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 <clk.h>
8 #include <cpu.h>
9 #include <dm.h>
10 #include <asm/global_data.h>
11 #include <dm/lists.h>
12 #include <dm/device_compat.h>
13 #include <dm/device-internal.h>
14 #include <dm/root.h>
15 #include <errno.h>
16 #include <init.h>
17 #include <timer.h>
18 #include <linux/err.h>
19
20 DECLARE_GLOBAL_DATA_PTR;
21
22 /*
23 * Implement a timer uclass to work with lib/time.c. The timer is usually
24 * a 32/64 bits free-running up counter. The get_rate() method is used to get
25 * the input clock frequency of the timer. The get_count() method is used
26 * to get the current 64 bits count value. If the hardware is counting down,
27 * the value should be inversed inside the method. There may be no real
28 * tick, and no timer interrupt.
29 */
30
timer_get_count(struct udevice * dev,u64 * count)31 int notrace timer_get_count(struct udevice *dev, u64 *count)
32 {
33 const struct timer_ops *ops = device_get_ops(dev);
34
35 if (!ops->get_count)
36 return -ENOSYS;
37
38 *count = ops->get_count(dev);
39 return 0;
40 }
41
timer_get_rate(struct udevice * dev)42 unsigned long notrace timer_get_rate(struct udevice *dev)
43 {
44 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
45
46 return uc_priv->clock_rate;
47 }
48
timer_pre_probe(struct udevice * dev)49 static int timer_pre_probe(struct udevice *dev)
50 {
51 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
52 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
53 struct clk timer_clk;
54 int err;
55 ulong ret;
56
57 /* It is possible that a timer device has a null ofnode */
58 if (!dev_has_ofnode(dev))
59 return 0;
60
61 err = clk_get_by_index(dev, 0, &timer_clk);
62 if (!err) {
63 ret = clk_get_rate(&timer_clk);
64 if (IS_ERR_VALUE(ret))
65 return ret;
66 uc_priv->clock_rate = ret;
67 } else {
68 uc_priv->clock_rate =
69 dev_read_u32_default(dev, "clock-frequency", 0);
70 }
71 #endif
72
73 return 0;
74 }
75
timer_post_probe(struct udevice * dev)76 static int timer_post_probe(struct udevice *dev)
77 {
78 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
79
80 if (!uc_priv->clock_rate)
81 return -EINVAL;
82
83 return 0;
84 }
85
86 #if CONFIG_IS_ENABLED(CPU)
timer_timebase_fallback(struct udevice * dev)87 int timer_timebase_fallback(struct udevice *dev)
88 {
89 struct udevice *cpu;
90 struct cpu_plat *cpu_plat;
91 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
92
93 /* Did we get our clock rate from the device tree? */
94 if (uc_priv->clock_rate)
95 return 0;
96
97 /* Fall back to timebase-frequency */
98 dev_dbg(dev, "missing clocks or clock-frequency property; falling back on timebase-frequency\n");
99 cpu = cpu_get_current_dev();
100 if (!cpu)
101 return -ENODEV;
102
103 cpu_plat = dev_get_parent_plat(cpu);
104 if (!cpu_plat)
105 return -ENODEV;
106
107 uc_priv->clock_rate = cpu_plat->timebase_freq;
108 return 0;
109 }
110 #endif
111
timer_conv_64(u32 count)112 u64 timer_conv_64(u32 count)
113 {
114 /* increment tbh if tbl has rolled over */
115 if (count < gd->timebase_l)
116 gd->timebase_h++;
117 gd->timebase_l = count;
118 return ((u64)gd->timebase_h << 32) | gd->timebase_l;
119 }
120
dm_timer_init(void)121 int notrace dm_timer_init(void)
122 {
123 struct udevice *dev = NULL;
124 __maybe_unused ofnode node;
125 int ret;
126
127 if (gd->timer)
128 return 0;
129
130 /*
131 * Directly access gd->dm_root to suppress error messages, if the
132 * virtual root driver does not yet exist.
133 */
134 if (gd->dm_root == NULL)
135 return -EAGAIN;
136
137 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
138 /* Check for a chosen timer to be used for tick */
139 node = ofnode_get_chosen_node("tick-timer");
140
141 if (ofnode_valid(node) &&
142 uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) {
143 /*
144 * If the timer is not marked to be bound before
145 * relocation, bind it anyway.
146 */
147 if (!lists_bind_fdt(dm_root(), node, &dev, false)) {
148 ret = device_probe(dev);
149 if (ret)
150 return ret;
151 }
152 }
153 #endif
154
155 if (!dev) {
156 /* Fall back to the first available timer */
157 ret = uclass_first_device_err(UCLASS_TIMER, &dev);
158 if (ret)
159 return ret;
160 }
161
162 if (dev) {
163 gd->timer = dev;
164 return 0;
165 }
166
167 return -ENODEV;
168 }
169
170 UCLASS_DRIVER(timer) = {
171 .id = UCLASS_TIMER,
172 .name = "timer",
173 .pre_probe = timer_pre_probe,
174 .flags = DM_UC_FLAG_SEQ_ALIAS,
175 .post_probe = timer_post_probe,
176 .per_device_auto = sizeof(struct timer_dev_priv),
177 };
178