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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#ifndef VIRT_DMA_H
8#define VIRT_DMA_H
9
10#include <linux/dmaengine.h>
11#include <linux/interrupt.h>
12
13#include "dmaengine.h"
14
15struct virt_dma_desc {
16 struct dma_async_tx_descriptor tx;
17 struct dmaengine_result tx_result;
18 /* protected by vc.lock */
19 struct list_head node;
20};
21
22struct virt_dma_chan {
23 struct dma_chan chan;
24 struct tasklet_struct task;
25 void (*desc_free)(struct virt_dma_desc *);
26
27 spinlock_t lock;
28
29 /* protected by vc.lock */
30 struct list_head desc_allocated;
31 struct list_head desc_submitted;
32 struct list_head desc_issued;
33 struct list_head desc_completed;
34
35 struct virt_dma_desc *cyclic;
36 struct virt_dma_desc *vd_terminated;
37};
38
39static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan)
40{
41 return container_of(chan, struct virt_dma_chan, chan);
42}
43
44void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head);
45void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev);
46struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t);
47extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *);
48extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *);
49
50/**
51 * vchan_tx_prep - prepare a descriptor
52 * @vc: virtual channel allocating this descriptor
53 * @vd: virtual descriptor to prepare
54 * @tx_flags: flags argument passed in to prepare function
55 */
56static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc,
57 struct virt_dma_desc *vd, unsigned long tx_flags)
58{
59 unsigned long flags;
60
61 dma_async_tx_descriptor_init(&vd->tx, &vc->chan);
62 vd->tx.flags = tx_flags;
63 vd->tx.tx_submit = vchan_tx_submit;
64 vd->tx.desc_free = vchan_tx_desc_free;
65
66 vd->tx_result.result = DMA_TRANS_NOERROR;
67 vd->tx_result.residue = 0;
68
69 spin_lock_irqsave(&vc->lock, flags);
70 list_add_tail(&vd->node, &vc->desc_allocated);
71 spin_unlock_irqrestore(&vc->lock, flags);
72
73 return &vd->tx;
74}
75
76/**
77 * vchan_issue_pending - move submitted descriptors to issued list
78 * @vc: virtual channel to update
79 *
80 * vc.lock must be held by caller
81 */
82static inline bool vchan_issue_pending(struct virt_dma_chan *vc)
83{
84 list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued);
85 return !list_empty(&vc->desc_issued);
86}
87
88/**
89 * vchan_cookie_complete - report completion of a descriptor
90 * @vd: virtual descriptor to update
91 *
92 * vc.lock must be held by caller
93 */
94static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
95{
96 struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
97 dma_cookie_t cookie;
98
99 cookie = vd->tx.cookie;
100 dma_cookie_complete(&vd->tx);
101 dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n",
102 vd, cookie);
103 list_add_tail(&vd->node, &vc->desc_completed);
104
105 tasklet_schedule(&vc->task);
106}
107
108/**
109 * vchan_vdesc_fini - Free or reuse a descriptor
110 * @vd: virtual descriptor to free/reuse
111 */
112static inline void vchan_vdesc_fini(struct virt_dma_desc *vd)
113{
114 struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
115
116 if (dmaengine_desc_test_reuse(&vd->tx))
117 list_add(&vd->node, &vc->desc_allocated);
118 else
119 vc->desc_free(vd);
120}
121
122/**
123 * vchan_cyclic_callback - report the completion of a period
124 * @vd: virtual descriptor
125 */
126static inline void vchan_cyclic_callback(struct virt_dma_desc *vd)
127{
128 struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
129
130 vc->cyclic = vd;
131 tasklet_schedule(&vc->task);
132}
133
134/**
135 * vchan_terminate_vdesc - Disable pending cyclic callback
136 * @vd: virtual descriptor to be terminated
137 *
138 * vc.lock must be held by caller
139 */
140static inline void vchan_terminate_vdesc(struct virt_dma_desc *vd)
141{
142 struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
143
144 /* free up stuck descriptor */
145 if (vc->vd_terminated)
146 vchan_vdesc_fini(vc->vd_terminated);
147
148 vc->vd_terminated = vd;
149 if (vc->cyclic == vd)
150 vc->cyclic = NULL;
151}
152
153/**
154 * vchan_next_desc - peek at the next descriptor to be processed
155 * @vc: virtual channel to obtain descriptor from
156 *
157 * vc.lock must be held by caller
158 */
159static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
160{
161 return list_first_entry_or_null(&vc->desc_issued,
162 struct virt_dma_desc, node);
163}
164
165/**
166 * vchan_get_all_descriptors - obtain all submitted and issued descriptors
167 * @vc: virtual channel to get descriptors from
168 * @head: list of descriptors found
169 *
170 * vc.lock must be held by caller
171 *
172 * Removes all submitted and issued descriptors from internal lists, and
173 * provides a list of all descriptors found
174 */
175static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc,
176 struct list_head *head)
177{
178 list_splice_tail_init(&vc->desc_allocated, head);
179 list_splice_tail_init(&vc->desc_submitted, head);
180 list_splice_tail_init(&vc->desc_issued, head);
181 list_splice_tail_init(&vc->desc_completed, head);
182}
183
184static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
185{
186 struct virt_dma_desc *vd;
187 unsigned long flags;
188 LIST_HEAD(head);
189
190 spin_lock_irqsave(&vc->lock, flags);
191 vchan_get_all_descriptors(vc, &head);
192 list_for_each_entry(vd, &head, node)
193 dmaengine_desc_clear_reuse(&vd->tx);
194 spin_unlock_irqrestore(&vc->lock, flags);
195
196 vchan_dma_desc_free_list(vc, &head);
197}
198
199/**
200 * vchan_synchronize() - synchronize callback execution to the current context
201 * @vc: virtual channel to synchronize
202 *
203 * Makes sure that all scheduled or active callbacks have finished running. For
204 * proper operation the caller has to ensure that no new callbacks are scheduled
205 * after the invocation of this function started.
