1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
new file mode 100644
index 000000000000..1e5cbc585ca2
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -0,0 +1,362 @@
+/*
+ * (C) Copyright 2016 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#include <linux/slab.h>
+#include <linux/fence.h>
+#include <linux/reservation.h>
+
+#include "i915_sw_fence.h"
+
+static DEFINE_SPINLOCK(i915_sw_fence_lock);
+
+static int __i915_sw_fence_notify(struct i915_sw_fence *fence,
+				  enum i915_sw_fence_notify state)
+{
+	i915_sw_fence_notify_t fn;
+
+	fn = (i915_sw_fence_notify_t)(fence->flags & I915_SW_FENCE_MASK);
+	return fn(fence, state);
+}
+
+static void i915_sw_fence_free(struct kref *kref)
+{
+	struct i915_sw_fence *fence = container_of(kref, typeof(*fence), kref);
+
+	WARN_ON(atomic_read(&fence->pending) > 0);
+
+	if (fence->flags & I915_SW_FENCE_MASK)
+		__i915_sw_fence_notify(fence, FENCE_FREE);
+	else
+		kfree(fence);
+}
+
+static void i915_sw_fence_put(struct i915_sw_fence *fence)
+{
+	kref_put(&fence->kref, i915_sw_fence_free);
+}
+
+static struct i915_sw_fence *i915_sw_fence_get(struct i915_sw_fence *fence)
+{
+	kref_get(&fence->kref);
+	return fence;
+}
+
+static void __i915_sw_fence_wake_up_all(struct i915_sw_fence *fence,
+					struct list_head *continuation)
+{
+	wait_queue_head_t *x = &fence->wait;
+	wait_queue_t *pos, *next;
+	unsigned long flags;
+
+	atomic_set_release(&fence->pending, -1); /* 0 -> -1 [done] */
+
+	/*
+	 * To prevent unbounded recursion as we traverse the graph of
+	 * i915_sw_fences, we move the task_list from this, the next ready
+	 * fence, to the tail of the original fence's task_list
+	 * (and so added to the list to be woken).
+	 */
+
+	spin_lock_irqsave_nested(&x->lock, flags, 1 + !!continuation);
+	if (continuation) {
+		list_for_each_entry_safe(pos, next, &x->task_list, task_list) {
+			if (pos->func == autoremove_wake_function)
+				pos->func(pos, TASK_NORMAL, 0, continuation);
+			else
+				list_move_tail(&pos->task_list, continuation);
+		}
+	} else {
+		LIST_HEAD(extra);
+
+		do {
+			list_for_each_entry_safe(pos, next,
+						 &x->task_list, task_list)
+				pos->func(pos, TASK_NORMAL, 0, &extra);
+
+			if (list_empty(&extra))
+				break;
+
+			list_splice_tail_init(&extra, &x->task_list);
+		} while (1);
+	}
+	spin_unlock_irqrestore(&x->lock, flags);
+}
+
+static void __i915_sw_fence_complete(struct i915_sw_fence *fence,
+				     struct list_head *continuation)
+{
+	if (!atomic_dec_and_test(&fence->pending))
+		return;
+
+	if (fence->flags & I915_SW_FENCE_MASK &&
+	    __i915_sw_fence_notify(fence, FENCE_COMPLETE) != NOTIFY_DONE)
+		return;
+
+	__i915_sw_fence_wake_up_all(fence, continuation);
+}
+
+static void i915_sw_fence_complete(struct i915_sw_fence *fence)
+{
+	if (WARN_ON(i915_sw_fence_done(fence)))
+		return;
+
+	__i915_sw_fence_complete(fence, NULL);
+}
+
+static void i915_sw_fence_await(struct i915_sw_fence *fence)
+{
+	WARN_ON(atomic_inc_return(&fence->pending) <= 1);
+}
+
+void i915_sw_fence_init(struct i915_sw_fence *fence, i915_sw_fence_notify_t fn)
+{
+	BUG_ON((unsigned long)fn & ~I915_SW_FENCE_MASK);
+
+	init_waitqueue_head(&fence->wait);
+	kref_init(&fence->kref);
+	atomic_set(&fence->pending, 1);
+	fence->flags = (unsigned long)fn;
+}
+
+void i915_sw_fence_commit(struct i915_sw_fence *fence)
+{
+	i915_sw_fence_complete(fence);
+	i915_sw_fence_put(fence);
+}
+
+static int i915_sw_fence_wake(wait_queue_t *wq, unsigned mode, int flags, void *key)
+{
+	list_del(&wq->task_list);
+	__i915_sw_fence_complete(wq->private, key);
+	i915_sw_fence_put(wq->private);
+	return 0;
+}
+
+static bool __i915_sw_fence_check_if_after(struct i915_sw_fence *fence,
+				    const struct i915_sw_fence * const signaler)
+{
+	wait_queue_t *wq;
+
+	if (__test_and_set_bit(I915_SW_FENCE_CHECKED_BIT, &fence->flags))
+		return false;
+
+	if (fence == signaler)
+		return true;
+
+	list_for_each_entry(wq, &fence->wait.task_list, task_list) {
+		if (wq->func != i915_sw_fence_wake)
+			continue;
+
+		if (__i915_sw_fence_check_if_after(wq->private, signaler))
+			return true;
+	}
+
+	return false;
+}
+
+static void __i915_sw_fence_clear_checked_bit(struct i915_sw_fence *fence)
+{
+	wait_queue_t *wq;
+
+	if (!__test_and_clear_bit(I915_SW_FENCE_CHECKED_BIT, &fence->flags))
+		return;
+
