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.
13 #include <linux/dmaengine.h>
14 #include <linux/interrupt.h>
16 #include "dmaengine.h"
18 struct virt_dma_desc
{
19 struct dma_async_tx_descriptor tx
;
20 /* protected by vc.lock */
21 struct list_head node
;
24 struct virt_dma_chan
{
26 struct tasklet_struct task
;
27 void (*desc_free
)(struct virt_dma_desc
*);
31 /* protected by vc.lock */
32 struct list_head desc_allocated
;
33 struct list_head desc_submitted
;
34 struct list_head desc_issued
;
35 struct list_head desc_completed
;
37 struct virt_dma_desc
*cyclic
;
40 static inline struct virt_dma_chan
*to_virt_chan(struct dma_chan
*chan
)
42 return container_of(chan
, struct virt_dma_chan
, chan
);
45 void vchan_dma_desc_free_list(struct virt_dma_chan
*vc
, struct list_head
*head
);
46 void vchan_init(struct virt_dma_chan
*vc
, struct dma_device
*dmadev
);
47 struct virt_dma_desc
*vchan_find_desc(struct virt_dma_chan
*, dma_cookie_t
);
50 * vchan_tx_prep - prepare a descriptor
51 * vc: virtual channel allocating this descriptor
52 * vd: virtual descriptor to prepare
53 * tx_flags: flags argument passed in to prepare function
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
)
58 extern dma_cookie_t
vchan_tx_submit(struct dma_async_tx_descriptor
*);
61 dma_async_tx_descriptor_init(&vd
->tx
, &vc
->chan
);
62 vd
->tx
.flags
= tx_flags
;
63 vd
->tx
.tx_submit
= vchan_tx_submit
;
65 spin_lock_irqsave(&vc
->lock
, flags
);
66 list_add_tail(&vd
->node
, &vc
->desc_allocated
);
67 spin_unlock_irqrestore(&vc
->lock
, flags
);
73 * vchan_issue_pending - move submitted descriptors to issued list
74 * vc: virtual channel to update
76 * vc.lock must be held by caller
78 static inline bool vchan_issue_pending(struct virt_dma_chan
*vc
)
80 list_splice_tail_init(&vc
->desc_submitted
, &vc
->desc_issued
);
81 return !list_empty(&vc
->desc_issued
);
85 * vchan_cookie_complete - report completion of a descriptor
86 * vd: virtual descriptor to update
88 * vc.lock must be held by caller
90 static inline void vchan_cookie_complete(struct virt_dma_desc
*vd
)
92 struct virt_dma_chan
*vc
= to_virt_chan(vd
->tx
.chan
);
95 cookie
= vd
->tx
.cookie
;
96 dma_cookie_complete(&vd
->tx
);
97 dev_vdbg(vc
->chan
.device
->dev
, "txd %p[%x]: marked complete\n",
99 list_add_tail(&vd
->node
, &vc
->desc_completed
);
101 tasklet_schedule(&vc
->task
);
105 * vchan_cyclic_callback - report the completion of a period
106 * vd: virtual descriptor
108 static inline void vchan_cyclic_callback(struct virt_dma_desc
*vd
)
110 struct virt_dma_chan
*vc
= to_virt_chan(vd
->tx
.chan
);
113 tasklet_schedule(&vc
->task
);
117 * vchan_next_desc - peek at the next descriptor to be processed
118 * vc: virtual channel to obtain descriptor from
120 * vc.lock must be held by caller
122 static inline struct virt_dma_desc
*vchan_next_desc(struct virt_dma_chan
*vc
)
124 if (list_empty(&vc
->desc_issued
))
127 return list_first_entry(&vc
->desc_issued
, struct virt_dma_desc
, node
);
131 * vchan_get_all_descriptors - obtain all allocated, submitted and issued
133 * vc: virtual channel to get descriptors from
134 * head: list of descriptors found
136 * vc.lock must be held by caller
138 * Removes all submitted and issued descriptors from internal lists, and
139 * provides a list of all descriptors found
141 static inline void vchan_get_all_descriptors(struct virt_dma_chan
*vc
,
142 struct list_head
*head
)
144 list_splice_tail_init(&vc
->desc_allocated
, head
);
145 list_splice_tail_init(&vc
->desc_submitted
, head
);
146 list_splice_tail_init(&vc
->desc_issued
, head
);
147 list_splice_tail_init(&vc
->desc_completed
, head
);
150 static inline void vchan_free_chan_resources(struct virt_dma_chan
*vc
)
152 struct virt_dma_desc
*vd
;
156 spin_lock_irqsave(&vc
->lock
, flags
);
157 vchan_get_all_descriptors(vc
, &head
);
158 list_for_each_entry(vd
, &head
, node
)
159 async_tx_clear_ack(&vd
->tx
);
160 spin_unlock_irqrestore(&vc
->lock
, flags
);
162 vchan_dma_desc_free_list(vc
, &head
);