Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 485 insertions, 0 deletions

diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
new file mode 100644
index 000000000..0637659a7
--- /dev/null
+++ b/include/linux/dma-resv.h
@@ -0,0 +1,485 @@
+/*
+ * Header file for reservations for dma-buf and ttm
+ *
+ * Copyright(C) 2011 Linaro Limited. All rights reserved.
+ * Copyright (C) 2012-2013 Canonical Ltd
+ * Copyright (C) 2012 Texas Instruments
+ *
+ * Authors:
+ * Rob Clark <robdclark@gmail.com>
+ * Maarten Lankhorst <maarten.lankhorst@canonical.com>
+ * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
+ *
+ * Based on bo.c which bears the following copyright notice,
+ * but is dual licensed:
+ *
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef _LINUX_RESERVATION_H
+#define _LINUX_RESERVATION_H
+
+#include <linux/ww_mutex.h>
+#include <linux/dma-fence.h>
+#include <linux/slab.h>
+#include <linux/seqlock.h>
+#include <linux/rcupdate.h>
+
+extern struct ww_class reservation_ww_class;
+
+struct dma_resv_list;
+
+/**
+ * enum dma_resv_usage - how the fences from a dma_resv obj are used
+ *
+ * This enum describes the different use cases for a dma_resv object and
+ * controls which fences are returned when queried.
+ *
+ * An important fact is that there is the order KERNEL<WRITE<READ<BOOKKEEP and
+ * when the dma_resv object is asked for fences for one use case the fences
+ * for the lower use case are returned as well.
+ *
+ * For example when asking for WRITE fences then the KERNEL fences are returned
+ * as well. Similar when asked for READ fences then both WRITE and KERNEL
+ * fences are returned as well.
+ *
+ * Already used fences can be promoted in the sense that a fence with
+ * DMA_RESV_USAGE_BOOKKEEP could become DMA_RESV_USAGE_READ by adding it again
+ * with this usage. But fences can never be degraded in the sense that a fence
+ * with DMA_RESV_USAGE_WRITE could become DMA_RESV_USAGE_READ.
+ */
+enum dma_resv_usage {
+	/**
+	 * @DMA_RESV_USAGE_KERNEL: For in kernel memory management only.
+	 *
+	 * This should only be used for things like copying or clearing memory
+	 * with a DMA hardware engine for the purpose of kernel memory
+	 * management.
+	 *
+	 * Drivers *always* must wait for those fences before accessing the
+	 * resource protected by the dma_resv object. The only exception for
+	 * that is when the resource is known to be locked down in place by
+	 * pinning it previously.
+	 */
+	DMA_RESV_USAGE_KERNEL,
+
+	/**
+	 * @DMA_RESV_USAGE_WRITE: Implicit write synchronization.
+	 *
+	 * This should only be used for userspace command submissions which add
+	 * an implicit write dependency.
+	 */
+	DMA_RESV_USAGE_WRITE,
+
+	/**
+	 * @DMA_RESV_USAGE_READ: Implicit read synchronization.
+	 *
+	 * This should only be used for userspace command submissions which add
+	 * an implicit read dependency.
+	 */
+	DMA_RESV_USAGE_READ,
+
+	/**
+	 * @DMA_RESV_USAGE_BOOKKEEP: No implicit sync.
+	 *
+	 * This should be used by submissions which don't want to participate in
+	 * any implicit synchronization.
+	 *
+	 * The most common case are preemption fences, page table updates, TLB
+	 * flushes as well as explicit synced user submissions.
+	 *
+	 * Explicit synced user user submissions can be promoted to
+	 * DMA_RESV_USAGE_READ or DMA_RESV_USAGE_WRITE as needed using
+	 * dma_buf_import_sync_file() when implicit synchronization should
+	 * become necessary after initial adding of the fence.
+	 */
+	DMA_RESV_USAGE_BOOKKEEP
+};
+
+/**
+ * dma_resv_usage_rw - helper for implicit sync
+ * @write: true if we create a new implicit sync write
+ *
+ * This returns the implicit synchronization usage for write or read accesses,
+ * see enum dma_resv_usage and &dma_buf.resv.
