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"Das U-Boot" Source Tree
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
4 * Author(s): Patrice Chotard, <patrice.chotard@foss.st.com> for STMicroelectronics.
5 *
6 * ARM Cortext A9 global timer driver
7 */
8
9#include <config.h>
10#include <dm.h>
11#include <clk.h>
12#include <timer.h>
13#include <linux/err.h>
14
15#include <asm/io.h>
16#include <asm/arch-armv7/globaltimer.h>
17
18struct arm_global_timer_priv {
19 struct globaltimer *global_timer;
20};
21
22static u64 arm_global_timer_get_count(struct udevice *dev)
23{
24 struct arm_global_timer_priv *priv = dev_get_priv(dev);
25 struct globaltimer *global_timer = priv->global_timer;
26 u32 low, high;
27 u64 timer;
28 u32 old = readl(&global_timer->cnt_h);
29
30 while (1) {
31 low = readl(&global_timer->cnt_l);
32 high = readl(&global_timer->cnt_h);
33 if (old == high)
34 break;
35 else
36 old = high;
37 }
38 timer = high;
39 return (u64)((timer << 32) | low);
40}
41
42static int arm_global_timer_probe(struct udevice *dev)
43{
44 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
45 struct arm_global_timer_priv *priv = dev_get_priv(dev);
46 struct clk clk;
47 int err;
48 ulong ret;
49
50 /* get arm global timer base address */
51 priv->global_timer = (struct globaltimer *)dev_read_addr_ptr(dev);
52 if (!priv->global_timer)
53 return -ENOENT;
54
55 err = clk_get_by_index(dev, 0, &clk);
56 if (!err) {
57 ret = clk_get_rate(&clk);
58 if (IS_ERR_VALUE(ret))
59 return ret;
60 uc_priv->clock_rate = ret;
61 } else {
62 uc_priv->clock_rate = CFG_SYS_HZ_CLOCK;
63 }
64
65 /* init timer */
66 writel(0x01, &priv->global_timer->ctl);
67
68 return 0;
69}
70
71static const struct timer_ops arm_global_timer_ops = {
72 .get_count = arm_global_timer_get_count,
73};
74
75static const struct udevice_id arm_global_timer_ids[] = {
76 { .compatible = "arm,cortex-a9-global-timer" },
77 {}
78};
79
80U_BOOT_DRIVER(arm_global_timer) = {
81 .name = "arm_global_timer",
82 .id = UCLASS_TIMER,
83 .of_match = arm_global_timer_ids,
84 .priv_auto = sizeof(struct arm_global_timer_priv),
85 .probe = arm_global_timer_probe,
86 .ops = &arm_global_timer_ops,
87};