1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * (C) Copyright 2000-2002
4 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 *
6 * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
7 * Scott McNutt <smcnutt@psyent.com>
8 */
9
10 #include <common.h>
11 #include <dm.h>
12 #include <errno.h>
13 #include <timer.h>
14 #include <asm/io.h>
15 #include <linux/bitops.h>
16
17 /* control register */
18 #define ALTERA_TIMER_CONT BIT(1) /* Continuous mode */
19 #define ALTERA_TIMER_START BIT(2) /* Start timer */
20 #define ALTERA_TIMER_STOP BIT(3) /* Stop timer */
21
22 struct altera_timer_regs {
23 u32 status; /* Timer status reg */
24 u32 control; /* Timer control reg */
25 u32 periodl; /* Timeout period low */
26 u32 periodh; /* Timeout period high */
27 u32 snapl; /* Snapshot low */
28 u32 snaph; /* Snapshot high */
29 };
30
31 struct altera_timer_plat {
32 struct altera_timer_regs *regs;
33 };
34
altera_timer_get_count(struct udevice * dev)35 static u64 altera_timer_get_count(struct udevice *dev)
36 {
37 struct altera_timer_plat *plat = dev_get_plat(dev);
38 struct altera_timer_regs *const regs = plat->regs;
39 u32 val;
40
41 /* Trigger update */
42 writel(0x0, ®s->snapl);
43
44 /* Read timer value */
45 val = readl(®s->snapl) & 0xffff;
46 val |= (readl(®s->snaph) & 0xffff) << 16;
47 return timer_conv_64(~val);
48 }
49
altera_timer_probe(struct udevice * dev)50 static int altera_timer_probe(struct udevice *dev)
51 {
52 struct altera_timer_plat *plat = dev_get_plat(dev);
53 struct altera_timer_regs *const regs = plat->regs;
54
55 writel(0, ®s->status);
56 writel(0, ®s->control);
57 writel(ALTERA_TIMER_STOP, ®s->control);
58
59 writel(0xffff, ®s->periodl);
60 writel(0xffff, ®s->periodh);
61 writel(ALTERA_TIMER_CONT | ALTERA_TIMER_START, ®s->control);
62
63 return 0;
64 }
65
altera_timer_of_to_plat(struct udevice * dev)66 static int altera_timer_of_to_plat(struct udevice *dev)
67 {
68 struct altera_timer_plat *plat = dev_get_plat(dev);
69
70 plat->regs = map_physmem(dev_read_addr(dev),
71 sizeof(struct altera_timer_regs),
72 MAP_NOCACHE);
73
74 return 0;
75 }
76
77 static const struct timer_ops altera_timer_ops = {
78 .get_count = altera_timer_get_count,
79 };
80
81 static const struct udevice_id altera_timer_ids[] = {
82 { .compatible = "altr,timer-1.0" },
83 {}
84 };
85
86 U_BOOT_DRIVER(altera_timer) = {
87 .name = "altera_timer",
88 .id = UCLASS_TIMER,
89 .of_match = altera_timer_ids,
90 .of_to_plat = altera_timer_of_to_plat,
91 .plat_auto = sizeof(struct altera_timer_plat),
92 .probe = altera_timer_probe,
93 .ops = &altera_timer_ops,
94 };
95