xref: /openbmc/linux/drivers/gpu/drm/msm/msm_fence.h (revision 2a598d0b)
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 #ifndef __MSM_FENCE_H__
8 #define __MSM_FENCE_H__
9 
10 #include "msm_drv.h"
11 
12 /**
13  * struct msm_fence_context - fence context for gpu
14  *
15  * Each ringbuffer has a single fence context, with the GPU writing an
16  * incrementing fence seqno at the end of each submit
17  */
18 struct msm_fence_context {
19 	struct drm_device *dev;
20 	/** name: human readable name for fence timeline */
21 	char name[32];
22 	/** context: see dma_fence_context_alloc() */
23 	unsigned context;
24 	/** index: similar to context, but local to msm_fence_context's */
25 	unsigned index;
26 
27 	/**
28 	 * last_fence:
29 	 *
30 	 * Last assigned fence, incremented each time a fence is created
31 	 * on this fence context.  If last_fence == completed_fence,
32 	 * there is no remaining pending work
33 	 */
34 	uint32_t last_fence;
35 
36 	/**
37 	 * completed_fence:
38 	 *
39 	 * The last completed fence, updated from the CPU after interrupt
40 	 * from GPU
41 	 */
42 	uint32_t completed_fence;
43 
44 	/**
45 	 * fenceptr:
46 	 *
47 	 * The address that the GPU directly writes with completed fence
48 	 * seqno.  This can be ahead of completed_fence.  We can peek at
49 	 * this to see if a fence has already signaled but the CPU hasn't
50 	 * gotten around to handling the irq and updating completed_fence
51 	 */
52 	volatile uint32_t *fenceptr;
53 
54 	spinlock_t spinlock;
55 
56 	/*
57 	 * TODO this doesn't really deal with multiple deadlines, like
58 	 * if userspace got multiple frames ahead.. OTOH atomic updates
59 	 * don't queue, so maybe that is ok
60 	 */
61 
62 	/** next_deadline: Time of next deadline */
63 	ktime_t next_deadline;
64 
65 	/**
66 	 * next_deadline_fence:
67 	 *
68 	 * Fence value for next pending deadline.  The deadline timer is
69 	 * canceled when this fence is signaled.
70 	 */
71 	uint32_t next_deadline_fence;
72 
73 	struct hrtimer deadline_timer;
74 	struct kthread_work deadline_work;
75 };
76 
77 struct msm_fence_context * msm_fence_context_alloc(struct drm_device *dev,
78 		volatile uint32_t *fenceptr, const char *name);
79 void msm_fence_context_free(struct msm_fence_context *fctx);
80 
81 bool msm_fence_completed(struct msm_fence_context *fctx, uint32_t fence);
82 void msm_update_fence(struct msm_fence_context *fctx, uint32_t fence);
83 
84 struct dma_fence * msm_fence_alloc(void);
85 void msm_fence_init(struct dma_fence *fence, struct msm_fence_context *fctx);
86 
87 static inline bool
88 fence_before(uint32_t a, uint32_t b)
89 {
90    return (int32_t)(a - b) < 0;
91 }
92 
93 static inline bool
94 fence_after(uint32_t a, uint32_t b)
95 {
96    return (int32_t)(a - b) > 0;
97 }
98 
99 #endif
100