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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 */ | |
b9855f03 | 32 | struct list_head desc_allocated; |
50437bff RK |
33 | struct list_head desc_submitted; |
34 | struct list_head desc_issued; | |
35 | struct list_head desc_completed; | |
571fa740 RK |
36 | |
37 | struct virt_dma_desc *cyclic; | |
50437bff RK |
38 | }; |
39 | ||
40 | static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan) | |
41 | { | |
42 | return container_of(chan, struct virt_dma_chan, chan); | |
43 | } | |
44 | ||
45 | void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head); | |
50437bff | 46 | void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev); |
fe045874 | 47 | struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t); |
50437bff RK |
48 | |
49 | /** | |
50 | * vchan_tx_prep - prepare a descriptor | |
51 | * vc: virtual channel allocating this descriptor | |
52 | * vd: virtual descriptor to prepare | |
53 | * tx_flags: flags argument passed in to prepare function | |
54 | */ | |
55 | static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc, | |
56 | struct virt_dma_desc *vd, unsigned long tx_flags) | |
57 | { | |
58 | extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); | |
b9855f03 | 59 | unsigned long flags; |
50437bff RK |
60 | |
61 | dma_async_tx_descriptor_init(&vd->tx, &vc->chan); | |
62 | vd->tx.flags = tx_flags; | |
63 | vd->tx.tx_submit = vchan_tx_submit; | |
64 | ||
b9855f03 RJ |
65 | spin_lock_irqsave(&vc->lock, flags); |
66 | list_add_tail(&vd->node, &vc->desc_allocated); | |
67 | spin_unlock_irqrestore(&vc->lock, flags); | |
68 | ||
50437bff RK |
69 | return &vd->tx; |
70 | } | |
71 | ||
72 | /** | |
73 | * vchan_issue_pending - move submitted descriptors to issued list | |
74 | * vc: virtual channel to update | |
75 | * | |
76 | * vc.lock must be held by caller | |
77 | */ | |
78 | static inline bool vchan_issue_pending(struct virt_dma_chan *vc) | |
79 | { | |
80 | list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued); | |
81 | return !list_empty(&vc->desc_issued); | |
82 | } | |
83 | ||
84 | /** | |
85 | * vchan_cookie_complete - report completion of a descriptor | |
86 | * vd: virtual descriptor to update | |
87 | * | |
88 | * vc.lock must be held by caller | |
89 | */ | |
90 | static inline void vchan_cookie_complete(struct virt_dma_desc *vd) | |
91 | { | |
92 | struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); | |
af58652a | 93 | dma_cookie_t cookie; |
50437bff | 94 | |
af58652a | 95 | cookie = vd->tx.cookie; |
50437bff RK |
96 | dma_cookie_complete(&vd->tx); |
97 | dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n", | |
af58652a | 98 | vd, cookie); |
50437bff RK |
99 | list_add_tail(&vd->node, &vc->desc_completed); |
100 | ||
101 | tasklet_schedule(&vc->task); | |
102 | } | |
103 | ||
571fa740 RK |
104 | /** |
105 | * vchan_cyclic_callback - report the completion of a period | |
106 | * vd: virtual descriptor | |
107 | */ | |
108 | static inline void vchan_cyclic_callback(struct virt_dma_desc *vd) | |
109 | { | |
110 | struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); | |
111 | ||
112 | vc->cyclic = vd; | |
113 | tasklet_schedule(&vc->task); | |
114 | } | |
115 | ||
50437bff RK |
116 | /** |
117 | * vchan_next_desc - peek at the next descriptor to be processed | |
118 | * vc: virtual channel to obtain descriptor from | |
119 | * | |
120 | * vc.lock must be held by caller | |
121 | */ | |
122 | static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) | |
123 | { | |
124 | if (list_empty(&vc->desc_issued)) | |
125 | return NULL; | |
126 | ||
127 | return list_first_entry(&vc->desc_issued, struct virt_dma_desc, node); | |
128 | } | |
129 | ||
130 | /** | |
b9855f03 RJ |
131 | * vchan_get_all_descriptors - obtain all allocated, submitted and issued |
132 | * descriptors | |
50437bff RK |
133 | * vc: virtual channel to get descriptors from |
134 | * head: list of descriptors found | |
135 | * | |
136 | * vc.lock must be held by caller | |
137 | * | |
138 | * Removes all submitted and issued descriptors from internal lists, and | |
139 | * provides a list of all descriptors found | |
140 | */ | |
141 | static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, | |
142 | struct list_head *head) | |
143 | { | |
b9855f03 | 144 | list_splice_tail_init(&vc->desc_allocated, head); |
50437bff RK |
145 | list_splice_tail_init(&vc->desc_submitted, head); |
146 | list_splice_tail_init(&vc->desc_issued, head); | |
147 | list_splice_tail_init(&vc->desc_completed, head); | |
148 | } | |
149 | ||
150 | static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) | |
151 | { | |
b9855f03 | 152 | struct virt_dma_desc *vd; |
50437bff RK |
153 | unsigned long flags; |
154 | LIST_HEAD(head); | |
155 | ||
156 | spin_lock_irqsave(&vc->lock, flags); | |
157 | vchan_get_all_descriptors(vc, &head); | |
b9855f03 RJ |
158 | list_for_each_entry(vd, &head, node) |
159 | async_tx_clear_ack(&vd->tx); | |
50437bff RK |
160 | spin_unlock_irqrestore(&vc->lock, flags); |
161 | ||
162 | vchan_dma_desc_free_list(vc, &head); | |
163 | } | |
164 | ||
165 | #endif |