LXR linux/crypto/async_tx/async

   1/*
   2 * copy offload engine support
   3 *
   4 * Copyright © 2006, Intel Corporation.
   5 *
   6 *      Dan Williams <dan.j.williams@intel.com>
   7 *
   8 *      with architecture considerations by:
   9 *      Neil Brown <neilb@suse.de>
  10 *      Jeff Garzik <jeff@garzik.org>
  11 *
  12 * This program is free software; you can redistribute it and/or modify it
  13 * under the terms and conditions of the GNU General Public License,
  14 * version 2, as published by the Free Software Foundation.
  15 *
  16 * This program is distributed in the hope it will be useful, but WITHOUT
  17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  18 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  19 * more details.
  20 *
  21 * You should have received a copy of the GNU General Public License along with
  22 * this program; if not, write to the Free Software Foundation, Inc.,
  23 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  24 *
  25 */
  26#include <linux/kernel.h>
  27#include <linux/highmem.h>
  28#include <linux/mm.h>
  29#include <linux/dma-mapping.h>
  30#include <linux/async_tx.h>
  31
  32/**
  33 * async_memcpy - attempt to copy memory with a dma engine.
  34 * @dest: destination page
  35 * @src: src page
  36 * @dest_offset: offset into 'dest' to start transaction
  37 * @src_offset: offset into 'src' to start transaction
  38 * @len: length in bytes
  39 * @submit: submission / completion modifiers
  40 *
  41 * honored flags: ASYNC_TX_ACK
  42 */
  43struct dma_async_tx_descriptor *
  44async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
  45             unsigned int src_offset, size_t len,
  46             struct async_submit_ctl *submit)
  47{
  48        struct dma_chan *chan = async_tx_find_channel(submit, DMA_MEMCPY,
  49                                                      &dest, 1, &src, 1, len);
  50        struct dma_device *device = chan ? chan->device : NULL;
  51        struct dma_async_tx_descriptor *tx = NULL;
  52
  53        if (device && is_dma_copy_aligned(device, src_offset, dest_offset, len)) {
  54                dma_addr_t dma_dest, dma_src;
  55                unsigned long dma_prep_flags = 0;
  56
  57                if (submit->cb_fn)
  58                        dma_prep_flags |= DMA_PREP_INTERRUPT;
  59                if (submit->flags & ASYNC_TX_FENCE)
  60                        dma_prep_flags |= DMA_PREP_FENCE;
  61                dma_dest = dma_map_page(device->dev, dest, dest_offset, len,
  62                                        DMA_FROM_DEVICE);
  63
  64                dma_src = dma_map_page(device->dev, src, src_offset, len,
  65                                       DMA_TO_DEVICE);
  66
  67                tx = device->device_prep_dma_memcpy(chan, dma_dest, dma_src,
  68                                                    len, dma_prep_flags);
  69        }
  70
  71        if (tx) {
  72                pr_debug("%s: (async) len: %zu\n", __func__, len);
  73                async_tx_submit(chan, tx, submit);
  74        } else {
  75                void *dest_buf, *src_buf;
  76                pr_debug("%s: (sync) len: %zu\n", __func__, len);
  77
  78                /* wait for any prerequisite operations */
  79                async_tx_quiesce(&submit->depend_tx);
  80
  81                dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
  82                src_buf = kmap_atomic(src, KM_USER1) + src_offset;
  83
  84                memcpy(dest_buf, src_buf, len);
  85
  86                kunmap_atomic(dest_buf, KM_USER0);
  87                kunmap_atomic(src_buf, KM_USER1);
  88
  89                async_tx_sync_epilog(submit);
  90        }
  91
  92        return tx;
  93}
  94EXPORT_SYMBOL_GPL(async_memcpy);
  95
  96MODULE_AUTHOR("Intel Corporation");
  97MODULE_DESCRIPTION("asynchronous memcpy api");
  98MODULE_LICENSE("GPL");
  99