1 files changed, 144 insertions, 0 deletions
diff --git a/drivers/dma-buf/fence-array.c b/drivers/dma-buf/fence-array.c
new file mode 100644
index 000000000000..a8731c853da6
--- /dev/null
+++ b/drivers/dma-buf/fence-array.c
@@ -0,0 +1,144 @@
+/*
+ * fence-array: aggregate fences to be waited together
+ *
+ * Copyright (C) 2016 Collabora Ltd
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ * Authors:
+ *	Gustavo Padovan <gustavo@padovan.org>
+ *	Christian König <christian.koenig@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/fence-array.h>
+
+static void fence_array_cb_func(struct fence *f, struct fence_cb *cb);
+
+static const char *fence_array_get_driver_name(struct fence *fence)
+{
+	return "fence_array";
+}
+
+static const char *fence_array_get_timeline_name(struct fence *fence)
+{
+	return "unbound";
+}
+
+static void fence_array_cb_func(struct fence *f, struct fence_cb *cb)
+{
+	struct fence_array_cb *array_cb =
+		container_of(cb, struct fence_array_cb, cb);
+	struct fence_array *array = array_cb->array;
+
+	if (atomic_dec_and_test(&array->num_pending))
+		fence_signal(&array->base);
+	fence_put(&array->base);
+}
+
+static bool fence_array_enable_signaling(struct fence *fence)
+{
+	struct fence_array *array = to_fence_array(fence);
+	struct fence_array_cb *cb = (void *)(&array[1]);
+	unsigned i;
+
+	for (i = 0; i < array->num_fences; ++i) {
+		cb[i].array = array;
+		/*
+		 * As we may report that the fence is signaled before all
+		 * callbacks are complete, we need to take an additional
+		 * reference count on the array so that we do not free it too
+		 * early. The core fence handling will only hold the reference
+		 * until we signal the array as complete (but that is now
+		 * insufficient).
+		 */
+		fence_get(&array->base);
+		if (fence_add_callback(array->fences[i], &cb[i].cb,
+				       fence_array_cb_func)) {
+			fence_put(&array->base);
+			if (atomic_dec_and_test(&array->num_pending))
+				return false;
+		}
+	}
+
+	return true;
+}
+
+static bool fence_array_signaled(struct fence *fence)
+{
+	struct fence_array *array = to_fence_array(fence);
+
+	return atomic_read(&array->num_pending) <= 0;
+}
+
+static void fence_array_release(struct fence *fence)
+{
+	struct fence_array *array = to_fence_array(fence);
+	unsigned i;
+
+	for (i = 0; i < array->num_fences; ++i)
+		fence_put(array->fences[i]);
+
+	kfree(array->fences);
+	fence_free(fence);
+}
+
+const struct fence_ops fence_array_ops = {
+	.get_driver_name = fence_array_get_driver_name,
+	.get_timeline_name = fence_array_get_timeline_name,
+	.enable_signaling = fence_array_enable_signaling,
+	.signaled = fence_array_signaled,
+	.wait = fence_default_wait,
+	.release = fence_array_release,
+};
+
+/**
+ * fence_array_create - Create a custom fence array
+ * @num_fences:		[in]	number of fences to add in the array
+ * @fences:		[in]	array containing the fences
+ * @context:		[in]	fence context to use
+ * @seqno:		[in]	sequence number to use
+ * @signal_on_any	[in]	signal on any fence in the array
+ *
+ * Allocate a fence_array object and initialize the base fence with fence_init().
+ * In case of error it returns NULL.
+ *
+ * The caller should allocte the fences array with num_fences size
+ * and fill it with the fences it wants to add to the object. Ownership of this
+ * array is take and fence_put() is used on each fence on release.
+ *
+ * If @signal_on_any is true the fence array signals if any fence in the array
+ * signals, otherwise it signals when all fences in the array signal.
+ */
+struct fence_array *fence_array_create(int num_fences, struct fence **fences,
+				       u64 context, unsigned seqno,
+				       bool signal_on_any)
+{
+	struct fence_array *array;
+	size_t size = sizeof(*array);
+
+	/* Allocate the callback structures behind the array. */
+	size += num_fences * sizeof(struct fence_array_cb);
+	array = kzalloc(size, GFP_KERNEL);
+	if (!array)
+		return NULL;
+
+	spin_lock_init(&array->lock);
+	fence_init(&array->base, &fence_array_ops, &array->lock,
+		   context, seqno);
+
+	array->num_fences = num_fences;
+	atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
+	array->fences = fences;
+
+	return array;
+}
+EXPORT_SYMBOL(fence_array_create);