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 * @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
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
, enum async_tx_flags flags
,
47 struct dma_async_tx_descriptor
*depend_tx
,
48 dma_async_tx_callback cb_fn
, void *cb_param
)
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
,
57 if (tx
) { /* run the memcpy asynchronously */
59 enum dma_data_direction dir
;
61 pr_debug("%s: (async) len: %zu\n", __FUNCTION__
, len
);
63 dir
= (flags
& ASYNC_TX_ASSUME_COHERENT
) ?
64 DMA_NONE
: DMA_FROM_DEVICE
;
66 addr
= dma_map_page(device
->dev
, dest
, dest_offset
, len
, dir
);
67 tx
->tx_set_dest(addr
, tx
, 0);
69 dir
= (flags
& ASYNC_TX_ASSUME_COHERENT
) ?
70 DMA_NONE
: DMA_TO_DEVICE
;
72 addr
= dma_map_page(device
->dev
, src
, src_offset
, len
, dir
);
73 tx
->tx_set_src(addr
, tx
, 0);
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
);
80 /* wait for any prerequisite operations */
82 /* if ack is already set then we cannot be sure
83 * we are referring to the correct operation
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",
91 if (flags
& ASYNC_TX_KMAP_DST
)
92 dest_buf
= kmap_atomic(dest
, KM_USER0
) + dest_offset
;
94 dest_buf
= page_address(dest
) + dest_offset
;
96 if (flags
& ASYNC_TX_KMAP_SRC
)
97 src_buf
= kmap_atomic(src
, KM_USER0
) + src_offset
;
99 src_buf
= page_address(src
) + src_offset
;
101 memcpy(dest_buf
, src_buf
, len
);
103 if (flags
& ASYNC_TX_KMAP_DST
)
104 kunmap_atomic(dest_buf
, KM_USER0
);
106 if (flags
& ASYNC_TX_KMAP_SRC
)
107 kunmap_atomic(src_buf
, KM_USER0
);
109 async_tx_sync_epilog(flags
, depend_tx
, cb_fn
, cb_param
);
114 EXPORT_SYMBOL_GPL(async_memcpy
);
116 static int __init
async_memcpy_init(void)
121 static void __exit
async_memcpy_exit(void)
126 module_init(async_memcpy_init
);
127 module_exit(async_memcpy_exit
);
129 MODULE_AUTHOR("Intel Corporation");
130 MODULE_DESCRIPTION("asynchronous memcpy api");
131 MODULE_LICENSE("GPL");