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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
50437bff RK |
2 | /* |
3 | * Virtual DMA channel support for DMAengine | |
4 | * | |
5 | * Copyright (C) 2012 Russell King | |
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6 | */ |
7 | #include <linux/device.h> | |
8 | #include <linux/dmaengine.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/spinlock.h> | |
11 | ||
12 | #include "virt-dma.h" | |
13 | ||
14 | static struct virt_dma_desc *to_virt_desc(struct dma_async_tx_descriptor *tx) | |
15 | { | |
16 | return container_of(tx, struct virt_dma_desc, tx); | |
17 | } | |
18 | ||
19 | dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx) | |
20 | { | |
21 | struct virt_dma_chan *vc = to_virt_chan(tx->chan); | |
22 | struct virt_dma_desc *vd = to_virt_desc(tx); | |
23 | unsigned long flags; | |
24 | dma_cookie_t cookie; | |
25 | ||
26 | spin_lock_irqsave(&vc->lock, flags); | |
27 | cookie = dma_cookie_assign(tx); | |
28 | ||
13bb26ae | 29 | list_move_tail(&vd->node, &vc->desc_submitted); |
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30 | spin_unlock_irqrestore(&vc->lock, flags); |
31 | ||
32 | dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n", | |
33 | vc, vd, cookie); | |
34 | ||
35 | return cookie; | |
36 | } | |
37 | EXPORT_SYMBOL_GPL(vchan_tx_submit); | |
38 | ||
13bb26ae RJ |
39 | /** |
40 | * vchan_tx_desc_free - free a reusable descriptor | |
41 | * @tx: the transfer | |
42 | * | |
43 | * This function frees a previously allocated reusable descriptor. The only | |
44 | * other way is to clear the DMA_CTRL_REUSE flag and submit one last time the | |
45 | * transfer. | |
46 | * | |
47 | * Returns 0 upon success | |
48 | */ | |
49 | int vchan_tx_desc_free(struct dma_async_tx_descriptor *tx) | |
50 | { | |
51 | struct virt_dma_chan *vc = to_virt_chan(tx->chan); | |
52 | struct virt_dma_desc *vd = to_virt_desc(tx); | |
53 | unsigned long flags; | |
54 | ||
55 | spin_lock_irqsave(&vc->lock, flags); | |
56 | list_del(&vd->node); | |
57 | spin_unlock_irqrestore(&vc->lock, flags); | |
58 | ||
59 | dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: freeing\n", | |
60 | vc, vd, vd->tx.cookie); | |
61 | vc->desc_free(vd); | |
62 | return 0; | |
63 | } | |
64 | EXPORT_SYMBOL_GPL(vchan_tx_desc_free); | |
65 | ||
fe045874 RK |
66 | struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *vc, |
67 | dma_cookie_t cookie) | |
68 | { | |
69 | struct virt_dma_desc *vd; | |
70 | ||
71 | list_for_each_entry(vd, &vc->desc_issued, node) | |
72 | if (vd->tx.cookie == cookie) | |
73 | return vd; | |
74 | ||
75 | return NULL; | |
76 | } | |
77 | EXPORT_SYMBOL_GPL(vchan_find_desc); | |
78 | ||
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79 | /* |
80 | * This tasklet handles the completion of a DMA descriptor by | |
81 | * calling its callback and freeing it. | |
82 | */ | |
83 | static void vchan_complete(unsigned long arg) | |
84 | { | |
85 | struct virt_dma_chan *vc = (struct virt_dma_chan *)arg; | |
fdb980fb | 86 | struct virt_dma_desc *vd, *_vd; |
4f03ac6a | 87 | struct dmaengine_desc_callback cb; |
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88 | LIST_HEAD(head); |
89 | ||
90 | spin_lock_irq(&vc->lock); | |
91 | list_splice_tail_init(&vc->desc_completed, &head); | |
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92 | vd = vc->cyclic; |
93 | if (vd) { | |
94 | vc->cyclic = NULL; | |
4f03ac6a DJ |
95 | dmaengine_desc_get_callback(&vd->tx, &cb); |
96 | } else { | |
97 | memset(&cb, 0, sizeof(cb)); | |
571fa740 | 98 | } |
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99 | spin_unlock_irq(&vc->lock); |
100 | ||
09d5b702 | 101 | dmaengine_desc_callback_invoke(&cb, &vd->tx_result); |
571fa740 | 102 | |
fdb980fb | 103 | list_for_each_entry_safe(vd, _vd, &head, node) { |
4f03ac6a | 104 | dmaengine_desc_get_callback(&vd->tx, &cb); |
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105 | |
106 | list_del(&vd->node); | |
09d5b702 | 107 | dmaengine_desc_callback_invoke(&cb, &vd->tx_result); |
24461d97 | 108 | vchan_vdesc_fini(vd); |
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109 | } |
110 | } | |
111 | ||
112 | void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head) | |
113 | { | |
fdb980fb AS |
114 | struct virt_dma_desc *vd, *_vd; |
115 | ||
116 | list_for_each_entry_safe(vd, _vd, head, node) { | |
b167f94d SH |
117 | list_del(&vd->node); |
118 | vchan_vdesc_fini(vd); | |
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119 | } |
120 | } | |
121 | EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list); | |
122 | ||
123 | void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev) | |
124 | { | |
125 | dma_cookie_init(&vc->chan); | |
126 | ||
127 | spin_lock_init(&vc->lock); | |
13bb26ae | 128 | INIT_LIST_HEAD(&vc->desc_allocated); |
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129 | INIT_LIST_HEAD(&vc->desc_submitted); |
130 | INIT_LIST_HEAD(&vc->desc_issued); | |
131 | INIT_LIST_HEAD(&vc->desc_completed); | |
f8821011 | 132 | INIT_LIST_HEAD(&vc->desc_terminated); |
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133 | |
134 | tasklet_init(&vc->task, vchan_complete, (unsigned long)vc); | |
135 | ||
136 | vc->chan.device = dmadev; | |
137 | list_add_tail(&vc->chan.device_node, &dmadev->channels); | |
138 | } | |
139 | EXPORT_SYMBOL_GPL(vchan_init); | |
140 | ||
141 | MODULE_AUTHOR("Russell King"); | |
142 | MODULE_LICENSE("GPL"); |