mtd_stresstest.c

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/*
 * 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 <[email protected]>
 */

#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>

#define PRINT_PREF KERN_INFO "mtd_stresstest: "

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:
    eb = random32();
    /* 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)
{
    unsigned int offs;

    offs = random32();
    offs %= bufsize;
    return offs;
}

static int rand_len(int offs)
{
    unsigned int len;

    len = random32();
    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;
    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 (mtd_is_bitflip(err))
        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;
    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 (random32() & 1)
        return do_read();
    else
        return do_write();
}

static int scan_for_bad_eraseblocks(void)
{
    int i, bad = 0;

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

    if (!mtd_can_have_bb(mtd))
        return 0;

    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");

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

    printk(PRINT_PREF "MTD device: %d\n", dev);

    mtd = get_mtd_device(NULL, dev);
    if (IS_ERR(mtd)) {
        err = PTR_ERR(mtd);
        printk(PRINT_PREF "error: cannot get MTD device\n");
        return err;
    }

    if (mtd->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 / pgsize;

    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);

    if (ebcnt < 2) {
        printk(PRINT_PREF "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(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;
    for (i = 0; i < bufsize; i++)
        writebuf[i] = random32();

    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);
out_put_mtd:
    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");