1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * A general-purpose cyclic execution infrastructure, to allow "small"
4 * (run-time wise) functions to be executed at a specified frequency.
5 * Things like LED blinking or watchdog triggering are examples for such
6 * tasks.
7 *
8 * Copyright (C) 2022 Stefan Roese <sr@denx.de>
9 */
10
11 #ifndef __cyclic_h
12 #define __cyclic_h
13
14 #include <linux/list.h>
15 #include <asm/types.h>
16
17 /**
18 * struct cyclic_info - Information about cyclic execution function
19 *
20 * @func: Function to call periodically
21 * @ctx: Context pointer to get passed to this function
22 * @name: Name of the cyclic function, e.g. shown in the commands
23 * @delay_ns: Delay is ns after which this function shall get executed
24 * @start_time_us: Start time in us, when this function started its execution
25 * @cpu_time_us: Total CPU time of this function
26 * @run_cnt: Counter of executions occurances
27 * @next_call: Next time in us, when the function shall be executed again
28 * @list: List node
29 * @already_warned: Flag that we've warned about exceeding CPU time usage
30 */
31 struct cyclic_info {
32 void (*func)(void *ctx);
33 void *ctx;
34 char *name;
35 uint64_t delay_us;
36 uint64_t start_time_us;
37 uint64_t cpu_time_us;
38 uint64_t run_cnt;
39 uint64_t next_call;
40 struct hlist_node list;
41 bool already_warned;
42 };
43
44 /** Function type for cyclic functions */
45 typedef void (*cyclic_func_t)(void *ctx);
46
47 #if defined(CONFIG_CYCLIC)
48 /**
49 * cyclic_register - Register a new cyclic function
50 *
51 * @func: Function to call periodically
52 * @delay_us: Delay is us after which this function shall get executed
53 * @name: Cyclic function name/id
54 * @ctx: Context to pass to the function
55 * @return: pointer to cyclic_struct if OK, NULL on error
56 */
57 struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us,
58 const char *name, void *ctx);
59
60 /**
61 * cyclic_unregister - Unregister a cyclic function
62 *
63 * @cyclic: Pointer to cyclic_struct of the function that shall be removed
64 * @return: 0 if OK, -ve on error
65 */
66 int cyclic_unregister(struct cyclic_info *cyclic);
67
68 /**
69 * cyclic_unregister_all() - Clean up cyclic functions
70 *
71 * This removes all cyclic functions
72 */
73 int cyclic_unregister_all(void);
74
75 /**
76 * cyclic_get_list() - Get cyclic list pointer
77 *
78 * Return the cyclic list pointer
79 *
80 * @return: pointer to cyclic_list
81 */
82 struct hlist_head *cyclic_get_list(void);
83
84 /**
85 * cyclic_run() - Interate over all registered cyclic functions
86 *
87 * Interate over all registered cyclic functions and if the it's function
88 * needs to be executed, then call into these registered functions.
89 */
90 void cyclic_run(void);
91
92 /**
93 * schedule() - Schedule all potentially waiting tasks
94 *
95 * Basically a wrapper for cyclic_run(), pontentially enhanced by some
96 * other parts, that need to get handled periodically.
97 */
98 void schedule(void);
99 #else
cyclic_register(cyclic_func_t func,uint64_t delay_us,const char * name,void * ctx)100 static inline struct cyclic_info *cyclic_register(cyclic_func_t func,
101 uint64_t delay_us,
102 const char *name,
103 void *ctx)
104 {
105 return NULL;
106 }
107
cyclic_unregister(struct cyclic_info * cyclic)108 static inline int cyclic_unregister(struct cyclic_info *cyclic)
109 {
110 return 0;
111 }
112
cyclic_run(void)113 static inline void cyclic_run(void)
114 {
115 }
116
schedule(void)117 static inline void schedule(void)
118 {
119 }
120
cyclic_unregister_all(void)121 static inline int cyclic_unregister_all(void)
122 {
123 return 0;
124 }
125 #endif
126
127 #endif
128