+	list_for_each_entry(wq, &fence->wait.task_list, task_list) {
+		if (wq->func != i915_sw_fence_wake)
+			continue;
+
+		__i915_sw_fence_clear_checked_bit(wq->private);
+	}
+}
+
+static bool i915_sw_fence_check_if_after(struct i915_sw_fence *fence,
+				  const struct i915_sw_fence * const signaler)
+{
+	unsigned long flags;
+	bool err;
+
+	if (!IS_ENABLED(CONFIG_I915_SW_FENCE_CHECK_DAG))
+		return false;
+
+	spin_lock_irqsave(&i915_sw_fence_lock, flags);
+	err = __i915_sw_fence_check_if_after(fence, signaler);
+	__i915_sw_fence_clear_checked_bit(fence);
+	spin_unlock_irqrestore(&i915_sw_fence_lock, flags);
+
+	return err;
+}
+
+int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
+				 struct i915_sw_fence *signaler,
+				 wait_queue_t *wq)
+{
+	unsigned long flags;
+	int pending;
+
+	if (i915_sw_fence_done(signaler))
+		return 0;
+
+	/* The dependency graph must be acyclic. */
+	if (unlikely(i915_sw_fence_check_if_after(fence, signaler)))
+		return -EINVAL;
+
+	INIT_LIST_HEAD(&wq->task_list);
+	wq->flags = 0;
+	wq->func = i915_sw_fence_wake;
+	wq->private = i915_sw_fence_get(fence);
+
+	i915_sw_fence_await(fence);
+
+	spin_lock_irqsave(&signaler->wait.lock, flags);
+	if (likely(!i915_sw_fence_done(signaler))) {
+		__add_wait_queue_tail(&signaler->wait, wq);
+		pending = 1;
+	} else {
+		i915_sw_fence_wake(wq, 0, 0, NULL);
+		pending = 0;
+	}
+	spin_unlock_irqrestore(&signaler->wait.lock, flags);
+
+	return pending;
+}
+
+struct dma_fence_cb {
+	struct fence_cb base;
+	struct i915_sw_fence *fence;
+	struct fence *dma;
+	struct timer_list timer;
+};
+
+static void timer_i915_sw_fence_wake(unsigned long data)
+{
+	struct dma_fence_cb *cb = (struct dma_fence_cb *)data;
+
+	printk(KERN_WARNING "asynchronous wait on fence %s:%s:%x timed out\n",
+	       cb->dma->ops->get_driver_name(cb->dma),
+	       cb->dma->ops->get_timeline_name(cb->dma),
+	       cb->dma->seqno);
+	fence_put(cb->dma);
+	cb->dma = NULL;
+
+	i915_sw_fence_commit(cb->fence);
+	cb->timer.function = NULL;
+}
+
+static void dma_i915_sw_fence_wake(struct fence *dma, struct fence_cb *data)
+{
+	struct dma_fence_cb *cb = container_of(data, typeof(*cb), base);
+
+	del_timer_sync(&cb->timer);
+	if (cb->timer.function)
+		i915_sw_fence_commit(cb->fence);
+	fence_put(cb->dma);
+
+	kfree(cb);
+}
+
+int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
+				  struct fence *dma,
+				  unsigned long timeout,
+				  gfp_t gfp)
+{
+	struct dma_fence_cb *cb;
+	int ret;
+
+	if (fence_is_signaled(dma))
+		return 0;
+
+	cb = kmalloc(sizeof(*cb), gfp);
+	if (!cb) {
+		if (!gfpflags_allow_blocking(gfp))
+			return -ENOMEM;
+
+		return fence_wait(dma, false);
+	}
+
+	cb->fence = i915_sw_fence_get(fence);
+	i915_sw_fence_await(fence);
+
+	cb->dma = NULL;
+	__setup_timer(&cb->timer,
+		      timer_i915_sw_fence_wake, (unsigned long)cb,
+		      TIMER_IRQSAFE);
+	if (timeout) {
+		cb->dma = fence_get(dma);
+		mod_timer(&cb->timer, round_jiffies_up(jiffies + timeout));
+	}
+
+	ret = fence_add_callback(dma, &cb->base, dma_i915_sw_fence_wake);
+	if (ret == 0) {
+		ret = 1;
+	} else {
+		dma_i915_sw_fence_wake(dma, &cb->base);
+		if (ret == -ENOENT) /* fence already signaled */
+			ret = 0;
+	}
+
+	return ret;
+}
+
+int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
+				    struct reservation_object *resv,
+				    const struct fence_ops *exclude,
+				    bool write,
+				    unsigned long timeout,
+				    gfp_t gfp)
+{
+	struct fence *excl;
+	int ret = 0, pending;
+
+	if (write) {
+		struct fence **shared;
+		unsigned int count, i;
+
+		ret = reservation_object_get_fences_rcu(resv,
+							&excl, &count, &shared);
+		if (ret)
+			return ret;
+
+		for (i = 0; i < count; i++) {
+			if (shared[i]->ops == exclude)
+				continue;
+
+			pending = i915_sw_fence_await_dma_fence(fence,
+								shared[i],
+								timeout,
+								gfp);
+			if (pending < 0) {
+				ret = pending;
+				break;
+			}
+
+			ret |= pending;
+		}
+
+		for (i = 0; i < count; i++)
+			fence_put(shared[i]);
+		kfree(shared);
+	} else {
+		excl = reservation_object_get_excl_rcu(resv);
+	}
+
+	if (ret >= 0 && excl && excl->ops != exclude) {
+		pending = i915_sw_fence_await_dma_fence(fence,
+							excl,
+							timeout,
+							gfp);
+		if (pending < 0)
+			ret = pending;
+		else
+			ret |= pending;
+	}
+
+	fence_put(excl);
+
+	return ret;
+}