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 <log.h>
13 #include <wdt.h>
14 #include <clk.h>
15 #include <asm/io.h>
16
17 /* WDT Value register */
18 #define WDT_VAL_REG 0x0
19 #define WDT_VAL_MIN 0x00000002
20 #define WDT_VAL_MAX 0xfffffffe
21
22 /* WDT Control register */
23 #define WDT_CTL_REG 0x4
24 #define WDT_CTL_START1_MASK 0x0000ff00
25 #define WDT_CTL_START2_MASK 0x000000ff
26 #define WDT_CTL_STOP1_MASK 0x0000ee00
27 #define WDT_CTL_STOP2_MASK 0x000000ee
28
29 struct bcm6345_wdt_priv {
30 void __iomem *regs;
31 unsigned long clk_rate;
32 };
33
bcm6345_wdt_reset(struct udevice * dev)34 static int bcm6345_wdt_reset(struct udevice *dev)
35 {
36 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
37
38 writel(WDT_CTL_START1_MASK, priv->regs + WDT_CTL_REG);
39 writel(WDT_CTL_START2_MASK, priv->regs + WDT_CTL_REG);
40
41 return 0;
42 }
43
bcm6345_wdt_start(struct udevice * dev,u64 timeout,ulong flags)44 static int bcm6345_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
45 {
46 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
47 u32 val = priv->clk_rate / 1000 * timeout;
48
49 if (val < WDT_VAL_MIN) {
50 debug("watchdog won't fire with less than 2 ticks\n");
51 val = WDT_VAL_MIN;
52 } else if (val > WDT_VAL_MAX) {
53 debug("maximum watchdog timeout exceeded\n");
54 val = WDT_VAL_MAX;
55 }
56
57 writel(val, priv->regs + WDT_VAL_REG);
58
59 return bcm6345_wdt_reset(dev);
60 }
61
bcm6345_wdt_expire_now(struct udevice * dev,ulong flags)62 static int bcm6345_wdt_expire_now(struct udevice *dev, ulong flags)
63 {
64 return bcm6345_wdt_start(dev, WDT_VAL_MIN, flags);
65 }
66
bcm6345_wdt_stop(struct udevice * dev)67 static int bcm6345_wdt_stop(struct udevice *dev)
68 {
69 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
70
71 writel(WDT_CTL_STOP1_MASK, priv->regs + WDT_CTL_REG);
72 writel(WDT_CTL_STOP2_MASK, priv->regs + WDT_CTL_REG);
73
74 return 0;
75 }
76
77 static const struct wdt_ops bcm6345_wdt_ops = {
78 .expire_now = bcm6345_wdt_expire_now,
79 .reset = bcm6345_wdt_reset,
80 .start = bcm6345_wdt_start,
81 .stop = bcm6345_wdt_stop,
82 };
83
84 static const struct udevice_id bcm6345_wdt_ids[] = {
85 { .compatible = "brcm,bcm6345-wdt" },
86 { /* sentinel */ }
87 };
88
bcm6345_wdt_probe(struct udevice * dev)89 static int bcm6345_wdt_probe(struct udevice *dev)
90 {
91 struct bcm6345_wdt_priv *priv = dev_get_priv(dev);
92 struct clk clk;
93 int ret;
94
95 priv->regs = dev_remap_addr(dev);
96 if (!priv->regs)
97 return -EINVAL;
98
99 ret = clk_get_by_index(dev, 0, &clk);
100 if (!ret)
101 priv->clk_rate = clk_get_rate(&clk);
102 else
103 return -EINVAL;
104
105 bcm6345_wdt_stop(dev);
106
107 return 0;
108 }
109
110 U_BOOT_DRIVER(wdt_bcm6345) = {
111 .name = "wdt_bcm6345",
112 .id = UCLASS_WDT,
113 .of_match = bcm6345_wdt_ids,
114 .ops = &bcm6345_wdt_ops,
115 .priv_auto = sizeof(struct bcm6345_wdt_priv),
116 .probe = bcm6345_wdt_probe,
117 };
118