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/*

 * memory fill offload engine support

 *

 * Copyright © 2006, Intel Corporation.

 *

 *      Dan Williams <dan.j.williams@intel.com>

 *

 *      with architecture considerations by:

 *      Neil Brown <neilb@suse.de>

 *      Jeff Garzik <jeff@garzik.org>

 *

 * 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/kernel.h>

#include <linux/interrupt.h>

#include <linux/mm.h>

#include <linux/dma-mapping.h>

#include <linux/async_tx.h>

/**

 * async_memset - attempt to fill memory with a dma engine.

 * @dest: destination page

 * @val: fill value

 * @offset: offset in pages to start transaction

 * @len: length in bytes

 * @flags: ASYNC_TX_ASSUME_COHERENT, ASYNC_TX_ACK, ASYNC_TX_DEP_ACK

 * @depend_tx: memset depends on the result of this transaction

 * @cb_fn: function to call when the memcpy completes

 * @cb_param: parameter to pass to the callback routine

 */

struct dma_async_tx_descriptor *

async_memset(struct page *dest, int val, unsigned int offset,

        size_t len, enum async_tx_flags flags,

        struct dma_async_tx_descriptor *depend_tx,

        dma_async_tx_callback cb_fn, void *cb_param)

{

        struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMSET);

        struct dma_device *device = chan ? chan->device : NULL;

        int int_en = cb_fn ? 1 : 0;

        struct dma_async_tx_descriptor *tx = device ?

                device->device_prep_dma_memset(chan, val, len,

                        int_en) : NULL;

        if (tx) { /* run the memset asynchronously */

                dma_addr_t dma_addr;

                enum dma_data_direction dir;

                pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);

                dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?

                        DMA_NONE : DMA_FROM_DEVICE;

                dma_addr = dma_map_page(device->dev, dest, offset, len, dir);

                tx->tx_set_dest(dma_addr, tx, 0);

                async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);

        } else { /* run the memset synchronously */

                void *dest_buf;

                pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);

                dest_buf = (void *) (((char *) page_address(dest)) + offset);

                /* wait for any prerequisite operations */

                if (depend_tx) {

                        /* if ack is already set then we cannot be sure

                         * we are referring to the correct operation

                         */

                        BUG_ON(depend_tx->ack);

                        if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)

                                panic("%s: DMA_ERROR waiting for depend_tx\n",

                                        __FUNCTION__);

                }

                memset(dest_buf, val, len);

                async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);

        }

        return tx;

}

EXPORT_SYMBOL_GPL(async_memset);

static int __init async_memset_init(void)

{

        return 0;

}

static void __exit async_memset_exit(void)

{

        do { } while (0);

}

module_init(async_memset_init);

module_exit(async_memset_exit);

MODULE_AUTHOR("Intel Corporation");

MODULE_DESCRIPTION("asynchronous memset api");

MODULE_LICENSE("GPL");