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 
13 struct 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 dev_priv->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