Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 3876 insertions, 0 deletions

diff --git a/drivers/mtd/tests/Makefile b/drivers/mtd/tests/Makefile
new file mode 100644
index 000000000..5de0378f9
--- /dev/null
+++ b/drivers/mtd/tests/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_MTD_TESTS) += mtd_oobtest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_pagetest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_readtest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_speedtest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_stresstest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_subpagetest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_torturetest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_nandecctest.o
+obj-$(CONFIG_MTD_TESTS) += mtd_nandbiterrs.o
+
+mtd_oobtest-objs := oobtest.o mtd_test.o
+mtd_pagetest-objs := pagetest.o mtd_test.o
+mtd_readtest-objs := readtest.o mtd_test.o
+mtd_speedtest-objs := speedtest.o mtd_test.o
+mtd_stresstest-objs := stresstest.o mtd_test.o
+mtd_subpagetest-objs := subpagetest.o mtd_test.o
+mtd_torturetest-objs := torturetest.o mtd_test.o
+mtd_nandbiterrs-objs := nandbiterrs.o mtd_test.o
diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
new file mode 100644
index 000000000..440988562
--- /dev/null
+++ b/drivers/mtd/tests/mtd_nandecctest.c
@@ -0,0 +1,329 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/random.h>
+#include <linux/string.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/mtd/nand-ecc-sw-hamming.h>
+
+#include "mtd_test.h"
+
+/*
+ * Test the implementation for software ECC
+ *
+ * No actual MTD device is needed, So we don't need to warry about losing
+ * important data by human error.
+ *
+ * This covers possible patterns of corruption which can be reliably corrected
+ * or detected.
+ */
+
+#if IS_ENABLED(CONFIG_MTD_RAW_NAND)
+
+struct nand_ecc_test {
+	const char *name;
+	void (*prepare)(void *, void *, void *, void *, const size_t);
+	int (*verify)(void *, void *, void *, const size_t);
+};
+
+/*
+ * The reason for this __change_bit_le() instead of __change_bit() is to inject
+ * bit error properly within the region which is not a multiple of
+ * sizeof(unsigned long) on big-endian systems
+ */
+#ifdef __LITTLE_ENDIAN
+#define __change_bit_le(nr, addr) __change_bit(nr, addr)
+#elif defined(__BIG_ENDIAN)
+#define __change_bit_le(nr, addr) \
+		__change_bit((nr) ^ ((BITS_PER_LONG - 1) & ~0x7), addr)
+#else
+#error "Unknown byte order"
+#endif
+
+static void single_bit_error_data(void *error_data, void *correct_data,
+				size_t size)
+{
+	unsigned int offset = prandom_u32_max(size * BITS_PER_BYTE);
+
+	memcpy(error_data, correct_data, size);
+	__change_bit_le(offset, error_data);
+}
+
+static void double_bit_error_data(void *error_data, void *correct_data,
+				size_t size)
+{
+	unsigned int offset[2];
+
+	offset[0] = prandom_u32_max(size * BITS_PER_BYTE);
+	do {
+		offset[1] = prandom_u32_max(size * BITS_PER_BYTE);
+	} while (offset[0] == offset[1]);
+
+	memcpy(error_data, correct_data, size);
+
+	__change_bit_le(offset[0], error_data);
+	__change_bit_le(offset[1], error_data);
+}
+
+static unsigned int random_ecc_bit(size_t size)
+{
+	unsigned int offset = prandom_u32_max(3 * BITS_PER_BYTE);
+
+	if (size == 256) {
+		/*
+		 * Don't inject a bit error into the insignificant bits (16th
+		 * and 17th bit) in ECC code for 256 byte data block
+		 */
+		while (offset == 16 || offset == 17)
+			offset = prandom_u32_max(3 * BITS_PER_BYTE);
+	}
+
+	return offset;
+}
+
+static void single_bit_error_ecc(void *error_ecc, void *correct_ecc,
+				size_t size)
+{
+	unsigned int offset = random_ecc_bit(size);
+
+	memcpy(error_ecc, correct_ecc, 3);
+	__change_bit_le(offset, error_ecc);
+}
+
+static void double_bit_error_ecc(void *error_ecc, void *correct_ecc,
+				size_t size)
+{
+	unsigned int offset[2];
+
+	offset[0] = random_ecc_bit(size);
+	do {
+		offset[1] = random_ecc_bit(size);
+	} while (offset[0] == offset[1]);
+
+	memcpy(error_ecc, correct_ecc, 3);
+	__change_bit_le(offset[0], error_ecc);
+	__change_bit_le(offset[1], error_ecc);
+}
+
+static void no_bit_error(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	memcpy(error_data, correct_data, size);
+	memcpy(error_ecc, correct_ecc, 3);
+}
+
+static int no_bit_error_verify(void *error_data, void *error_ecc,
+				void *correct_data, const size_t size)
+{
+	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
+	unsigned char calc_ecc[3];
+	int ret;
+
+	ecc_sw_hamming_calculate(error_data, size, calc_ecc, sm_order);
+	ret = ecc_sw_hamming_correct(error_data, error_ecc, calc_ecc, size,
+				     sm_order);
+	if (ret == 0 && !memcmp(correct_data, error_data, size))
+		return 0;
+
+	return -EINVAL;
+}
+
+static void single_bit_error_in_data(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	single_bit_error_data(error_data, correct_data, size);
+	memcpy(error_ecc, correct_ecc, 3);
+}
+
+static void single_bit_error_in_ecc(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	memcpy(error_data, correct_data, size);
+	single_bit_error_ecc(error_ecc, correct_ecc, size);
+}
+
+static int single_bit_error_correct(void *error_data, void *error_ecc,
+				void *correct_data, const size_t size)
+{
+	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
+	unsigned char calc_ecc[3];
+	int ret;
+
+	ecc_sw_hamming_calculate(error_data, size, calc_ecc, sm_order);
+	ret = ecc_sw_hamming_correct(error_data, error_ecc, calc_ecc, size,
+				     sm_order);
+	if (ret == 1 && !memcmp(correct_data, error_data, size))
+		return 0;
+
+	return -EINVAL;
+}
+
+static void double_bit_error_in_data(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	double_bit_error_data(error_data, correct_data, size);
+	memcpy(error_ecc, correct_ecc, 3);
+}
+
+static void single_bit_error_in_data_and_ecc(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	single_bit_error_data(error_data, correct_data, size);
+	single_bit_error_ecc(error_ecc, correct_ecc, size);
+}
+
+static void double_bit_error_in_ecc(void *error_data, void *error_ecc,
+		void *correct_data, void *correct_ecc, const size_t size)
+{
+	memcpy(error_data, correct_data, size);
+	double_bit_error_ecc(error_ecc, correct_ecc, size);
+}
+
+static int double_bit_error_detect(void *error_data, void *error_ecc,
+				void *correct_data, const size_t size)
+{
+	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
+	unsigned char calc_ecc[3];
+	int ret;
+
+	ecc_sw_hamming_calculate(error_data, size, calc_ecc, sm_order);
+	ret = ecc_sw_hamming_correct(error_data, error_ecc, calc_ecc, size,
+				     sm_order);
+
+	return (ret == -EBADMSG) ? 0 : -EINVAL;
+}
+
+static const struct nand_ecc_test nand_ecc_test[] = {
+	{
+		.name = "no-bit-error",
+		.prepare = no_bit_error,
+		.verify = no_bit_error_verify,
+	},
+	{
+		.name = "single-bit-error-in-data-correct",
+		.prepare = single_bit_error_in_data,
+		.verify = single_bit_error_correct,
+	},
+	{
+		.name = "single-bit-error-in-ecc-correct",
+		.prepare = single_bit_error_in_ecc,
+		.verify = single_bit_error_correct,
+	},
+	{
+		.name = "double-bit-error-in-data-detect",
+		.prepare = double_bit_error_in_data,
