[PATCH] drm/i915/selftests: Test i915_sw_fence/dma_fence interop

[Chris Wilson]

Check that we can successfully wait upon a dma_fence using the
i915_sw_fence, including the optional timeout mechanism.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/selftests/i915_sw_fence.c | 139 +++++++++++++++++++++++++
 1 file changed, 139 insertions(+)

diff --git a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
index ea01d0fe3ace..599063fc3b37 100644
--- a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
@@ -27,6 +27,7 @@
 #include <linux/prime_numbers.h>
 
 #include "../i915_selftest.h"
+#include "../i915_utils.h"
 
 static int __i915_sw_fence_call
 fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
@@ -606,6 +607,143 @@ static int test_timer(void *arg)
 	return -EINVAL;
 }
 
+static const char *mock_name(struct dma_fence *fence)
+{
+	return "mock";
+}
+
+static bool mock_enable_signaling(struct dma_fence *fence)
+{
+	return true;
+}
+
+static const struct dma_fence_ops mock_fence_ops = {
+	.get_driver_name = mock_name,
+	.get_timeline_name = mock_name,
+	.enable_signaling = mock_enable_signaling,
+	.wait = dma_fence_default_wait,
+	.release = dma_fence_free,
+};
+
+static DEFINE_SPINLOCK(mock_fence_lock);
+
+static struct dma_fence *alloc_dma_fence(void)
+{
+	struct dma_fence *dma;
+
+	dma = kmalloc(sizeof(*dma), GFP_KERNEL);
+	if (dma)
+		dma_fence_init(dma, &mock_fence_ops, &mock_fence_lock, 0, 0);
+
+	return dma;
+}
+
+static struct i915_sw_fence *
+wrap_dma_fence(struct dma_fence *dma, unsigned long delay)
+{
+	struct i915_sw_fence *fence;
+	int err;
+
+	fence = alloc_fence();
+	if (!fence)
+		return ERR_PTR(-ENOMEM);
+
+	err = i915_sw_fence_await_dma_fence(fence, dma, delay, GFP_NOWAIT);
+	i915_sw_fence_commit(fence);
+	if (err) {
+		free_fence(fence);
+		return ERR_PTR(err);
+	}
+
+	return fence;
+}
+
+static int test_dma_fence(void *arg)
+{
+	struct i915_sw_fence *timeout = NULL, *not = NULL;
+	struct dma_fence *dma;
+	unsigned long delay;
+	int err;
+
+	for_each_prime_number(delay, i915_selftest.timeout_jiffies/2) {
+		unsigned long end = jiffies + delay;
+		unsigned long sleep;
+
+		dma = alloc_dma_fence();
+		if (!dma)
+			return -ENOMEM;
+
+		timeout = wrap_dma_fence(dma, delay);
+		if (IS_ERR(timeout)) {
+			err = PTR_ERR(timeout);
+			goto err;
+		}
+
+		not = wrap_dma_fence(dma, 0);
+		if (IS_ERR(not)) {
+			err = PTR_ERR(not);
+			goto err;
+		}
+
+		err = -EINVAL;
+		if (i915_sw_fence_done(timeout) || i915_sw_fence_done(not)) {
+			pr_err("Fences immediately signaled\n");
+			goto err;
+		}
+
+		sleep = jiffies_to_usecs(delay) / 2;
+		usleep_range(sleep, sleep);
+		if (time_after(jiffies, end)) {
+			pr_debug("Slept too long skipping pass, delay=%lu\n",
+				 delay);
+			goto skip;
+		}
+
+		if (i915_sw_fence_done(timeout) || i915_sw_fence_done(not)) {
+			pr_err("Fences signaled too early\n");
+			goto err;
+		}
+
+		do {
+			sleep = jiffies_to_usecs(end - jiffies + 1);
+			usleep_range(sleep, 2 * sleep);
+		} while (time_before(jiffies, end));
+
+		if (i915_sw_fence_done(not)) {
+			pr_err("No tiemout fence signaled!\n");
+			goto err;
+		}
+
+		if (!i915_sw_fence_done(timeout)) {
+			pr_err("Tiemout fence unsignaled!\n");
+			goto err;
+		}
+
+skip:
+		dma_fence_signal(dma);
+
+		if (!i915_sw_fence_done(timeout) || !i915_sw_fence_done(not)) {
+			pr_err("Fences unsignaled\n");
+			goto err;
+		}
+
+		free_fence(fetch_and_zero(&not));
+		free_fence(fetch_and_zero(&timeout));
+		dma_fence_put(dma);
+	}
+
+	return 0;
+
+err:
+	dma_fence_signal(dma);
+	if (!IS_ERR_OR_NULL(timeout))
+		free_fence(timeout);
+	if (!IS_ERR_OR_NULL(not))
+		free_fence(not);
+	dma_fence_put(dma);
+	return err;
+}
+
 int i915_sw_fence_mock_selftests(void)
 {
 	static const struct i915_subtest tests[] = {
@@ -618,6 +756,7 @@ int i915_sw_fence_mock_selftests(void)
 		SUBTEST(test_chain),
 		SUBTEST(test_ipc),
 		SUBTEST(test_timer),
+		SUBTEST(test_dma_fence),
 	};
 
 	return i915_subtests(tests, NULL);
-- 
2.15.1