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-rw-r--r--drivers/dma-buf/fence-array.c144
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);