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 | #include <linux/device.h> | |
11 | #include <linux/dmaengine.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/spinlock.h> | |
14 | ||
15 | #include "virt-dma.h" | |
16 | ||
17 | static struct virt_dma_desc *to_virt_desc(struct dma_async_tx_descriptor *tx) | |
18 | { | |
19 | return container_of(tx, struct virt_dma_desc, tx); | |
20 | } | |
21 | ||
22 | dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *tx) | |
23 | { | |
24 | struct virt_dma_chan *vc = to_virt_chan(tx->chan); | |
25 | struct virt_dma_desc *vd = to_virt_desc(tx); | |
26 | unsigned long flags; | |
27 | dma_cookie_t cookie; | |
28 | ||
29 | spin_lock_irqsave(&vc->lock, flags); | |
30 | cookie = dma_cookie_assign(tx); | |
31 | ||
32 | list_add_tail(&vd->node, &vc->desc_submitted); | |
33 | spin_unlock_irqrestore(&vc->lock, flags); | |
34 | ||
35 | dev_dbg(vc->chan.device->dev, "vchan %p: txd %p[%x]: submitted\n", | |
36 | vc, vd, cookie); | |
37 | ||
38 | return cookie; | |
39 | } | |
40 | EXPORT_SYMBOL_GPL(vchan_tx_submit); | |
41 | ||
42 | /* | |
43 | * This tasklet handles the completion of a DMA descriptor by | |
44 | * calling its callback and freeing it. | |
45 | */ | |
46 | static void vchan_complete(unsigned long arg) | |
47 | { | |
48 | struct virt_dma_chan *vc = (struct virt_dma_chan *)arg; | |
49 | LIST_HEAD(head); | |
50 | ||
51 | spin_lock_irq(&vc->lock); | |
52 | list_splice_tail_init(&vc->desc_completed, &head); | |
53 | spin_unlock_irq(&vc->lock); | |
54 | ||
55 | while (!list_empty(&head)) { | |
56 | struct virt_dma_desc *vd = list_first_entry(&head, | |
57 | struct virt_dma_desc, node); | |
58 | dma_async_tx_callback cb = vd->tx.callback; | |
59 | void *cb_data = vd->tx.callback_param; | |
60 | ||
61 | list_del(&vd->node); | |
62 | ||
63 | vc->desc_free(vd); | |
64 | ||
65 | if (cb) | |
66 | cb(cb_data); | |
67 | } | |
68 | } | |
69 | ||
70 | void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head) | |
71 | { | |
72 | while (!list_empty(head)) { | |
73 | struct virt_dma_desc *vd = list_first_entry(head, | |
74 | struct virt_dma_desc, node); | |
75 | list_del(&vd->node); | |
76 | dev_dbg(vc->chan.device->dev, "txd %p: freeing\n", vd); | |
77 | vc->desc_free(vd); | |
78 | } | |
79 | } | |
80 | EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list); | |
81 | ||
82 | void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev) | |
83 | { | |
84 | dma_cookie_init(&vc->chan); | |
85 | ||
86 | spin_lock_init(&vc->lock); | |
87 | INIT_LIST_HEAD(&vc->desc_submitted); | |
88 | INIT_LIST_HEAD(&vc->desc_issued); | |
89 | INIT_LIST_HEAD(&vc->desc_completed); | |
90 | ||
91 | tasklet_init(&vc->task, vchan_complete, (unsigned long)vc); | |
92 | ||
93 | vc->chan.device = dmadev; | |
94 | list_add_tail(&vc->chan.device_node, &dmadev->channels); | |
95 | } | |
96 | EXPORT_SYMBOL_GPL(vchan_init); | |
97 | ||
98 | MODULE_AUTHOR("Russell King"); | |
99 | MODULE_LICENSE("GPL"); |