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 König <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 
24 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
25 {
26 	return "dma_fence_array";
27 }
28 
29 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
30 {
31 	return "unbound";
32 }
33 
34 static void dma_fence_array_cb_func(struct dma_fence *f,
35 				    struct dma_fence_cb *cb)
36 {
37 	struct dma_fence_array_cb *array_cb =
38 		container_of(cb, struct dma_fence_array_cb, cb);
39 	struct dma_fence_array *array = array_cb->array;
40 
41 	if (atomic_dec_and_test(&array->num_pending))
42 		dma_fence_signal(&array->base);
43 	dma_fence_put(&array->base);
44 }
45 
46 static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
47 {
48 	struct dma_fence_array *array = to_dma_fence_array(fence);
49 	struct dma_fence_array_cb *cb = (void *)(&array[1]);
50 	unsigned i;
51 
52 	for (i = 0; i < array->num_fences; ++i) {
53 		cb[i].array = array;
54 		/*
55 		 * As we may report that the fence is signaled before all
56 		 * callbacks are complete, we need to take an additional
57 		 * reference count on the array so that we do not free it too
58 		 * early. The core fence handling will only hold the reference
59 		 * until we signal the array as complete (but that is now
60 		 * insufficient).
61 		 */
62 		dma_fence_get(&array->base);
63 		if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
64 					   dma_fence_array_cb_func)) {
65 			dma_fence_put(&array->base);
66 			if (atomic_dec_and_test(&array->num_pending))
67 				return false;
68 		}
69 	}
70 
71 	return true;
72 }
73 
74 static bool dma_fence_array_signaled(struct dma_fence *fence)
75 {
76 	struct dma_fence_array *array = to_dma_fence_array(fence);
77 
78 	return atomic_read(&array->num_pending) <= 0;
79 }
80 
81 static void dma_fence_array_release(struct dma_fence *fence)
82 {
83 	struct dma_fence_array *array = to_dma_fence_array(fence);
84 	unsigned i;
85 
86 	for (i = 0; i < array->num_fences; ++i)
87 		dma_fence_put(array->fences[i]);
88 
89 	kfree(array->fences);
90 	dma_fence_free(fence);
91 }
92 
93 const struct dma_fence_ops dma_fence_array_ops = {
94 	.get_driver_name = dma_fence_array_get_driver_name,
95 	.get_timeline_name = dma_fence_array_get_timeline_name,
96 	.enable_signaling = dma_fence_array_enable_signaling,
97 	.signaled = dma_fence_array_signaled,
98 	.wait = dma_fence_default_wait,
99 	.release = dma_fence_array_release,
100 };
101 EXPORT_SYMBOL(dma_fence_array_ops);
102 
103 /**
104  * dma_fence_array_create - Create a custom fence array
105  * @num_fences:		[in]	number of fences to add in the array
106  * @fences:		[in]	array containing the fences
107  * @context:		[in]	fence context to use
108  * @seqno:		[in]	sequence number to use
109  * @signal_on_any:	[in]	signal on any fence in the array
110  *
111  * Allocate a dma_fence_array object and initialize the base fence with
112  * dma_fence_init().
113  * In case of error it returns NULL.
114  *
115  * The caller should allocate the fences array with num_fences size
116  * and fill it with the fences it wants to add to the object. Ownership of this
117  * array is taken and dma_fence_put() is used on each fence on release.
118  *
119  * If @signal_on_any is true the fence array signals if any fence in the array
120  * signals, otherwise it signals when all fences in the array signal.
121  */
122 struct dma_fence_array *dma_fence_array_create(int num_fences,
123 					       struct dma_fence **fences,
124 					       u64 context, unsigned seqno,
125 					       bool signal_on_any)
126 {
127 	struct dma_fence_array *array;
128 	size_t size = sizeof(*array);
129 
130 	/* Allocate the callback structures behind the array. */
131 	size += num_fences * sizeof(struct dma_fence_array_cb);
132 	array = kzalloc(size, GFP_KERNEL);
133 	if (!array)
134 		return NULL;
135 
136 	spin_lock_init(&array->lock);
137 	dma_fence_init(&array->base, &dma_fence_array_ops, &array->lock,
138 		       context, seqno);
139 
140 	array->num_fences = num_fences;
141 	atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
142 	array->fences = fences;
143 
144 	return array;
145 }
146 EXPORT_SYMBOL(dma_fence_array_create);
147 
148 /**
149  * dma_fence_match_context - Check if all fences are from the given context
150  * @fence:		[in]	fence or fence array
151  * @context:		[in]	fence context to check all fences against
152  *
153  * Checks the provided fence or, for a fence array, all fences in the array
154  * against the given context. Returns false if any fence is from a different
155  * context.
156  */
157 bool dma_fence_match_context(struct dma_fence *fence, u64 context)
158 {
159 	struct dma_fence_array *array = to_dma_fence_array(fence);
160 	unsigned i;
161 
162 	if (!dma_fence_is_array(fence))
163 		return fence->context == context;
164 
165 	for (i = 0; i < array->num_fences; i++) {
166 		if (array->fences[i]->context != context)
167 			return false;
168 	}
169 
170 	return true;
171 }
172 EXPORT_SYMBOL(dma_fence_match_context);
173