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 | |
15 | struct 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 | |
22 | struct 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 | struct list_head desc_terminated; |
35 | |
36 | struct virt_dma_desc *cyclic; |
37 | }; |
38 | |
39 | static 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 | |
44 | void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head); |
45 | void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev); |
46 | struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t); |
47 | extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *); |
48 | extern 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 | */ |
56 | static 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(tx: &vd->tx, chan: &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(new: &vd->node, head: &vc->desc_allocated); |
71 | spin_unlock_irqrestore(lock: &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 | */ |
82 | static inline bool vchan_issue_pending(struct virt_dma_chan *vc) |
83 | { |
84 | list_splice_tail_init(list: &vc->desc_submitted, head: &vc->desc_issued); |
85 | return !list_empty(head: &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 | */ |
94 | static inline void vchan_cookie_complete(struct virt_dma_desc *vd) |
95 | { |
96 | struct virt_dma_chan *vc = to_virt_chan(chan: vd->tx.chan); |
97 | dma_cookie_t cookie; |
98 | |
99 | cookie = vd->tx.cookie; |
100 | dma_cookie_complete(tx: &vd->tx); |
101 | dev_vdbg(vc->chan.device->dev, "txd %p[%x]: marked complete\n" , |
102 | vd, cookie); |
103 | list_add_tail(new: &vd->node, head: &vc->desc_completed); |
104 | |
105 | tasklet_schedule(t: &vc->task); |
106 | } |
107 | |
108 | /** |
109 | * vchan_vdesc_fini - Free or reuse a descriptor |
110 | * @vd: virtual descriptor to free/reuse |
111 | */ |
112 | static inline void vchan_vdesc_fini(struct virt_dma_desc *vd) |
113 | { |
114 | struct virt_dma_chan *vc = to_virt_chan(chan: vd->tx.chan); |
115 | |
116 | if (dmaengine_desc_test_reuse(tx: &vd->tx)) { |
117 | unsigned long flags; |
118 | |
119 | spin_lock_irqsave(&vc->lock, flags); |
120 | list_add(new: &vd->node, head: &vc->desc_allocated); |
121 | spin_unlock_irqrestore(lock: &vc->lock, flags); |
122 | } else { |
123 | vc->desc_free(vd); |
124 | } |
125 | } |
126 | |
127 | /** |
128 | * vchan_cyclic_callback - report the completion of a period |
129 | * @vd: virtual descriptor |
130 | */ |
131 | static inline void vchan_cyclic_callback(struct virt_dma_desc *vd) |
132 | { |
133 | struct virt_dma_chan *vc = to_virt_chan(chan: vd->tx.chan); |
134 | |
135 | vc->cyclic = vd; |
136 | tasklet_schedule(t: &vc->task); |
137 | } |
138 | |
139 | /** |
140 | * vchan_terminate_vdesc - Disable pending cyclic callback |
141 | * @vd: virtual descriptor to be terminated |
142 | * |
143 | * vc.lock must be held by caller |
144 | */ |
145 | static inline void vchan_terminate_vdesc(struct virt_dma_desc *vd) |
146 | { |
147 | struct virt_dma_chan *vc = to_virt_chan(chan: vd->tx.chan); |
148 | |
149 | list_add_tail(new: &vd->node, head: &vc->desc_terminated); |
150 | |
151 | if (vc->cyclic == vd) |
152 | vc->cyclic = NULL; |
153 | } |
154 | |
155 | /** |
156 | * vchan_next_desc - peek at the next descriptor to be processed |
157 | * @vc: virtual channel to obtain descriptor from |
158 | * |
159 | * vc.lock must be held by caller |
160 | */ |
161 | static inline struct virt_dma_desc *vchan_next_desc(struct virt_dma_chan *vc) |
162 | { |
163 | return list_first_entry_or_null(&vc->desc_issued, |
164 | struct virt_dma_desc, node); |
165 | } |
166 | |
167 | /** |
168 | * vchan_get_all_descriptors - obtain all submitted and issued descriptors |
169 | * @vc: virtual channel to get descriptors from |
170 | * @head: list of descriptors found |
171 | * |
172 | * vc.lock must be held by caller |
173 | * |
174 | * Removes all submitted and issued descriptors from internal lists, and |
175 | * provides a list of all descriptors found |
176 | */ |
177 | static inline void vchan_get_all_descriptors(struct virt_dma_chan *vc, |
178 | struct list_head *head) |
179 | { |
180 | list_splice_tail_init(list: &vc->desc_allocated, head); |
181 | list_splice_tail_init(list: &vc->desc_submitted, head); |
182 | list_splice_tail_init(list: &vc->desc_issued, head); |
183 | list_splice_tail_init(list: &vc->desc_completed, head); |
184 | list_splice_tail_init(list: &vc->desc_terminated, head); |
185 | } |
186 | |
187 | static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) |
188 | { |
189 | struct virt_dma_desc *vd; |
190 | unsigned long flags; |
191 | LIST_HEAD(head); |
192 | |
193 | spin_lock_irqsave(&vc->lock, flags); |
194 | vchan_get_all_descriptors(vc, head: &head); |
195 | list_for_each_entry(vd, &head, node) |
196 | dmaengine_desc_clear_reuse(tx: &vd->tx); |
197 | spin_unlock_irqrestore(lock: &vc->lock, flags); |
198 | |
199 | vchan_dma_desc_free_list(vc, head: &head); |
200 | } |
201 | |
202 | /** |
203 | * vchan_synchronize() - synchronize callback execution to the current context |
204 | * @vc: virtual channel to synchronize |
205 | * |
206 | * Makes sure that all scheduled or active callbacks have finished running. For |
207 | * proper operation the caller has to ensure that no new callbacks are scheduled |
208 | * after the invocation of this function started. |
209 | * Free up the terminated cyclic descriptor to prevent memory leakage. |
210 | */ |
211 | static inline void vchan_synchronize(struct virt_dma_chan *vc) |
212 | { |
213 | LIST_HEAD(head); |
214 | unsigned long flags; |
215 | |
216 | tasklet_kill(t: &vc->task); |
217 | |
218 | spin_lock_irqsave(&vc->lock, flags); |
219 | |
220 | list_splice_tail_init(list: &vc->desc_terminated, head: &head); |
221 | |
222 | spin_unlock_irqrestore(lock: &vc->lock, flags); |
223 | |
224 | vchan_dma_desc_free_list(vc, head: &head); |
225 | } |
226 | |
227 | #endif |
228 | |