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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 */ | |
13bb26ae | 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 | |
28ca3e85 LPC |
51 | * @vc: virtual channel allocating this descriptor |
52 | * @vd: virtual descriptor to prepare | |
53 | * @tx_flags: flags argument passed in to prepare function | |
50437bff RK |
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 *); | |
13bb26ae RJ |
59 | extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *); |
60 | unsigned long flags; | |
50437bff RK |
61 | |
62 | dma_async_tx_descriptor_init(&vd->tx, &vc->chan); | |
63 | vd->tx.flags = tx_flags; | |
64 | vd->tx.tx_submit = vchan_tx_submit; | |
13bb26ae RJ |
65 | vd->tx.desc_free = vchan_tx_desc_free; |
66 | ||
67 | spin_lock_irqsave(&vc->lock, flags); | |
68 | list_add_tail(&vd->node, &vc->desc_allocated); | |
69 | spin_unlock_irqrestore(&vc->lock, flags); | |
50437bff RK |
70 | |
71 | return &vd->tx; | |
72 | } | |
73 | ||
74 | /** | |
75 | * vchan_issue_pending - move submitted descriptors to issued list | |
28ca3e85 | 76 | * @vc: virtual channel to update |
50437bff RK |
77 | * |
78 | * vc.lock must be held by caller | |
79 | */ | |
80 | static inline bool vchan_issue_pending(struct virt_dma_chan *vc) | |
81 | { | |
82 | list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued); | |
83 | return !list_empty(&vc->desc_issued); | |
84 | } | |
85 | ||
86 | /** | |
87 | * vchan_cookie_complete - report completion of a descriptor | |
28ca3e85 | 88 | * @vd: virtual descriptor to update |
50437bff RK |
89 | * |
90 | * vc.lock must be held by caller | |
91 | */ | |
92 | static inline void vchan_cookie_complete(struct virt_dma_desc *vd) | |
93 | { | |
94 | struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); | |
af58652a | 95 | dma_cookie_t cookie; |
50437bff | 96 | |
af58652a | 97 | cookie = vd->tx.cookie; |
50437bff RK |
98 | dma_cookie_complete(&vd->tx); |
99 | dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n", | |
af58652a | 100 | vd, cookie); |
50437bff RK |
101 | list_add_tail(&vd->node, &vc->desc_completed); |
102 | ||
103 | tasklet_schedule(&vc->task); | |
104 | } | |
105 | ||
571fa740 RK |
106 | /** |
107 | * vchan_cyclic_callback - report the completion of a period | |
28ca3e85 | 108 | * @vd: virtual descriptor |
571fa740 RK |
109 | */ |
110 | static inline void vchan_cyclic_callback(struct virt_dma_desc *vd) | |
111 | { | |
112 | struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan); | |
113 | ||
114 | vc->cyclic = vd; | |
115 | tasklet_schedule(&vc->task); | |
116 | } | |
117 | ||
50437bff RK |
118 | /** |
119 | * vchan_next_desc - peek at the next descriptor to be processed | |
28ca3e85 | 120 | * @vc: virtual channel to obtain descriptor from |
50437bff RK |
121 | * |
122 | * vc.lock must be held by caller | |
123 | */ | |
124 | static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) | |
125 | { | |
126 | if (list_empty(&vc->desc_issued)) | |
127 | return NULL; | |
128 | ||
129 | return list_first_entry(&vc->desc_issued, struct virt_dma_desc, node); | |
130 | } | |
131 | ||
132 | /** | |
8c8fe97b | 133 | * vchan_get_all_descriptors - obtain all submitted and issued descriptors |
28ca3e85 LPC |
134 | * @vc: virtual channel to get descriptors from |
135 | * @head: list of descriptors found | |
50437bff RK |
136 | * |
137 | * vc.lock must be held by caller | |
138 | * | |
139 | * Removes all submitted and issued descriptors from internal lists, and | |
140 | * provides a list of all descriptors found | |
141 | */ | |
142 | static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, | |
143 | struct list_head *head) | |
144 | { | |
13bb26ae | 145 | list_splice_tail_init(&vc->desc_allocated, head); |
50437bff RK |
146 | list_splice_tail_init(&vc->desc_submitted, head); |
147 | list_splice_tail_init(&vc->desc_issued, head); | |
148 | list_splice_tail_init(&vc->desc_completed, head); | |
149 | } | |
150 | ||
151 | static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) | |
152 | { | |
13bb26ae | 153 | struct virt_dma_desc *vd; |
50437bff RK |
154 | unsigned long flags; |
155 | LIST_HEAD(head); | |
156 | ||
157 | spin_lock_irqsave(&vc->lock, flags); | |
158 | vchan_get_all_descriptors(vc, &head); | |
13bb26ae RJ |
159 | list_for_each_entry(vd, &head, node) |
160 | dmaengine_desc_clear_reuse(&vd->tx); | |
50437bff RK |
161 | spin_unlock_irqrestore(&vc->lock, flags); |
162 | ||
163 | vchan_dma_desc_free_list(vc, &head); | |
164 | } | |
165 | ||
2ed08629 LPC |
166 | /** |
167 | * vchan_synchronize() - synchronize callback execution to the current context | |
168 | * @vc: virtual channel to synchronize | |
169 | * | |
170 | * Makes sure that all scheduled or active callbacks have finished running. For | |
171 | * proper operation the caller has to ensure that no new callbacks are scheduled | |
172 | * after the invocation of this function started. | |
173 | */ | |
174 | static inline void vchan_synchronize(struct virt_dma_chan *vc) | |
175 | { | |
176 | tasklet_kill(&vc->task); | |
177 | } | |
178 | ||
50437bff | 179 | #endif |