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 */
13 enum 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 */
23 enum 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  */
45 struct counter_component {
46 	__u8 type;
47 	__u8 scope;
48 	__u8 parent;
49 	__u8 id;
50 };
51 
52 /* Event type definitions */
53 enum 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 	/* State of counter is changed */
65 	COUNTER_EVENT_CHANGE_OF_STATE,
66 };
67 
68 /**
69  * struct counter_watch - Counter component watch configuration
70  * @component: component to watch when event triggers
71  * @event: event that triggers (one of enum counter_event_type)
72  * @channel: event channel (typically 0 unless the device supports concurrent
73  *	     events of the same type)
74  */
75 struct counter_watch {
76 	struct counter_component component;
77 	__u8 event;
78 	__u8 channel;
79 };
80 
81 /*
82  * Queues a Counter watch for the specified event.
83  *
84  * The queued watches will not be applied until COUNTER_ENABLE_EVENTS_IOCTL is
85  * called.
86  */
87 #define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch)
88 /*
89  * Enables monitoring the events specified by the Counter watches that were
90  * queued by COUNTER_ADD_WATCH_IOCTL.
91  *
92  * If events are already enabled, the new set of watches replaces the old one.
93  * Calling this ioctl also has the effect of clearing the queue of watches added
94  * by COUNTER_ADD_WATCH_IOCTL.
95  */
96 #define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01)
97 /*
98  * Stops monitoring the previously enabled events.
99  */
100 #define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02)
101 
102 /**
103  * struct counter_event - Counter event data
104  * @timestamp: best estimate of time of event occurrence, in nanoseconds
105  * @value: component value
106  * @watch: component watch configuration
107  * @status: return status (system error number)
108  */
109 struct counter_event {
110 	__aligned_u64 timestamp;
111 	__aligned_u64 value;
112 	struct counter_watch watch;
113 	__u8 status;
114 };
115 
116 /* Count direction values */
117 enum counter_count_direction {
118 	COUNTER_COUNT_DIRECTION_FORWARD,
119 	COUNTER_COUNT_DIRECTION_BACKWARD,
120 };
121 
122 /* Count mode values */
123 enum counter_count_mode {
124 	COUNTER_COUNT_MODE_NORMAL,
125 	COUNTER_COUNT_MODE_RANGE_LIMIT,
126 	COUNTER_COUNT_MODE_NON_RECYCLE,
127 	COUNTER_COUNT_MODE_MODULO_N,
128 };
129 
130 /* Count function values */
131 enum counter_function {
132 	COUNTER_FUNCTION_INCREASE,
133 	COUNTER_FUNCTION_DECREASE,
134 	COUNTER_FUNCTION_PULSE_DIRECTION,
135 	COUNTER_FUNCTION_QUADRATURE_X1_A,
136 	COUNTER_FUNCTION_QUADRATURE_X1_B,
137 	COUNTER_FUNCTION_QUADRATURE_X2_A,
138 	COUNTER_FUNCTION_QUADRATURE_X2_B,
139 	COUNTER_FUNCTION_QUADRATURE_X4,
140 };
141 
142 /* Signal values */
143 enum counter_signal_level {
144 	COUNTER_SIGNAL_LEVEL_LOW,
145 	COUNTER_SIGNAL_LEVEL_HIGH,
146 };
147 
148 /* Action mode values */
149 enum counter_synapse_action {
150 	COUNTER_SYNAPSE_ACTION_NONE,
151 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
152 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
153 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
154 };
155 
156 #endif /* _UAPI_COUNTER_H_ */
157