+		.verify = double_bit_error_detect,
+	},
+	{
+		.name = "single-bit-error-in-data-and-ecc-detect",
+		.prepare = single_bit_error_in_data_and_ecc,
+		.verify = double_bit_error_detect,
+	},
+	{
+		.name = "double-bit-error-in-ecc-detect",
+		.prepare = double_bit_error_in_ecc,
+		.verify = double_bit_error_detect,
+	},
+};
+
+static void dump_data_ecc(void *error_data, void *error_ecc, void *correct_data,
+			void *correct_ecc, const size_t size)
+{
+	pr_info("hexdump of error data:\n");
+	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4,
+			error_data, size, false);
+	print_hex_dump(KERN_INFO, "hexdump of error ecc: ",
+			DUMP_PREFIX_NONE, 16, 1, error_ecc, 3, false);
+
+	pr_info("hexdump of correct data:\n");
+	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_OFFSET, 16, 4,
+			correct_data, size, false);
+	print_hex_dump(KERN_INFO, "hexdump of correct ecc: ",
+			DUMP_PREFIX_NONE, 16, 1, correct_ecc, 3, false);
+}
+
+static int nand_ecc_test_run(const size_t size)
+{
+	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
+	int i;
+	int err = 0;
+	void *error_data;
+	void *error_ecc;
+	void *correct_data;
+	void *correct_ecc;
+
+	error_data = kmalloc(size, GFP_KERNEL);
+	error_ecc = kmalloc(3, GFP_KERNEL);
+	correct_data = kmalloc(size, GFP_KERNEL);
+	correct_ecc = kmalloc(3, GFP_KERNEL);
+
+	if (!error_data || !error_ecc || !correct_data || !correct_ecc) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	get_random_bytes(correct_data, size);
+	ecc_sw_hamming_calculate(correct_data, size, correct_ecc, sm_order);
+	for (i = 0; i < ARRAY_SIZE(nand_ecc_test); i++) {
+		nand_ecc_test[i].prepare(error_data, error_ecc,
+				correct_data, correct_ecc, size);
+		err = nand_ecc_test[i].verify(error_data, error_ecc,
+						correct_data, size);
+
+		if (err) {
+			pr_err("not ok - %s-%zd\n",
+				nand_ecc_test[i].name, size);
+			dump_data_ecc(error_data, error_ecc,
+				correct_data, correct_ecc, size);
+			break;
+		}
+		pr_info("ok - %s-%zd\n",
+			nand_ecc_test[i].name, size);
+
+		err = mtdtest_relax();
+		if (err)
+			break;
+	}
+error:
+	kfree(error_data);
+	kfree(error_ecc);
+	kfree(correct_data);
+	kfree(correct_ecc);
+
+	return err;
+}
+
+#else
+
+static int nand_ecc_test_run(const size_t size)
+{
+	return 0;
+}
+
+#endif
+
+static int __init ecc_test_init(void)
+{
+	int err;
+
+	err = nand_ecc_test_run(256);
+	if (err)
+		return err;
+
+	return nand_ecc_test_run(512);
+}
+
+static void __exit ecc_test_exit(void)
+{
+}
+
+module_init(ecc_test_init);
+module_exit(ecc_test_exit);
+
+MODULE_DESCRIPTION("NAND ECC function test module");
+MODULE_AUTHOR("Akinobu Mita");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mtd/tests/mtd_test.c b/drivers/mtd/tests/mtd_test.c
new file mode 100644
index 000000000..c84250bef
--- /dev/null
+++ b/drivers/mtd/tests/mtd_test.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) "mtd_test: " fmt
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/printk.h>
+
+#include "mtd_test.h"
+
+int mtdtest_erase_eraseblock(struct mtd_info *mtd, unsigned int ebnum)
+{
+	int err;
+	struct erase_info ei;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	memset(&ei, 0, sizeof(struct erase_info));
+	ei.addr = addr;
+	ei.len  = mtd->erasesize;
+
+	err = mtd_erase(mtd, &ei);
+	if (err) {
+		pr_info("error %d while erasing EB %d\n", err, ebnum);
+		return err;
+	}
+
+	return 0;
+}
+
+static int is_block_bad(struct mtd_info *mtd, unsigned int ebnum)
+{
+	int ret;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	ret = mtd_block_isbad(mtd, addr);
+	if (ret)
+		pr_info("block %d is bad\n", ebnum);
+
+	return ret;
+}
+
+int mtdtest_scan_for_bad_eraseblocks(struct mtd_info *mtd, unsigned char *bbt,
+					unsigned int eb, int ebcnt)
+{
+	int i, bad = 0;
+
+	if (!mtd_can_have_bb(mtd))
+		return 0;
+
+	pr_info("scanning for bad eraseblocks\n");
+	for (i = 0; i < ebcnt; ++i) {
+		bbt[i] = is_block_bad(mtd, eb + i) ? 1 : 0;
+		if (bbt[i])
+			bad += 1;
+		cond_resched();
+	}
+	pr_info("scanned %d eraseblocks, %d are bad\n", i, bad);
+
+	return 0;
+}
+
+int mtdtest_erase_good_eraseblocks(struct mtd_info *mtd, unsigned char *bbt,
+				unsigned int eb, int ebcnt)
+{
+	int err;
+	unsigned int i;
+
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = mtdtest_erase_eraseblock(mtd, eb + i);
+		if (err)
+			return err;
+		cond_resched();
+	}
+
+	return 0;
+}
+
+int mtdtest_read(struct mtd_info *mtd, loff_t addr, size_t size, void *buf)
+{
+	size_t read;
+	int err;
+
+	err = mtd_read(mtd, addr, size, &read, buf);
+	/* Ignore corrected ECC errors */
+	if (mtd_is_bitflip(err))
+		err = 0;
+	if (!err && read != size)
+		err = -EIO;
+	if (err)
+		pr_err("error: read failed at %#llx\n", addr);
+
+	return err;
+}
+
+int mtdtest_write(struct mtd_info *mtd, loff_t addr, size_t size,
+		const void *buf)
+{
+	size_t written;
+	int err;
+
+	err = mtd_write(mtd, addr, size, &written, buf);
+	if (!err && written != size)
+		err = -EIO;
+	if (err)
+		pr_err("error: write failed at %#llx\n", addr);
+
+	return err;
+}
diff --git a/drivers/mtd/tests/mtd_test.h b/drivers/mtd/tests/mtd_test.h
new file mode 100644
index 000000000..5a6e3bbe0
--- /dev/null
+++ b/drivers/mtd/tests/mtd_test.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/mtd/mtd.h>
+#include <linux/sched/signal.h>
+
+static inline int mtdtest_relax(void)
+{
+	cond_resched();
+	if (signal_pending(current)) {
+		pr_info("aborting test due to pending signal!\n");
+		return -EINTR;
+	}
+
+	return 0;
+}
+
+int mtdtest_erase_eraseblock(struct mtd_info *mtd, unsigned int ebnum);
+int mtdtest_scan_for_bad_eraseblocks(struct mtd_info *mtd, unsigned char *bbt,
+					unsigned int eb, int ebcnt);
+int mtdtest_erase_good_eraseblocks(struct mtd_info *mtd, unsigned char *bbt,
+				unsigned int eb, int ebcnt);
+
+int mtdtest_read(struct mtd_info *mtd, loff_t addr, size_t size, void *buf);
+int mtdtest_write(struct mtd_info *mtd, loff_t addr, size_t size,
+		const void *buf);
diff --git a/drivers/mtd/tests/nandbiterrs.c b/drivers/mtd/tests/nandbiterrs.c
new file mode 100644
index 000000000..98d7508f9
--- /dev/null
+++ b/drivers/mtd/tests/nandbiterrs.c
@@ -0,0 +1,419 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright © 2012 NetCommWireless
+ * Iwo Mergler <Iwo.Mergler@netcommwireless.com.au>
+ *
+ * Test for multi-bit error recovery on a NAND page This mostly tests the
+ * ECC controller / driver.
+ *
+ * There are two test modes:
+ *
+ *	0 - artificially inserting bit errors until the ECC fails
+ *	    This is the default method and fairly quick. It should
+ *	    be independent of the quality of the FLASH.
+ *
+ *	1 - re-writing the same pattern repeatedly until the ECC fails.
+ *	    This method relies on the physics of NAND FLASH to eventually
+ *	    generate '0' bits if '1' has been written sufficient times.
+ *	    Depending on the NAND, the first bit errors will appear after
+ *	    1000 or more writes and then will usually snowball, reaching the
+ *	    limits of the ECC quickly.
+ *
+ *	    The test stops after 10000 cycles, should your FLASH be
+ *	    exceptionally good and not generate bit errors before that. Try
+ *	    a different page in that case.
