xref: /openbmc/u-boot/drivers/timer/sti-timer.c (revision 44262327)
1 /*
2  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
3  * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <dm.h>
10 #include <fdtdec.h>
11 #include <timer.h>
12 
13 #include <asm/io.h>
14 #include <asm/arch-armv7/globaltimer.h>
15 
16 DECLARE_GLOBAL_DATA_PTR;
17 
18 struct sti_timer_priv {
19 	struct globaltimer *global_timer;
20 };
21 
22 static int sti_timer_get_count(struct udevice *dev, u64 *count)
23 {
24 	struct sti_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 	*count = (u64)((timer << 32) | low);
40 
41 	return 0;
42 }
43 
44 static int sti_timer_probe(struct udevice *dev)
45 {
46 	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
47 	struct sti_timer_priv *priv = dev_get_priv(dev);
48 	fdt_addr_t addr;
49 
50 	uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
51 
52 	/* get arm global timer base address */
53 	addr = fdtdec_get_addr(gd->fdt_blob, dev_of_offset(dev), "reg");
54 	priv->global_timer = (struct globaltimer *)addr;
55 
56 	/* init timer */
57 	writel(0x01, &priv->global_timer->ctl);
58 
59 	return 0;
60 }
61 
62 static const struct timer_ops sti_timer_ops = {
63 	.get_count = sti_timer_get_count,
64 };
65 
66 static const struct udevice_id sti_timer_ids[] = {
67 	{ .compatible = "arm,cortex-a9-global-timer" },
68 	{}
69 };
70 
71 U_BOOT_DRIVER(sti_timer) = {
72 	.name = "sti_timer",
73 	.id = UCLASS_TIMER,
74 	.of_match = sti_timer_ids,
75 	.priv_auto_alloc_size = sizeof(struct sti_timer_priv),
76 	.probe = sti_timer_probe,
77 	.ops = &sti_timer_ops,
78 	.flags = DM_FLAG_PRE_RELOC,
79 };
80