5 files changed, 733 insertions, 77 deletions

diff --git a/drivers/mtd/tests/Makefile b/drivers/mtd/tests/Makefile
index b44dcab940d8..bd0065c0d359 100644
--- a/drivers/mtd/tests/Makefile
+++ b/drivers/mtd/tests/Makefile
@@ -6,3 +6,4 @@ 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
diff --git a/drivers/mtd/tests/mtd_nandbiterrs.c b/drivers/mtd/tests/mtd_nandbiterrs.c
new file mode 100644
index 000000000000..cc8d62cb280c
--- /dev/null
+++ b/drivers/mtd/tests/mtd_nandbiterrs.c
@@ -0,0 +1,460 @@
+/*
+ * 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.
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; see the file COPYING. If not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mtd/mtd.h>
+#include <linux/err.h>
+#include <linux/mtd/nand.h>
+#include <linux/slab.h>
+
+#define msg(FMT, VA...) pr_info("mtd_nandbiterrs: "FMT, ##VA)
+
+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;
+}
+
+static int erase_block(void)
+{
+	int err;
+	struct erase_info ei;
+	loff_t addr = eraseblock * mtd->erasesize;
+
+	msg("erase_block\n");
+
+	memset(&ei, 0, sizeof(struct erase_info));
+	ei.mtd  = mtd;
+	ei.addr = addr;
+	ei.len  = mtd->erasesize;
+
+	err = mtd_erase(mtd, &ei);
+	if (err || ei.state == MTD_ERASE_FAILED) {
+		msg("error %d while erasing\n", err);
+		if (!err)
+			err = -EIO;
+		return err;
+	}
+
+	return 0;
+}
+
+/* Writes wbuffer to page */
+static int write_page(int log)
+{
+	int err = 0;
+	size_t written;
+
+	if (log)
+		msg("write_page\n");
+
+	err = mtd_write(mtd, offset, mtd->writesize, &written, wbuffer);
+	if (err || written != mtd->writesize) {
+		msg("error: write failed at %#llx\n", (long long)offset);
+		if (!err)
+			err = -EIO;
+	}
+
+	return err;
+}
+
+/* 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)
+		msg("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) {
+		msg("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)
+		msg("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 == -EUCLEAN)
+		err = mtd->ecc_stats.corrected - oldstats.corrected;
+
+	if (err < 0 || read != mtd->writesize) {
+		msg("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)
+		msg("verify_page\n");
+
+	for (i = 0; i < mtd->writesize; i++) {
+		if (rbuffer[i] != hash(i+seed)) {
+			msg("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);
+				msg("Inserted biterror @ %u/%u\n", byte, bit);
+				return 0;
+			}
+		}
+		byte++;
+	}
+	msg("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;
+
+	msg("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)
+			msg("Read reported %d corrected bit errors\n", err);
+		if (err < 0) {
+			msg("After %d biterrors per subpage, read reported error %d\n",
+				errs_per_subpage, err);
+			err = 0;
+			goto exit;
+		}
+
+		err = verify_page(1);
+		if (err) {
+			msg("ECC failure, read data is incorrect despite read success\n");
+			goto exit;
+		}
+
+		msg("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));
+
+	msg("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 = rewrite_page(0);
+		if (err)
+			break;
+
+		err = read_page(0);
+		if (err >= 0) {
+			if (err >= MAXBITS) {
+				msg("Implausible number of bit errors corrected\n");
+				err = -EIO;
+				break;
+			}
+			bitstats[err]++;
+			if (err > max_corrected) {
+				max_corrected = err;
+				msg("Read reported %d corrected bit errors\n",
+					err);
+			}
+		} else { /* err < 0 */
+			msg("Read reported error %d\n", err);
+			err = 0;
+			break;
+		}
+
+		err = verify_page(0);
+		if (err) {
+			bitstats[max_corrected] = opno;
+			msg("ECC failure, read data is incorrect despite read success\n");
+			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. */
+	msg("Bit error histogram (%d operations total):\n", opno);
+	for (i = 0; i < max_corrected; i++)
+		msg("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;
+
+	msg("\n");
+	msg("==================================================\n");
+	msg("MTD device: %d\n", dev);
+
+	mtd = get_mtd_device(NULL, dev);
+	if (IS_ERR(mtd)) {
+		err = PTR_ERR(mtd);
+		msg("error: cannot get MTD device\n");
+		goto exit_mtddev;
+	}
+
+	if (mtd->type != MTD_NANDFLASH) {
+		msg("this test requires NAND flash\n");
+		err = -ENODEV;
+		goto exit_nand;
+	}
+
+	msg("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;
+
+	msg("Device uses %d subpages of %d bytes\n", subcount, subsize);
+
+	offset     = page_offset * mtd->writesize;
+	eraseblock = mtd_div_by_eb(offset, mtd);
+
+	msg("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 = erase_block();
+	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 = erase_block();
+	if (err)
+		goto exit_error;
+
+	err = -EIO;
+	msg("finished successfully.\n");
+	msg("==================================================\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/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
index 70d6d7d0d656..b437fa425077 100644
--- a/drivers/mtd/tests/mtd_nandecctest.c
+++ b/drivers/mtd/tests/mtd_nandecctest.c
@@ -4,60 +4,287 @@
 #include <linux/random.h>
 #include <linux/string.h>
 #include <linux/bitops.h>
-#include <linux/jiffies.h>
+#include <linux/slab.h>
 #include <linux/mtd/nand_ecc.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 defined(CONFIG_MTD_NAND) || defined(CONFIG_MTD_NAND_MODULE)
 
