/*
   * asynchronous raid6 recovery self test
   * Copyright (c) 2009, Intel Corporation.
   *
   * based on drivers/md/raid6test/test.c:
   * 	Copyright 2002-2007 H. Peter Anvin
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope 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; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
   *
   */
  #include <linux/async_tx.h>

  #include <linux/gfp.h>

  #include <linux/mm.h>

  #include <linux/random.h>

  #include <linux/module.h>

  
  #undef pr
  #define pr(fmt, args...) pr_info("raid6test: " fmt, ##args)

  #define NDISKS 64 /* Including P and Q */

  
  static struct page *dataptrs[NDISKS];

  static addr_conv_t addr_conv[NDISKS];

  static struct page *data[NDISKS+3];
  static struct page *spare;
  static struct page *recovi;
  static struct page *recovj;
  
  static void callback(void *param)
  {
  	struct completion *cmp = param;
  
  	complete(cmp);
  }
  
  static void makedata(int disks)
  {

  	int i;

  
  	for (i = 0; i < disks; i++) {

  		prandom_bytes(page_address(data[i]), PAGE_SIZE);

  		dataptrs[i] = data[i];
  	}
  }
  
  static char disk_type(int d, int disks)
  {
  	if (d == disks - 2)
  		return 'P';
  	else if (d == disks - 1)
  		return 'Q';
  	else
  		return 'D';
  }
  
  /* Recover two failed blocks. */
  static void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, struct page **ptrs)
  {
  	struct async_submit_ctl submit;

  	struct completion cmp;
  	struct dma_async_tx_descriptor *tx = NULL;
  	enum sum_check_flags result = ~0;
  
  	if (faila > failb)
  		swap(faila, failb);
  
  	if (failb == disks-1) {
  		if (faila == disks-2) {
  			/* P+Q failure.  Just rebuild the syndrome. */
  			init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
  			tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
  		} else {
  			struct page *blocks[disks];
  			struct page *dest;
  			int count = 0;
  			int i;
  
  			/* data+Q failure.  Reconstruct data from P,
  			 * then rebuild syndrome
  			 */
  			for (i = disks; i-- ; ) {
  				if (i == faila || i == failb)
  					continue;
  				blocks[count++] = ptrs[i];
  			}
  			dest = ptrs[faila];
  			init_async_submit(&submit, ASYNC_TX_XOR_ZERO_DST, NULL,
  					  NULL, NULL, addr_conv);
  			tx = async_xor(dest, blocks, 0, count, bytes, &submit);
  
  			init_async_submit(&submit, 0, tx, NULL, NULL, addr_conv);
  			tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
  		}
  	} else {
  		if (failb == disks-2) {
  			/* data+P failure. */
  			init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
  			tx = async_raid6_datap_recov(disks, bytes, faila, ptrs, &submit);
  		} else {
  			/* data+data failure. */
  			init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
  			tx = async_raid6_2data_recov(disks, bytes, faila, failb, ptrs, &submit);
  		}
  	}
  	init_completion(&cmp);
  	init_async_submit(&submit, ASYNC_TX_ACK, tx, callback, &cmp, addr_conv);
  	tx = async_syndrome_val(ptrs, 0, disks, bytes, &result, spare, &submit);
  	async_tx_issue_pending(tx);
  
  	if (wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000)) == 0)
  		pr("%s: timeout! (faila: %d failb: %d disks: %d)
  ",
  		   __func__, faila, failb, disks);
  
  	if (result != 0)
  		pr("%s: validation failure! faila: %d failb: %d sum_check_flags: %x
  ",
  		   __func__, faila, failb, result);
  }
  
  static int test_disks(int i, int j, int disks)
  {
  	int erra, errb;
  
  	memset(page_address(recovi), 0xf0, PAGE_SIZE);
  	memset(page_address(recovj), 0xba, PAGE_SIZE);
  
  	dataptrs[i] = recovi;
  	dataptrs[j] = recovj;
  
  	raid6_dual_recov(disks, PAGE_SIZE, i, j, dataptrs);
  
