1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2025, Kuan-Wei Chiu <[email protected]>
*
* Goldfish Timer driver
*/
#include <dm.h>
#include <goldfish_timer.h>
#include <mapmem.h>
#include <timer.h>
#include <asm/io.h>
#include <linux/errno.h>
struct goldfish_timer_priv {
void __iomem *base;
};
/* Goldfish RTC registers used as Timer */
#define TIMER_TIME_LOW 0x00
#define TIMER_TIME_HIGH 0x04
static u64 goldfish_timer_get_count(struct udevice *dev)
{
struct goldfish_timer_priv *priv = dev_get_priv(dev);
u32 low, high;
u64 time;
/*
* TIMER_TIME_HIGH is only updated when TIMER_TIME_LOW is read.
* We must read LOW before HIGH to latch the high 32-bit value
* and ensure a consistent 64-bit timestamp.
*/
low = readl(priv->base + TIMER_TIME_LOW);
high = readl(priv->base + TIMER_TIME_HIGH);
time = ((u64)high << 32) | low;
return time;
}
static int goldfish_timer_of_to_plat(struct udevice *dev)
{
struct goldfish_timer_plat *plat = dev_get_plat(dev);
fdt_addr_t addr;
addr = dev_read_addr(dev);
if (addr != FDT_ADDR_T_NONE)
plat->reg = addr;
return 0;
}
static int goldfish_timer_probe(struct udevice *dev)
{
struct goldfish_timer_plat *plat = dev_get_plat(dev);
struct goldfish_timer_priv *priv = dev_get_priv(dev);
struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
if (!plat->reg)
return -EINVAL;
priv->base = map_sysmem(plat->reg, 0x20);
/* Goldfish RTC counts in nanoseconds, so the rate is 1GHz */
uc_priv->clock_rate = 1000000000;
return 0;
}
static const struct timer_ops goldfish_timer_ops = {
.get_count = goldfish_timer_get_count,
};
static const struct udevice_id goldfish_timer_ids[] = {
{ .compatible = "google,goldfish-rtc" },
{ }
};
U_BOOT_DRIVER(goldfish_timer) = {
.name = "goldfish_timer",
.id = UCLASS_TIMER,
.of_match = goldfish_timer_ids,
.of_to_plat = goldfish_timer_of_to_plat,
.plat_auto = sizeof(struct goldfish_timer_plat),
.ops = &goldfish_timer_ops,
.probe = goldfish_timer_probe,
.priv_auto = sizeof(struct goldfish_timer_priv),
};
|
