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, false)) {
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