crypto/async_tx/async_memcpy.c

   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/module.h>
  29 #include <linux/mm.h>
  30 #include <linux/dma-mapping.h>
  31 #include <linux/async_tx.h>
  32
  33 /**
  34  * async_memcpy - attempt to copy memory with a dma engine.
  35  * @dest: destination page
  36  * @src: src page
  37  * @dest_offset: offset into 'dest' to start transaction
  38  * @src_offset: offset into 'src' to start transaction
  39  * @len: length in bytes
  40  * @submit: submission / completion modifiers
  41  *
  42  * honored flags: ASYNC_TX_ACK
  43  */
  44 struct dma_async_tx_descriptor *
  45 async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
  46              unsigned int src_offset, size_t len,
  47              struct async_submit_ctl *submit)
  48 {
  49         struct dma_chan *chan = async_tx_find_channel(submit, 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         struct dmaengine_unmap_data *unmap = NULL;
  54
  55         if (device)
  56                 unmap = dmaengine_get_unmap_data(device->dev, 2, GFP_NOWAIT);
  57
  58         if (unmap && is_dma_copy_aligned(device, src_offset, dest_offset, len)) {
  59                 unsigned long dma_prep_flags = 0;
  60
  61                 if (submit->cb_fn)
  62                         dma_prep_flags |= DMA_PREP_INTERRUPT;
  63                 if (submit->flags & ASYNC_TX_FENCE)
  64                         dma_prep_flags |= DMA_PREP_FENCE;
  65
  66                 unmap->to_cnt = 1;
  67                 unmap->addr[0] = dma_map_page(device->dev, src, src_offset, len,
  68                                               DMA_TO_DEVICE);
  69                 unmap->from_cnt = 1;
  70                 unmap->addr[1] = dma_map_page(device->dev, dest, dest_offset, len,
  71                                               DMA_FROM_DEVICE);
  72                 unmap->len = len;
  73
  74                 tx = device->device_prep_dma_memcpy(chan, unmap->addr[1],
  75                                                     unmap->addr[0], len,
  76                                                     dma_prep_flags);
  77         }
  78
  79         if (tx) {
  80                 pr_debug("%s: (async) len: %zu\n", __func__, len);
  81
  82                 dma_set_unmap(tx, unmap);
  83                 async_tx_submit(chan, tx, submit);
  84         } else {
  85                 void *dest_buf, *src_buf;
  86                 pr_debug("%s: (sync) len: %zu\n", __func__, len);
  87
  88                 /* wait for any prerequisite operations */
  89                 async_tx_quiesce(&submit->depend_tx);
  90
  91                 dest_buf = kmap_atomic(dest) + dest_offset;
  92                 src_buf = kmap_atomic(src) + src_offset;
  93
  94                 memcpy(dest_buf, src_buf, len);
  95
  96                 kunmap_atomic(src_buf);
  97                 kunmap_atomic(dest_buf);
  98
  99                 async_tx_sync_epilog(submit);
 100         }
 101
 102         dmaengine_unmap_put(unmap);
 103
 104         return tx;
 105 }
 106 EXPORT_SYMBOL_GPL(async_memcpy);
 107
 108 MODULE_AUTHOR("Intel Corporation");
 109 MODULE_DESCRIPTION("asynchronous memcpy api");
 110 MODULE_LICENSE("GPL");