1/* SPDX-License-Identifier: MIT */
2/*
3 * Copyright �� 2019 Intel Corporation
4 */
5
6#ifndef __INTEL_RESET_TYPES_H_
7#define __INTEL_RESET_TYPES_H_
8
9#include <linux/mutex.h>
10#include <linux/wait.h>
11#include <linux/srcu.h>
12
13struct intel_reset {
14	/**
15	 * flags: Control various stages of the GPU reset
16	 *
17	 * #I915_RESET_BACKOFF - When we start a global reset, we need to
18	 * serialise with any other users attempting to do the same, and
19	 * any global resources that may be clobber by the reset (such as
20	 * FENCE registers).
21	 *
22	 * #I915_RESET_ENGINE[num_engines] - Since the driver doesn't need to
23	 * acquire the struct_mutex to reset an engine, we need an explicit
24	 * flag to prevent two concurrent reset attempts in the same engine.
25	 * As the number of engines continues to grow, allocate the flags from
26	 * the most significant bits.
27	 *
28	 * #I915_WEDGED - If reset fails and we can no longer use the GPU,
29	 * we set the #I915_WEDGED bit. Prior to command submission, e.g.
30	 * i915_request_alloc(), this bit is checked and the sequence
31	 * aborted (with -EIO reported to userspace) if set.
32	 *
33	 * #I915_WEDGED_ON_INIT - If we fail to initialize the GPU we can no
34	 * longer use the GPU - similar to #I915_WEDGED bit. The difference in
35	 * the way we're handling "forced" unwedged (e.g. through debugfs),
36	 * which is not allowed in case we failed to initialize.
37	 *
38	 * #I915_WEDGED_ON_FINI - Similar to #I915_WEDGED_ON_INIT, except we
39	 * use it to mark that the GPU is no longer available (and prevent
40	 * users from using it).
41	 */
42	unsigned long flags;
43#define I915_RESET_BACKOFF	0
44#define I915_RESET_MODESET	1
45#define I915_RESET_ENGINE	2
46#define I915_WEDGED_ON_INIT	(BITS_PER_LONG - 3)
47#define I915_WEDGED_ON_FINI	(BITS_PER_LONG - 2)
48#define I915_WEDGED		(BITS_PER_LONG - 1)
49
50	struct mutex mutex; /* serialises wedging/unwedging */
51
52	/**
53	 * Waitqueue to signal when the reset has completed. Used by clients
54	 * that wait for i915->mm.wedged to settle.
55	 */
56	wait_queue_head_t queue;
57
58	struct srcu_struct backoff_srcu;
59};
60
61#endif /* _INTEL_RESET_TYPES_H_ */
62