+ *
+ * Please note that neither of these tests will significantly 'use up' any
+ * FLASH endurance. Only a maximum of two erase operations will be performed.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mtd/mtd.h>
+#include <linux/err.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/slab.h>
+#include "mtd_test.h"
+
+static int dev;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+static unsigned page_offset;
+module_param(page_offset, uint, S_IRUGO);
+MODULE_PARM_DESC(page_offset, "Page number relative to dev start");
+
+static unsigned seed;
+module_param(seed, uint, S_IRUGO);
+MODULE_PARM_DESC(seed, "Random seed");
+
+static int mode;
+module_param(mode, int, S_IRUGO);
+MODULE_PARM_DESC(mode, "0=incremental errors, 1=overwrite test");
+
+static unsigned max_overwrite = 10000;
+
+static loff_t   offset;     /* Offset of the page we're using. */
+static unsigned eraseblock; /* Eraseblock number for our page. */
+
+/* We assume that the ECC can correct up to a certain number
+ * of biterrors per subpage. */
+static unsigned subsize;  /* Size of subpages */
+static unsigned subcount; /* Number of subpages per page */
+
+static struct mtd_info *mtd;   /* MTD device */
+
+static uint8_t *wbuffer; /* One page write / compare buffer */
+static uint8_t *rbuffer; /* One page read buffer */
+
+/* 'random' bytes from known offsets */
+static uint8_t hash(unsigned offset)
+{
+	unsigned v = offset;
+	unsigned char c;
+	v ^= 0x7f7edfd3;
+	v = v ^ (v >> 3);
+	v = v ^ (v >> 5);
+	v = v ^ (v >> 13);
+	c = v & 0xFF;
+	/* Reverse bits of result. */
+	c = (c & 0x0F) << 4 | (c & 0xF0) >> 4;
+	c = (c & 0x33) << 2 | (c & 0xCC) >> 2;
+	c = (c & 0x55) << 1 | (c & 0xAA) >> 1;
+	return c;
+}
+
+/* Writes wbuffer to page */
+static int write_page(int log)
+{
+	if (log)
+		pr_info("write_page\n");
+
+	return mtdtest_write(mtd, offset, mtd->writesize, wbuffer);
+}
+
+/* Re-writes the data area while leaving the OOB alone. */
+static int rewrite_page(int log)
+{
+	int err = 0;
+	struct mtd_oob_ops ops = { };
+
+	if (log)
+		pr_info("rewrite page\n");
+
+	ops.mode      = MTD_OPS_RAW; /* No ECC */
+	ops.len       = mtd->writesize;
+	ops.retlen    = 0;
+	ops.ooblen    = 0;
+	ops.oobretlen = 0;
+	ops.ooboffs   = 0;
+	ops.datbuf    = wbuffer;
+	ops.oobbuf    = NULL;
+
+	err = mtd_write_oob(mtd, offset, &ops);
+	if (err || ops.retlen != mtd->writesize) {
+		pr_err("error: write_oob failed (%d)\n", err);
+		if (!err)
+			err = -EIO;
+	}
+
+	return err;
+}
+
+/* Reads page into rbuffer. Returns number of corrected bit errors (>=0)
+ * or error (<0) */
+static int read_page(int log)
+{
+	int err = 0;
+	size_t read;
+	struct mtd_ecc_stats oldstats;
+
+	if (log)
+		pr_info("read_page\n");
+
+	/* Saving last mtd stats */
+	memcpy(&oldstats, &mtd->ecc_stats, sizeof(oldstats));
+
+	err = mtd_read(mtd, offset, mtd->writesize, &read, rbuffer);
+	if (!err || err == -EUCLEAN)
+		err = mtd->ecc_stats.corrected - oldstats.corrected;
+
+	if (err < 0 || read != mtd->writesize) {
+		pr_err("error: read failed at %#llx\n", (long long)offset);
+		if (err >= 0)
+			err = -EIO;
+	}
+
+	return err;
+}
+
+/* Verifies rbuffer against random sequence */
+static int verify_page(int log)
+{
+	unsigned i, errs = 0;
+
+	if (log)
+		pr_info("verify_page\n");
+
+	for (i = 0; i < mtd->writesize; i++) {
+		if (rbuffer[i] != hash(i+seed)) {
+			pr_err("Error: page offset %u, expected %02x, got %02x\n",
+				i, hash(i+seed), rbuffer[i]);
+			errs++;
+		}
+	}
+
+	if (errs)
+		return -EIO;
+	else
+		return 0;
+}
+
+#define CBIT(v, n) ((v) & (1 << (n)))
+#define BCLR(v, n) ((v) = (v) & ~(1 << (n)))
+
+/* Finds the first '1' bit in wbuffer starting at offset 'byte'
+ * and sets it to '0'. */
+static int insert_biterror(unsigned byte)
+{
+	int bit;
+
+	while (byte < mtd->writesize) {
+		for (bit = 7; bit >= 0; bit--) {
+			if (CBIT(wbuffer[byte], bit)) {
+				BCLR(wbuffer[byte], bit);
+				pr_info("Inserted biterror @ %u/%u\n", byte, bit);
+				return 0;
+			}
+		}
+		byte++;
+	}
+	pr_err("biterror: Failed to find a '1' bit\n");
+	return -EIO;
+}
+
+/* Writes 'random' data to page and then introduces deliberate bit
+ * errors into the page, while verifying each step. */
+static int incremental_errors_test(void)
+{
+	int err = 0;
+	unsigned i;
+	unsigned errs_per_subpage = 0;
+
+	pr_info("incremental biterrors test\n");
+
+	for (i = 0; i < mtd->writesize; i++)
+		wbuffer[i] = hash(i+seed);
+
+	err = write_page(1);
+	if (err)
+		goto exit;
+
+	while (1) {
+
+		err = rewrite_page(1);
+		if (err)
+			goto exit;
+
+		err = read_page(1);
+		if (err > 0)
+			pr_info("Read reported %d corrected bit errors\n", err);
+		if (err < 0) {
+			pr_err("After %d biterrors per subpage, read reported error %d\n",
+				errs_per_subpage, err);
+			err = 0;
+			goto exit;
+		}
+
+		err = verify_page(1);
+		if (err) {
+			pr_err("ECC failure, read data is incorrect despite read success\n");
+			goto exit;
+		}
+
+		pr_info("Successfully corrected %d bit errors per subpage\n",
+			errs_per_subpage);
+
+		for (i = 0; i < subcount; i++) {
+			err = insert_biterror(i * subsize);
+			if (err < 0)
+				goto exit;
+		}
+		errs_per_subpage++;
+	}
+
+exit:
+	return err;
+}
+
+
+/* Writes 'random' data to page and then re-writes that same data repeatedly.
