1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
4  */
5 
6 #ifndef _TIMER_H_
7 #define _TIMER_H_
8 
9 /**
10  * dm_timer_init() - initialize a timer for time keeping. On success
11  * initializes gd->timer so that lib/timer can use it for future
12  * referrence.
13  *
14  * Return: 0 on success or error number
15  */
16 int dm_timer_init(void);
17 
18 /**
19  * timer_timebase_fallback() - Helper for timers using timebase fallback
20  * @dev: A timer partially-probed timer device
21  *
22  * This is a helper function designed for timers which need to fall back on the
23  * cpu's timebase. This function is designed to be called during the driver's
24  * probe(). If there is a clocks or clock-frequency property in the timer's
25  * binding, then it will be used. Otherwise, the timebase of the current cpu
26  * will be used. This is initialized by the cpu driver, and usually gotten from
27  * ``/cpus/timebase-frequency`` or ``/cpus/cpu@X/timebase-frequency``.
28  *
29  * Return: 0 if OK, or negative error code on failure
30  */
31 int timer_timebase_fallback(struct udevice *dev);
32 
33 /**
34  * timer_conv_64() - convert 32-bit counter value to 64-bit
35  * @count: 32-bit counter value
36  *
37  * Return: 64-bit counter value
38  */
39 u64 timer_conv_64(u32 count);
40 
41 /**
42  * timer_get_count() - Get the current timer count
43  * @dev: The timer device
44  * @count: pointer that returns the current timer count
45  *
46  * Return: 0 if OK, -ve on error
47  */
48 int timer_get_count(struct udevice *dev, u64 *count);
49 
50 /**
51  * timer_get_rate() - Get the timer input clock frequency
52  * @dev: The timer device
53  *
54  * Return: the timer input clock frequency
55  */
56 unsigned long timer_get_rate(struct udevice *dev);
57 
58 /**
59  * struct timer_ops - Driver model timer operations
60  *
61  * The uclass interface is implemented by all timer devices which use
62  * driver model.
63  */
64 struct timer_ops {
65 	/**
66 	 * @get_count: Get the current timer count
67 	 *
68 	 * @dev: The timer device
69 	 *
70 	 * This function may be called at any time after the driver is probed.
71 	 * All necessary initialization must be completed by the time probe()
72 	 * returns. The count returned by this functions should be monotonic.
73 	 * This function must succeed.
74 	 *
75 	 * Return: The current 64-bit timer count
76 	 */
77 	u64 (*get_count)(struct udevice *dev);
78 };
79 
80 /**
81  * struct timer_dev_priv - information about a device used by the uclass
82  *
83  * @clock_rate: the timer input clock frequency
84  */
85 struct timer_dev_priv {
86 	unsigned long clock_rate;
87 };
88 
89 /**
90  * timer_early_get_count() - Implement timer_get_count() before driver model
91  *
92  * If ``CONFIG_TIMER_EARLY`` is enabled, this function wil be called to return
93  * the current timer value before the proper driver model timer is ready.
94  * It should be implemented by one of the timer values. This is mostly useful
95  * for tracing.
96  */
97 u64 timer_early_get_count(void);
98 
99 /**
100  * timer_early_get_rate() - Get the timer rate before driver model
101  *
102  * If ``CONFIG_TIMER_EARLY`` is enabled, this function wil be called to return
103  * the current timer rate in Hz before the proper driver model timer is ready.
104  * It should be implemented by one of the timer values. This is mostly useful
105  * for tracing. This corresponds to the clock_rate value in struct
106  * timer_dev_priv.
107  */
108 unsigned long timer_early_get_rate(void);
109 
110 #endif	/* _TIMER_H_ */
111