1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * dma-fence-array: aggregate fences to be waited together
4  *
5  * Copyright (C) 2016 Collabora Ltd
6  * Copyright (C) 2016 Advanced Micro Devices, Inc.
7  * Authors:
8  *	Gustavo Padovan <gustavo@padovan.org>
9  *	Christian König <christian.koenig@amd.com>
10  */
11 
12 #include <linux/export.h>
13 #include <linux/slab.h>
14 #include <linux/dma-fence-array.h>
15 
16 static const char *dma_fence_array_get_driver_name(struct dma_fence *fence)
17 {
18 	return "dma_fence_array";
19 }
20 
21 static const char *dma_fence_array_get_timeline_name(struct dma_fence *fence)
22 {
23 	return "unbound";
24 }
25 
26 static void irq_dma_fence_array_work(struct irq_work *wrk)
27 {
28 	struct dma_fence_array *array = container_of(wrk, typeof(*array), work);
29 
30 	dma_fence_signal(&array->base);
31 	dma_fence_put(&array->base);
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 		irq_work_queue(&array->work);
43 	else
44 		dma_fence_put(&array->base);
45 }
46 
47 static bool dma_fence_array_enable_signaling(struct dma_fence *fence)
48 {
49 	struct dma_fence_array *array = to_dma_fence_array(fence);
50 	struct dma_fence_array_cb *cb = (void *)(&array[1]);
51 	unsigned i;
52 
53 	for (i = 0; i < array->num_fences; ++i) {
54 		cb[i].array = array;
55 		/*
56 		 * As we may report that the fence is signaled before all
57 		 * callbacks are complete, we need to take an additional
58 		 * reference count on the array so that we do not free it too
59 		 * early. The core fence handling will only hold the reference
60 		 * until we signal the array as complete (but that is now
61 		 * insufficient).
62 		 */
63 		dma_fence_get(&array->base);
64 		if (dma_fence_add_callback(array->fences[i], &cb[i].cb,
65 					   dma_fence_array_cb_func)) {
66 			dma_fence_put(&array->base);
67 			if (atomic_dec_and_test(&array->num_pending))
68 				return false;
69 		}
70 	}
71 
72 	return true;
73 }
74 
75 static bool dma_fence_array_signaled(struct dma_fence *fence)
76 {
77 	struct dma_fence_array *array = to_dma_fence_array(fence);
78 
79 	return atomic_read(&array->num_pending) <= 0;
80 }
81 
82 static void dma_fence_array_release(struct dma_fence *fence)
83 {
84 	struct dma_fence_array *array = to_dma_fence_array(fence);
85 	unsigned i;
86 
87 	for (i = 0; i < array->num_fences; ++i)
88 		dma_fence_put(array->fences[i]);
89 
90 	kfree(array->fences);
91 	dma_fence_free(fence);
92 }
93 
94 const struct dma_fence_ops dma_fence_array_ops = {
95 	.get_driver_name = dma_fence_array_get_driver_name,
96 	.get_timeline_name = dma_fence_array_get_timeline_name,
97 	.enable_signaling = dma_fence_array_enable_signaling,
98 	.signaled = dma_fence_array_signaled,
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 	init_irq_work(&array->work, irq_dma_fence_array_work);
140 
141 	array->num_fences = num_fences;
142 	atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
143 	array->fences = fences;
144 
145 	return array;
146 }
147 EXPORT_SYMBOL(dma_fence_array_create);
148 
149 /**
150  * dma_fence_match_context - Check if all fences are from the given context
151  * @fence:		[in]	fence or fence array
152  * @context:		[in]	fence context to check all fences against
153  *
154  * Checks the provided fence or, for a fence array, all fences in the array
155  * against the given context. Returns false if any fence is from a different
156  * context.
157  */
158 bool dma_fence_match_context(struct dma_fence *fence, u64 context)
159 {
160 	struct dma_fence_array *array = to_dma_fence_array(fence);
161 	unsigned i;
162 
163 	if (!dma_fence_is_array(fence))
164 		return fence->context == context;
165 
166 	for (i = 0; i < array->num_fences; i++) {
167 		if (array->fences[i]->context != context)
168 			return false;
169 	}
170 
171 	return true;
172 }
173 EXPORT_SYMBOL(dma_fence_match_context);
174