+   This eventually develops bit errors (bits written as '1' will slowly become
+   '0'), which are corrected as far as the ECC is capable of. */
+static int overwrite_test(void)
+{
+	int err = 0;
+	unsigned i;
+	unsigned max_corrected = 0;
+	unsigned opno = 0;
+	/* We don't expect more than this many correctable bit errors per
+	 * page. */
+	#define MAXBITS 512
+	static unsigned bitstats[MAXBITS]; /* bit error histogram. */
+
+	memset(bitstats, 0, sizeof(bitstats));
+
+	pr_info("overwrite biterrors test\n");
+
+	for (i = 0; i < mtd->writesize; i++)
+		wbuffer[i] = hash(i+seed);
+
+	err = write_page(1);
+	if (err)
+		goto exit;
+
+	while (opno < max_overwrite) {
+
+		err = write_page(0);
+		if (err)
+			break;
+
+		err = read_page(0);
+		if (err >= 0) {
+			if (err >= MAXBITS) {
+				pr_info("Implausible number of bit errors corrected\n");
+				err = -EIO;
+				break;
+			}
+			bitstats[err]++;
+			if (err > max_corrected) {
+				max_corrected = err;
+				pr_info("Read reported %d corrected bit errors\n",
+					err);
+			}
+		} else { /* err < 0 */
+			pr_info("Read reported error %d\n", err);
+			err = 0;
+			break;
+		}
+
+		err = verify_page(0);
+		if (err) {
+			bitstats[max_corrected] = opno;
+			pr_info("ECC failure, read data is incorrect despite read success\n");
+			break;
+		}
+
+		err = mtdtest_relax();
+		if (err)
+			break;
+
+		opno++;
+	}
+
+	/* At this point bitstats[0] contains the number of ops with no bit
+	 * errors, bitstats[1] the number of ops with 1 bit error, etc. */
+	pr_info("Bit error histogram (%d operations total):\n", opno);
+	for (i = 0; i < max_corrected; i++)
+		pr_info("Page reads with %3d corrected bit errors: %d\n",
+			i, bitstats[i]);
+
+exit:
+	return err;
+}
+
+static int __init mtd_nandbiterrs_init(void)
+{
+	int err = 0;
+
+	printk("\n");
+	printk(KERN_INFO "==================================================\n");
+	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");
+		goto exit_mtddev;
+	}
+
+	if (!mtd_type_is_nand(mtd)) {
+		pr_info("this test requires NAND flash\n");
+		err = -ENODEV;
+		goto exit_nand;
+	}
+
+	pr_info("MTD device size %llu, eraseblock=%u, page=%u, oob=%u\n",
+		(unsigned long long)mtd->size, mtd->erasesize,
+		mtd->writesize, mtd->oobsize);
+
+	subsize  = mtd->writesize >> mtd->subpage_sft;
+	subcount = mtd->writesize / subsize;
+
+	pr_info("Device uses %d subpages of %d bytes\n", subcount, subsize);
+
+	offset     = (loff_t)page_offset * mtd->writesize;
+	eraseblock = mtd_div_by_eb(offset, mtd);
+
+	pr_info("Using page=%u, offset=%llu, eraseblock=%u\n",
+		page_offset, offset, eraseblock);
+
+	wbuffer = kmalloc(mtd->writesize, GFP_KERNEL);
+	if (!wbuffer) {
+		err = -ENOMEM;
+		goto exit_wbuffer;
+	}
+
+	rbuffer = kmalloc(mtd->writesize, GFP_KERNEL);
+	if (!rbuffer) {
+		err = -ENOMEM;
+		goto exit_rbuffer;
+	}
+
+	err = mtdtest_erase_eraseblock(mtd, eraseblock);
+	if (err)
+		goto exit_error;
+
+	if (mode == 0)
+		err = incremental_errors_test();
+	else
+		err = overwrite_test();
+
+	if (err)
+		goto exit_error;
+
+	/* We leave the block un-erased in case of test failure. */
+	err = mtdtest_erase_eraseblock(mtd, eraseblock);
+	if (err)
+		goto exit_error;
+
+	err = -EIO;
+	pr_info("finished successfully.\n");
+	printk(KERN_INFO "==================================================\n");
+
+exit_error:
+	kfree(rbuffer);
+exit_rbuffer:
+	kfree(wbuffer);
+exit_wbuffer:
+	/* Nothing */
+exit_nand:
+	put_mtd_device(mtd);
+exit_mtddev:
+	return err;
+}
+
+static void __exit mtd_nandbiterrs_exit(void)
+{
+	return;
+}
+
+module_init(mtd_nandbiterrs_init);
+module_exit(mtd_nandbiterrs_exit);
+
+MODULE_DESCRIPTION("NAND bit error recovery test");
+MODULE_AUTHOR("Iwo Mergler");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mtd/tests/oobtest.c b/drivers/mtd/tests/oobtest.c
new file mode 100644
index 000000000..13fed3989
--- /dev/null
+++ b/drivers/mtd/tests/oobtest.c
@@ -0,0 +1,733 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * 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 memcmpshowoffset(loff_t addr, loff_t offset, 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%lx] 0x%x -> 0x%x diff 0x%x\n",
+				(unsigned long)addr, (unsigned long)offset + i,
+				*su1, *su2, res);
+			bitflips += hweight8(res);
+		}
+	}
+
+	return bitflips;
+}
+
+#define memcmpshow(addr, cs, ct, count) memcmpshowoffset((addr), 0, (cs), (ct),\
+							 (count))
+
+/*
+ * 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 (mtd_is_bitflip(err))
+			err = 0;
+
+		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->oobavail) {
+			int k;
+
+			ops.mode      = MTD_OPS_AUTO_OOB;
+			ops.len       = 0;
+			ops.retlen    = 0;
+			ops.ooblen    = mtd->oobavail;
+			ops.oobretlen = 0;
+			ops.ooboffs   = 0;
+			ops.datbuf    = NULL;
+			ops.oobbuf    = readbuf;
+			err = mtd_read_oob(mtd, addr, &ops);
+			if (mtd_is_bitflip(err))
+				err = 0;
+
+			if (err || ops.oobretlen != mtd->oobavail) {
+				pr_err("error: readoob failed at %#llx\n",
+						(long long)addr);
+				errcnt += 1;
+				return err ? err : -1;
+			}
+			bitflips = memcmpshowoffset(addr, use_offset,
+						    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->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->oobavail * pgcnt;
+	size_t oobavail = mtd->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 (mtd_is_bitflip(err))
+		err = 0;
+
+	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->oobavail;
+	use_len_max = mtd->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->oobavail;
+	use_len_max = mtd->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->oobavail;
+	use_len_max = mtd->oobavail;
+	vary_offset = 1;
+	prandom_seed_state(&rnd_state, 5);
+	err = verify_all_eraseblocks();
+	if (err)
+		goto out;
+
+	use_offset = 0;
+	use_len = mtd->oobavail;
+	use_len_max = mtd->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->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");
+	} 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->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 (mtd_is_bitflip(err))
+		err = 0;
+
+	if (err) {
+		pr_info("error occurred as expected\n");
+	} 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->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");
+		} 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->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 (mtd_is_bitflip(err))
+			err = 0;
+
+		if (err) {
+			pr_info("error occurred as expected\n");
+		} 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->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");
+		} 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->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 (mtd_is_bitflip(err))
+			err = 0;
+
+		if (err) {
+			pr_info("error occurred as expected\n");
+		} 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->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->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->oobavail * 2;
+		ops.oobretlen = 0;
+		ops.ooboffs   = 0;
+		ops.datbuf    = NULL;
+		ops.oobbuf    = readbuf;
+		err = mtd_read_oob(mtd, addr, &ops);
+		if (mtd_is_bitflip(err))
+			err = 0;
+
+		if (err)
+			goto out;
+		if (memcmpshow(addr, readbuf, writebuf,
+			       mtd->oobavail * 2)) {
+			pr_err("error: verify failed at %#llx\n",
+			       (long long)addr);
+			errcnt += 1;
+			if (errcnt > 1000) {
+				err = -EINVAL;
+				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");
diff --git a/drivers/mtd/tests/pagetest.c b/drivers/mtd/tests/pagetest.c
new file mode 100644
index 000000000..8eb40b6e6
--- /dev/null
+++ b/drivers/mtd/tests/pagetest.c
@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Test page 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;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+static struct mtd_info *mtd;
+static unsigned char *twopages;
+static unsigned char *writebuf;
+static unsigned char *boundary;
+static unsigned char *bbt;
+
+static int pgsize;
+static int bufsize;
+static int ebcnt;
+static int pgcnt;
+static int errcnt;
+static struct rnd_state rnd_state;
+
+static int write_eraseblock(int ebnum)
+{
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	prandom_bytes_state(&rnd_state, writebuf, mtd->erasesize);
+	cond_resched();
+	return mtdtest_write(mtd, addr, mtd->erasesize, writebuf);
+}
+
+static int verify_eraseblock(int ebnum)
+{
+	uint32_t j;
+	int err = 0, i;
+	loff_t addr0, addrn;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	addr0 = 0;
+	for (i = 0; i < ebcnt && bbt[i]; ++i)
+		addr0 += mtd->erasesize;
