xref: /linux/drivers/gpu/drm/msm/msm_fence.c (revision 31354121bf03dac6498a4236928a38490745d601)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2013-2016 Red Hat
4  * Author: Rob Clark <robdclark@gmail.com>
5  */
6 
7 #include <linux/dma-fence.h>
8 
9 #include "msm_drv.h"
10 #include "msm_fence.h"
11 
12 
13 struct msm_fence_context *
14 msm_fence_context_alloc(struct drm_device *dev, volatile uint32_t *fenceptr,
15 		const char *name)
16 {
17 	struct msm_fence_context *fctx;
18 	static int index = 0;
19 
20 	fctx = kzalloc(sizeof(*fctx), GFP_KERNEL);
21 	if (!fctx)
22 		return ERR_PTR(-ENOMEM);
23 
24 	fctx->dev = dev;
25 	strncpy(fctx->name, name, sizeof(fctx->name));
26 	fctx->context = dma_fence_context_alloc(1);
27 	fctx->index = index++;
28 	fctx->fenceptr = fenceptr;
29 	spin_lock_init(&fctx->spinlock);
30 
31 	/*
32 	 * Start out close to the 32b fence rollover point, so we can
33 	 * catch bugs with fence comparisons.
34 	 */
35 	fctx->last_fence = 0xffffff00;
36 	fctx->completed_fence = fctx->last_fence;
37 	*fctx->fenceptr = fctx->last_fence;
38 
39 	return fctx;
40 }
41 
42 void msm_fence_context_free(struct msm_fence_context *fctx)
43 {
44 	kfree(fctx);
45 }
46 
47 bool msm_fence_completed(struct msm_fence_context *fctx, uint32_t fence)
48 {
49 	/*
50 	 * Note: Check completed_fence first, as fenceptr is in a write-combine
51 	 * mapping, so it will be more expensive to read.
52 	 */
53 	return (int32_t)(fctx->completed_fence - fence) >= 0 ||
54 		(int32_t)(*fctx->fenceptr - fence) >= 0;
55 }
56 
57 /* called from irq handler and workqueue (in recover path) */
58 void msm_update_fence(struct msm_fence_context *fctx, uint32_t fence)
59 {
60 	unsigned long flags;
61 
62 	spin_lock_irqsave(&fctx->spinlock, flags);
63 	if (fence_after(fence, fctx->completed_fence))
64 		fctx->completed_fence = fence;
65 	spin_unlock_irqrestore(&fctx->spinlock, flags);
66 }
67 
68 struct msm_fence {
69 	struct dma_fence base;
70 	struct msm_fence_context *fctx;
71 };
72 
73 static inline struct msm_fence *to_msm_fence(struct dma_fence *fence)
74 {
75 	return container_of(fence, struct msm_fence, base);
76 }
77 
78 static const char *msm_fence_get_driver_name(struct dma_fence *fence)
79 {
80 	return "msm";
81 }
82 
83 static const char *msm_fence_get_timeline_name(struct dma_fence *fence)
84 {
85 	struct msm_fence *f = to_msm_fence(fence);
86 	return f->fctx->name;
87 }
88 
89 static bool msm_fence_signaled(struct dma_fence *fence)
90 {
91 	struct msm_fence *f = to_msm_fence(fence);
92 	return msm_fence_completed(f->fctx, f->base.seqno);
93 }
94 
95 static const struct dma_fence_ops msm_fence_ops = {
96 	.get_driver_name = msm_fence_get_driver_name,
97 	.get_timeline_name = msm_fence_get_timeline_name,
98 	.signaled = msm_fence_signaled,
99 };
100 
101 struct dma_fence *
102 msm_fence_alloc(struct msm_fence_context *fctx)
103 {
104 	struct msm_fence *f;
105 
106 	f = kzalloc(sizeof(*f), GFP_KERNEL);
107 	if (!f)
108 		return ERR_PTR(-ENOMEM);
109 
110 	f->fctx = fctx;
111 
112 	dma_fence_init(&f->base, &msm_fence_ops, &fctx->spinlock,
113 		       fctx->context, ++fctx->last_fence);
114 
115 	return &f->base;
116 }
117