Merge tag 'drm-misc-next-fixes-2022-04-07' of git://anongit.freedesktop.org/drm/drm-misc into drm-fixes

drm-misc-next-fixes for v5.18-rc2:
- fix warning about fence containers
- fix logic error in new fence merge code
- handle empty dma_fence_arrays gracefully
- Try all possible cases for bridge/panel detection.

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3b8e6439-612e-f640-e380-51e834393e94@linux.intel.com

3 files changed, 116 insertions, 0 deletions

diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h
index fec374f69e1255..ec7f25def39290 100644
--- a/include/linux/dma-fence-array.h
+++ b/include/linux/dma-fence-array.h
@@ -61,6 +61,21 @@ to_dma_fence_array(struct dma_fence *fence)
 	return container_of(fence, struct dma_fence_array, base);
 }
 
+/**
+ * dma_fence_array_for_each - iterate over all fences in array
+ * @fence: current fence
+ * @index: index into the array
+ * @head: potential dma_fence_array object
+ *
+ * Test if @array is a dma_fence_array object and if yes iterate over all fences
+ * in the array. If not just iterate over the fence in @array itself.
+ *
+ * For a deep dive iterator see dma_fence_unwrap_for_each().
+ */
+#define dma_fence_array_for_each(fence, index, head)			\
+	for (index = 0, fence = dma_fence_array_first(head); fence;	\
+	     ++(index), fence = dma_fence_array_next(head, index))
+
 struct dma_fence_array *dma_fence_array_create(int num_fences,
 					       struct dma_fence **fences,
 					       u64 context, unsigned seqno,
@@ -68,4 +83,8 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
 
 bool dma_fence_match_context(struct dma_fence *fence, u64 context);
 
+struct dma_fence *dma_fence_array_first(struct dma_fence *head);
+struct dma_fence *dma_fence_array_next(struct dma_fence *head,
+				       unsigned int index);
+
 #endif /* __LINUX_DMA_FENCE_ARRAY_H */
diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h
index 10d51bcdf7b794..4bdf0b96da2831 100644
--- a/include/linux/dma-fence-chain.h
+++ b/include/linux/dma-fence-chain.h
@@ -112,6 +112,8 @@ static inline void dma_fence_chain_free(struct dma_fence_chain *chain)
  *
  * Iterate over all fences in the chain. We keep a reference to the current
  * fence while inside the loop which must be dropped when breaking out.
+ *
+ * For a deep dive iterator see dma_fence_unwrap_for_each().
  */
 #define dma_fence_chain_for_each(iter, head)	\
 	for (iter = dma_fence_get(head); iter; \
diff --git a/include/linux/dma-fence-unwrap.h b/include/linux/dma-fence-unwrap.h
new file mode 100644
index 00000000000000..77e335a1bcac8c
--- /dev/null
+++ b/include/linux/dma-fence-unwrap.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * fence-chain: chain fences together in a timeline
+ *
+ * Copyright (C) 2022 Advanced Micro Devices, Inc.
+ * Authors:
+ *	Christian König <christian.koenig@amd.com>
+ */
+
+#ifndef __LINUX_DMA_FENCE_UNWRAP_H
+#define __LINUX_DMA_FENCE_UNWRAP_H
+
+#include <linux/dma-fence-chain.h>
+#include <linux/dma-fence-array.h>
+
+/**
+ * struct dma_fence_unwrap - cursor into the container structure
+ *
+ * Should be used with dma_fence_unwrap_for_each() iterator macro.
+ */
+struct dma_fence_unwrap {
+	/**
+	 * @chain: potential dma_fence_chain, but can be other fence as well
+	 */
+	struct dma_fence *chain;
+	/**
+	 * @array: potential dma_fence_array, but can be other fence as well
+	 */
+	struct dma_fence *array;
+	/**
+	 * @index: last returned index if @array is really a dma_fence_array
+	 */
+	unsigned int index;
+};
+
+/* Internal helper to start new array iteration, don't use directly */
+static inline struct dma_fence *
+__dma_fence_unwrap_array(struct dma_fence_unwrap * cursor)
+{
+	cursor->array = dma_fence_chain_contained(cursor->chain);
+	cursor->index = 0;
+	return dma_fence_array_first(cursor->array);
+}
+
+/**
+ * dma_fence_unwrap_first - return the first fence from fence containers
+ * @head: the entrypoint into the containers
+ * @cursor: current position inside the containers
+ *
+ * Unwraps potential dma_fence_chain/dma_fence_array containers and return the
+ * first fence.
+ */
+static inline struct dma_fence *
+dma_fence_unwrap_first(struct dma_fence *head, struct dma_fence_unwrap *cursor)
+{
+	cursor->chain = dma_fence_get(head);
+	return __dma_fence_unwrap_array(cursor);
+}
+
+/**
+ * dma_fence_unwrap_next - return the next fence from a fence containers
+ * @cursor: current position inside the containers
+ *
+ * Continue unwrapping the dma_fence_chain/dma_fence_array containers and return
+ * the next fence from them.
+ */
+static inline struct dma_fence *
+dma_fence_unwrap_next(struct dma_fence_unwrap *cursor)
+{
+	struct dma_fence *tmp;
+
+	++cursor->index;
+	tmp = dma_fence_array_next(cursor->array, cursor->index);
+	if (tmp)
+		return tmp;
+
+	cursor->chain = dma_fence_chain_walk(cursor->chain);
+	return __dma_fence_unwrap_array(cursor);
+}
+
+/**
+ * dma_fence_unwrap_for_each - iterate over all fences in containers
+ * @fence: current fence
+ * @cursor: current position inside the containers
+ * @head: starting point for the iterator
+ *
+ * Unwrap dma_fence_chain and dma_fence_array containers and deep dive into all
+ * potential fences in them. If @head is just a normal fence only that one is
+ * returned.
+ */
+#define dma_fence_unwrap_for_each(fence, cursor, head)			\
+	for (fence = dma_fence_unwrap_first(head, cursor); fence;	\
+	     fence = dma_fence_unwrap_next(cursor))
+
+#endif