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path: root/drivers/gpu/drm/i915/gt/selftest_ring.c
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Diffstat (limited to 'drivers/gpu/drm/i915/gt/selftest_ring.c')
-rw-r--r--drivers/gpu/drm/i915/gt/selftest_ring.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gt/selftest_ring.c b/drivers/gpu/drm/i915/gt/selftest_ring.c
new file mode 100644
index 000000000000..2a8c534dc125
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/selftest_ring.c
@@ -0,0 +1,110 @@
+// 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);
+}