2 * copy offload engine support
4 * Copyright © 2006, Intel Corporation.
6 * Dan Williams <dan.j.williams@intel.com>
8 * with architecture considerations by:
9 * Neil Brown <neilb@suse.de>
10 * Jeff Garzik <jeff@garzik.org>
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.
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
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.
26 #include <linux/kernel.h>
27 #include <linux/highmem.h>
29 #include <linux/dma-mapping.h>
30 #include <linux/async_tx.h>
33 * async_memcpy - attempt to copy memory with a dma engine.
34 * @dest: destination 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
41 * honored flags: ASYNC_TX_ACK
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
)
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
;
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;
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
,
64 dma_src
= dma_map_page(device
->dev
, src
, src_offset
, len
,
67 tx
= device
->device_prep_dma_memcpy(chan
, dma_dest
, dma_src
,
72 pr_debug("%s: (async) len: %zu\n", __func__
, len
);
73 async_tx_submit(chan
, tx
, submit
);
75 void *dest_buf
, *src_buf
;
76 pr_debug("%s: (sync) len: %zu\n", __func__
, len
);
78 /* wait for any prerequisite operations */
79 async_tx_quiesce(&submit
->depend_tx
);
81 dest_buf
= kmap_atomic(dest
, KM_USER0
) + dest_offset
;
82 src_buf
= kmap_atomic(src
, KM_USER1
) + src_offset
;
84 memcpy(dest_buf
, src_buf
, len
);
86 kunmap_atomic(dest_buf
, KM_USER0
);
87 kunmap_atomic(src_buf
, KM_USER1
);
89 async_tx_sync_epilog(submit
);
94 EXPORT_SYMBOL_GPL(async_memcpy
);
96 MODULE_AUTHOR("Intel Corporation");
97 MODULE_DESCRIPTION("asynchronous memcpy api");
98 MODULE_LICENSE("GPL");
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