1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/staging/goldfish/goldfish_sync_timeline_fence.c b/drivers/staging/goldfish/goldfish_sync_timeline_fence.c
new file mode 100644
index 000000000000..e671618cf888
--- /dev/null
+++ b/drivers/staging/goldfish/goldfish_sync_timeline_fence.c
@@ -0,0 +1,254 @@
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/syscalls.h>
+#include <linux/sync_file.h>
+#include <linux/fence.h>
+
+#include "goldfish_sync_timeline_fence.h"
+
+/*
+ * Timeline-based sync for Goldfish Sync
+ * Based on "Sync File validation framework"
+ * (drivers/dma-buf/sw_sync.c)
+ *
+ * Copyright (C) 2017 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+/**
+ * struct goldfish_sync_timeline - sync object
+ * @kref:		reference count on fence.
+ * @name:		name of the goldfish_sync_timeline. Useful for debugging
+ * @child_list_head:	list of children sync_pts for this goldfish_sync_timeline
+ * @child_list_lock:	lock protecting @child_list_head and fence.status
+ * @active_list_head:	list of active (unsignaled/errored) sync_pts
+ */
+struct goldfish_sync_timeline {
+	struct kref		kref;
+	char			name[32];
+
+	/* protected by child_list_lock */
+	u64			context;
+	int			value;
+
+	struct list_head	child_list_head;
+	spinlock_t		child_list_lock;
+
+	struct list_head	active_list_head;
+};
+
+static inline struct goldfish_sync_timeline *fence_parent(struct fence *fence)
+{
+	return container_of(fence->lock, struct goldfish_sync_timeline,
+				child_list_lock);
+}
+
+static const struct fence_ops goldfish_sync_timeline_fence_ops;
+
+static inline struct sync_pt *goldfish_sync_fence_to_sync_pt(struct fence *fence)
+{
+	if (fence->ops != &goldfish_sync_timeline_fence_ops)
+		return NULL;
+	return container_of(fence, struct sync_pt, base);
+}
+
+/**
+ * goldfish_sync_timeline_create_internal() - creates a sync object
+ * @name:	sync_timeline name
+ *
+ * Creates a new sync_timeline. Returns the sync_timeline object or NULL in
+ * case of error.
+ */
+struct goldfish_sync_timeline
+*goldfish_sync_timeline_create_internal(const char *name)
+{
+	struct goldfish_sync_timeline *obj;
+
+	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
+	if (!obj)
+		return NULL;
+
+	kref_init(&obj->kref);
+	obj->context = fence_context_alloc(1);
+	strlcpy(obj->name, name, sizeof(obj->name));
+
+	INIT_LIST_HEAD(&obj->child_list_head);
+	INIT_LIST_HEAD(&obj->active_list_head);
+	spin_lock_init(&obj->child_list_lock);
+
+	return obj;
+}
+
+static void goldfish_sync_timeline_free_internal(struct kref *kref)
+{
+	struct goldfish_sync_timeline *obj =
+		container_of(kref, struct goldfish_sync_timeline, kref);
+
+	kfree(obj);
+}
+
+static void goldfish_sync_timeline_get_internal(
+					struct goldfish_sync_timeline *obj)
+{
+	kref_get(&obj->kref);
+}
+
+void goldfish_sync_timeline_put_internal(struct goldfish_sync_timeline *obj)
+{
+	kref_put(&obj->kref, goldfish_sync_timeline_free_internal);
+}
+
+/**
+ * goldfish_sync_timeline_signal() -
+ * signal a status change on a goldfish_sync_timeline
+ * @obj:	sync_timeline to signal
+ * @inc:	num to increment on timeline->value
+ *
+ * A sync implementation should call this any time one of it's fences
+ * has signaled or has an error condition.
+ */
+void goldfish_sync_timeline_signal_internal(struct goldfish_sync_timeline *obj,
+											unsigned int inc)
+{
+	unsigned long flags;
+	struct sync_pt *pt, *next;
+
+	spin_lock_irqsave(&obj->child_list_lock, flags);
+
+	obj->value += inc;
+
+	list_for_each_entry_safe(pt, next, &obj->active_list_head,
+				 active_list) {
+		if (fence_is_signaled_locked(&pt->base))
+			list_del_init(&pt->active_list);
+	}
+
+	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+}
+
+/**
+ * goldfish_sync_pt_create_internal() - creates a sync pt
+ * @parent:	fence's parent sync_timeline
+ * @size:	size to allocate for this pt
+ * @inc:	value of the fence
+ *
+ * Creates a new sync_pt as a child of @parent.  @size bytes will be
+ * allocated allowing for implementation specific data to be kept after
+ * the generic sync_timeline struct. Returns the sync_pt object or
+ * NULL in case of error.
