LXR linux/crypto/async_tx/async

   1/*
   2 * copy offload engine support
   3 *
   4 * Copyright \xC2\xA9 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 * @offset: offset in pages to start transaction
  37 * @len: length in bytes
  38 * @flags: ASYNC_TX_ACK, ASYNC_TX_DEP_ACK,
  39 * @depend_tx: memcpy depends on the result of this transaction
  40 * @cb_fn: function to call when the memcpy completes
  41 * @cb_param: parameter to pass to the callback routine
  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, enum async_tx_flags flags,
  46        struct dma_async_tx_descriptor *depend_tx,
  47        dma_async_tx_callback cb_fn, void *cb_param)
  48{
  49        struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMCPY,
  50                                                      &dest, 1, &src, 1, len);
  51        struct dma_device *device = chan ? chan->device : NULL;
  52        struct dma_async_tx_descriptor *tx = NULL;
  53
  54        if (device) {
  55                dma_addr_t dma_dest, dma_src;
  56                unsigned long dma_prep_flags = cb_fn ? DMA_PREP_INTERRUPT : 0;
  57
  58                dma_dest = dma_map_page(device->dev, dest, dest_offset, len,
  59                                        DMA_FROM_DEVICE);
  60
  61                dma_src = dma_map_page(device->dev, src, src_offset, len,
  62                                       DMA_TO_DEVICE);
  63
  64                tx = device->device_prep_dma_memcpy(chan, dma_dest, dma_src,
  65                                                    len, dma_prep_flags);
  66        }
  67
  68        if (tx) {
  69                pr_debug("%s: (async) len: %zu\n", __func__, len);
  70                async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
  71        } else {
  72                void *dest_buf, *src_buf;
  73                pr_debug("%s: (sync) len: %zu\n", __func__, len);
  74
  75                /* wait for any prerequisite operations */
  76                async_tx_quiesce(&depend_tx);
  77
  78                dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
  79                src_buf = kmap_atomic(src, KM_USER1) + src_offset;
  80
  81                memcpy(dest_buf, src_buf, len);
  82
  83                kunmap_atomic(dest_buf, KM_USER0);
  84                kunmap_atomic(src_buf, KM_USER1);
  85
  86                async_tx_sync_epilog(cb_fn, cb_param);
  87        }
  88
  89        return tx;
  90}
  91EXPORT_SYMBOL_GPL(async_memcpy);
  92
  93static int __init async_memcpy_init(void)
  94{
  95        return 0;
  96}
  97
  98static void __exit async_memcpy_exit(void)
  99{
 100        do { } while (0);
 101}
 102
 103module_init(async_memcpy_init);
 104module_exit(async_memcpy_exit);
 105
 106MODULE_AUTHOR("Intel Corporation");
 107MODULE_DESCRIPTION("asynchronous memcpy api");
 108MODULE_LICENSE("GPL");
 109