v4.19.13 snapshot.
diff --git a/drivers/mtd/tests/pagetest.c b/drivers/mtd/tests/pagetest.c
new file mode 100644
index 0000000..7568736
--- /dev/null
+++ b/drivers/mtd/tests/pagetest.c
@@ -0,0 +1,473 @@
+/*
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; see the file COPYING. If not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Test 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");