+
+	addrn = mtd->size;
+	for (i = 0; i < ebcnt && bbt[ebcnt - i - 1]; ++i)
+		addrn -= mtd->erasesize;
+
+	prandom_bytes_state(&rnd_state, writebuf, mtd->erasesize);
+	for (j = 0; j < pgcnt - 1; ++j, addr += pgsize) {
+		/* Do a read to set the internal dataRAMs to different data */
+		err = mtdtest_read(mtd, addr0, bufsize, twopages);
+		if (err)
+			return err;
+		err = mtdtest_read(mtd, addrn - bufsize, bufsize, twopages);
+		if (err)
+			return err;
+		memset(twopages, 0, bufsize);
+		err = mtdtest_read(mtd, addr, bufsize, twopages);
+		if (err)
+			break;
+		if (memcmp(twopages, writebuf + (j * pgsize), bufsize)) {
+			pr_err("error: verify failed at %#llx\n",
+			       (long long)addr);
+			errcnt += 1;
+		}
+	}
+	/* Check boundary between eraseblocks */
+	if (addr <= addrn - pgsize - pgsize && !bbt[ebnum + 1]) {
+		struct rnd_state old_state = rnd_state;
+
+		/* Do a read to set the internal dataRAMs to different data */
+		err = mtdtest_read(mtd, addr0, bufsize, twopages);
+		if (err)
+			return err;
+		err = mtdtest_read(mtd, addrn - bufsize, bufsize, twopages);
+		if (err)
+			return err;
+		memset(twopages, 0, bufsize);
+		err = mtdtest_read(mtd, addr, bufsize, twopages);
+		if (err)
+			return err;
+		memcpy(boundary, writebuf + mtd->erasesize - pgsize, pgsize);
+		prandom_bytes_state(&rnd_state, boundary + pgsize, pgsize);
+		if (memcmp(twopages, boundary, bufsize)) {
+			pr_err("error: verify failed at %#llx\n",
+			       (long long)addr);
+			errcnt += 1;
+		}
+		rnd_state = old_state;
+	}
+	return err;
+}
+
+static int crosstest(void)
+{
+	int err = 0, i;
+	loff_t addr, addr0, addrn;
+	unsigned char *pp1, *pp2, *pp3, *pp4;
+
+	pr_info("crosstest\n");
+	pp1 = kcalloc(pgsize, 4, GFP_KERNEL);
+	if (!pp1)
+		return -ENOMEM;
+	pp2 = pp1 + pgsize;
+	pp3 = pp2 + pgsize;
+	pp4 = pp3 + pgsize;
+
+	addr0 = 0;
+	for (i = 0; i < ebcnt && bbt[i]; ++i)
+		addr0 += mtd->erasesize;
+
+	addrn = mtd->size;
+	for (i = 0; i < ebcnt && bbt[ebcnt - i - 1]; ++i)
+		addrn -= mtd->erasesize;
+
+	/* Read 2nd-to-last page to pp1 */
+	addr = addrn - pgsize - pgsize;
+	err = mtdtest_read(mtd, addr, pgsize, pp1);
+	if (err) {
+		kfree(pp1);
+		return err;
+	}
+
+	/* Read 3rd-to-last page to pp1 */
+	addr = addrn - pgsize - pgsize - pgsize;
+	err = mtdtest_read(mtd, addr, pgsize, pp1);
+	if (err) {
+		kfree(pp1);
+		return err;
+	}
+
+	/* Read first page to pp2 */
+	addr = addr0;
+	pr_info("reading page at %#llx\n", (long long)addr);
+	err = mtdtest_read(mtd, addr, pgsize, pp2);
+	if (err) {
+		kfree(pp1);
+		return err;
+	}
+
+	/* Read last page to pp3 */
+	addr = addrn - pgsize;
+	pr_info("reading page at %#llx\n", (long long)addr);
+	err = mtdtest_read(mtd, addr, pgsize, pp3);
+	if (err) {
+		kfree(pp1);
+		return err;
+	}
+
+	/* Read first page again to pp4 */
+	addr = addr0;
+	pr_info("reading page at %#llx\n", (long long)addr);
+	err = mtdtest_read(mtd, addr, pgsize, pp4);
+	if (err) {
+		kfree(pp1);
+		return err;
+	}
+
+	/* pp2 and pp4 should be the same */
+	pr_info("verifying pages read at %#llx match\n",
+	       (long long)addr0);
+	if (memcmp(pp2, pp4, pgsize)) {
+		pr_err("verify failed!\n");
+		errcnt += 1;
+	} else if (!err)
+		pr_info("crosstest ok\n");
+	kfree(pp1);
+	return err;
+}
+
+static int erasecrosstest(void)
+{
+	int err = 0, i, ebnum, ebnum2;
+	loff_t addr0;
+	char *readbuf = twopages;
+
+	pr_info("erasecrosstest\n");
+
+	ebnum = 0;
+	addr0 = 0;
+	for (i = 0; i < ebcnt && bbt[i]; ++i) {
+		addr0 += mtd->erasesize;
+		ebnum += 1;
+	}
+
+	ebnum2 = ebcnt - 1;
+	while (ebnum2 && bbt[ebnum2])
+		ebnum2 -= 1;
+
+	pr_info("erasing block %d\n", ebnum);
+	err = mtdtest_erase_eraseblock(mtd, ebnum);
+	if (err)
+		return err;
+
+	pr_info("writing 1st page of block %d\n", ebnum);
+	prandom_bytes_state(&rnd_state, writebuf, pgsize);
+	strcpy(writebuf, "There is no data like this!");
+	err = mtdtest_write(mtd, addr0, pgsize, writebuf);
+	if (err)
+		return err;
+
+	pr_info("reading 1st page of block %d\n", ebnum);
+	memset(readbuf, 0, pgsize);
+	err = mtdtest_read(mtd, addr0, pgsize, readbuf);
+	if (err)
+		return err;
+
+	pr_info("verifying 1st page of block %d\n", ebnum);
+	if (memcmp(writebuf, readbuf, pgsize)) {
+		pr_err("verify failed!\n");
+		errcnt += 1;
+		return -1;
+	}
+
+	pr_info("erasing block %d\n", ebnum);
+	err = mtdtest_erase_eraseblock(mtd, ebnum);
+	if (err)
+		return err;
+
+	pr_info("writing 1st page of block %d\n", ebnum);
+	prandom_bytes_state(&rnd_state, writebuf, pgsize);
+	strcpy(writebuf, "There is no data like this!");
+	err = mtdtest_write(mtd, addr0, pgsize, writebuf);
+	if (err)
+		return err;
+
+	pr_info("erasing block %d\n", ebnum2);
+	err = mtdtest_erase_eraseblock(mtd, ebnum2);
+	if (err)
+		return err;
+
+	pr_info("reading 1st page of block %d\n", ebnum);
+	memset(readbuf, 0, pgsize);
+	err = mtdtest_read(mtd, addr0, pgsize, readbuf);
+	if (err)
+		return err;
+
+	pr_info("verifying 1st page of block %d\n", ebnum);
+	if (memcmp(writebuf, readbuf, pgsize)) {
+		pr_err("verify failed!\n");
+		errcnt += 1;
+		return -1;
+	}
+
+	if (!err)
+		pr_info("erasecrosstest ok\n");
+	return err;
+}
+
+static int erasetest(void)
+{
+	int err = 0, i, ebnum, ok = 1;
+	loff_t addr0;
+
+	pr_info("erasetest\n");
+
+	ebnum = 0;
+	addr0 = 0;
+	for (i = 0; i < ebcnt && bbt[i]; ++i) {
+		addr0 += mtd->erasesize;
+		ebnum += 1;
+	}
+
+	pr_info("erasing block %d\n", ebnum);
+	err = mtdtest_erase_eraseblock(mtd, ebnum);
+	if (err)
+		return err;
+
+	pr_info("writing 1st page of block %d\n", ebnum);
+	prandom_bytes_state(&rnd_state, writebuf, pgsize);
+	err = mtdtest_write(mtd, addr0, pgsize, writebuf);
+	if (err)
+		return err;
+
+	pr_info("erasing block %d\n", ebnum);
+	err = mtdtest_erase_eraseblock(mtd, ebnum);
+	if (err)
+		return err;
+
+	pr_info("reading 1st page of block %d\n", ebnum);
+	err = mtdtest_read(mtd, addr0, pgsize, twopages);
+	if (err)
+		return err;
+
+	pr_info("verifying 1st page of block %d is all 0xff\n",
+	       ebnum);
+	for (i = 0; i < pgsize; ++i)
+		if (twopages[i] != 0xff) {
+			pr_err("verifying all 0xff failed at %d\n",
+			       i);
+			errcnt += 1;
+			ok = 0;
+			break;
+		}
+
+	if (ok && !err)
+		pr_info("erasetest ok\n");
+
+	return err;
+}
+
+static int __init mtd_pagetest_init(void)
+{
+	int err = 0;
+	uint64_t tmp;
+	uint32_t i;
+
+	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;
+	pgsize = 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,
+	       pgsize, ebcnt, pgcnt, mtd->oobsize);
+
+	err = -ENOMEM;
+	bufsize = pgsize * 2;
+	writebuf = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!writebuf)
+		goto out;
+	twopages = kmalloc(bufsize, GFP_KERNEL);
+	if (!twopages)
+		goto out;
+	boundary = kmalloc(bufsize, GFP_KERNEL);
+	if (!boundary)
+		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;
+
+	/* Erase all eraseblocks */
+	pr_info("erasing whole device\n");
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+	pr_info("erased %u eraseblocks\n", ebcnt);
+
+	/* Write all eraseblocks */
+	prandom_seed_state(&rnd_state, 1);
+	pr_info("writing whole device\n");
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock(i);
+		if (err)
+			goto out;
+		if (i % 256 == 0)
+			pr_info("written up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("written %u eraseblocks\n", i);
+
+	/* Check all eraseblocks */
+	prandom_seed_state(&rnd_state, 1);
+	pr_info("verifying all eraseblocks\n");
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = verify_eraseblock(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);
+
+	err = crosstest();
+	if (err)
+		goto out;
+
+	if (ebcnt > 1) {
+		err = erasecrosstest();
+		if (err)
+			goto out;
+	} else {
+		pr_info("skipping erasecrosstest, 2 erase blocks needed\n");
+	}
+
+	err = erasetest();
+	if (err)
+		goto out;
+
+	pr_info("finished with %d errors\n", errcnt);
+out:
+
+	kfree(bbt);
+	kfree(boundary);
+	kfree(twopages);
+	kfree(writebuf);
+	put_mtd_device(mtd);
+	if (err)
+		pr_info("error %d occurred\n", err);
+	printk(KERN_INFO "=================================================\n");
+	return err;
+}
+module_init(mtd_pagetest_init);
+
+static void __exit mtd_pagetest_exit(void)
+{
+	return;
+}
+module_exit(mtd_pagetest_exit);
+
+MODULE_DESCRIPTION("NAND page test");
+MODULE_AUTHOR("Adrian Hunter");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mtd/tests/readtest.c b/drivers/mtd/tests/readtest.c
new file mode 100644
index 000000000..99670ef91
--- /dev/null
+++ b/drivers/mtd/tests/readtest.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Check MTD device read.
