tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * memory fill 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/interrupt.h>
28#include <linux/module.h>
29#include <linux/mm.h>
30#include <linux/dma-mapping.h>
31#include <linux/async_tx.h>
32
33/**
34 * async_memset - attempt to fill memory with a dma engine.
35 * @dest: destination page
36 * @val: fill value
37 * @offset: offset in pages to start transaction
38 * @len: length in bytes
39 *
40 * honored flags: ASYNC_TX_ACK
41 */
42struct dma_async_tx_descriptor *
43async_memset(struct page *dest, int val, unsigned int offset, size_t len,
44 struct async_submit_ctl *submit)
45{
46 struct dma_chan *chan = async_tx_find_channel(submit, DMA_MEMSET,
47 &dest, 1, NULL, 0, len);
48 struct dma_device *device = chan ? chan->device : NULL;
49 struct dma_async_tx_descriptor *tx = NULL;
50
51 if (device && is_dma_fill_aligned(device, offset, 0, len)) {
52 dma_addr_t dma_dest;
53 unsigned long dma_prep_flags = 0;
54
55 if (submit->cb_fn)
56 dma_prep_flags |= DMA_PREP_INTERRUPT;
57 if (submit->flags & ASYNC_TX_FENCE)
58 dma_prep_flags |= DMA_PREP_FENCE;
59 dma_dest = dma_map_page(device->dev, dest, offset, len,
60 DMA_FROM_DEVICE);
61
62 tx = device->device_prep_dma_memset(chan, dma_dest, val, len,
63 dma_prep_flags);
64 }
65
66 if (tx) {
67 pr_debug("%s: (async) len: %zu\n", __func__, len);
68 async_tx_submit(chan, tx, submit);
69 } else { /* run the memset synchronously */
70 void *dest_buf;
71 pr_debug("%s: (sync) len: %zu\n", __func__, len);
72
73 dest_buf = page_address(dest) + offset;
74
75 /* wait for any prerequisite operations */
76 async_tx_quiesce(&submit->depend_tx);
77
78 memset(dest_buf, val, len);
79
80 async_tx_sync_epilog(submit);
81 }
82
83 return tx;
84}
85EXPORT_SYMBOL_GPL(async_memset);
86
87MODULE_AUTHOR("Intel Corporation");
88MODULE_DESCRIPTION("asynchronous memset api");
89MODULE_LICENSE("GPL");