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_ASSUME_COHERENT, 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        struct dma_device *device = chan ? chan->device : NULL;
  51        int int_en = cb_fn ? 1 : 0;
  52        struct dma_async_tx_descriptor *tx = device ?
  53                device->device_prep_dma_memcpy(chan, len,
  54                int_en) : NULL;
  55
  56        if (tx) { /* run the memcpy asynchronously */
  57                dma_addr_t addr;
  58                enum dma_data_direction dir;
  59
  60                pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
  61
  62                dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
  63                        DMA_NONE : DMA_FROM_DEVICE;
  64
  65                addr = dma_map_page(device->dev, dest, dest_offset, len, dir);
  66                tx->tx_set_dest(addr, tx, 0);
  67
  68                dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
  69                        DMA_NONE : DMA_TO_DEVICE;
  70
  71                addr = dma_map_page(device->dev, src, src_offset, len, dir);
  72                tx->tx_set_src(addr, tx, 0);
  73
  74                async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
  75        } else { /* run the memcpy synchronously */
  76                void *dest_buf, *src_buf;
  77                pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);
  78
  79                /* wait for any prerequisite operations */
  80                if (depend_tx) {
  81                        /* if ack is already set then we cannot be sure
  82                         * we are referring to the correct operation
  83                         */
  84                        BUG_ON(depend_tx->ack);
  85                        if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
  86                                panic("%s: DMA_ERROR waiting for depend_tx\n",
  87                                        __FUNCTION__);
  88                }
  89
  90                dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
  91                src_buf = kmap_atomic(src, KM_USER1) + src_offset;
  92
  93                memcpy(dest_buf, src_buf, len);
  94
  95                kunmap_atomic(dest_buf, KM_USER0);
  96                kunmap_atomic(src_buf, KM_USER1);
  97
  98                async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
  99        }
 100
 101        return tx;
 102}
 103EXPORT_SYMBOL_GPL(async_memcpy);
 104
 105static int __init async_memcpy_init(void)
 106{
 107        return 0;
 108}
 109
 110static void __exit async_memcpy_exit(void)
 111{
 112        do { } while (0);
 113}
 114
 115module_init(async_memcpy_init);
 116module_exit(async_memcpy_exit);
 117
 118MODULE_AUTHOR("Intel Corporation");
 119MODULE_DESCRIPTION("asynchronous memcpy api");
 120MODULE_LICENSE("GPL");
 121