 		set_random_data(writebuf, subpgsize * k);
 		clear_data(readbuf, subpgsize * k);
 		read = 0;
 		err = mtd->read(mtd, addr, subpgsize * k, &read, readbuf);
 		if (unlikely(err || read != subpgsize * k)) {
 			if (mtd_is_bitflip(err) && read == subpgsize * k) {
 				printk(PRINT_PREF "ECC correction at %#llx\n",
 				       (long long)addr);
 				err = 0;
 			} else {
 				printk(PRINT_PREF "error: read failed at "
 				       "%#llx\n", (long long)addr);
 				return err ? err : -1;
 			}
 		}
 		if (unlikely(memcmp(readbuf, writebuf, subpgsize * k))) {
 			printk(PRINT_PREF "error: verify failed at %#llx\n",
 			       (long long)addr);
 			errcnt += 1;
 		}
 		addr += subpgsize * k;
 	}

 	return err;
 }

 static int verify_eraseblock_ff(int ebnum)
 {
 	uint32_t j;
 	size_t read = 0;
 	int err = 0;
 	loff_t addr = ebnum * mtd->erasesize;

 	memset(writebuf, 0xff, subpgsize);
 	for (j = 0; j < mtd->erasesize / subpgsize; ++j) {
 		clear_data(readbuf, subpgsize);
 		read = 0;
 		err = mtd->read(mtd, addr, subpgsize, &read, readbuf);
 		if (unlikely(err || read != subpgsize)) {
 			if (mtd_is_bitflip(err) && read == subpgsize) {
 				printk(PRINT_PREF "ECC correction at %#llx\n",
 				       (long long)addr);
 				err = 0;
 			} else {
 				printk(PRINT_PREF "error: read failed at "
 				       "%#llx\n", (long long)addr);
 				return err ? err : -1;
 			}
 		}
 		if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
 			printk(PRINT_PREF "error: verify 0xff failed at "
 			       "%#llx\n", (long long)addr);
 			errcnt += 1;
 		}
 		addr += subpgsize;
 	}

 	return err;
 }

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

 	printk(PRINT_PREF "verifying all eraseblocks for 0xff\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = verify_eraseblock_ff(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)
 {
 	loff_t addr = ebnum * mtd->erasesize;
 	int ret;

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

 	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_subpagetest_init(void)
 {
 	int err = 0;
 	uint32_t i;
 	uint64_t tmp;

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

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

 	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;
 	}

 	subpgsize = mtd->writesize >> mtd->subpage_sft;
 	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, subpage size %u, count of eraseblocks %u, "
 	       "pages per eraseblock %u, OOB size %u\n",
 	       (unsigned long long)mtd->size, mtd->erasesize,
 	       mtd->writesize, subpgsize, ebcnt, pgcnt, mtd->oobsize);

 	err = -ENOMEM;
 	bufsize = subpgsize * 32;
 	writebuf = kmalloc(bufsize, GFP_KERNEL);
 	if (!writebuf) {
 		printk(PRINT_PREF "error: cannot allocate memory\n");
 		goto out;
 	}
 	readbuf = kmalloc(bufsize, GFP_KERNEL);
 	if (!readbuf) {
 		printk(PRINT_PREF "error: cannot allocate memory\n");
 		goto out;
 	}

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

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

 	printk(PRINT_PREF "writing whole device\n");
 	simple_srand(1);
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = write_eraseblock(i);
 		if (unlikely(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);

 	simple_srand(1);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = verify_eraseblock(i);
 		if (unlikely(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);

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

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

 	/* Write all eraseblocks */
 	simple_srand(3);
 	printk(PRINT_PREF "writing whole device\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = write_eraseblock2(i);
 		if (unlikely(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 */
 	simple_srand(3);
 	printk(PRINT_PREF "verifying all eraseblocks\n");
 	for (i = 0; i < ebcnt; ++i) {
 		if (bbt[i])
 			continue;
 		err = verify_eraseblock2(i);
 		if (unlikely(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);

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

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

 	printk(PRINT_PREF "finished with %d errors\n", errcnt);

 out:
 	kfree(bbt);
 	kfree(readbuf);
 	kfree(writebuf);
 	put_mtd_device(mtd);
 	if (err)
 		printk(PRINT_PREF "error %d occurred\n", err);
 	printk(KERN_INFO "=================================================\n");
 	return err;
 }
 module_init(mtd_subpagetest_init);

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

 MODULE_DESCRIPTION("Subpage test module");
 MODULE_AUTHOR("Adrian Hunter");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2006-2007 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 sub-page read and write on MTD device.
	* Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
	*
	*/

