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Dan Williams9bc89cd2007-01-02 11:10:44 -07001/*
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 * @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 * ASYNC_TX_KMAP_SRC, ASYNC_TX_KMAP_DST
40 * @depend_tx: memcpy depends on the result of this transaction
41 * @cb_fn: function to call when the memcpy completes
42 * @cb_param: parameter to pass to the callback routine
43 */
44struct dma_async_tx_descriptor *
45async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset,
46 unsigned int src_offset, size_t len, enum async_tx_flags flags,
47 struct dma_async_tx_descriptor *depend_tx,
48 dma_async_tx_callback cb_fn, void *cb_param)
49{
50 struct dma_chan *chan = async_tx_find_channel(depend_tx, DMA_MEMCPY);
51 struct dma_device *device = chan ? chan->device : NULL;
52 int int_en = cb_fn ? 1 : 0;
53 struct dma_async_tx_descriptor *tx = device ?
54 device->device_prep_dma_memcpy(chan, len,
55 int_en) : NULL;
56
57 if (tx) { /* run the memcpy asynchronously */
58 dma_addr_t addr;
59 enum dma_data_direction dir;
60
61 pr_debug("%s: (async) len: %zu\n", __FUNCTION__, len);
62
63 dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
64 DMA_NONE : DMA_FROM_DEVICE;
65
66 addr = dma_map_page(device->dev, dest, dest_offset, len, dir);
67 tx->tx_set_dest(addr, tx, 0);
68
69 dir = (flags & ASYNC_TX_ASSUME_COHERENT) ?
70 DMA_NONE : DMA_TO_DEVICE;
71
72 addr = dma_map_page(device->dev, src, src_offset, len, dir);
73 tx->tx_set_src(addr, tx, 0);
74
75 async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param);
76 } else { /* run the memcpy synchronously */
77 void *dest_buf, *src_buf;
78 pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len);
79
80 /* wait for any prerequisite operations */
81 if (depend_tx) {
82 /* if ack is already set then we cannot be sure
83 * we are referring to the correct operation
84 */
85 BUG_ON(depend_tx->ack);
86 if (dma_wait_for_async_tx(depend_tx) == DMA_ERROR)
87 panic("%s: DMA_ERROR waiting for depend_tx\n",
88 __FUNCTION__);
89 }
90
91 if (flags & ASYNC_TX_KMAP_DST)
92 dest_buf = kmap_atomic(dest, KM_USER0) + dest_offset;
93 else
94 dest_buf = page_address(dest) + dest_offset;
95
96 if (flags & ASYNC_TX_KMAP_SRC)
97 src_buf = kmap_atomic(src, KM_USER0) + src_offset;
98 else
99 src_buf = page_address(src) + src_offset;
100
101 memcpy(dest_buf, src_buf, len);
102
103 if (flags & ASYNC_TX_KMAP_DST)
104 kunmap_atomic(dest_buf, KM_USER0);
105
106 if (flags & ASYNC_TX_KMAP_SRC)
107 kunmap_atomic(src_buf, KM_USER0);
108
109 async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param);
110 }
111
112 return tx;
113}
114EXPORT_SYMBOL_GPL(async_memcpy);
115
116static int __init async_memcpy_init(void)
117{
118 return 0;
119}
120
121static void __exit async_memcpy_exit(void)
122{
123 do { } while (0);
124}
125
126module_init(async_memcpy_init);
127module_exit(async_memcpy_exit);
128
129MODULE_AUTHOR("Intel Corporation");
130MODULE_DESCRIPTION("asynchronous memcpy api");
131MODULE_LICENSE("GPL");