/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2019 Intel Corporation
 */

#ifndef __I915_GEM_CONTEXT_TYPES_H__
#define __I915_GEM_CONTEXT_TYPES_H__

#include <linux/atomic.h>
#include <linux/list.h>
#include <linux/llist.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/radix-tree.h>
#include <linux/rbtree.h>
#include <linux/rcupdate.h>
#include <linux/types.h>

#include "gt/intel_context_types.h"

#include "i915_scheduler.h"

struct pid;

struct drm_i915_private;
struct drm_i915_file_private;
struct i915_address_space;
struct intel_timeline;
struct intel_ring;

struct i915_gem_engines {
	struct rcu_head rcu;
	unsigned int num_engines;
	struct intel_context *engines[];
};

struct i915_gem_engines_iter {
	unsigned int idx;
	const struct i915_gem_engines *engines;
};

/**
 * struct i915_gem_context - client state
 *
 * The struct i915_gem_context represents the combined view of the driver and
 * logical hardware state for a particular client.
 */
struct i915_gem_context {
	/** i915: i915 device backpointer */
	struct drm_i915_private *i915;

	/** file_priv: owning file descriptor */
	struct drm_i915_file_private *file_priv;

	/**
	 * @engines: User defined engines for this context
	 *
	 * Various uAPI offer the ability to lookup up an
	 * index from this array to select an engine operate on.
	 *
	 * Multiple logically distinct instances of the same engine
	 * may be defined in the array, as well as composite virtual
	 * engines.
	 *
	 * Execbuf uses the I915_EXEC_RING_MASK as an index into this
	 * array to select which HW context + engine to execute on. For
	 * the default array, the user_ring_map[] is used to translate
	 * the legacy uABI onto the approprate index (e.g. both
	 * I915_EXEC_DEFAULT and I915_EXEC_RENDER select the same
	 * context, and I915_EXEC_BSD is weird). For a use defined
	 * array, execbuf uses I915_EXEC_RING_MASK as a plain index.
	 *
	 * User defined by I915_CONTEXT_PARAM_ENGINE (when the
	 * CONTEXT_USER_ENGINES flag is set).
	 */
	struct i915_gem_engines __rcu *engines;
	struct mutex engines_mutex; /* guards writes to engines */

	struct intel_timeline *timeline;

	/**
	 * @vm: unique address space (GTT)
	 *
	 * In full-ppgtt mode, each context has its own address space ensuring
	 * complete seperation of one client from all others.
	 *
	 * In other modes, this is a NULL pointer with the expectation that
	 * the caller uses the shared global GTT.
	 */
	struct i915_address_space __rcu *vm;

	/**
	 * @pid: process id of creator
	 *
	 * Note that who created the context may not be the principle user,
	 * as the context may be shared across a local socket. However,
	 * that should only affect the default context, all contexts created
	 * explicitly by the client are expected to be isolated.
	 */
	struct pid *pid;

	/** link: place with &drm_i915_private.context_list */
	struct list_head link;
	struct llist_node free_link;

	/**
	 * @ref: reference count
	 *
	 * A reference to a context is held by both the client who created it
	 * and on each request submitted to the hardware using the request
	 * (to ensure the hardware has access to the state until it has
	 * finished all pending writes). See i915_gem_context_get() and
	 * i915_gem_context_put() for access.
	 */
	struct kref ref;

	/**
	 * @rcu: rcu_head for deferred freeing.
	 */
	struct rcu_head rcu;

	/**
	 * @user_flags: small set of booleans controlled by the user
	 */
	unsigned long user_flags;
#define UCONTEXT_NO_ZEROMAP		0
#define UCONTEXT_NO_ERROR_CAPTURE	1
#define UCONTEXT_BANNABLE		2
#define UCONTEXT_RECOVERABLE		3
#define UCONTEXT_PERSISTENCE		4

	/**
	 * @flags: small set of booleans
	 */
	unsigned long flags;
#define CONTEXT_CLOSED			0
#define CONTEXT_USER_ENGINES		1

	struct mutex mutex;

	struct i915_sched_attr sched;

	/** guilty_count: How many times this context has caused a GPU hang. */
	atomic_t guilty_count;
	/**
	 * @active_count: How many times this context was active during a GPU
	 * hang, but did not cause it.
	 */
	atomic_t active_count;

	/**
	 * @hang_timestamp: The last time(s) this context caused a GPU hang
	 */
	unsigned long hang_timestamp[2];
#define CONTEXT_FAST_HANG_JIFFIES (120 * HZ) /* 3 hangs within 120s? Banned! */

	/** remap_slice: Bitmask of cache lines that need remapping */
	u8 remap_slice;

	/**
	 * handles_vma: rbtree to look up our context specific obj/vma for
	 * the user handle. (user handles are per fd, but the binding is
	 * per vm, which may be one per context or shared with the global GTT)
	 */
	struct radix_tree_root handles_vma;

	/**
	 * @name: arbitrary name, used for user debug
	 *
	 * A name is constructed for the context from the creator's process
	 * name, pid and user handle in order to uniquely identify the
	 * context in messages.
	 */
	char name[TASK_COMM_LEN + 8];
};

#endif /* __I915_GEM_CONTEXT_TYPES_H__ */