+ *
+ * Author: Adrian Hunter <ext-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 "mtd_test.h"
+
+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 *iobuf;
+static unsigned char *iobuf1;
+static unsigned char *bbt;
+
+static int pgsize;
+static int ebcnt;
+static int pgcnt;
+
+static int read_eraseblock_by_page(int ebnum)
+{
+	int i, ret, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+	void *oobbuf = iobuf1;
+
+	for (i = 0; i < pgcnt; i++) {
+		memset(buf, 0 , pgsize);
+		ret = mtdtest_read(mtd, addr, pgsize, buf);
+		if (ret) {
+			if (!err)
+				err = ret;
+		}
+		if (mtd->oobsize) {
+			struct mtd_oob_ops ops = { };
+
+			ops.mode      = MTD_OPS_PLACE_OOB;
+			ops.len       = 0;
+			ops.retlen    = 0;
+			ops.ooblen    = mtd->oobsize;
+			ops.oobretlen = 0;
+			ops.ooboffs   = 0;
+			ops.datbuf    = NULL;
+			ops.oobbuf    = oobbuf;
+			ret = mtd_read_oob(mtd, addr, &ops);
+			if ((ret && !mtd_is_bitflip(ret)) ||
+					ops.oobretlen != mtd->oobsize) {
+				pr_err("error: read oob failed at "
+						  "%#llx\n", (long long)addr);
+				if (!err)
+					err = ret;
+				if (!err)
+					err = -EINVAL;
+			}
+			oobbuf += mtd->oobsize;
+		}
+		addr += pgsize;
+		buf += pgsize;
+	}
+
+	return err;
+}
+
+static void dump_eraseblock(int ebnum)
+{
+	int i, j, n;
+	char line[128];
+	int pg, oob;
+
+	pr_info("dumping eraseblock %d\n", ebnum);
+	n = mtd->erasesize;
+	for (i = 0; i < n;) {
+		char *p = line;
+
+		p += sprintf(p, "%05x: ", i);
+		for (j = 0; j < 32 && i < n; j++, i++)
+			p += sprintf(p, "%02x", (unsigned int)iobuf[i]);
+		printk(KERN_CRIT "%s\n", line);
+		cond_resched();
+	}
+	if (!mtd->oobsize)
+		return;
+	pr_info("dumping oob from eraseblock %d\n", ebnum);
+	n = mtd->oobsize;
+	for (pg = 0, i = 0; pg < pgcnt; pg++)
+		for (oob = 0; oob < n;) {
+			char *p = line;
+
+			p += sprintf(p, "%05x: ", i);
+			for (j = 0; j < 32 && oob < n; j++, oob++, i++)
+				p += sprintf(p, "%02x",
+					     (unsigned int)iobuf1[i]);
+			printk(KERN_CRIT "%s\n", line);
+			cond_resched();
+		}
+}
+
+static int __init mtd_readtest_init(void)
+{
+	uint64_t tmp;
+	int err, i;
+
+	printk(KERN_INFO "\n");
+	printk(KERN_INFO "=================================================\n");
+
+	if (dev < 0) {
+		pr_info("Please specify a valid mtd-device via module parameter\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->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);
+
+	err = -ENOMEM;
+	iobuf = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!iobuf)
+		goto out;
+	iobuf1 = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!iobuf1)
+		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;
+
+	/* Read all eraseblocks 1 page at a time */
+	pr_info("testing page read\n");
+	for (i = 0; i < ebcnt; ++i) {
+		int ret;
+
+		if (bbt[i])
+			continue;
+		ret = read_eraseblock_by_page(i);
+		if (ret) {
+			dump_eraseblock(i);
+			if (!err)
+				err = ret;
+		}
+
+		ret = mtdtest_relax();
+		if (ret) {
+			err = ret;
+			goto out;
+		}
+	}
+
+	if (err)
+		pr_info("finished with errors\n");
+	else
+		pr_info("finished\n");
+
+out:
+
+	kfree(iobuf);
+	kfree(iobuf1);
+	kfree(bbt);
+	put_mtd_device(mtd);
+	if (err)
+		pr_info("error %d occurred\n", err);
+	printk(KERN_INFO "=================================================\n");
+	return err;
+}
+module_init(mtd_readtest_init);
+
+static void __exit mtd_readtest_exit(void)
+{
+	return;
+}
+module_exit(mtd_readtest_exit);
+
+MODULE_DESCRIPTION("Read test module");
+MODULE_AUTHOR("Adrian Hunter");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mtd/tests/speedtest.c b/drivers/mtd/tests/speedtest.c
new file mode 100644
index 000000000..075bce32c
--- /dev/null
+++ b/drivers/mtd/tests/speedtest.c
@@ -0,0 +1,418 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2007 Nokia Corporation
+ *
+ * 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/ktime.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;
+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 ktime_t start, finish;
+
+static int multiblock_erase(int ebnum, int blocks)
+{
+	int err;
+	struct erase_info ei;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	memset(&ei, 0, sizeof(struct erase_info));
+	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;
+	}
+
+	return 0;
+}
+
+static int write_eraseblock(int ebnum)
+{
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	return mtdtest_write(mtd, addr, mtd->erasesize, iobuf);
+}
+
+static int write_eraseblock_by_page(int ebnum)
+{
+	int i, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < pgcnt; i++) {
+		err = mtdtest_write(mtd, addr, pgsize, buf);
+		if (err)
+			break;
+		addr += pgsize;
+		buf += pgsize;
+	}
+
+	return err;
+}
+
+static int write_eraseblock_by_2pages(int ebnum)
+{
+	size_t sz = pgsize * 2;
+	int i, n = pgcnt / 2, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < n; i++) {
+		err = mtdtest_write(mtd, addr, sz, buf);
+		if (err)
+			return err;
+		addr += sz;
+		buf += sz;
+	}
+	if (pgcnt % 2)
+		err = mtdtest_write(mtd, addr, pgsize, buf);
+
+	return err;
+}
+
+static int read_eraseblock(int ebnum)
+{
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	return mtdtest_read(mtd, addr, mtd->erasesize, iobuf);
+}
+
+static int read_eraseblock_by_page(int ebnum)
+{
+	int i, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < pgcnt; i++) {
+		err = mtdtest_read(mtd, addr, pgsize, buf);
+		if (err)
+			break;
+		addr += pgsize;
+		buf += pgsize;
+	}
+
+	return err;
+}
+
+static int read_eraseblock_by_2pages(int ebnum)
+{
+	size_t sz = pgsize * 2;
+	int i, n = pgcnt / 2, err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+	void *buf = iobuf;
+
+	for (i = 0; i < n; i++) {
+		err = mtdtest_read(mtd, addr, sz, buf);
+		if (err)
+			return err;
+		addr += sz;
+		buf += sz;
+	}
+	if (pgcnt % 2)
+		err = mtdtest_read(mtd, addr, pgsize, buf);
+
+	return err;
+}
+
+static inline void start_timing(void)
+{
+	start = ktime_get();
+}
+
+static inline void stop_timing(void)
+{
+	finish = ktime_get();
+}
+
+static long calc_speed(void)
+{
+	uint64_t k, us;
+
+	us = ktime_us_delta(finish, start);
+	if (us == 0)
+		return 0;
+	k = (uint64_t)goodebcnt * (mtd->erasesize / 1024) * 1000000;
+	do_div(k, us);
+	return k;
+}
+
+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)
+		goto out;
+
+	get_random_bytes(iobuf, mtd->erasesize);
+
+	bbt = kzalloc(ebcnt, GFP_KERNEL);
+	if (!bbt)
+		goto out;
+	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+	for (i = 0; i < ebcnt; i++) {
+		if (!bbt[i])
+			goodebcnt++;
+	}
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	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;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	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;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("eraseblock read speed is %ld KiB/s\n", speed);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	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;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	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;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	stop_timing();
+	speed = calc_speed();
+	pr_info("page read speed is %ld KiB/s\n", speed);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	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;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	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;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	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();
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+	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;
+
+			err = mtdtest_relax();
+			if (err)
+				goto out;
+
+			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");
diff --git a/drivers/mtd/tests/stresstest.c b/drivers/mtd/tests/stresstest.c
new file mode 100644
index 000000000..75b6ddc5d
--- /dev/null
+++ b/drivers/mtd/tests/stresstest.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Test random reads, writes and erases on MTD device.
