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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 | */ |
43 | struct dma_async_tx_descriptor * |
44 | async_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 | } |
94 | EXPORT_SYMBOL_GPL(async_memcpy); |
95 | |
96 | MODULE_AUTHOR("Intel Corporation"); |
97 | MODULE_DESCRIPTION("asynchronous memcpy api"); |
98 | MODULE_LICENSE("GPL"); |
99 |
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