1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
4 *
5 * Derived from linux/drivers/watchdog/bcm63xx_wdt.c:
6 * Copyright (C) 2007 Miguel Gaio <miguel.gaio@efixo.com>
7 * Copyright (C) 2008 Florian Fainelli <florian@openwrt.org>
8 */
9
10 #include <common.h>
11 #include <dm.h>
12 #include <wdt.h>
13 #include <clk.h>
14 #include <asm/io.h>
15
16 /* WDT Value register */
17 #define WDT_VAL_REG 0x0
18 #define WDT_VAL_MIN 0x00000002
19 #define WDT_VAL_MAX 0xfffffffe
20
21 /* WDT Control register */
22 #define WDT_CTL_REG 0x4
23 #define WDT_CTL_START1_MASK 0x0000ff00
24 #define WDT_CTL_START2_MASK 0x000000ff
25 #define WDT_CTL_STOP1_MASK 0x0000ee00
26 #define WDT_CTL_STOP2_MASK 0x000000ee
27
28 struct bcm6345_wdt_priv {
29 void __iomem *regs;
30 unsigned long clk_rate;
31 };
32
bcm6345_wdt_reset(struct udevice * dev)33 static int bcm6345_wdt_reset(struct udevice *dev)
34 {
35 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
36
37 writel(WDT_CTL_START1_MASK, priv->regs + WDT_CTL_REG);
38 writel(WDT_CTL_START2_MASK, priv->regs + WDT_CTL_REG);
39
40 return 0;
41 }
42
bcm6345_wdt_start(struct udevice * dev,u64 timeout,ulong flags)43 static int bcm6345_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
44 {
45 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
46 u32 val = priv->clk_rate / 1000 * timeout;
47
48 if (val < WDT_VAL_MIN) {
49 debug("watchdog won't fire with less than 2 ticks\n");
50 val = WDT_VAL_MIN;
51 } else if (val > WDT_VAL_MAX) {
52 debug("maximum watchdog timeout exceeded\n");
53 val = WDT_VAL_MAX;
54 }
55
56 writel(val, priv->regs + WDT_VAL_REG);
57
58 return bcm6345_wdt_reset(dev);
59 }
60
bcm6345_wdt_expire_now(struct udevice * dev,ulong flags)61 static int bcm6345_wdt_expire_now(struct udevice *dev, ulong flags)
62 {
63 return bcm6345_wdt_start(dev, WDT_VAL_MIN, flags);
64 }
65
bcm6345_wdt_stop(struct udevice * dev)66 static int bcm6345_wdt_stop(struct udevice *dev)
67 {
68 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
69
70 writel(WDT_CTL_STOP1_MASK, priv->regs + WDT_CTL_REG);
71 writel(WDT_CTL_STOP2_MASK, priv->regs + WDT_CTL_REG);
72
73 return 0;
74 }
75
76 static const struct wdt_ops bcm6345_wdt_ops = {
77 .expire_now = bcm6345_wdt_expire_now,
78 .reset = bcm6345_wdt_reset,
79 .start = bcm6345_wdt_start,
80 .stop = bcm6345_wdt_stop,
81 };
82
83 static const struct udevice_id bcm6345_wdt_ids[] = {
84 { .compatible = "brcm,bcm6345-wdt" },
85 { /* sentinel */ }
86 };
87
bcm6345_wdt_probe(struct udevice * dev)88 static int bcm6345_wdt_probe(struct udevice *dev)
89 {
90 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
91 struct clk clk;
92 int ret;
93
94 priv->regs = dev_remap_addr(dev);
95 if (!priv->regs)
96 return -EINVAL;
97
98 ret = clk_get_by_index(dev, 0, &clk);
99 if (!ret)
100 priv->clk_rate = clk_get_rate(&clk);
101 else
102 return -EINVAL;
103
104 bcm6345_wdt_stop(dev);
105
106 return 0;
107 }
108
109 U_BOOT_DRIVER(wdt_bcm6345) = {
110 .name = "wdt_bcm6345",
111 .id = UCLASS_WDT,
112 .of_match = bcm6345_wdt_ids,
113 .ops = &bcm6345_wdt_ops,
114 .priv_auto_alloc_size = sizeof(struct bcm6345_wdt_priv),
115 .probe = bcm6345_wdt_probe,
116 };
117