1/*
2 * dma-fence-array: aggregate fences to be waited together
3 *
4 * Copyright (C) 2016 Collabora Ltd
5 * Copyright (C) 2016 Advanced Micro Devices, Inc.
6 * Authors:
7 * Gustavo Padovan <gustavo@padovan.org>
8 * Christian K├Ânig <christian.koenig@amd.com>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License version 2 as published by
12 * the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 * more details.
18 */
19
20#include <linux/export.h>
21#include <linux/slab.h>
22#include <linux/dma-fence-array.h>
23
24static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
25{
26 return "dma_fence_array";
27}
28
29static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
30{
31 return "unbound";
32}
33
34static void irq_dma_fence_array_work(struct irq_work *wrk)
35{
36 struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
37
38 dma_fence_signal(&array->base);
39 dma_fence_put(&array->base);
40}
41
42static void dma_fence_array_cb_func(struct dma_fence *f,
43 struct dma_fence_cb *cb)
44{
45 struct dma_fence_array_cb *array_cb =
46 container_of(cb, struct dma_fence_array_cb, cb);
47 struct dma_fence_array *array = array_cb->array;
48
49 if (atomic_dec_and_test(&array->num_pending))
50 irq_work_queue(&array->work);
51 else
52 dma_fence_put(&array->base);
53}
54
55static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
56{
57 struct dma_fence_array *array = to_dma_fence_array(fence);
58 struct dma_fence_array_cb *cb = (void *)(&array[1]);
59 unsigned i;
60
61 for (i = 0; i < array->num_fences; ++i) {
62 cb[i].array = array;
63 /*
64 * As we may report that the fence is signaled before all
65 * callbacks are complete, we need to take an additional
66 * reference count on the array so that we do not free it too
67 * early. The core fence handling will only hold the reference
68 * until we signal the array as complete (but that is now
69 * insufficient).
70 */
71 dma_fence_get(&array->base);
72 if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
73 dma_fence_array_cb_func)) {
74 dma_fence_put(&array->base);
75 if (atomic_dec_and_test(&array->num_pending))
76 return false;
77 }
78 }
79
80 return true;
81}
82
83static bool dma_fence_array_signaled(struct dma_fence *fence)
84{
85 struct dma_fence_array *array = to_dma_fence_array(fence);
86
87 return atomic_read(&array->num_pending) <= 0;
88}
89
90static void dma_fence_array_release(struct dma_fence *fence)
91{
92 struct dma_fence_array *array = to_dma_fence_array(fence);
93 unsigned i;
94
95 for (i = 0; i < array->num_fences; ++i)
96 dma_fence_put(array->fences[i]);
97
98 kfree(array->fences);
99 dma_fence_free(fence);
100}
101
102const struct dma_fence_ops dma_fence_array_ops = {
103 .get_driver_name = dma_fence_array_get_driver_name,
104 .get_timeline_name = dma_fence_array_get_timeline_name,
105 .enable_signaling = dma_fence_array_enable_signaling,
106 .signaled = dma_fence_array_signaled,
107 .release = dma_fence_array_release,
108};
109EXPORT_SYMBOL(dma_fence_array_ops);
110
111/**
112 * dma_fence_array_create - Create a custom fence array
113 * @num_fences: [in] number of fences to add in the array
114 * @fences: [in] array containing the fences
115 * @context: [in] fence context to use
116 * @seqno: [in] sequence number to use
117 * @signal_on_any: [in] signal on any fence in the array
118 *
119 * Allocate a dma_fence_array object and initialize the base fence with
120 * dma_fence_init().
121 * In case of error it returns NULL.
122 *
123 * The caller should allocate the fences array with num_fences size
124 * and fill it with the fences it wants to add to the object. Ownership of this
125 * array is taken and dma_fence_put() is used on each fence on release.
126 *
127 * If @signal_on_any is true the fence array signals if any fence in the array
128 * signals, otherwise it signals when all fences in the array signal.
129 */
130struct dma_fence_array *dma_fence_array_create(int num_fences,
131 struct dma_fence **fences,
132 u64 context, unsigned seqno,
133 bool signal_on_any)
134{
135 struct dma_fence_array *array;
136 size_t size = sizeof(*array);
137
138 /* Allocate the callback structures behind the array. */
139 size += num_fences * sizeof(struct dma_fence_array_cb);
140 array = kzalloc(size, GFP_KERNEL);
141 if (!array)
142 return NULL;
143
144 spin_lock_init(&array->lock);
145 dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
146 context, seqno);
147 init_irq_work(&array->work, irq_dma_fence_array_work);
148
149 array->num_fences = num_fences;
150 atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
151 array->fences = fences;
152
153 return array;
154}
155EXPORT_SYMBOL(dma_fence_array_create);
156
157/**
158 * dma_fence_match_context - Check if all fences are from the given context
159 * @fence: [in] fence or fence array
160 * @context: [in] fence context to check all fences against
161 *
162 * Checks the provided fence or, for a fence array, all fences in the array
163 * against the given context. Returns false if any fence is from a different
164 * context.
165 */
166bool dma_fence_match_context(struct dma_fence *fence, u64 context)
167{
168 struct dma_fence_array *array = to_dma_fence_array(fence);
169 unsigned i;
170
171 if (!dma_fence_is_array(fence))
172 return fence->context == context;
173
174 for (i = 0; i < array->num_fences; i++) {
175 if (array->fences[i]->context != context)
176 return false;
177 }
178
179 return true;
180}
181EXPORT_SYMBOL(dma_fence_match_context);
182