virt-dma.c
2.88 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
/*
* Virtual DMA channel support for DMAengine
*
* Copyright (C) 2012 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include "virt-dma.h"
static struct virt_dma_desc *to_virt_desc(struct dma_async_tx_descriptor *tx)
{
return container_of(tx, struct virt_dma_desc, tx);
}
dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct virt_dma_chan *vc = to_virt_chan(tx->chan);
struct virt_dma_desc *vd = to_virt_desc(tx);
unsigned long flags;
dma_cookie_t cookie;
spin_lock_irqsave(&vc->lock, flags);
cookie = dma_cookie_assign(tx);
list_add_tail(&vd->node, &vc->desc_submitted);
spin_unlock_irqrestore(&vc->lock, flags);
dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n",
vc, vd, cookie);
return cookie;
}
EXPORT_SYMBOL_GPL(vchan_tx_submit);
struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *vc,
dma_cookie_t cookie)
{
struct virt_dma_desc *vd;
list_for_each_entry(vd, &vc->desc_issued, node)
if (vd->tx.cookie == cookie)
return vd;
return NULL;
}
EXPORT_SYMBOL_GPL(vchan_find_desc);
/*
* This tasklet handles the completion of a DMA descriptor by
* calling its callback and freeing it.
*/
static void vchan_complete(unsigned long arg)
{
struct virt_dma_chan *vc = (struct virt_dma_chan *)arg;
struct virt_dma_desc *vd;
dma_async_tx_callback cb = NULL;
void *cb_data = NULL;
LIST_HEAD(head);
spin_lock_irq(&vc->lock);
list_splice_tail_init(&vc->desc_completed, &head);
vd = vc->cyclic;
if (vd) {
vc->cyclic = NULL;
cb = vd->tx.callback;
cb_data = vd->tx.callback_param;
}
spin_unlock_irq(&vc->lock);
if (cb)
cb(cb_data);
while (!list_empty(&head)) {
vd = list_first_entry(&head, struct virt_dma_desc, node);
cb = vd->tx.callback;
cb_data = vd->tx.callback_param;
list_del(&vd->node);
vc->desc_free(vd);
if (cb)
cb(cb_data);
}
}
void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head)
{
while (!list_empty(head)) {
struct virt_dma_desc *vd = list_first_entry(head,
struct virt_dma_desc, node);
list_del(&vd->node);
dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd);
vc->desc_free(vd);
}
}
EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list);
void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev)
{
dma_cookie_init(&vc->chan);
spin_lock_init(&vc->lock);
INIT_LIST_HEAD(&vc->desc_submitted);
INIT_LIST_HEAD(&vc->desc_issued);
INIT_LIST_HEAD(&vc->desc_completed);
tasklet_init(&vc->task, vchan_complete, (unsigned long)vc);
vc->chan.device = dmadev;
list_add_tail(&vc->chan.device_node, &dmadev->channels);
}
EXPORT_SYMBOL_GPL(vchan_init);
MODULE_AUTHOR("Russell King");
MODULE_LICENSE("GPL");