xref: /openbmc/u-boot/drivers/timer/altera_timer.c (revision 1d6edcbf)
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 
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 
21 struct 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 
30 struct altera_timer_platdata {
31 	struct altera_timer_regs *regs;
32 };
33 
altera_timer_get_count(struct udevice * dev,u64 * count)34 static int altera_timer_get_count(struct udevice *dev, u64 *count)
35 {
36 	struct altera_timer_platdata *plat = dev->platdata;
37 	struct altera_timer_regs *const regs = plat->regs;
38 	u32 val;
39 
40 	/* Trigger update */
41 	writel(0x0, &regs->snapl);
42 
43 	/* Read timer value */
44 	val = readl(&regs->snapl) & 0xffff;
45 	val |= (readl(&regs->snaph) & 0xffff) << 16;
46 	*count = timer_conv_64(~val);
47 
48 	return 0;
49 }
50 
altera_timer_probe(struct udevice * dev)51 static int altera_timer_probe(struct udevice *dev)
52 {
53 	struct altera_timer_platdata *plat = dev->platdata;
54 	struct altera_timer_regs *const regs = plat->regs;
55 
56 	writel(0, &regs->status);
57 	writel(0, &regs->control);
58 	writel(ALTERA_TIMER_STOP, &regs->control);
59 
60 	writel(0xffff, &regs->periodl);
61 	writel(0xffff, &regs->periodh);
62 	writel(ALTERA_TIMER_CONT | ALTERA_TIMER_START, &regs->control);
63 
64 	return 0;
65 }
66 
altera_timer_ofdata_to_platdata(struct udevice * dev)67 static int altera_timer_ofdata_to_platdata(struct udevice *dev)
68 {
69 	struct altera_timer_platdata *plat = dev_get_platdata(dev);
70 
71 	plat->regs = map_physmem(devfdt_get_addr(dev),
72 				 sizeof(struct altera_timer_regs),
73 				 MAP_NOCACHE);
74 
75 	return 0;
76 }
77 
78 static const struct timer_ops altera_timer_ops = {
79 	.get_count = altera_timer_get_count,
80 };
81 
82 static const struct udevice_id altera_timer_ids[] = {
83 	{ .compatible = "altr,timer-1.0" },
84 	{}
85 };
86 
87 U_BOOT_DRIVER(altera_timer) = {
88 	.name	= "altera_timer",
89 	.id	= UCLASS_TIMER,
90 	.of_match = altera_timer_ids,
91 	.ofdata_to_platdata = altera_timer_ofdata_to_platdata,
92 	.platdata_auto_alloc_size = sizeof(struct altera_timer_platdata),
93 	.probe = altera_timer_probe,
94 	.ops	= &altera_timer_ops,
95 };
96