linux-imx

/*

 * drivers/dma/fsl_raid.c

 *

 * Freescale RAID Engine device driver

 *

 * Author:

 *  Harninder Rai <harninder.rai@freescale.com>

 *  Naveen Burmi <naveenburmi@freescale.com>

 *

 * Rewrite:

 *  Xuelin Shi <xuelin.shi@freescale.com>

 *

 * Copyright (c) 2010-2014 Freescale Semiconductor, Inc.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *     * Redistributions of source code must retain the above copyright

 *       notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above copyright

 *       notice, this list of conditions and the following disclaimer in the

 *       documentation and/or other materials provided with the distribution.

 *     * Neither the name of Freescale Semiconductor nor the

 *       names of its contributors may be used to endorse or promote products

 *       derived from this software without specific prior written permission.

 *

 * ALTERNATIVELY, this software may be distributed under the terms of the

 * GNU General Public License ("GPL") as published by the Free Software

 * Foundation, either version 2 of that License or (at your option) any

 * later version.

 *

 * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL Freescale Semiconductor BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *

 * Theory of operation:

 *

 * General capabilities:

 *  RAID Engine (RE) block is capable of offloading XOR, memcpy and P/Q

 *  calculations required in RAID5 and RAID6 operations. RE driver

 *  registers with Linux's ASYNC layer as dma driver. RE hardware

 *  maintains strict ordering of the requests through chained

 *  command queueing.

 *

 * Data flow:

 *  Software RAID layer of Linux (MD layer) maintains RAID partitions,

 *  strips, stripes etc. It sends requests to the underlying ASYNC layer

 *  which further passes it to RE driver. ASYNC layer decides which request

 *  goes to which job ring of RE hardware. For every request processed by

 *  RAID Engine, driver gets an interrupt unless coalescing is set. The

 *  per job ring interrupt handler checks the status register for errors,

 *  clears the interrupt and leave the post interrupt processing to the irq

 *  thread.

 */

#include <linux/interrupt.h>

#include <linux/module.h>

#include <linux/of_irq.h>

#include <linux/of_address.h>

#include <linux/of_platform.h>

#include <linux/dma-mapping.h>

#include <linux/dmapool.h>

#include <linux/dmaengine.h>

#include <linux/io.h>

#include <linux/spinlock.h>

#include <linux/slab.h>

​

#include "dmaengine.h"

#include "fsl_raid.h"

​

#define FSL_RE_MAX_XOR_SRCS 16

#define FSL_RE_MAX_PQ_SRCS  16

#define FSL_RE_MIN_DESCS    256

#define FSL_RE_MAX_DESCS    (4 * FSL_RE_MIN_DESCS)

#define FSL_RE_FRAME_FORMAT 0x1

#define FSL_RE_MAX_DATA_LEN (1024*1024)

​

#define to_fsl_re_dma_desc(tx) container_of(tx, struct fsl_re_desc, async_tx)

​

/* Add descriptors into per chan software queue - submit_q */

static dma_cookie_t fsl_re_tx_submit(struct dma_async_tx_descriptor *tx)

{

    struct fsl_re_desc *desc;

    struct fsl_re_chan *re_chan;

    dma_cookie_t cookie;

    unsigned long flags;

​