2 * Virtual DMA channel support for DMAengine
4 * Copyright (C) 2012 Russell King
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.
10 #include <linux/device.h>
11 #include <linux/dmaengine.h>
12 #include <linux/module.h>
13 #include <linux/spinlock.h>
17 static struct virt_dma_desc
*to_virt_desc(struct dma_async_tx_descriptor
*tx
)
19 return container_of(tx
, struct virt_dma_desc
, tx
);
22 dma_cookie_t
vchan_tx_submit(struct dma_async_tx_descriptor
*tx
)
24 struct virt_dma_chan
*vc
= to_virt_chan(tx
->chan
);
25 struct virt_dma_desc
*vd
= to_virt_desc(tx
);
29 spin_lock_irqsave(&vc
->lock
, flags
);
30 cookie
= dma_cookie_assign(tx
);
32 list_add_tail(&vd
->node
, &vc
->desc_submitted
);
33 spin_unlock_irqrestore(&vc
->lock
, flags
);
35 dev_dbg(vc
->chan
.device
->dev
, "vchan %p: txd %p[%x]: submitted\n",
40 EXPORT_SYMBOL_GPL(vchan_tx_submit
);
42 struct virt_dma_desc
*vchan_find_desc(struct virt_dma_chan
*vc
,
45 struct virt_dma_desc
*vd
;
47 list_for_each_entry(vd
, &vc
->desc_issued
, node
)
48 if (vd
->tx
.cookie
== cookie
)
53 EXPORT_SYMBOL_GPL(vchan_find_desc
);
56 * This tasklet handles the completion of a DMA descriptor by
57 * calling its callback and freeing it.
59 static void vchan_complete(unsigned long arg
)
61 struct virt_dma_chan
*vc
= (struct virt_dma_chan
*)arg
;
62 struct virt_dma_desc
*vd
;
63 dma_async_tx_callback cb
= NULL
;
67 spin_lock_irq(&vc
->lock
);
68 list_splice_tail_init(&vc
->desc_completed
, &head
);
73 cb_data
= vd
->tx
.callback_param
;
75 spin_unlock_irq(&vc
->lock
);
80 while (!list_empty(&head
)) {
81 vd
= list_first_entry(&head
, struct virt_dma_desc
, node
);
83 cb_data
= vd
->tx
.callback_param
;
94 void vchan_dma_desc_free_list(struct virt_dma_chan
*vc
, struct list_head
*head
)
96 while (!list_empty(head
)) {
97 struct virt_dma_desc
*vd
= list_first_entry(head
,
98 struct virt_dma_desc
, node
);
100 dev_dbg(vc
->chan
.device
->dev
, "txd %p: freeing\n", vd
);
104 EXPORT_SYMBOL_GPL(vchan_dma_desc_free_list
);
106 void vchan_init(struct virt_dma_chan
*vc
, struct dma_device
*dmadev
)
108 dma_cookie_init(&vc
->chan
);
110 spin_lock_init(&vc
->lock
);
111 INIT_LIST_HEAD(&vc
->desc_submitted
);
112 INIT_LIST_HEAD(&vc
->desc_issued
);
113 INIT_LIST_HEAD(&vc
->desc_completed
);
115 tasklet_init(&vc
->task
, vchan_complete
, (unsigned long)vc
);
117 vc
->chan
.device
= dmadev
;
118 list_add_tail(&vc
->chan
.device_node
, &dmadev
->channels
);
120 EXPORT_SYMBOL_GPL(vchan_init
);
122 MODULE_AUTHOR("Russell King");
123 MODULE_LICENSE("GPL");
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