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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2/*
3 * Userspace ABI for Counter character devices
4 * Copyright (C) 2020 William Breathitt Gray
5 */
6#ifndef _UAPI_COUNTER_H_
7#define _UAPI_COUNTER_H_
8
9#include <linux/ioctl.h>
10#include <linux/types.h>
11
12/* Component type definitions */
13enum counter_component_type {
14 COUNTER_COMPONENT_NONE,
15 COUNTER_COMPONENT_SIGNAL,
16 COUNTER_COMPONENT_COUNT,
17 COUNTER_COMPONENT_FUNCTION,
18 COUNTER_COMPONENT_SYNAPSE_ACTION,
19 COUNTER_COMPONENT_EXTENSION,
20};
21
22/* Component scope definitions */
23enum counter_scope {
24 COUNTER_SCOPE_DEVICE,
25 COUNTER_SCOPE_SIGNAL,
26 COUNTER_SCOPE_COUNT,
27};
28
29/**
30 * struct counter_component - Counter component identification
31 * @type: component type (one of enum counter_component_type)
32 * @scope: component scope (one of enum counter_scope)
33 * @parent: parent ID (matching the ID suffix of the respective parent sysfs
34 * path as described by the ABI documentation file
35 * Documentation/ABI/testing/sysfs-bus-counter)
36 * @id: component ID (matching the ID provided by the respective *_component_id
37 * sysfs attribute of the desired component)
38 *
39 * For example, if the Count 2 ceiling extension of Counter device 4 is desired,
40 * set type equal to COUNTER_COMPONENT_EXTENSION, scope equal to
41 * COUNTER_COUNT_SCOPE, parent equal to 2, and id equal to the value provided by
42 * the respective /sys/bus/counter/devices/counter4/count2/ceiling_component_id
43 * sysfs attribute.
44 */
45struct counter_component {
46 __u8 type;
47 __u8 scope;
48 __u8 parent;
49 __u8 id;
50};
51
52/* Event type definitions */
53enum counter_event_type {
54 /* Count value increased past ceiling */
55 COUNTER_EVENT_OVERFLOW,
56 /* Count value decreased past floor */
57 COUNTER_EVENT_UNDERFLOW,
58 /* Count value increased past ceiling, or decreased past floor */
59 COUNTER_EVENT_OVERFLOW_UNDERFLOW,
60 /* Count value reached threshold */
61 COUNTER_EVENT_THRESHOLD,
62 /* Index signal detected */
63 COUNTER_EVENT_INDEX,
64};
65
66/**
67 * struct counter_watch - Counter component watch configuration
68 * @component: component to watch when event triggers
69 * @event: event that triggers (one of enum counter_event_type)
70 * @channel: event channel (typically 0 unless the device supports concurrent
71 * events of the same type)
72 */
73struct counter_watch {
74 struct counter_component component;
75 __u8 event;
76 __u8 channel;
77};
78
79/*
80 * Queues a Counter watch for the specified event.
81 *
82 * The queued watches will not be applied until COUNTER_ENABLE_EVENTS_IOCTL is
83 * called.
84 */
85#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch)
86/*
87 * Enables monitoring the events specified by the Counter watches that were
88 * queued by COUNTER_ADD_WATCH_IOCTL.
89 *
90 * If events are already enabled, the new set of watches replaces the old one.
91 * Calling this ioctl also has the effect of clearing the queue of watches added
92 * by COUNTER_ADD_WATCH_IOCTL.
93 */
94#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01)
95/*
96 * Stops monitoring the previously enabled events.
97 */
98#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02)
99
100/**
101 * struct counter_event - Counter event data
102 * @timestamp: best estimate of time of event occurrence, in nanoseconds
103 * @value: component value
104 * @watch: component watch configuration
105 * @status: return status (system error number)
106 */
107struct counter_event {
108 __aligned_u64 timestamp;
109 __aligned_u64 value;
110 struct counter_watch watch;
111 __u8 status;
112};
113
114/* Count direction values */
115enum counter_count_direction {
116 COUNTER_COUNT_DIRECTION_FORWARD,
117 COUNTER_COUNT_DIRECTION_BACKWARD,
118};
119
120/* Count mode values */
121enum counter_count_mode {
122 COUNTER_COUNT_MODE_NORMAL,
123 COUNTER_COUNT_MODE_RANGE_LIMIT,
124 COUNTER_COUNT_MODE_NON_RECYCLE,
125 COUNTER_COUNT_MODE_MODULO_N,
126};
127
128/* Count function values */
129enum counter_function {
130 COUNTER_FUNCTION_INCREASE,
131 COUNTER_FUNCTION_DECREASE,
132 COUNTER_FUNCTION_PULSE_DIRECTION,
133 COUNTER_FUNCTION_QUADRATURE_X1_A,
134 COUNTER_FUNCTION_QUADRATURE_X1_B,
135 COUNTER_FUNCTION_QUADRATURE_X2_A,
136 COUNTER_FUNCTION_QUADRATURE_X2_B,
137 COUNTER_FUNCTION_QUADRATURE_X4,
138};
139
140/* Signal values */
141enum counter_signal_level {
142 COUNTER_SIGNAL_LEVEL_LOW,
143 COUNTER_SIGNAL_LEVEL_HIGH,
144};
145
146/* Action mode values */
147enum counter_synapse_action {
148 COUNTER_SYNAPSE_ACTION_NONE,
149 COUNTER_SYNAPSE_ACTION_RISING_EDGE,
150 COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
151 COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
152};
153
154#endif /* _UAPI_COUNTER_H_ */