Commit | Line | Data |
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50437bff RK |
1 | /* |
2 | * Virtual DMA channel support for DMAengine | |
3 | * | |
4 | * Copyright (C) 2012 Russell King | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | #ifndef VIRT_DMA_H | |
11 | #define VIRT_DMA_H | |
12 | ||
13 | #include <linux/dmaengine.h> | |
14 | #include <linux/interrupt.h> | |
15 | ||
16 | #include "dmaengine.h" | |
17 | ||
18 | struct virt_dma_desc { | |
19 | struct dma_async_tx_descriptor tx; | |
20 | /* protected by vc.lock */ | |
21 | struct list_head node; | |
22 | }; | |
23 | ||
24 | struct virt_dma_chan { | |
25 | struct dma_chan chan; | |
26 | struct tasklet_struct task; | |
27 | void (*desc_free)(struct virt_dma_desc *); | |
28 | ||
29 | spinlock_t lock; | |
30 | ||
31 | /* protected by vc.lock */ | |
32 | struct list_head desc_submitted; | |
33 | struct list_head desc_issued; | |
34 | struct list_head desc_completed; | |
35 | }; | |
36 | ||
37 | static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan) | |
38 | { | |
39 | return container_of(chan, struct virt_dma_chan, chan); | |
40 | } | |
41 | ||
42 | void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head); | |
50437bff | 43 | void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev); |
fe045874 | 44 | struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t); |
50437bff RK |
45 | |
46 | /** | |
47 | * vchan_tx_prep - prepare a descriptor | |
48 | * vc: virtual channel allocating this descriptor | |
49 | * vd: virtual descriptor to prepare | |
50 | * tx_flags: flags argument passed in to prepare function | |
51 | */ | |
52 | static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc, | |
53 | struct virt_dma_desc *vd, unsigned long tx_flags) | |
54 | { | |
55 | extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); | |
56 | ||
57 | dma_async_tx_descriptor_init(&vd->tx, &vc->chan); | |
58 | vd->tx.flags = tx_flags; | |
59 | vd->tx.tx_submit = vchan_tx_submit; | |
60 | ||
61 | return &vd->tx; | |
62 | } | |
63 | ||
64 | /** | |
65 | * vchan_issue_pending - move submitted descriptors to issued list | |
66 | * vc: virtual channel to update | |
67 | * | |
68 | * vc.lock must be held by caller | |
69 | */ | |
70 | static inline bool vchan_issue_pending(struct virt_dma_chan *vc) | |
71 | { | |
72 | list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued); | |
73 | return !list_empty(&vc->desc_issued); | |
74 | } | |
75 | ||
76 | /** | |
77 | * vchan_cookie_complete - report completion of a descriptor | |
78 | * vd: virtual descriptor to update | |
79 | * | |
80 | * vc.lock must be held by caller | |
81 | */ | |
82 | static inline void vchan_cookie_complete(struct virt_dma_desc *vd) | |
83 | { | |
84 | struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); | |
85 | ||
86 | dma_cookie_complete(&vd->tx); | |
87 | dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n", | |
88 | vd, vd->tx.cookie); | |
89 | list_add_tail(&vd->node, &vc->desc_completed); | |
90 | ||
91 | tasklet_schedule(&vc->task); | |
92 | } | |
93 | ||
94 | /** | |
95 | * vchan_next_desc - peek at the next descriptor to be processed | |
96 | * vc: virtual channel to obtain descriptor from | |
97 | * | |
98 | * vc.lock must be held by caller | |
99 | */ | |
100 | static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) | |
101 | { | |
102 | if (list_empty(&vc->desc_issued)) | |
103 | return NULL; | |
104 | ||
105 | return list_first_entry(&vc->desc_issued, struct virt_dma_desc, node); | |
106 | } | |
107 | ||
108 | /** | |
109 | * vchan_get_all_descriptors - obtain all submitted and issued descriptors | |
110 | * vc: virtual channel to get descriptors from | |
111 | * head: list of descriptors found | |
112 | * | |
113 | * vc.lock must be held by caller | |
114 | * | |
115 | * Removes all submitted and issued descriptors from internal lists, and | |
116 | * provides a list of all descriptors found | |
117 | */ | |
118 | static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, | |
119 | struct list_head *head) | |
120 | { | |
121 | list_splice_tail_init(&vc->desc_submitted, head); | |
122 | list_splice_tail_init(&vc->desc_issued, head); | |
123 | list_splice_tail_init(&vc->desc_completed, head); | |
124 | } | |
125 | ||
126 | static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) | |
127 | { | |
128 | unsigned long flags; | |
129 | LIST_HEAD(head); | |
130 | ||
131 | spin_lock_irqsave(&vc->lock, flags); | |
132 | vchan_get_all_descriptors(vc, &head); | |
133 | spin_unlock_irqrestore(&vc->lock, flags); | |
134 | ||
135 | vchan_dma_desc_free_list(vc, &head); | |
136 | } | |
137 | ||
138 | #endif |