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      1 /*	$NetBSD: intel_timeline_types.h,v 1.2 2021/12/18 23:45:30 riastradh Exp $	*/
      2 
      3 /*
      4  * SPDX-License-Identifier: MIT
      5  *
      6  * Copyright  2016 Intel Corporation
      7  */
      8 
      9 #ifndef __I915_TIMELINE_TYPES_H__
     10 #define __I915_TIMELINE_TYPES_H__
     11 
     12 #include <linux/list.h>
     13 #include <linux/kref.h>
     14 #include <linux/mutex.h>
     15 #include <linux/rcupdate.h>
     16 #include <linux/types.h>
     17 
     18 #include "i915_active_types.h"
     19 
     20 struct i915_vma;
     21 struct i915_syncmap;
     22 struct intel_gt;
     23 struct intel_timeline_hwsp;
     24 
     25 struct intel_timeline {
     26 	u64 fence_context;
     27 	u32 seqno;
     28 
     29 	struct mutex mutex; /* protects the flow of requests */
     30 
     31 	/*
     32 	 * pin_count and active_count track essentially the same thing:
     33 	 * How many requests are in flight or may be under construction.
     34 	 *
     35 	 * We need two distinct counters so that we can assign different
     36 	 * lifetimes to the events for different use-cases. For example,
     37 	 * we want to permanently keep the timeline pinned for the kernel
     38 	 * context so that we can issue requests at any time without having
     39 	 * to acquire space in the GGTT. However, we want to keep tracking
     40 	 * the activity (to be able to detect when we become idle) along that
     41 	 * permanently pinned timeline and so end up requiring two counters.
     42 	 *
     43 	 * Note that the active_count is protected by the intel_timeline.mutex,
     44 	 * but the pin_count is protected by a combination of serialisation
     45 	 * from the intel_context caller plus internal atomicity.
     46 	 */
     47 	atomic_t pin_count;
     48 	atomic_t active_count;
     49 
     50 	const u32 *hwsp_seqno;
     51 	struct i915_vma *hwsp_ggtt;
     52 	u32 hwsp_offset;
     53 
     54 	struct intel_timeline_cacheline *hwsp_cacheline;
     55 
     56 	bool has_initial_breadcrumb;
     57 
     58 	/**
     59 	 * List of breadcrumbs associated with GPU requests currently
     60 	 * outstanding.
     61 	 */
     62 	struct list_head requests;
     63 
     64 	/*
     65 	 * Contains an RCU guarded pointer to the last request. No reference is
     66 	 * held to the request, users must carefully acquire a reference to
     67 	 * the request using i915_active_fence_get(), or manage the RCU
     68 	 * protection themselves (cf the i915_active_fence API).
     69 	 */
     70 	struct i915_active_fence last_request;
     71 
     72 	/** A chain of completed timelines ready for early retirement. */
     73 	struct intel_timeline *retire;
     74 
     75 	/**
     76 	 * We track the most recent seqno that we wait on in every context so
     77 	 * that we only have to emit a new await and dependency on a more
     78 	 * recent sync point. As the contexts may be executed out-of-order, we
     79 	 * have to track each individually and can not rely on an absolute
     80 	 * global_seqno. When we know that all tracked fences are completed
     81 	 * (i.e. when the driver is idle), we know that the syncmap is
     82 	 * redundant and we can discard it without loss of generality.
     83 	 */
     84 	struct i915_syncmap *sync;
     85 
     86 	struct list_head link;
     87 	struct intel_gt *gt;
     88 
     89 	struct kref kref;
     90 	struct rcu_head rcu;
     91 };
     92 
     93 struct intel_timeline_cacheline {
     94 	struct i915_active active;
     95 
     96 	struct intel_timeline_hwsp *hwsp;
     97 	void *vaddr;
     98 
     99 	struct rcu_head rcu;
    100 };
    101 
    102 #endif /* __I915_TIMELINE_TYPES_H__ */
    103