1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Syncpoint dma_fence implementation
4 *
5 * Copyright (c) 2020, NVIDIA Corporation.
6 */
7
8 #include <linux/dma-fence.h>
9 #include <linux/file.h>
10 #include <linux/fs.h>
11 #include <linux/slab.h>
12 #include <linux/sync_file.h>
13
14 #include "fence.h"
15 #include "intr.h"
16 #include "syncpt.h"
17
18 static DEFINE_SPINLOCK(lock);
19
20 struct host1x_syncpt_fence {
21 struct dma_fence base;
22
23 atomic_t signaling;
24
25 struct host1x_syncpt *sp;
26 u32 threshold;
27
28 struct host1x_waitlist *waiter;
29 void *waiter_ref;
30
31 struct delayed_work timeout_work;
32 };
33
host1x_syncpt_fence_get_driver_name(struct dma_fence * f)34 static const char *host1x_syncpt_fence_get_driver_name(struct dma_fence *f)
35 {
36 return "host1x";
37 }
38
host1x_syncpt_fence_get_timeline_name(struct dma_fence * f)39 static const char *host1x_syncpt_fence_get_timeline_name(struct dma_fence *f)
40 {
41 return "syncpoint";
42 }
43
to_host1x_fence(struct dma_fence * f)44 static struct host1x_syncpt_fence *to_host1x_fence(struct dma_fence *f)
45 {
46 return container_of(f, struct host1x_syncpt_fence, base);
47 }
48
host1x_syncpt_fence_enable_signaling(struct dma_fence * f)49 static bool host1x_syncpt_fence_enable_signaling(struct dma_fence *f)
50 {
51 struct host1x_syncpt_fence *sf = to_host1x_fence(f);
52 int err;
53
54 if (host1x_syncpt_is_expired(sf->sp, sf->threshold))
55 return false;
56
57 dma_fence_get(f);
58
59 /*
60 * The dma_fence framework requires the fence driver to keep a
61 * reference to any fences for which 'enable_signaling' has been
62 * called (and that have not been signalled).
63 *
64 * We provide a userspace API to create arbitrary syncpoint fences,
65 * so we cannot normally guarantee that all fences get signalled.
66 * As such, setup a timeout, so that long-lasting fences will get
67 * reaped eventually.
68 */
69 schedule_delayed_work(&sf->timeout_work, msecs_to_jiffies(30000));
70
71 err = host1x_intr_add_action(sf->sp->host, sf->sp, sf->threshold,
72 HOST1X_INTR_ACTION_SIGNAL_FENCE, f,
73 sf->waiter, &sf->waiter_ref);
74 if (err) {
75 cancel_delayed_work_sync(&sf->timeout_work);
76 dma_fence_put(f);
77 return false;
78 }
79
80 /* intr framework takes ownership of waiter */
81 sf->waiter = NULL;
82
83 /*
84 * The fence may get signalled at any time after the above call,
85 * so we need to initialize all state used by signalling
86 * before it.
87 */
88
89 return true;
90 }
91
host1x_syncpt_fence_release(struct dma_fence * f)92 static void host1x_syncpt_fence_release(struct dma_fence *f)
93 {
94 struct host1x_syncpt_fence *sf = to_host1x_fence(f);
95
96 if (sf->waiter)
97 kfree(sf->waiter);
98
99 dma_fence_free(f);
100 }
101
102 const struct dma_fence_ops host1x_syncpt_fence_ops = {
103 .get_driver_name = host1x_syncpt_fence_get_driver_name,
104 .get_timeline_name = host1x_syncpt_fence_get_timeline_name,
105 .enable_signaling = host1x_syncpt_fence_enable_signaling,
106 .release = host1x_syncpt_fence_release,
107 };
108
host1x_fence_signal(struct host1x_syncpt_fence * f)109 void host1x_fence_signal(struct host1x_syncpt_fence *f)
110 {
111 if (atomic_xchg(&f->signaling, 1))
112 return;
113
114 /*
115 * Cancel pending timeout work - if it races, it will
116 * not get 'f->signaling' and return.
117 */
118 cancel_delayed_work_sync(&f->timeout_work);
119
120 host1x_intr_put_ref(f->sp->host, f->sp->id, f->waiter_ref, false);
121
122 dma_fence_signal(&f->base);
123 dma_fence_put(&f->base);
124 }
125
do_fence_timeout(struct work_struct * work)126 static void do_fence_timeout(struct work_struct *work)
127 {
128 struct delayed_work *dwork = (struct delayed_work *)work;
129 struct host1x_syncpt_fence *f =
130 container_of(dwork, struct host1x_syncpt_fence, timeout_work);
131
132 if (atomic_xchg(&f->signaling, 1))
133 return;
134
135 /*
136 * Cancel pending timeout work - if it races, it will
137 * not get 'f->signaling' and return.
138 */
139 host1x_intr_put_ref(f->sp->host, f->sp->id, f->waiter_ref, true);
140
141 dma_fence_set_error(&f->base, -ETIMEDOUT);
142 dma_fence_signal(&f->base);
143 dma_fence_put(&f->base);
144 }
145
host1x_fence_create(struct host1x_syncpt * sp,u32 threshold)146 struct dma_fence *host1x_fence_create(struct host1x_syncpt *sp, u32 threshold)
147 {
148 struct host1x_syncpt_fence *fence;
149
150 fence = kzalloc(sizeof(*fence), GFP_KERNEL);
151 if (!fence)
152 return ERR_PTR(-ENOMEM);
153
154 fence->waiter = kzalloc(sizeof(*fence->waiter), GFP_KERNEL);
155 if (!fence->waiter) {
156 kfree(fence);
157 return ERR_PTR(-ENOMEM);
158 }
159
160 fence->sp = sp;
161 fence->threshold = threshold;
162
163 dma_fence_init(&fence->base, &host1x_syncpt_fence_ops, &lock,
164 dma_fence_context_alloc(1), 0);
165
166 INIT_DELAYED_WORK(&fence->timeout_work, do_fence_timeout);
167
168 return &fence->base;
169 }
170 EXPORT_SYMBOL(host1x_fence_create);
171