1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Virtual DMA channel support for DMAengine |
4 | * |
5 | * Copyright (C) 2012 Russell King |
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(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 | |
29 | list_move_tail(list: &vd->node, head: &vc->desc_submitted); |
30 | spin_unlock_irqrestore(lock: &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 | |
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(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(entry: &vd->node); |
57 | spin_unlock_irqrestore(lock: &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 | |
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 | |
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(struct tasklet_struct *t) |
84 | { |
85 | struct virt_dma_chan *vc = from_tasklet(vc, t, task); |
86 | struct virt_dma_desc *vd, *_vd; |
87 | struct dmaengine_desc_callback cb; |
88 | LIST_HEAD(head); |
89 | |
90 | spin_lock_irq(lock: &vc->lock); |
91 | list_splice_tail_init(list: &vc->desc_completed, head: &head); |
92 | vd = vc->cyclic; |
93 | if (vd) { |
94 | vc->cyclic = NULL; |
95 | dmaengine_desc_get_callback(tx: &vd->tx, cb: &cb); |
96 | } else { |
97 | memset(&cb, 0, sizeof(cb)); |
98 | } |
99 | spin_unlock_irq(lock: &vc->lock); |
100 | |
101 | dmaengine_desc_callback_invoke(cb: &cb, result: &vd->tx_result); |
102 | |
103 | list_for_each_entry_safe(vd, _vd, &head, node) { |
104 | dmaengine_desc_get_callback(tx: &vd->tx, cb: &cb); |
105 | |
106 | list_del(entry: &vd->node); |
107 | dmaengine_desc_callback_invoke(cb: &cb, result: &vd->tx_result); |
108 | vchan_vdesc_fini(vd); |
109 | } |
110 | } |
111 | |
112 | void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head) |
113 | { |
114 | struct virt_dma_desc *vd, *_vd; |
115 | |
116 | list_for_each_entry_safe(vd, _vd, head, node) { |
117 | list_del(entry: &vd->node); |
118 | vchan_vdesc_fini(vd); |
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(chan: &vc->chan); |
126 | |
127 | spin_lock_init(&vc->lock); |
128 | INIT_LIST_HEAD(list: &vc->desc_allocated); |
129 | INIT_LIST_HEAD(list: &vc->desc_submitted); |
130 | INIT_LIST_HEAD(list: &vc->desc_issued); |
131 | INIT_LIST_HEAD(list: &vc->desc_completed); |
132 | INIT_LIST_HEAD(list: &vc->desc_terminated); |
133 | |
134 | tasklet_setup(t: &vc->task, callback: vchan_complete); |
135 | |
136 | vc->chan.device = dmadev; |
137 | list_add_tail(new: &vc->chan.device_node, head: &dmadev->channels); |
138 | } |
139 | EXPORT_SYMBOL_GPL(vchan_init); |
140 | |
141 | MODULE_AUTHOR("Russell King" ); |
142 | MODULE_LICENSE("GPL" ); |
143 | |