Linux Kernel  3.7.1
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async_memcpy.c
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1 /*
2  * copy offload engine support
3  *
4  * Copyright © 2006, Intel Corporation.
5  *
6  * Dan Williams <[email protected]>
7  *
8  * with architecture considerations by:
9  * Neil Brown <[email protected]>
10  * Jeff Garzik <[email protected]>
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 
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 {
50  &dest, 1, &src, 1, len);
51  struct dma_device *device = chan ? chan->device : NULL;
53 
54  if (device && is_dma_copy_aligned(device, src_offset, dest_offset, len)) {
55  dma_addr_t dma_dest, dma_src;
56  unsigned long dma_prep_flags = 0;
57 
58  if (submit->cb_fn)
59  dma_prep_flags |= DMA_PREP_INTERRUPT;
60  if (submit->flags & ASYNC_TX_FENCE)
61  dma_prep_flags |= DMA_PREP_FENCE;
62  dma_dest = dma_map_page(device->dev, dest, dest_offset, len,
64 
65  dma_src = dma_map_page(device->dev, src, src_offset, len,
67 
68  tx = device->device_prep_dma_memcpy(chan, dma_dest, dma_src,
69  len, dma_prep_flags);
70  }
71 
72  if (tx) {
73  pr_debug("%s: (async) len: %zu\n", __func__, len);
74  async_tx_submit(chan, tx, submit);
75  } else {
76  void *dest_buf, *src_buf;
77  pr_debug("%s: (sync) len: %zu\n", __func__, len);
78 
79  /* wait for any prerequisite operations */
80  async_tx_quiesce(&submit->depend_tx);
81 
82  dest_buf = kmap_atomic(dest) + dest_offset;
83  src_buf = kmap_atomic(src) + src_offset;
84 
85  memcpy(dest_buf, src_buf, len);
86 
87  kunmap_atomic(src_buf);
88  kunmap_atomic(dest_buf);
89 
90  async_tx_sync_epilog(submit);
91  }
92 
93  return tx;
94 }
96 
97 MODULE_AUTHOR("Intel Corporation");
98 MODULE_DESCRIPTION("asynchronous memcpy api");
99 MODULE_LICENSE("GPL");