+ *
+ * Author: Adrian Hunter <ext-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/vmalloc.h>
+#include <linux/random.h>
+
+#include "mtd_test.h"
+
+static int dev = -EINVAL;
+module_param(dev, int, S_IRUGO);
+MODULE_PARM_DESC(dev, "MTD device number to use");
+
+static int count = 10000;
+module_param(count, int, S_IRUGO);
+MODULE_PARM_DESC(count, "Number of operations to do (default is 10000)");
+
+static struct mtd_info *mtd;
+static unsigned char *writebuf;
+static unsigned char *readbuf;
+static unsigned char *bbt;
+static int *offsets;
+
+static int pgsize;
+static int bufsize;
+static int ebcnt;
+static int pgcnt;
+
+static int rand_eb(void)
+{
+	unsigned int eb;
+
+again:
+	/* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
+	eb = prandom_u32_max(ebcnt - 1);
+	if (bbt[eb])
+		goto again;
+	return eb;
+}
+
+static int rand_offs(void)
+{
+	return prandom_u32_max(bufsize);
+}
+
+static int rand_len(int offs)
+{
+	return prandom_u32_max(bufsize - offs);
+}
+
+static int do_read(void)
+{
+	int eb = rand_eb();
+	int offs = rand_offs();
+	int len = rand_len(offs);
+	loff_t addr;
+
+	if (bbt[eb + 1]) {
+		if (offs >= mtd->erasesize)
+			offs -= mtd->erasesize;
+		if (offs + len > mtd->erasesize)
+			len = mtd->erasesize - offs;
+	}
+	addr = (loff_t)eb * mtd->erasesize + offs;
+	return mtdtest_read(mtd, addr, len, readbuf);
+}
+
+static int do_write(void)
+{
+	int eb = rand_eb(), offs, err, len;
+	loff_t addr;
+
+	offs = offsets[eb];
+	if (offs >= mtd->erasesize) {
+		err = mtdtest_erase_eraseblock(mtd, eb);
+		if (err)
+			return err;
+		offs = offsets[eb] = 0;
+	}
+	len = rand_len(offs);
+	len = ((len + pgsize - 1) / pgsize) * pgsize;
+	if (offs + len > mtd->erasesize) {
+		if (bbt[eb + 1])
+			len = mtd->erasesize - offs;
+		else {
+			err = mtdtest_erase_eraseblock(mtd, eb + 1);
+			if (err)
+				return err;
+			offsets[eb + 1] = 0;
+		}
+	}
+	addr = (loff_t)eb * mtd->erasesize + offs;
+	err = mtdtest_write(mtd, addr, len, writebuf);
+	if (unlikely(err))
+		return err;
+	offs += len;
+	while (offs > mtd->erasesize) {
+		offsets[eb++] = mtd->erasesize;
+		offs -= mtd->erasesize;
+	}
+	offsets[eb] = offs;
+	return 0;
+}
+
+static int do_operation(void)
+{
+	if (prandom_u32_max(2))
+		return do_read();
+	else
+		return do_write();
+}
+
+static int __init mtd_stresstest_init(void)
+{
+	int err;
+	int i, op;
+	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;
+	}
+
+	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 (ebcnt < 2) {
+		pr_err("error: need at least 2 eraseblocks\n");
+		err = -ENOSPC;
+		goto out_put_mtd;
+	}
+
+	/* Read or write up 2 eraseblocks at a time */
+	bufsize = mtd->erasesize * 2;
+
+	err = -ENOMEM;
+	readbuf = vmalloc(bufsize);
+	writebuf = vmalloc(bufsize);
+	offsets = kmalloc_array(ebcnt, sizeof(int), GFP_KERNEL);
+	if (!readbuf || !writebuf || !offsets)
+		goto out;
+	for (i = 0; i < ebcnt; i++)
+		offsets[i] = mtd->erasesize;
+	get_random_bytes(writebuf, bufsize);
+
+	bbt = kzalloc(ebcnt, GFP_KERNEL);
+	if (!bbt)
+		goto out;
+	err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	/* Do operations */
+	pr_info("doing operations\n");
+	for (op = 0; op < count; op++) {
+		if ((op & 1023) == 0)
+			pr_info("%d operations done\n", op);
+		err = do_operation();
+		if (err)
+			goto out;
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("finished, %d operations done\n", op);
+
+out:
+	kfree(offsets);
+	kfree(bbt);
+	vfree(writebuf);
+	vfree(readbuf);
+out_put_mtd:
+	put_mtd_device(mtd);
+	if (err)
+		pr_info("error %d occurred\n", err);
+	printk(KERN_INFO "=================================================\n");
+	return err;
+}
+module_init(mtd_stresstest_init);
+
+static void __exit mtd_stresstest_exit(void)
+{
+	return;
+}
+module_exit(mtd_stresstest_exit);
+
+MODULE_DESCRIPTION("Stress test module");
+MODULE_AUTHOR("Adrian Hunter");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mtd/tests/subpagetest.c b/drivers/mtd/tests/subpagetest.c
new file mode 100644
index 000000000..05250a080
--- /dev/null
+++ b/drivers/mtd/tests/subpagetest.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2007 Nokia Corporation
+ *
+ * Test sub-page read and write on MTD device.