  	erra = memcmp(page_address(data[i]), page_address(recovi), PAGE_SIZE);
  	errb = memcmp(page_address(data[j]), page_address(recovj), PAGE_SIZE);
  
  	pr("%s(%d, %d): faila=%3d(%c)  failb=%3d(%c)  %s
  ",
  	   __func__, i, j, i, disk_type(i, disks), j, disk_type(j, disks),
  	   (!erra && !errb) ? "OK" : !erra ? "ERRB" : !errb ? "ERRA" : "ERRAB");
  
  	dataptrs[i] = data[i];
  	dataptrs[j] = data[j];
  
  	return erra || errb;
  }
  
  static int test(int disks, int *tests)
  {

  	struct dma_async_tx_descriptor *tx;
  	struct async_submit_ctl submit;
  	struct completion cmp;
  	int err = 0;
  	int i, j;
  
  	recovi = data[disks];
  	recovj = data[disks+1];
  	spare  = data[disks+2];
  
  	makedata(disks);
  
  	/* Nuke syndromes */
  	memset(page_address(data[disks-2]), 0xee, PAGE_SIZE);
  	memset(page_address(data[disks-1]), 0xee, PAGE_SIZE);
  
  	/* Generate assumed good syndrome */
  	init_completion(&cmp);
  	init_async_submit(&submit, ASYNC_TX_ACK, NULL, callback, &cmp, addr_conv);
  	tx = async_gen_syndrome(dataptrs, 0, disks, PAGE_SIZE, &submit);
  	async_tx_issue_pending(tx);
  
  	if (wait_for_completion_timeout(&cmp, msecs_to_jiffies(3000)) == 0) {
  		pr("error: initial gen_syndrome(%d) timed out
  ", disks);
  		return 1;
  	}
  
  	pr("testing the %d-disk case...
  ", disks);
  	for (i = 0; i < disks-1; i++)
  		for (j = i+1; j < disks; j++) {
  			(*tests)++;
  			err += test_disks(i, j, disks);
  		}
  
  	return err;
  }
  
  
  static int raid6_test(void)
  {
  	int err = 0;
  	int tests = 0;
  	int i;
  
  	for (i = 0; i < NDISKS+3; i++) {
  		data[i] = alloc_page(GFP_KERNEL);
  		if (!data[i]) {
  			while (i--)
  				put_page(data[i]);
  			return -ENOMEM;
  		}
  	}
  
  	/* the 4-disk and 5-disk cases are special for the recovery code */
  	if (NDISKS > 4)
  		err += test(4, &tests);
  	if (NDISKS > 5)
  		err += test(5, &tests);

  	/* the 11 and 12 disk cases are special for ioatdma (p-disabled
  	 * q-continuation without extended descriptor)
  	 */
  	if (NDISKS > 12) {
  		err += test(11, &tests);
  		err += test(12, &tests);
  	}

  
  	/* the 24 disk case is special for ioatdma as it is the boudary point
  	 * at which it needs to switch from 8-source ops to 16-source
  	 * ops for continuation (assumes DMA_HAS_PQ_CONTINUE is not set)
  	 */
  	if (NDISKS > 24)
  		err += test(24, &tests);

  	err += test(NDISKS, &tests);
  
  	pr("
  ");
  	pr("complete (%d tests, %d failure%s)
  ",
  	   tests, err, err == 1 ? "" : "s");
  
  	for (i = 0; i < NDISKS+3; i++)
  		put_page(data[i]);
  
  	return 0;
  }
  
  static void raid6_test_exit(void)
  {
  }
  
  /* when compiled-in wait for drivers to load first (assumes dma drivers
   * are also compliled-in)
   */
  late_initcall(raid6_test);
  module_exit(raid6_test_exit);
  MODULE_AUTHOR("Dan Williams <dan.j.williams@intel.com>");
  MODULE_DESCRIPTION("asynchronous RAID-6 recovery self tests");
  MODULE_LICENSE("GPL");