+ */
+static inline enum dma_resv_usage dma_resv_usage_rw(bool write)
+{
+	/* This looks confusing at first sight, but is indeed correct.
+	 *
+	 * The rational is that new write operations needs to wait for the
+	 * existing read and write operations to finish.
+	 * But a new read operation only needs to wait for the existing write
+	 * operations to finish.
+	 */
+	return write ? DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE;
+}
+
+/**
+ * struct dma_resv - a reservation object manages fences for a buffer
+ *
+ * This is a container for dma_fence objects which needs to handle multiple use
+ * cases.
+ *
+ * One use is to synchronize cross-driver access to a struct dma_buf, either for
+ * dynamic buffer management or just to handle implicit synchronization between
+ * different users of the buffer in userspace. See &dma_buf.resv for a more
+ * in-depth discussion.
+ *
+ * The other major use is to manage access and locking within a driver in a
+ * buffer based memory manager. struct ttm_buffer_object is the canonical
+ * example here, since this is where reservation objects originated from. But
+ * use in drivers is spreading and some drivers also manage struct
+ * drm_gem_object with the same scheme.
+ */
+struct dma_resv {
+	/**
+	 * @lock:
+	 *
+	 * Update side lock. Don't use directly, instead use the wrapper
+	 * functions like dma_resv_lock() and dma_resv_unlock().
+	 *
+	 * Drivers which use the reservation object to manage memory dynamically
+	 * also use this lock to protect buffer object state like placement,
+	 * allocation policies or throughout command submission.
+	 */
+	struct ww_mutex lock;
+
+	/**
+	 * @fences:
+	 *
+	 * Array of fences which where added to the dma_resv object
+	 *
+	 * A new fence is added by calling dma_resv_add_fence(). Since this
+	 * often needs to be done past the point of no return in command
+	 * submission it cannot fail, and therefore sufficient slots need to be
+	 * reserved by calling dma_resv_reserve_fences().
+	 */
+	struct dma_resv_list __rcu *fences;
+};
+
+/**
+ * struct dma_resv_iter - current position into the dma_resv fences
+ *
+ * Don't touch this directly in the driver, use the accessor function instead.
+ *
+ * IMPORTANT
+ *
+ * When using the lockless iterators like dma_resv_iter_next_unlocked() or
+ * dma_resv_for_each_fence_unlocked() beware that the iterator can be restarted.
+ * Code which accumulates statistics or similar needs to check for this with
+ * dma_resv_iter_is_restarted().
+ */
+struct dma_resv_iter {
+	/** @obj: The dma_resv object we iterate over */
+	struct dma_resv *obj;
+
+	/** @usage: Return fences with this usage or lower. */
+	enum dma_resv_usage usage;
+
+	/** @fence: the currently handled fence */
+	struct dma_fence *fence;
+
+	/** @fence_usage: the usage of the current fence */
+	enum dma_resv_usage fence_usage;
+
+	/** @index: index into the shared fences */
+	unsigned int index;
+
+	/** @fences: the shared fences; private, *MUST* not dereference  */
+	struct dma_resv_list *fences;
+
+	/** @num_fences: number of fences */
+	unsigned int num_fences;
+
+	/** @is_restarted: true if this is the first returned fence */
+	bool is_restarted;
+};
+
+struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor);
+struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor);
+struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor);
+struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor);
+
+/**
+ * dma_resv_iter_begin - initialize a dma_resv_iter object
+ * @cursor: The dma_resv_iter object to initialize
+ * @obj: The dma_resv object which we want to iterate over
+ * @usage: controls which fences to include, see enum dma_resv_usage.
+ */
+static inline void dma_resv_iter_begin(struct dma_resv_iter *cursor,
+				       struct dma_resv *obj,
+				       enum dma_resv_usage usage)
+{
+	cursor->obj = obj;
+	cursor->usage = usage;
+	cursor->fence = NULL;
+}
+
+/**
+ * dma_resv_iter_end - cleanup a dma_resv_iter object
+ * @cursor: the dma_resv_iter object which should be cleaned up
+ *
+ * Make sure that the reference to the fence in the cursor is properly
+ * dropped.
