MTD: tests: add mtd_stresstest

This test just performs random operations on random eraseblocks.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/tests/mtd_stresstest.c

+/*
+ * 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 random reads, writes and erases on MTD device.
+ *
+ * Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/err.h>
+#include <linux/mtd/mtd.h>
+#include <linux/sched.h>
+#include <linux/vmalloc.h>
+
+#define PRINT_PREF KERN_INFO "mtd_stresstest: "
+
+static int dev;
+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 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;
+
+again:
+	if (ebcnt < 32768)
+		eb = simple_rand();
+	else
+		eb = (simple_rand() << 15) | simple_rand();
+	/* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
+	eb %= (ebcnt - 1);
+	if (bbt[eb])
+		goto again;
+	return eb;
+}
+
+static int rand_offs(void)
+{
+	int offs;
+
+	if (bufsize < 32768)
+		offs = simple_rand();
+	else
+		offs = (simple_rand() << 15) | simple_rand();
+	offs %= bufsize;
+	return offs;
+}
+
+static int rand_len(int offs)
+{
+	int len;
+
+	if (bufsize < 32768)
+		len = simple_rand();
+	else
+		len = (simple_rand() << 15) | simple_rand();
+	len %= (bufsize - offs);
+	return len;
+}
+
+static int erase_eraseblock(int ebnum)
+{
+	int err;
+	struct erase_info ei;
+	loff_t addr = ebnum * mtd->erasesize;
+
+	memset(&ei, 0, sizeof(struct erase_info));
+	ei.mtd  = mtd;
+	ei.addr = addr;
+	ei.len  = mtd->erasesize;
+
+	err = mtd->erase(mtd, &ei);
+	if (unlikely(err)) {
+		printk(PRINT_PREF "error %d while erasing EB %d\n", err, ebnum);
+		return err;
+	}
+
+	if (unlikely(ei.state == MTD_ERASE_FAILED)) {
+		printk(PRINT_PREF "some erase error occurred at EB %d\n",
+		       ebnum);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int is_block_bad(int ebnum)
+{
+	loff_t addr = ebnum * mtd->erasesize;
+	int ret;
+
+	ret = mtd->block_isbad(mtd, addr);
+	if (ret)
+		printk(PRINT_PREF "block %d is bad\n", ebnum);
+	return ret;
+}
+
+static int do_read(void)
+{
+	size_t read = 0;
+	int eb = rand_eb();
+	int offs = rand_offs();
+	int len = rand_len(offs), err;
+	loff_t addr;
+
+	if (bbt[eb + 1]) {
+		if (offs >= mtd->erasesize)
+			offs -= mtd->erasesize;
+		if (offs + len > mtd->erasesize)
+			len = mtd->erasesize - offs;
+	}
+	addr = eb * mtd->erasesize + offs;
+	err = mtd->read(mtd, addr, len, &read, readbuf);
+	if (err == -EUCLEAN)
+		err = 0;
+	if (unlikely(err || read != len)) {
+		printk(PRINT_PREF "error: read failed at 0x%llx\n",
+		       (long long)addr);
+		if (!err)
+			err = -EINVAL;
+		return err;
+	}
+	return 0;
+}
+
+static int do_write(void)
+{
+	int eb = rand_eb(), offs, err, len;
+	size_t written = 0;
+	loff_t addr;
+
+	offs = offsets[eb];
+	if (offs >= mtd->erasesize) {
+		err = erase_eraseblock(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 = erase_eraseblock(eb + 1);
+			if (err)
+				return err;
+			offsets[eb + 1] = 0;
+		}
+	}
+	addr = eb * mtd->erasesize + offs;
+	err = mtd->write(mtd, addr, len, &written, writebuf);
+	if (unlikely(err || written != len)) {
+		printk(PRINT_PREF "error: write failed at 0x%llx\n",
+		       (long long)addr);
+		if (!err)
+			err = -EINVAL;
+		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 (simple_rand() & 1)
+		return do_read();
+	else
+		return do_write();
+}
+
+static int scan_for_bad_eraseblocks(void)
+{
+	int i, bad = 0;
+
+	bbt = kmalloc(ebcnt, GFP_KERNEL);
+	if (!bbt) {
+		printk(PRINT_PREF "error: cannot allocate memory\n");
+		return -ENOMEM;
+	}
+	memset(bbt, 0 , ebcnt);
+
+	printk(PRINT_PREF "scanning for bad eraseblocks\n");
+	for (i = 0; i < ebcnt; ++i) {
+		bbt[i] = is_block_bad(i) ? 1 : 0;
+		if (bbt[i])
+			bad += 1;
+		cond_resched();
+	}
+	printk(PRINT_PREF "scanned %d eraseblocks, %d are bad\n", i, bad);
+	return 0;
+}
+
+static int __init mtd_stresstest_init(void)
+{
+	int err;
+	int i, op;
+	uint64_t tmp;
+
+	printk(KERN_INFO "\n");
+	printk(KERN_INFO "=================================================\n");
+	printk(PRINT_PREF "MTD device: %d\n", dev);
+
+	mtd = get_mtd_device(NULL, dev);
+	if (IS_ERR(mtd)) {
+		err = PTR_ERR(mtd);
+		printk(PRINT_PREF "error: cannot get MTD device\n");
+		return err;
+	}
+
+	if (mtd->writesize == 1) {
+		printk(PRINT_PREF "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 / mtd->writesize;
+
+	printk(PRINT_PREF "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);
+
+	/* Read or write up 2 eraseblocks at a time */
+	bufsize = mtd->erasesize * 2;
+
+	err = -ENOMEM;
+	readbuf = vmalloc(bufsize);
+	writebuf = vmalloc(bufsize);
+	offsets = kmalloc(ebcnt * sizeof(int), GFP_KERNEL);
+	if (!readbuf || !writebuf || !offsets) {
+		printk(PRINT_PREF "error: cannot allocate memory\n");
+		goto out;
+	}
+	for (i = 0; i < ebcnt; i++)
+		offsets[i] = mtd->erasesize;
+	simple_srand(current->pid);
+	for (i = 0; i < bufsize; i++)
+		writebuf[i] = simple_rand();
+
+	err = scan_for_bad_eraseblocks();
+	if (err)
+		goto out;
+
+	/* Do operations */
+	printk(PRINT_PREF "doing operations\n");
+	for (op = 0; op < count; op++) {
+		if ((op & 1023) == 0)
+			printk(PRINT_PREF "%d operations done\n", op);
+		err = do_operation();
+		if (err)
+			goto out;
+		cond_resched();
+	}
+	printk(PRINT_PREF "finished, %d operations done\n", op);
+
+out:
+	kfree(offsets);
+	kfree(bbt);
+	vfree(writebuf);
+	vfree(readbuf);
+	put_mtd_device(mtd);
+	if (err)
+		printk(PRINT_PREF "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");