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 /*
87 * TODO: should be CONFIG_IS_ENABLED(CPU), but the SPL config has _SUPPORT on
88 * the end...
89 */
90 #if defined(CONFIG_CPU) || defined(CONFIG_SPL_CPU_SUPPORT)
timer_timebase_fallback(struct udevice * dev)91 int timer_timebase_fallback(struct udevice *dev)
92 {
93 struct udevice *cpu;
94 struct cpu_plat *cpu_plat;
95 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
96
97 /* Did we get our clock rate from the device tree? */
98 if (uc_priv->clock_rate)
99 return 0;
100
101 /* Fall back to timebase-frequency */
102 dev_dbg(dev, "missing clocks or clock-frequency property; falling back on timebase-frequency\n");
103 cpu = cpu_get_current_dev();
104 if (!cpu)
105 return -ENODEV;
106
107 cpu_plat = dev_get_parent_plat(cpu);
108 if (!cpu_plat)
109 return -ENODEV;
110
111 uc_priv->clock_rate = cpu_plat->timebase_freq;
112 return 0;
113 }
114 #endif
115
timer_conv_64(u32 count)116 u64 timer_conv_64(u32 count)
117 {
118 /* increment tbh if tbl has rolled over */
119 if (count < gd->timebase_l)
120 gd->timebase_h++;
121 gd->timebase_l = count;
122 return ((u64)gd->timebase_h << 32) | gd->timebase_l;
123 }
124
dm_timer_init(void)125 int notrace dm_timer_init(void)
126 {
127 struct udevice *dev = NULL;
128 __maybe_unused ofnode node;
129 int ret;
130
131 if (gd->timer)
132 return 0;
133
134 /*
135 * Directly access gd->dm_root to suppress error messages, if the
136 * virtual root driver does not yet exist.
137 */
138 if (gd->dm_root == NULL)
139 return -EAGAIN;
140
141 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
142 /* Check for a chosen timer to be used for tick */
143 node = ofnode_get_chosen_node("tick-timer");
144
145 if (ofnode_valid(node) &&
146 uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) {
147 /*
148 * If the timer is not marked to be bound before
149 * relocation, bind it anyway.
150 */
151 if (!lists_bind_fdt(dm_root(), node, &dev, false)) {
152 ret = device_probe(dev);
153 if (ret)
154 return ret;
155 }
156 }
157 #endif
158
159 if (!dev) {
160 /* Fall back to the first available timer */
161 ret = uclass_first_device_err(UCLASS_TIMER, &dev);
162 if (ret)
163 return ret;
164 }
165
166 if (dev) {
167 gd->timer = dev;
168 return 0;
169 }
170
171 return -ENODEV;
172 }
173
174 UCLASS_DRIVER(timer) = {
175 .id = UCLASS_TIMER,
176 .name = "timer",
177 .pre_probe = timer_pre_probe,
178 .flags = DM_UC_FLAG_SEQ_ALIAS,
179 .post_probe = timer_post_probe,
180 .per_device_auto = sizeof(struct timer_dev_priv),
181 };
182