1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright © 2020 Intel Corporation
4 */
5
mock_ring(unsigned long sz)6 static struct intel_ring *mock_ring(unsigned long sz)
7 {
8 struct intel_ring *ring;
9
10 ring = kzalloc(sizeof(*ring) + sz, GFP_KERNEL);
11 if (!ring)
12 return NULL;
13
14 kref_init(&ring->ref);
15 ring->size = sz;
16 ring->wrap = BITS_PER_TYPE(ring->size) - ilog2(sz);
17 ring->effective_size = sz;
18 ring->vaddr = (void *)(ring + 1);
19 atomic_set(&ring->pin_count, 1);
20
21 intel_ring_update_space(ring);
22
23 return ring;
24 }
25
mock_ring_free(struct intel_ring * ring)26 static void mock_ring_free(struct intel_ring *ring)
27 {
28 kfree(ring);
29 }
30
check_ring_direction(struct intel_ring * ring,u32 next,u32 prev,int expected)31 static int check_ring_direction(struct intel_ring *ring,
32 u32 next, u32 prev,
33 int expected)
34 {
35 int result;
36
37 result = intel_ring_direction(ring, next, prev);
38 if (result < 0)
39 result = -1;
40 else if (result > 0)
41 result = 1;
42
43 if (result != expected) {
44 pr_err("intel_ring_direction(%u, %u):%d != %d\n",
45 next, prev, result, expected);
46 return -EINVAL;
47 }
48
49 return 0;
50 }
51
check_ring_step(struct intel_ring * ring,u32 x,u32 step)52 static int check_ring_step(struct intel_ring *ring, u32 x, u32 step)
53 {
54 u32 prev = x, next = intel_ring_wrap(ring, x + step);
55 int err = 0;
56
57 err |= check_ring_direction(ring, next, next, 0);
58 err |= check_ring_direction(ring, prev, prev, 0);
59 err |= check_ring_direction(ring, next, prev, 1);
60 err |= check_ring_direction(ring, prev, next, -1);
61
62 return err;
63 }
64
check_ring_offset(struct intel_ring * ring,u32 x,u32 step)65 static int check_ring_offset(struct intel_ring *ring, u32 x, u32 step)
66 {
67 int err = 0;
68
69 err |= check_ring_step(ring, x, step);
70 err |= check_ring_step(ring, intel_ring_wrap(ring, x + 1), step);
71 err |= check_ring_step(ring, intel_ring_wrap(ring, x - 1), step);
72
73 return err;
74 }
75
igt_ring_direction(void * dummy)76 static int igt_ring_direction(void *dummy)
77 {
78 struct intel_ring *ring;
79 unsigned int half = 2048;
80 int step, err = 0;
81
82 ring = mock_ring(2 * half);
83 if (!ring)
84 return -ENOMEM;
85
86 GEM_BUG_ON(ring->size != 2 * half);
87
88 /* Precision of wrap detection is limited to ring->size / 2 */
89 for (step = 1; step < half; step <<= 1) {
90 err |= check_ring_offset(ring, 0, step);
91 err |= check_ring_offset(ring, half, step);
92 }
93 err |= check_ring_step(ring, 0, half - 64);
94
95 /* And check unwrapped handling for good measure */
96 err |= check_ring_offset(ring, 0, 2 * half + 64);
97 err |= check_ring_offset(ring, 3 * half, 1);
98
99 mock_ring_free(ring);
100 return err;
101 }
102
intel_ring_mock_selftests(void)103 int intel_ring_mock_selftests(void)
104 {
105 static const struct i915_subtest tests[] = {
106 SUBTEST(igt_ring_direction),
107 };
108
109 return i915_subtests(tests, NULL);
110 }
111