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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright © 2020 Intel Corporation
*/
static struct intel_ring *mock_ring(unsigned long sz)
{
struct intel_ring *ring;
ring = kzalloc(sizeof(*ring) + sz, GFP_KERNEL);
if (!ring)
return NULL;
kref_init(&ring->ref);
ring->size = sz;
ring->wrap = BITS_PER_TYPE(ring->size) - ilog2(sz);
ring->effective_size = sz;
ring->vaddr = (void *)(ring + 1);
atomic_set(&ring->pin_count, 1);
intel_ring_update_space(ring);
return ring;
}
static void mock_ring_free(struct intel_ring *ring)
{
kfree(ring);
}
static int check_ring_direction(struct intel_ring *ring,
u32 next, u32 prev,
int expected)
{
int result;
result = intel_ring_direction(ring, next, prev);
if (result < 0)
result = -1;
else if (result > 0)
result = 1;
if (result != expected) {
pr_err("intel_ring_direction(%u, %u):%d != %d\n",
next, prev, result, expected);
return -EINVAL;
}
return 0;
}
static int check_ring_step(struct intel_ring *ring, u32 x, u32 step)
{
u32 prev = x, next = intel_ring_wrap(ring, x + step);
int err = 0;
err |= check_ring_direction(ring, next, next, 0);
err |= check_ring_direction(ring, prev, prev, 0);
err |= check_ring_direction(ring, next, prev, 1);
err |= check_ring_direction(ring, prev, next, -1);
return err;
}
static int check_ring_offset(struct intel_ring *ring, u32 x, u32 step)
{
int err = 0;
err |= check_ring_step(ring, x, step);
err |= check_ring_step(ring, intel_ring_wrap(ring, x + 1), step);
err |= check_ring_step(ring, intel_ring_wrap(ring, x - 1), step);
return err;
}
static int igt_ring_direction(void *dummy)
{
struct intel_ring *ring;
unsigned int half = 2048;
int step, err = 0;
ring = mock_ring(2 * half);
if (!ring)
return -ENOMEM;
GEM_BUG_ON(ring->size != 2 * half);
/* Precision of wrap detection is limited to ring->size / 2 */
for (step = 1; step < half; step <<= 1) {
err |= check_ring_offset(ring, 0, step);
err |= check_ring_offset(ring, half, step);
}
err |= check_ring_step(ring, 0, half - 64);
/* And check unwrapped handling for good measure */
err |= check_ring_offset(ring, 0, 2 * half + 64);
err |= check_ring_offset(ring, 3 * half, 1);
mock_ring_free(ring);
return err;
}
int intel_ring_mock_selftests(void)
{
static const struct i915_subtest tests[] = {
SUBTEST(igt_ring_direction),
};
return i915_subtests(tests, NULL);
}
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