+ */
+static inline void dma_resv_iter_end(struct dma_resv_iter *cursor)
+{
+	dma_fence_put(cursor->fence);
+}
+
+/**
+ * dma_resv_iter_usage - Return the usage of the current fence
+ * @cursor: the cursor of the current position
+ *
+ * Returns the usage of the currently processed fence.
+ */
+static inline enum dma_resv_usage
+dma_resv_iter_usage(struct dma_resv_iter *cursor)
+{
+	return cursor->fence_usage;
+}
+
+/**
+ * dma_resv_iter_is_restarted - test if this is the first fence after a restart
+ * @cursor: the cursor with the current position
+ *
+ * Return true if this is the first fence in an iteration after a restart.
+ */
+static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor)
+{
+	return cursor->is_restarted;
+}
+
+/**
+ * dma_resv_for_each_fence_unlocked - unlocked fence iterator
+ * @cursor: a struct dma_resv_iter pointer
+ * @fence: the current fence
+ *
+ * Iterate over the fences in a struct dma_resv object without holding the
+ * &dma_resv.lock and using RCU instead. The cursor needs to be initialized
+ * with dma_resv_iter_begin() and cleaned up with dma_resv_iter_end(). Inside
+ * the iterator a reference to the dma_fence is held and the RCU lock dropped.
+ *
+ * Beware that the iterator can be restarted when the struct dma_resv for
+ * @cursor is modified. Code which accumulates statistics or similar needs to
+ * check for this with dma_resv_iter_is_restarted(). For this reason prefer the
+ * lock iterator dma_resv_for_each_fence() whenever possible.
+ */
+#define dma_resv_for_each_fence_unlocked(cursor, fence)			\
+	for (fence = dma_resv_iter_first_unlocked(cursor);		\
+	     fence; fence = dma_resv_iter_next_unlocked(cursor))
+
+/**
+ * dma_resv_for_each_fence - fence iterator
+ * @cursor: a struct dma_resv_iter pointer
+ * @obj: a dma_resv object pointer
+ * @usage: controls which fences to return
+ * @fence: the current fence
+ *
+ * Iterate over the fences in a struct dma_resv object while holding the
+ * &dma_resv.lock. @all_fences controls if the shared fences are returned as
+ * well. The cursor initialisation is part of the iterator and the fence stays
+ * valid as long as the lock is held and so no extra reference to the fence is
+ * taken.
+ */
+#define dma_resv_for_each_fence(cursor, obj, usage, fence)	\
+	for (dma_resv_iter_begin(cursor, obj, usage),	\
+	     fence = dma_resv_iter_first(cursor); fence;	\
+	     fence = dma_resv_iter_next(cursor))
+
+#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
+#define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
+
+#ifdef CONFIG_DEBUG_MUTEXES
+void dma_resv_reset_max_fences(struct dma_resv *obj);
+#else
+static inline void dma_resv_reset_max_fences(struct dma_resv *obj) {}
+#endif
+
+/**
+ * dma_resv_lock - lock the reservation object
+ * @obj: the reservation object
+ * @ctx: the locking context
+ *
+ * Locks the reservation object for exclusive access and modification. Note,
+ * that the lock is only against other writers, readers will run concurrently
+ * with a writer under RCU. The seqlock is used to notify readers if they
+ * overlap with a writer.
+ *
+ * As the reservation object may be locked by multiple parties in an
+ * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
+ * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
+ * object may be locked by itself by passing NULL as @ctx.
+ *
+ * When a die situation is indicated by returning -EDEADLK all locks held by
+ * @ctx must be unlocked and then dma_resv_lock_slow() called on @obj.
+ *
+ * Unlocked by calling dma_resv_unlock().
+ *
+ * See also dma_resv_lock_interruptible() for the interruptible variant.
+ */
+static inline int dma_resv_lock(struct dma_resv *obj,
+				struct ww_acquire_ctx *ctx)
+{
+	return ww_mutex_lock(&obj->lock, ctx);
+}
+
+/**
+ * dma_resv_lock_interruptible - lock the reservation object
+ * @obj: the reservation object
+ * @ctx: the locking context
+ *
+ * Locks the reservation object interruptible for exclusive access and
+ * modification. Note, that the lock is only against other writers, readers
+ * will run concurrently with a writer under RCU. The seqlock is used to
+ * notify readers if they overlap with a writer.
