1// SPDX-License-Identifier: MIT
2/*
3 * Copyright �� 2022 Intel Corporation
4 */
5
6#include "xe_preempt_fence.h"
7
8#include <linux/slab.h>
9
10#include "xe_exec_queue.h"
11#include "xe_vm.h"
12
13static void preempt_fence_work_func(struct work_struct *w)
14{
15	bool cookie = dma_fence_begin_signalling();
16	struct xe_preempt_fence *pfence =
17		container_of(w, typeof(*pfence), preempt_work);
18	struct xe_exec_queue *q = pfence->q;
19
20	if (pfence->error)
21		dma_fence_set_error(&pfence->base, pfence->error);
22	else
23		q->ops->suspend_wait(q);
24
25	dma_fence_signal(&pfence->base);
26	dma_fence_end_signalling(cookie);
27
28	xe_vm_queue_rebind_worker(q->vm);
29
30	xe_exec_queue_put(q);
31}
32
33static const char *
34preempt_fence_get_driver_name(struct dma_fence *fence)
35{
36	return "xe";
37}
38
39static const char *
40preempt_fence_get_timeline_name(struct dma_fence *fence)
41{
42	return "preempt";
43}
44
45static bool preempt_fence_enable_signaling(struct dma_fence *fence)
46{
47	struct xe_preempt_fence *pfence =
48		container_of(fence, typeof(*pfence), base);
49	struct xe_exec_queue *q = pfence->q;
50
51	pfence->error = q->ops->suspend(q);
52	queue_work(q->vm->xe->preempt_fence_wq, &pfence->preempt_work);
53	return true;
54}
55
56static const struct dma_fence_ops preempt_fence_ops = {
57	.get_driver_name = preempt_fence_get_driver_name,
58	.get_timeline_name = preempt_fence_get_timeline_name,
59	.enable_signaling = preempt_fence_enable_signaling,
60};
61
62/**
63 * xe_preempt_fence_alloc() - Allocate a preempt fence with minimal
64 * initialization
65 *
66 * Allocate a preempt fence, and initialize its list head.
67 * If the preempt_fence allocated has been armed with
68 * xe_preempt_fence_arm(), it must be freed using dma_fence_put(). If not,
69 * it must be freed using xe_preempt_fence_free().
70 *
71 * Return: A struct xe_preempt_fence pointer used for calling into
72 * xe_preempt_fence_arm() or xe_preempt_fence_free().
73 * An error pointer on error.
74 */
75struct xe_preempt_fence *xe_preempt_fence_alloc(void)
76{
77	struct xe_preempt_fence *pfence;
78
79	pfence = kmalloc(sizeof(*pfence), GFP_KERNEL);
80	if (!pfence)
81		return ERR_PTR(-ENOMEM);
82
83	INIT_LIST_HEAD(&pfence->link);
84	INIT_WORK(&pfence->preempt_work, preempt_fence_work_func);
85
86	return pfence;
87}
88
89/**
90 * xe_preempt_fence_free() - Free a preempt fence allocated using
91 * xe_preempt_fence_alloc().
92 * @pfence: pointer obtained from xe_preempt_fence_alloc();
93 *
94 * Free a preempt fence that has not yet been armed.
95 */
96void xe_preempt_fence_free(struct xe_preempt_fence *pfence)
97{
98	list_del(&pfence->link);
99	kfree(pfence);
100}
101
102/**
103 * xe_preempt_fence_arm() - Arm a preempt fence allocated using
104 * xe_preempt_fence_alloc().
105 * @pfence: The struct xe_preempt_fence pointer returned from
106 *          xe_preempt_fence_alloc().
107 * @q: The struct xe_exec_queue used for arming.
108 * @context: The dma-fence context used for arming.
109 * @seqno: The dma-fence seqno used for arming.
110 *
111 * Inserts the preempt fence into @context's timeline, takes @link off any
112 * list, and registers the struct xe_exec_queue as the xe_engine to be preempted.
113 *
114 * Return: A pointer to a struct dma_fence embedded into the preempt fence.
115 * This function doesn't error.
116 */
117struct dma_fence *
118xe_preempt_fence_arm(struct xe_preempt_fence *pfence, struct xe_exec_queue *q,
119		     u64 context, u32 seqno)
120{
121	list_del_init(&pfence->link);
122	pfence->q = xe_exec_queue_get(q);
123	dma_fence_init(&pfence->base, &preempt_fence_ops,
124		      &q->compute.lock, context, seqno);
125
126	return &pfence->base;
127}
128
129/**
130 * xe_preempt_fence_create() - Helper to create and arm a preempt fence.
131 * @q: The struct xe_exec_queue used for arming.
132 * @context: The dma-fence context used for arming.
133 * @seqno: The dma-fence seqno used for arming.
134 *
135 * Allocates and inserts the preempt fence into @context's timeline,
136 * and registers @e as the struct xe_exec_queue to be preempted.
137 *
138 * Return: A pointer to the resulting struct dma_fence on success. An error
139 * pointer on error. In particular if allocation fails it returns
140 * ERR_PTR(-ENOMEM);
141 */
142struct dma_fence *
143xe_preempt_fence_create(struct xe_exec_queue *q,
144			u64 context, u32 seqno)
145{
146	struct xe_preempt_fence *pfence;
147
148	pfence = xe_preempt_fence_alloc();
149	if (IS_ERR(pfence))
150		return ERR_CAST(pfence);
151
152	return xe_preempt_fence_arm(pfence, q, context, seqno);
153}
154
155bool xe_fence_is_xe_preempt(const struct dma_fence *fence)
156{
157	return fence->ops == &preempt_fence_ops;
158}
159