-static void inject_single_bit_error(void *data, size_t size)
+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 long offset = random32() % (size * BITS_PER_BYTE);
+	unsigned int offset = random32() % (size * BITS_PER_BYTE);
 
-	__change_bit(offset, data);
+	memcpy(error_data, correct_data, size);
+	__change_bit_le(offset, error_data);
 }
 
-static unsigned char data[512];
-static unsigned char error_data[512];
+static void double_bit_error_data(void *error_data, void *correct_data,
+				size_t size)
+{
+	unsigned int offset[2];
+
+	offset[0] = random32() % (size * BITS_PER_BYTE);
+	do {
+		offset[1] = random32() % (size * BITS_PER_BYTE);
+	} while (offset[0] == offset[1]);
 
-static int nand_ecc_test(const size_t size)
+	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 char code[3];
-	unsigned char error_code[3];
-	char testname[30];
+	unsigned int offset = random32() % (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 = random32() % (3 * BITS_PER_BYTE);
+	}
 
-	BUG_ON(sizeof(data) < size);
+	return offset;
+}
 
-	sprintf(testname, "nand-ecc-%zu", size);
+static void single_bit_error_ecc(void *error_ecc, void *correct_ecc,
+				size_t size)
+{
+	unsigned int offset = random_ecc_bit(size);
 
-	get_random_bytes(data, size);
+	memcpy(error_ecc, correct_ecc, 3);
+	__change_bit_le(offset, error_ecc);
+}
 
-	memcpy(error_data, data, size);
-	inject_single_bit_error(error_data, size);
+static void double_bit_error_ecc(void *error_ecc, void *correct_ecc,
+				size_t size)
+{
+	unsigned int offset[2];
 
-	__nand_calculate_ecc(data, size, code);
-	__nand_calculate_ecc(error_data, size, error_code);
-	__nand_correct_data(error_data, code, error_code, size);
+	offset[0] = random_ecc_bit(size);
+	do {
+		offset[1] = random_ecc_bit(size);
+	} while (offset[0] == offset[1]);
 
-	if (!memcmp(data, error_data, size)) {
-		printk(KERN_INFO "mtd_nandecctest: ok - %s\n", testname);
+	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)
+{
+	unsigned char calc_ecc[3];
+	int ret;
+
+	__nand_calculate_ecc(error_data, size, calc_ecc);
+	ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+	if (ret == 0 && !memcmp(correct_data, error_data, size))
 		return 0;
-	}
 
-	printk(KERN_ERR "mtd_nandecctest: not ok - %s\n", testname);
+	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)
+{
+	unsigned char calc_ecc[3];
+	int ret;
 
-	printk(KERN_DEBUG "hexdump of data:\n");
-	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 16, 4,
-			data, size, false);
-	printk(KERN_DEBUG "hexdump of error data:\n");
-	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 16, 4,
+	__nand_calculate_ecc(error_data, size, calc_ecc);
+	ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+	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)
+{
+	unsigned char calc_ecc[3];
+	int ret;
+
+	__nand_calculate_ecc(error_data, size, calc_ecc);
+	ret = __nand_correct_data(error_data, error_ecc, calc_ecc, size);
+
+	return (ret == -1) ? 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)
+{
+	int i;
+	int err = 0;
+	void *error_data;
+	void *error_ecc;
+	void *correct_data;
+	void *correct_ecc;
 
-	return -1;
+	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);
+	__nand_calculate_ecc(correct_data, size, correct_ecc);
+
+	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("mtd_nandecctest: 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("mtd_nandecctest: ok - %s-%zd\n",
+			nand_ecc_test[i].name, size);
+	}
+error:
+	kfree(error_data);
+	kfree(error_ecc);
+	kfree(correct_data);
+	kfree(correct_ecc);
+
+	return err;
 }
 