+ *
+ * As the reservation object may be locked by multiple parties in an
+ * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
+ * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
+ * object may be locked by itself by passing NULL as @ctx.
+ *
+ * When a die situation is indicated by returning -EDEADLK all locks held by
+ * @ctx must be unlocked and then dma_resv_lock_slow_interruptible() called on
+ * @obj.
+ *
+ * Unlocked by calling dma_resv_unlock().
+ */
+static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
+					      struct ww_acquire_ctx *ctx)
+{
+	return ww_mutex_lock_interruptible(&obj->lock, ctx);
+}
+
+/**
+ * dma_resv_lock_slow - slowpath lock the reservation object
+ * @obj: the reservation object
+ * @ctx: the locking context
+ *
+ * Acquires the reservation object after a die case. This function
+ * will sleep until the lock becomes available. See dma_resv_lock() as
+ * well.
+ *
+ * See also dma_resv_lock_slow_interruptible() for the interruptible variant.
+ */
+static inline void dma_resv_lock_slow(struct dma_resv *obj,
+				      struct ww_acquire_ctx *ctx)
+{
+	ww_mutex_lock_slow(&obj->lock, ctx);
+}
+
+/**
+ * dma_resv_lock_slow_interruptible - slowpath lock the reservation
+ * object, interruptible
+ * @obj: the reservation object
+ * @ctx: the locking context
+ *
+ * Acquires the reservation object interruptible after a die case. This function
+ * will sleep until the lock becomes available. See
+ * dma_resv_lock_interruptible() as well.
+ */
+static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
+						   struct ww_acquire_ctx *ctx)
+{
+	return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
+}
+
+/**
+ * dma_resv_trylock - trylock the reservation object
+ * @obj: the reservation object
+ *
+ * Tries to lock the reservation object for exclusive access and modification.
+ * Note, that the lock is only against other writers, readers will run
+ * concurrently with a writer under RCU. The seqlock is used to notify readers
+ * if they overlap with a writer.
+ *
+ * Also note that since no context is provided, no deadlock protection is
+ * possible, which is also not needed for a trylock.
+ *
+ * Returns true if the lock was acquired, false otherwise.
+ */
+static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
+{
+	return ww_mutex_trylock(&obj->lock, NULL);
+}
+
+/**
+ * dma_resv_is_locked - is the reservation object locked
+ * @obj: the reservation object
+ *
+ * Returns true if the mutex is locked, false if unlocked.
+ */
+static inline bool dma_resv_is_locked(struct dma_resv *obj)
+{
+	return ww_mutex_is_locked(&obj->lock);
+}
+
+/**
+ * dma_resv_locking_ctx - returns the context used to lock the object
+ * @obj: the reservation object
+ *
+ * Returns the context used to lock a reservation object or NULL if no context
+ * was used or the object is not locked at all.
+ *
+ * WARNING: This interface is pretty horrible, but TTM needs it because it
+ * doesn't pass the struct ww_acquire_ctx around in some very long callchains.
+ * Everyone else just uses it to check whether they're holding a reservation or
+ * not.
+ */
+static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
+{
+	return READ_ONCE(obj->lock.ctx);
+}
+
+/**
+ * dma_resv_unlock - unlock the reservation object
+ * @obj: the reservation object
+ *
+ * Unlocks the reservation object following exclusive access.
+ */
+static inline void dma_resv_unlock(struct dma_resv *obj)
+{
+	dma_resv_reset_max_fences(obj);
+	ww_mutex_unlock(&obj->lock);
+}
+
+void dma_resv_init(struct dma_resv *obj);
+void dma_resv_fini(struct dma_resv *obj);
+int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences);
+void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
+			enum dma_resv_usage usage);
+void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
+			     struct dma_fence *fence,
+			     enum dma_resv_usage usage);
+int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,
+			unsigned int *num_fences, struct dma_fence ***fences);
+int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,
+			   struct dma_fence **fence);
+int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
+long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
+			   bool intr, unsigned long timeout);
+bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage);
+void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq);
+
+#endif /* _LINUX_RESERVATION_H */