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
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/*
* 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.
*/
#ifndef VIRT_DMA_H
#define VIRT_DMA_H
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include "dmaengine.h"
struct virt_dma_desc {
struct dma_async_tx_descriptor tx;
/* protected by vc.lock */
struct list_head node;
};
struct virt_dma_chan {
struct dma_chan chan;
struct tasklet_struct task;
void (*desc_free)(struct virt_dma_desc *);
spinlock_t lock;
/* protected by vc.lock */
struct list_head desc_allocated;
struct list_head desc_submitted;
struct list_head desc_issued;
struct list_head desc_completed;
struct virt_dma_desc *cyclic;
};
static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan)
{
return container_of(chan, struct virt_dma_chan, chan);
}
void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head);
void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev);
struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t);
extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *);
extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *);
/**
* vchan_tx_prep - prepare a descriptor
* @vc: virtual channel allocating this descriptor
* @vd: virtual descriptor to prepare
* @tx_flags: flags argument passed in to prepare function
*/
static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc,
struct virt_dma_desc *vd, unsigned long tx_flags)
{
unsigned long flags;
dma_async_tx_descriptor_init(&vd->tx, &vc->chan);
vd->tx.flags = tx_flags;
vd->tx.tx_submit = vchan_tx_submit;
vd->tx.desc_free = vchan_tx_desc_free;
spin_lock_irqsave(&vc->lock, flags);
list_add_tail(&vd->node, &vc->desc_allocated);
spin_unlock_irqrestore(&vc->lock, flags);
return &vd->tx;
}
/**
* vchan_issue_pending - move submitted descriptors to issued list
* @vc: virtual channel to update
*
* vc.lock must be held by caller
*/
static inline bool vchan_issue_pending(struct virt_dma_chan *vc)
{
list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued);
return !list_empty(&vc->desc_issued);
}
/**
* vchan_cookie_complete - report completion of a descriptor
* @vd: virtual descriptor to update
*
* vc.lock must be held by caller
*/
static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
{
struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
dma_cookie_t cookie;
cookie = vd->tx.cookie;
dma_cookie_complete(&vd->tx);
dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n",
vd, cookie);
list_add_tail(&vd->node, &vc->desc_completed);
tasklet_schedule(&vc->task);
}
/**
* vchan_cyclic_callback - report the completion of a period
* @vd: virtual descriptor
*/
static inline void vchan_cyclic_callback(struct virt_dma_desc *vd)
{
struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
vc->cyclic = vd;
tasklet_schedule(&vc->task);
}
/**
* vchan_next_desc - peek at the next descriptor to be processed
* @vc: virtual channel to obtain descriptor from
*
* vc.lock must be held by caller
*/
static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
{
return list_first_entry_or_null(&vc->desc_issued,
struct virt_dma_desc, node);
}
/**
* vchan_get_all_descriptors - obtain all submitted and issued descriptors
* @vc: virtual channel to get descriptors from
* @head: list of descriptors found
*
* vc.lock must be held by caller
*
* Removes all submitted and issued descriptors from internal lists, and
* provides a list of all descriptors found
*/
static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc,
struct list_head *head)
{
list_splice_tail_init(&vc->desc_allocated, head);
list_splice_tail_init(&vc->desc_submitted, head);
list_splice_tail_init(&vc->desc_issued, head);
list_splice_tail_init(&vc->desc_completed, head);
}
static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
{
struct virt_dma_desc *vd;
unsigned long flags;
LIST_HEAD(head);
spin_lock_irqsave(&vc->lock, flags);
vchan_get_all_descriptors(vc, &head);
list_for_each_entry(vd, &head, node)
dmaengine_desc_clear_reuse(&vd->tx);
spin_unlock_irqrestore(&vc->lock, flags);
vchan_dma_desc_free_list(vc, &head);
}
/**
* vchan_synchronize() - synchronize callback execution to the current context
* @vc: virtual channel to synchronize
*
* Makes sure that all scheduled or active callbacks have finished running. For
* proper operation the caller has to ensure that no new callbacks are scheduled
* after the invocation of this function started.
*/
static inline void vchan_synchronize(struct virt_dma_chan *vc)
{
tasklet_kill(&vc->task);
}
#endif
|
