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