+ * Author: Adrian Hunter <ext-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>
+
+#include "mtd_test.h"
+
+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 struct rnd_state rnd_state;
+
+static inline void clear_data(unsigned char *buf, size_t len)
+{
+	memset(buf, 0, len);
+}
+
+static int write_eraseblock(int ebnum)
+{
+	size_t written;
+	int err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
+	if (unlikely(err || written != subpgsize)) {
+		pr_err("error: write failed at %#llx\n",
+		       (long long)addr);
+		if (written != subpgsize) {
+			pr_err("  write size: %#x\n", subpgsize);
+			pr_err("  written: %#zx\n", written);
+		}
+		return err ? err : -1;
+	}
+
+	addr += subpgsize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	err = mtd_write(mtd, addr, subpgsize, &written, writebuf);
+	if (unlikely(err || written != subpgsize)) {
+		pr_err("error: write failed at %#llx\n",
+		       (long long)addr);
+		if (written != subpgsize) {
+			pr_err("  write size: %#x\n", subpgsize);
+			pr_err("  written: %#zx\n", written);
+		}
+		return err ? err : -1;
+	}
+
+	return err;
+}
+
+static int write_eraseblock2(int ebnum)
+{
+	size_t written;
+	int err = 0, k;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	for (k = 1; k < 33; ++k) {
+		if (addr + (subpgsize * k) > (loff_t)(ebnum + 1) * mtd->erasesize)
+			break;
+		prandom_bytes_state(&rnd_state, writebuf, subpgsize * k);
+		err = mtd_write(mtd, addr, subpgsize * k, &written, writebuf);
+		if (unlikely(err || written != subpgsize * k)) {
+			pr_err("error: write failed at %#llx\n",
+			       (long long)addr);
+			if (written != subpgsize * k) {
+				pr_err("  write size: %#x\n",
+				       subpgsize * k);
+				pr_err("  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;
+	int err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	clear_data(readbuf, subpgsize);
+	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
+	if (unlikely(err || read != subpgsize)) {
+		if (mtd_is_bitflip(err) && read == subpgsize) {
+			pr_info("ECC correction at %#llx\n",
+			       (long long)addr);
+			err = 0;
+		} else {
+			pr_err("error: read failed at %#llx\n",
+			       (long long)addr);
+			return err ? err : -1;
+		}
+	}
+	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
+		pr_err("error: verify failed at %#llx\n",
+		       (long long)addr);
+		pr_info("------------- written----------------\n");
+		print_subpage(writebuf);
+		pr_info("------------- read ------------------\n");
+		print_subpage(readbuf);
+		pr_info("-------------------------------------\n");
+		errcnt += 1;
+	}
+
+	addr += subpgsize;
+
+	prandom_bytes_state(&rnd_state, writebuf, subpgsize);
+	clear_data(readbuf, subpgsize);
+	err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
+	if (unlikely(err || read != subpgsize)) {
+		if (mtd_is_bitflip(err) && read == subpgsize) {
+			pr_info("ECC correction at %#llx\n",
+			       (long long)addr);
+			err = 0;
+		} else {
+			pr_err("error: read failed at %#llx\n",
+			       (long long)addr);
+			return err ? err : -1;
+		}
+	}
+	if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
+		pr_info("error: verify failed at %#llx\n",
+		       (long long)addr);
+		pr_info("------------- written----------------\n");
+		print_subpage(writebuf);
+		pr_info("------------- read ------------------\n");
+		print_subpage(readbuf);
+		pr_info("-------------------------------------\n");
+		errcnt += 1;
+	}
+
+	return err;
+}
+
+static int verify_eraseblock2(int ebnum)
+{
+	size_t read;
+	int err = 0, k;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	for (k = 1; k < 33; ++k) {
+		if (addr + (subpgsize * k) > (loff_t)(ebnum + 1) * mtd->erasesize)
+			break;
+		prandom_bytes_state(&rnd_state, writebuf, subpgsize * k);
+		clear_data(readbuf, subpgsize * k);
+		err = mtd_read(mtd, addr, subpgsize * k, &read, readbuf);
+		if (unlikely(err || read != subpgsize * k)) {
+			if (mtd_is_bitflip(err) && read == subpgsize * k) {
+				pr_info("ECC correction at %#llx\n",
+				       (long long)addr);
+				err = 0;
+			} else {
+				pr_err("error: read failed at "
+				       "%#llx\n", (long long)addr);
+				return err ? err : -1;
+			}
+		}
+		if (unlikely(memcmp(readbuf, writebuf, subpgsize * k))) {
+			pr_err("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;
+	int err = 0;
+	loff_t addr = (loff_t)ebnum * mtd->erasesize;
+
+	memset(writebuf, 0xff, subpgsize);
+	for (j = 0; j < mtd->erasesize / subpgsize; ++j) {
+		clear_data(readbuf, subpgsize);
+		err = mtd_read(mtd, addr, subpgsize, &read, readbuf);
+		if (unlikely(err || read != subpgsize)) {
+			if (mtd_is_bitflip(err) && read == subpgsize) {
+				pr_info("ECC correction at %#llx\n",
+				       (long long)addr);
+				err = 0;
+			} else {
+				pr_err("error: read failed at "
+				       "%#llx\n", (long long)addr);
+				return err ? err : -1;
+			}
+		}
+		if (unlikely(memcmp(readbuf, writebuf, subpgsize))) {
+			pr_err("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;
+
+	pr_info("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)
+			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_subpagetest_init(void)
+{
+	int err = 0;
+	uint32_t i;
+	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;
+	}
+
+	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;
+	}
+
+	subpgsize = mtd->writesize >> mtd->subpage_sft;
+	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, 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)
+		goto out;
+	readbuf = kmalloc(bufsize, GFP_KERNEL);
+	if (!readbuf)
+		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;
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	pr_info("writing whole device\n");
+	prandom_seed_state(&rnd_state, 1);
+	for (i = 0; i < ebcnt; ++i) {
+		if (bbt[i])
+			continue;
+		err = write_eraseblock(i);
+		if (unlikely(err))
+			goto out;
+		if (i % 256 == 0)
+			pr_info("written up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("written %u eraseblocks\n", i);
+
+	prandom_seed_state(&rnd_state, 1);
+	pr_info("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)
+			pr_info("verified up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("verified %u eraseblocks\n", i);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	err = verify_all_eraseblocks_ff();
+	if (err)
+		goto out;
+
+	/* Write all eraseblocks */
+	prandom_seed_state(&rnd_state, 3);
+	pr_info("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)
+			pr_info("written up to eraseblock %u\n", i);
+
+		err = mtdtest_relax();
+		if (err)
+			goto out;
+	}
+	pr_info("written %u eraseblocks\n", i);
+
+	/* 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_eraseblock2(i);
+		if (unlikely(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);
+
+	err = mtdtest_erase_good_eraseblocks(mtd, bbt, 0, ebcnt);
+	if (err)
+		goto out;
+
+	err = verify_all_eraseblocks_ff();
+	if (err)
+		goto out;
+
+	pr_info("finished with %d errors\n", errcnt);
+
+out:
+	kfree(bbt);
+	kfree(readbuf);
+	kfree(writebuf);
+	put_mtd_device(mtd);
+	if (err)
+		pr_info("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");
diff --git a/drivers/mtd/tests/torturetest.c b/drivers/mtd/tests/torturetest.c
new file mode 100644
index 000000000..841689b4d
--- /dev/null
+++ b/drivers/mtd/tests/torturetest.c
@@ -0,0 +1,480 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2006-2008 Artem Bityutskiy
+ * Copyright (C) 2006-2008 Jarkko Lavinen
+ * Copyright (C) 2006-2008 Adrian Hunter
+ *
+ * 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/ktime.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 "mtd_test.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 ktime_t start, finish;
+
+static void report_corrupt(unsigned char *read, unsigned char *written);
+
+static inline void start_timing(void)
+{
+	start = ktime_get();
+}
+
+static inline void stop_timing(void)
+{
+	finish = ktime_get();
+}
+
+/*
+ * 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 = (loff_t)ebnum * mtd->erasesize;
+	size_t len = mtd->erasesize;
+
+	if (pgcnt) {
+		addr = (loff_t)(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 = (loff_t)ebnum * mtd->erasesize;
+	size_t len = mtd->erasesize;
+
+	if (pgcnt) {
+		addr = (loff_t)(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;
+	unsigned char *bad_ebs;
+
+	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)
+		goto out_mtd;
+
+	patt_A5A = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!patt_A5A)
+		goto out_patt_5A5;
+
+	patt_FF = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!patt_FF)
+		goto out_patt_A5A;
+
+	check_buf = kmalloc(mtd->erasesize, GFP_KERNEL);
+	if (!check_buf)
+		goto out_patt_FF;
+
+	bad_ebs = kzalloc(ebcnt, GFP_KERNEL);
+	if (!bad_ebs)
+		goto out_check_buf;
+
+	/* 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);
+		}
+	}
+
+	err = mtdtest_scan_for_bad_eraseblocks(mtd, bad_ebs, eb, ebcnt);
+	if (err)
+		goto out;
+
+	start_timing();
+	while (1) {
+		int i;
+		void *patt;
+
+		err = mtdtest_erase_good_eraseblocks(mtd, bad_ebs, eb, ebcnt);
+		if (err)
+			goto out;
+
+		/* 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;
+				}
+
+				err = mtdtest_relax();
+				if (err)
+					goto out;
+			}
+		}
+
+		/* 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;
+
+			err = mtdtest_relax();
+			if (err)
+				goto out;
+		}
+
+		/* 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;
+				}
+
+				err = mtdtest_relax();
+				if (err)
+					goto out;
+			}
+		}
+
+		erase_cycles += 1;
+
+		if (erase_cycles % gran == 0) {
+			long ms;
+
+			stop_timing();
+			ms = ktime_ms_delta(finish, start);
+			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(bad_ebs);
+out_check_buf:
+	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");