/*
   * 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>
   */
  
  #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:
  	eb = prandom_u32();
  	/* 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 = prandom_u32();
  	offs %= bufsize;
  	return offs;
  }
  
  static int rand_len(int offs)
  {
  	unsigned int len;
  
  	len = prandom_u32();
  	len %= (bufsize - offs);
  	return len;
  }
  
  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 = 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 = 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() & 1)
  		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 "
  ");
  	printk(KERN_INFO "=================================================
  ");
  
  	if (dev < 0) {
  		pr_info("Please specify a valid mtd-device via module parameter
  ");
  		pr_crit("CAREFUL: This test wipes all data on the specified MTD device!
  ");
  		return -EINVAL;
  	}
  
  	pr_info("MTD device: %d
  ", dev);
  
  	mtd = get_mtd_device(NULL, dev);
  	if (IS_ERR(mtd)) {
  		err = PTR_ERR(mtd);
  		pr_err("error: cannot get MTD device
  ");
  		return err;
  	}
  
  	if (mtd->writesize == 1) {
  		pr_info("not NAND flash, assume page size is 512 "
  		       "bytes.
  ");
  		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
  ",
  	       (unsigned long long)mtd->size, mtd->erasesize,
  	       pgsize, ebcnt, pgcnt, mtd->oobsize);
  
  	if (ebcnt < 2) {
  		pr_err("error: need at least 2 eraseblocks
  ");
  		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)
  		goto out;
  	for (i = 0; i < ebcnt; i++)
  		offsets[i] = mtd->erasesize;
  	prandom_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
  ");
  	for (op = 0; op < count; op++) {
  		if ((op & 1023) == 0)
  			pr_info("%d operations done
  ", op);
  		err = do_operation();
  		if (err)
  			goto out;
  		cond_resched();
  	}
  	pr_info("finished, %d operations done
  ", op);
  
  out:
  	kfree(offsets);
  	kfree(bbt);
  	vfree(writebuf);
  	vfree(readbuf);
  out_put_mtd:
  	put_mtd_device(mtd);
  	if (err)
  		pr_info("error %d occurred
  ", err);
  	printk(KERN_INFO "=================================================
  ");
  	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");