+ */
+struct sync_pt *goldfish_sync_pt_create_internal(
+					struct goldfish_sync_timeline *obj, int size,
+				 	unsigned int value)
+{
+	unsigned long flags;
+	struct sync_pt *pt;
+
+	if (size < sizeof(*pt))
+		return NULL;
+
+	pt = kzalloc(size, GFP_KERNEL);
+	if (!pt)
+		return NULL;
+
+	spin_lock_irqsave(&obj->child_list_lock, flags);
+	goldfish_sync_timeline_get_internal(obj);
+	fence_init(&pt->base, &goldfish_sync_timeline_fence_ops, &obj->child_list_lock,
+		   obj->context, value);
+	list_add_tail(&pt->child_list, &obj->child_list_head);
+	INIT_LIST_HEAD(&pt->active_list);
+	spin_unlock_irqrestore(&obj->child_list_lock, flags);
+	return pt;
+}
+
+static const char *goldfish_sync_timeline_fence_get_driver_name(
+						struct fence *fence)
+{
+	return "sw_sync";
+}
+
+static const char *goldfish_sync_timeline_fence_get_timeline_name(
+						struct fence *fence)
+{
+	struct goldfish_sync_timeline *parent = fence_parent(fence);
+
+	return parent->name;
+}
+
+static void goldfish_sync_timeline_fence_release(struct fence *fence)
+{
+	struct sync_pt *pt = goldfish_sync_fence_to_sync_pt(fence);
+	struct goldfish_sync_timeline *parent = fence_parent(fence);
+	unsigned long flags;
+
+	spin_lock_irqsave(fence->lock, flags);
+	list_del(&pt->child_list);
+	if (!list_empty(&pt->active_list))
+		list_del(&pt->active_list);
+	spin_unlock_irqrestore(fence->lock, flags);
+
+	goldfish_sync_timeline_put_internal(parent);
+	fence_free(fence);
+}
+
+static bool goldfish_sync_timeline_fence_signaled(struct fence *fence)
+{
+	struct goldfish_sync_timeline *parent = fence_parent(fence);
+
+	return (fence->seqno > parent->value) ? false : true;
+}
+
+static bool goldfish_sync_timeline_fence_enable_signaling(struct fence *fence)
+{
+	struct sync_pt *pt = goldfish_sync_fence_to_sync_pt(fence);
+	struct goldfish_sync_timeline *parent = fence_parent(fence);
+
+	if (goldfish_sync_timeline_fence_signaled(fence))
+		return false;
+
+	list_add_tail(&pt->active_list, &parent->active_list_head);
+	return true;
+}
+
+static void goldfish_sync_timeline_fence_disable_signaling(struct fence *fence)
+{
+	struct sync_pt *pt = container_of(fence, struct sync_pt, base);
+
+	list_del_init(&pt->active_list);
+}
+
+static void goldfish_sync_timeline_fence_value_str(struct fence *fence,
+					char *str, int size)
+{
+	snprintf(str, size, "%d", fence->seqno);
+}
+
+static void goldfish_sync_timeline_fence_timeline_value_str(
+				struct fence *fence,
+				char *str, int size)
+{
+	struct goldfish_sync_timeline *parent = fence_parent(fence);
+
+	snprintf(str, size, "%d", parent->value);
+}
+
+static const struct fence_ops goldfish_sync_timeline_fence_ops = {
+	.get_driver_name = goldfish_sync_timeline_fence_get_driver_name,
+	.get_timeline_name = goldfish_sync_timeline_fence_get_timeline_name,
+	.enable_signaling = goldfish_sync_timeline_fence_enable_signaling,
+	.disable_signaling = goldfish_sync_timeline_fence_disable_signaling,
+	.signaled = goldfish_sync_timeline_fence_signaled,
+	.wait = fence_default_wait,
+	.release = goldfish_sync_timeline_fence_release,
+	.fence_value_str = goldfish_sync_timeline_fence_value_str,
+	.timeline_value_str = goldfish_sync_timeline_fence_timeline_value_str,
+};