	#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 PRINT_PREF KERN_INFO "mtd_subpagetest: "

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

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

	static int subpgsize;
	static int bufsize;
	static int ebcnt;
	static int pgcnt;
	static int errcnt;
	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 inline void clear_data(unsigned char *buf, size_t len)
	{
	memset(buf, 0, len);
	}

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

	set_random_data(writebuf, subpgsize);
	err = mtd->write(mtd, addr, subpgsize, &written, writebuf);
	if (unlikely(err \|\| written != subpgsize)) {
	printk(PRINT_PREF "error: write failed at %#llx\n",
	(long long)addr);
	if (written != subpgsize) {
	printk(PRINT_PREF " write size: %#x\n", subpgsize);
	printk(PRINT_PREF " written: %#zx\n", written);
	}
	return err ? err : -1;
	}

	addr += subpgsize;

	set_random_data(writebuf, subpgsize);
	err = mtd->write(mtd, addr, subpgsize, &written, writebuf);
	if (unlikely(err \|\| written != subpgsize)) {
	printk(PRINT_PREF "error: write failed at %#llx\n",
	(long long)addr);
	if (written != subpgsize) {
	printk(PRINT_PREF " write size: %#x\n", subpgsize);
	printk(PRINT_PREF " written: %#zx\n", written);
	}
	return err ? err : -1;
	}

	return err;
	}

	static int write_eraseblock2(int ebnum)
	{
	size_t written = 0;
	int err = 0, k;
	loff_t addr = ebnum * mtd->erasesize;

	for (k = 1; k < 33; ++k) {
	if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
	break;
	set_random_data(writebuf, subpgsize * k);
	err = mtd->write(mtd, addr, subpgsize * k, &written, writebuf);
	if (unlikely(err \|\| written != subpgsize * k)) {
	printk(PRINT_PREF "error: write failed at %#llx\n",
	(long long)addr);
	if (written != subpgsize) {
	printk(PRINT_PREF " write size: %#x\n",
	subpgsize * k);
	printk(PRINT_PREF " written: %#08zx\n",
	written);
	}
	return err ? err : -1;
	}
	addr += subpgsize * k;
	}

	return err;
	}

	static void print_subpage(unsigned char *p)
	{
	int i, j;

	for (i = 0; i < subpgsize; ) {
	for (j = 0; i < subpgsize && j < 32; ++i, ++j)
	printk("%02x", *p++);
	printk("\n");
	}
	}

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

	set_random_data(writebuf, subpgsize);
	clear_data(readbuf, subpgsize);
	read = 0;
	err = mtd->read(mtd, addr, subpgsize, &read, readbuf);
	if (unlikely(err \|\| read != subpgsize)) {
	if (mtd_is_bitflip(err) && read == subpgsize) {
	printk(PRINT_PREF "ECC correction at %#llx\n",
	(long long)addr);
	err = 0;
	} else {
	printk(PRINT_PREF "error: read failed at %#llx\n",
	(long long)addr);
	return err ? err : -1;
	}
	}
	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
	printk(PRINT_PREF "error: verify failed at %#llx\n",
	(long long)addr);
	printk(PRINT_PREF "------------- written----------------\n");
	print_subpage(writebuf);
	printk(PRINT_PREF "------------- read ------------------\n");
	print_subpage(readbuf);
	printk(PRINT_PREF "-------------------------------------\n");
	errcnt += 1;
	}

	addr += subpgsize;

	set_random_data(writebuf, subpgsize);
	clear_data(readbuf, subpgsize);
	read = 0;
	err = mtd->read(mtd, addr, subpgsize, &read, readbuf);
	if (unlikely(err \|\| read != subpgsize)) {
	if (mtd_is_bitflip(err) && read == subpgsize) {
	printk(PRINT_PREF "ECC correction at %#llx\n",
	(long long)addr);
	err = 0;
	} else {
	printk(PRINT_PREF "error: read failed at %#llx\n",
	(long long)addr);
	return err ? err : -1;
	}
	}
	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
	printk(PRINT_PREF "error: verify failed at %#llx\n",
	(long long)addr);
	printk(PRINT_PREF "------------- written----------------\n");
	print_subpage(writebuf);
	printk(PRINT_PREF "------------- read ------------------\n");
	print_subpage(readbuf);
	printk(PRINT_PREF "-------------------------------------\n");
	errcnt += 1;
	}