 #else
 
-static int nand_ecc_test(const size_t size)
+static int nand_ecc_test_run(const size_t size)
 {
 	return 0;
 }
@@ -66,12 +293,13 @@ static int nand_ecc_test(const size_t size)
 
 static int __init ecc_test_init(void)
 {
-	srandom32(jiffies);
+	int err;
 
-	nand_ecc_test(256);
-	nand_ecc_test(512);
+	err = nand_ecc_test_run(256);
+	if (err)
+		return err;
 
-	return 0;
+	return nand_ecc_test_run(512);
 }
 
 static void __exit ecc_test_exit(void)
diff --git a/drivers/mtd/tests/mtd_speedtest.c b/drivers/mtd/tests/mtd_speedtest.c
index 2aec4f3b72be..42b0f7456fc4 100644
--- a/drivers/mtd/tests/mtd_speedtest.c
+++ b/drivers/mtd/tests/mtd_speedtest.c
@@ -26,6 +26,7 @@
 #include <linux/mtd/mtd.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_speedtest: "
 
@@ -47,25 +48,13 @@ static int ebcnt;
 static int pgcnt;
 static int goodebcnt;
 static struct timeval start, finish;
-static unsigned long next = 1;
-
-static inline unsigned int simple_rand(void)
-{
-	next = next * 1103515245 + 12345;
-	return (unsigned int)((next / 65536) % 32768);
-}
-
-static inline void simple_srand(unsigned long seed)
-{
-	next = seed;
-}
 
 static void set_random_data(unsigned char *buf, size_t len)
 {
 	size_t i;
 
 	for (i = 0; i < len; ++i)
-		buf[i] = simple_rand();
+		buf[i] = random32();
 }
 
 static int erase_eraseblock(int ebnum)
@@ -407,7 +396,6 @@ static int __init mtd_speedtest_init(void)
 		goto out;
 	}
 
-	simple_srand(1);
 	set_random_data(iobuf, mtd->erasesize);
 
 	err = scan_for_bad_eraseblocks();
diff --git a/drivers/mtd/tests/mtd_stresstest.c b/drivers/mtd/tests/mtd_stresstest.c
index 7b33f22d0b58..cb268cebf01a 100644
--- a/drivers/mtd/tests/mtd_stresstest.c
+++ b/drivers/mtd/tests/mtd_stresstest.c
@@ -27,6 +27,7 @@
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/vmalloc.h>
+#include <linux/random.h>
 
 #define PRINT_PREF KERN_INFO "mtd_stresstest: "
 
@@ -48,28 +49,13 @@ static int pgsize;
 static int bufsize;
 static int ebcnt;
 static int pgcnt;
-static unsigned long next = 1;
-
-static inline unsigned int simple_rand(void)
-{
-	next = next * 1103515245 + 12345;
-	return (unsigned int)((next / 65536) % 32768);
-}
-
-static inline void simple_srand(unsigned long seed)
-{
-	next = seed;
-}
 
 static int rand_eb(void)
 {
-	int eb;
+	unsigned int eb;
 
 again:
-	if (ebcnt < 32768)
-		eb = simple_rand();
-	else
-		eb = (simple_rand() << 15) | simple_rand();
+	eb = random32();
 	/* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
 	eb %= (ebcnt - 1);
 	if (bbt[eb])
@@ -79,24 +65,18 @@ again:
 
 static int rand_offs(void)
 {
-	int offs;
+	unsigned int offs;
 
-	if (bufsize < 32768)
-		offs = simple_rand();
-	else
-		offs = (simple_rand() << 15) | simple_rand();
+	offs = random32();
 	offs %= bufsize;
 	return offs;
 }
 
 static int rand_len(int offs)
 {
-	int len;
+	unsigned int len;
 
-	if (bufsize < 32768)
-		len = simple_rand();
-	else
-		len = (simple_rand() << 15) | simple_rand();
+	len = random32();
 	len %= (bufsize - offs);
 	return len;
 }
@@ -211,7 +191,7 @@ static int do_write(void)
 
 static int do_operation(void)
 {
-	if (simple_rand() & 1)
+	if (random32() & 1)
 		return do_read();
 	else
 		return do_write();
@@ -302,9 +282,8 @@ static int __init mtd_stresstest_init(void)
 	}
 	for (i = 0; i < ebcnt; i++)
 		offsets[i] = mtd->erasesize;
-	simple_srand(current->pid);
 	for (i = 0; i < bufsize; i++)
-		writebuf[i] = simple_rand();
+		writebuf[i] = random32();
 
 	err = scan_for_bad_eraseblocks();
 	if (err)