206 * Free up the terminated cyclic descriptor to prevent memory leakage.
207 */
208static inline void vchan_synchronize(struct virt_dma_chan *vc)
209{
210 unsigned long flags;
211
212 tasklet_kill(&vc->task);
213
214 spin_lock_irqsave(&vc->lock, flags);
215 if (vc->vd_terminated) {
216 vchan_vdesc_fini(vc->vd_terminated);
217 vc->vd_terminated = NULL;
218 }
219 spin_unlock_irqrestore(&vc->lock, flags);
220}
221
222#endif
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#ifndef VIRT_DMA_H
11#define VIRT_DMA_H
12
13#include <linux/dmaengine.h>
14#include <linux/interrupt.h>
15
16#include "dmaengine.h"
17
18struct virt_dma_desc {
19 struct dma_async_tx_descriptor tx;
20 /* protected by vc.lock */
21 struct list_head node;
22};
23
24struct virt_dma_chan {
25 struct dma_chan chan;
26 struct tasklet_struct task;
27 void (*desc_free)(struct virt_dma_desc *);
28
29 spinlock_t lock;
30
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;
36
37 struct virt_dma_desc *cyclic;
38};
39
40static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan)
41{
42 return container_of(chan, struct virt_dma_chan, chan);
43}
44
45void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head);
46void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev);
47struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t);
48extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *);
49extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *);
50
51/**
52 * vchan_tx_prep - prepare a descriptor
53 * @vc: virtual channel allocating this descriptor
54 * @vd: virtual descriptor to prepare
55 * @tx_flags: flags argument passed in to prepare function
56 */
57static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc,
58 struct virt_dma_desc *vd, unsigned long tx_flags)
59{
60 unsigned long flags;
61
62 dma_async_tx_descriptor_init(&vd->tx, &vc->chan);
63 vd->tx.flags = tx_flags;
64 vd->tx.tx_submit = vchan_tx_submit;
65 vd->tx.desc_free = vchan_tx_desc_free;
66
67 spin_lock_irqsave(&vc->lock, flags);
68 list_add_tail(&vd->node, &vc->desc_allocated);
69 spin_unlock_irqrestore(&vc->lock, flags);
70
71 return &vd->tx;
72}
73
74/**
75 * vchan_issue_pending - move submitted descriptors to issued list
76 * @vc: virtual channel to update
77 *
78 * vc.lock must be held by caller
79 */
80static inline bool vchan_issue_pending(struct virt_dma_chan *vc)
81{
82 list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued);
83 return !list_empty(&vc->desc_issued);
84}
85
86/**
87 * vchan_cookie_complete - report completion of a descriptor
88 * @vd: virtual descriptor to update
89 *
90 * vc.lock must be held by caller
91 */
92static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
93{
94 struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
95 dma_cookie_t cookie;
96
97 cookie = vd->tx.cookie;
98 dma_cookie_complete(&vd->tx);
99 dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n",
100 vd, cookie);
101 list_add_tail(&vd->node, &vc->desc_completed);
102
103 tasklet_schedule(&vc->task);
104}
105
106/**
107 * vchan_cyclic_callback - report the completion of a period
108 * @vd: virtual descriptor
109 */
110static inline void vchan_cyclic_callback(struct virt_dma_desc *vd)
111{
112 struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
113
114 vc->cyclic = vd;
115 tasklet_schedule(&vc->task);
116}
117
118/**
119 * vchan_next_desc - peek at the next descriptor to be processed
120 * @vc: virtual channel to obtain descriptor from
121 *
122 * vc.lock must be held by caller
123 */
124static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc)
125{
126 return list_first_entry_or_null(&vc->desc_issued,
127 struct virt_dma_desc, node);
128}
129
130/**
131 * vchan_get_all_descriptors - obtain all submitted and issued descriptors
132 * @vc: virtual channel to get descriptors from
133 * @head: list of descriptors found
134 *
135 * vc.lock must be held by caller
136 *
137 * Removes all submitted and issued descriptors from internal lists, and
138 * provides a list of all descriptors found
139 */
140static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc,
141 struct list_head *head)
142{
143 list_splice_tail_init(&vc->desc_allocated, head);
144 list_splice_tail_init(&vc->desc_submitted, head);
145 list_splice_tail_init(&vc->desc_issued, head);
146 list_splice_tail_init(&vc->desc_completed, head);
147}
148
149static inline void vchan_free_chan_resources(struct virt_dma_chan *vc)
150{
151 struct virt_dma_desc *vd;
152 unsigned long flags;
153 LIST_HEAD(head);
154
155 spin_lock_irqsave(&vc->lock, flags);
156 vchan_get_all_descriptors(vc, &head);
157 list_for_each_entry(vd, &head, node)
158 dmaengine_desc_clear_reuse(&vd->tx);
159 spin_unlock_irqrestore(&vc->lock, flags);
160
161 vchan_dma_desc_free_list(vc, &head);
162}
163
164/**
165 * vchan_synchronize() - synchronize callback execution to the current context
166 * @vc: virtual channel to synchronize
167 *
168 * Makes sure that all scheduled or active callbacks have finished running. For
169 * proper operation the caller has to ensure that no new callbacks are scheduled
170 * after the invocation of this function started.
171 */
172static inline void vchan_synchronize(struct virt_dma_chan *vc)
173{
174 tasklet_kill(&vc->task);
175}
176
177#endif