	return err;
	}

	static int verify_eraseblock2(int ebnum)
	{
	size_t read = 0;
	int err = 0, k;
	loff_t addr = ebnum * mtd->erasesize;

	for (k = 1; k < 33; ++k) {
	if (addr + (subpgsize * k) > (ebnum + 1) * mtd->erasesize)
	break;
	set_random_data(writebuf, subpgsize * k);
	clear_data(readbuf, subpgsize * k);
	read = 0;
	err = mtd->read(mtd, addr, subpgsize * k, &read, readbuf);
	if (unlikely(err \|\| read != subpgsize * k)) {
	if (mtd_is_bitflip(err) && read == subpgsize * k) {
	printk(PRINT_PREF "ECC correction at %#llx\n",
	(long long)addr);
	err = 0;
	} else {
	printk(PRINT_PREF "error: read failed at "
	"%#llx\n", (long long)addr);
	return err ? err : -1;
	}
	}
	if (unlikely(memcmp(readbuf, writebuf, subpgsize * k))) {
	printk(PRINT_PREF "error: verify failed at %#llx\n",
	(long long)addr);
	errcnt += 1;
	}
	addr += subpgsize * k;
	}

	return err;
	}

	static int verify_eraseblock_ff(int ebnum)
	{
	uint32_t j;
	size_t read = 0;
	int err = 0;
	loff_t addr = ebnum * mtd->erasesize;

	memset(writebuf, 0xff, subpgsize);
	for (j = 0; j < mtd->erasesize / subpgsize; ++j) {
	clear_data(readbuf, subpgsize);
	read = 0;
	err = mtd->read(mtd, addr, subpgsize, &read, readbuf);
	if (unlikely(err \|\| read != subpgsize)) {
	if (mtd_is_bitflip(err) && read == subpgsize) {
	printk(PRINT_PREF "ECC correction at %#llx\n",
	(long long)addr);
	err = 0;
	} else {
	printk(PRINT_PREF "error: read failed at "
	"%#llx\n", (long long)addr);
	return err ? err : -1;
	}
	}
	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
	printk(PRINT_PREF "error: verify 0xff failed at "
	"%#llx\n", (long long)addr);
	errcnt += 1;
	}
	addr += subpgsize;
	}

	return err;
	}

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

	printk(PRINT_PREF "verifying all eraseblocks for 0xff\n");
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = verify_eraseblock_ff(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)
	{
	loff_t addr = ebnum * mtd->erasesize;
	int ret;

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

	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_subpagetest_init(void)
	{
	int err = 0;
	uint32_t i;
	uint64_t tmp;

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

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

	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;
	}

	subpgsize = mtd->writesize >> mtd->subpage_sft;
	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, subpage size %u, count of eraseblocks %u, "
	"pages per eraseblock %u, OOB size %u\n",
	(unsigned long long)mtd->size, mtd->erasesize,
	mtd->writesize, subpgsize, ebcnt, pgcnt, mtd->oobsize);

	err = -ENOMEM;
	bufsize = subpgsize * 32;
	writebuf = kmalloc(bufsize, GFP_KERNEL);
	if (!writebuf) {
	printk(PRINT_PREF "error: cannot allocate memory\n");
	goto out;
	}
	readbuf = kmalloc(bufsize, GFP_KERNEL);
	if (!readbuf) {
	printk(PRINT_PREF "error: cannot allocate memory\n");
	goto out;
	}

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

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

	printk(PRINT_PREF "writing whole device\n");
	simple_srand(1);
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = write_eraseblock(i);
	if (unlikely(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);

	simple_srand(1);
	printk(PRINT_PREF "verifying all eraseblocks\n");
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = verify_eraseblock(i);
	if (unlikely(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);

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

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

	/* Write all eraseblocks */
	simple_srand(3);
	printk(PRINT_PREF "writing whole device\n");
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = write_eraseblock2(i);
	if (unlikely(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 */
	simple_srand(3);
	printk(PRINT_PREF "verifying all eraseblocks\n");
	for (i = 0; i < ebcnt; ++i) {
	if (bbt[i])
	continue;
	err = verify_eraseblock2(i);
	if (unlikely(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);

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

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

	printk(PRINT_PREF "finished with %d errors\n", errcnt);

	out:
	kfree(bbt);
	kfree(readbuf);
	kfree(writebuf);
	put_mtd_device(mtd);
	if (err)
	printk(PRINT_PREF "error %d occurred\n", err);
	printk(KERN_INFO "=================================================\n");
	return err;
	}
	module_init(mtd_subpagetest_init);

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

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