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1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
4  */
5 
6 #include <common.h>
7 #include <dm.h>
8 #include <dm/lists.h>
9 #include <dm/device-internal.h>
10 #include <dm/root.h>
11 #include <clk.h>
12 #include <errno.h>
13 #include <timer.h>
14 
15 DECLARE_GLOBAL_DATA_PTR;
16 
17 /*
18  * Implement a timer uclass to work with lib/time.c. The timer is usually
19  * a 32/64 bits free-running up counter. The get_rate() method is used to get
20  * the input clock frequency of the timer. The get_count() method is used
21  * to get the current 64 bits count value. If the hardware is counting down,
22  * the value should be inversed inside the method. There may be no real
23  * tick, and no timer interrupt.
24  */
25 
timer_get_count(struct udevice * dev,u64 * count)26 int notrace timer_get_count(struct udevice *dev, u64 *count)
27 {
28 	const struct timer_ops *ops = device_get_ops(dev);
29 
30 	if (!ops->get_count)
31 		return -ENOSYS;
32 
33 	return ops->get_count(dev, count);
34 }
35 
timer_get_rate(struct udevice * dev)36 unsigned long notrace timer_get_rate(struct udevice *dev)
37 {
38 	struct timer_dev_priv *uc_priv = dev->uclass_priv;
39 
40 	return uc_priv->clock_rate;
41 }
42 
timer_pre_probe(struct udevice * dev)43 static int timer_pre_probe(struct udevice *dev)
44 {
45 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
46 	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
47 	struct clk timer_clk;
48 	int err;
49 	ulong ret;
50 
51 	err = clk_get_by_index(dev, 0, &timer_clk);
52 	if (!err) {
53 		ret = clk_get_rate(&timer_clk);
54 		if (IS_ERR_VALUE(ret))
55 			return ret;
56 		uc_priv->clock_rate = ret;
57 	} else {
58 		uc_priv->clock_rate =
59 			dev_read_u32_default(dev, "clock-frequency", 0);
60 	}
61 #endif
62 
63 	return 0;
64 }
65 
timer_post_probe(struct udevice * dev)66 static int timer_post_probe(struct udevice *dev)
67 {
68 	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
69 
70 	if (!uc_priv->clock_rate)
71 		return -EINVAL;
72 
73 	return 0;
74 }
75 
timer_conv_64(u32 count)76 u64 timer_conv_64(u32 count)
77 {
78 	/* increment tbh if tbl has rolled over */
79 	if (count < gd->timebase_l)
80 		gd->timebase_h++;
81 	gd->timebase_l = count;
82 	return ((u64)gd->timebase_h << 32) | gd->timebase_l;
83 }
84 
dm_timer_init(void)85 int notrace dm_timer_init(void)
86 {
87 	struct udevice *dev = NULL;
88 	__maybe_unused ofnode node;
89 	int ret;
90 
91 	if (gd->timer)
92 		return 0;
93 
94 	/*
95 	 * Directly access gd->dm_root to suppress error messages, if the
96 	 * virtual root driver does not yet exist.
97 	 */
98 	if (gd->dm_root == NULL)
99 		return -EAGAIN;
100 
101 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
102 	/* Check for a chosen timer to be used for tick */
103 	node = ofnode_get_chosen_node("tick-timer");
104 
105 	if (ofnode_valid(node) &&
106 	    uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) {
107 		/*
108 		 * If the timer is not marked to be bound before
109 		 * relocation, bind it anyway.
110 		 */
111 		if (!lists_bind_fdt(dm_root(), node, &dev)) {
112 			ret = device_probe(dev);
113 			if (ret)
114 				return ret;
115 		}
116 	}
117 #endif
118 
119 	if (!dev) {
120 		/* Fall back to the first available timer */
121 		ret = uclass_first_device_err(UCLASS_TIMER, &dev);
122 		if (ret)
123 			return ret;
124 	}
125 
126 	if (dev) {
127 		gd->timer = dev;
128 		return 0;
129 	}
130 
131 	return -ENODEV;
132 }
133 
134 UCLASS_DRIVER(timer) = {
135 	.id		= UCLASS_TIMER,
136 	.name		= "timer",
137 	.pre_probe	= timer_pre_probe,
138 	.flags		= DM_UC_FLAG_SEQ_ALIAS,
139 	.post_probe	= timer_post_probe,
140 	.per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
141 };
142