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c5b8e464 NI |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (c) 2020 TOSHIBA CORPORATION | |
4 | * Copyright (c) 2020 Toshiba Electronic Devices & Storage Corporation | |
5 | * Copyright (c) 2020 Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> | |
6 | */ | |
7 | ||
8 | #include <linux/clk.h> | |
9 | #include <linux/io.h> | |
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/of.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/watchdog.h> | |
15 | ||
16 | #define WDT_CNT 0x00 | |
17 | #define WDT_MIN 0x04 | |
18 | #define WDT_MAX 0x08 | |
19 | #define WDT_CTL 0x0c | |
20 | #define WDT_CMD 0x10 | |
21 | #define WDT_CMD_CLEAR 0x4352 | |
22 | #define WDT_CMD_START_STOP 0x5354 | |
23 | #define WDT_DIV 0x30 | |
24 | ||
25 | #define VISCONTI_WDT_FREQ 2000000 /* 2MHz */ | |
26 | #define WDT_DEFAULT_TIMEOUT 10U /* in seconds */ | |
27 | ||
28 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
29 | module_param(nowayout, bool, 0); | |
30 | MODULE_PARM_DESC( | |
31 | nowayout, | |
32 | "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT)")"); | |
33 | ||
34 | struct visconti_wdt_priv { | |
35 | struct watchdog_device wdev; | |
36 | void __iomem *base; | |
37 | u32 div; | |
38 | }; | |
39 | ||
40 | static int visconti_wdt_start(struct watchdog_device *wdev) | |
41 | { | |
42 | struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
43 | u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ; | |
44 | ||
45 | writel(priv->div, priv->base + WDT_DIV); | |
46 | writel(0, priv->base + WDT_MIN); | |
47 | writel(timeout, priv->base + WDT_MAX); | |
48 | writel(0, priv->base + WDT_CTL); | |
49 | writel(WDT_CMD_START_STOP, priv->base + WDT_CMD); | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
54 | static int visconti_wdt_stop(struct watchdog_device *wdev) | |
55 | { | |
56 | struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
57 | ||
58 | writel(1, priv->base + WDT_CTL); | |
59 | writel(WDT_CMD_START_STOP, priv->base + WDT_CMD); | |
60 | ||
61 | return 0; | |
62 | } | |
63 | ||
64 | static int visconti_wdt_ping(struct watchdog_device *wdd) | |
65 | { | |
66 | struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdd); | |
67 | ||
68 | writel(WDT_CMD_CLEAR, priv->base + WDT_CMD); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
73 | static unsigned int visconti_wdt_get_timeleft(struct watchdog_device *wdev) | |
74 | { | |
75 | struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
76 | u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ; | |
77 | u32 cnt = readl(priv->base + WDT_CNT); | |
78 | ||
79 | if (timeout <= cnt) | |
80 | return 0; | |
81 | timeout -= cnt; | |
82 | ||
83 | return timeout / VISCONTI_WDT_FREQ; | |
84 | } | |
85 | ||
86 | static int visconti_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout) | |
87 | { | |
88 | u32 val; | |
89 | struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
90 | ||
91 | wdev->timeout = timeout; | |
92 | val = wdev->timeout * VISCONTI_WDT_FREQ; | |
93 | ||
94 | /* Clear counter before setting timeout because WDT expires */ | |
95 | writel(WDT_CMD_CLEAR, priv->base + WDT_CMD); | |
96 | writel(val, priv->base + WDT_MAX); | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | static const struct watchdog_info visconti_wdt_info = { | |
102 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, | |
103 | .identity = "Visconti Watchdog", | |
104 | }; | |
105 | ||
106 | static const struct watchdog_ops visconti_wdt_ops = { | |
107 | .owner = THIS_MODULE, | |
108 | .start = visconti_wdt_start, | |
109 | .stop = visconti_wdt_stop, | |
110 | .ping = visconti_wdt_ping, | |
111 | .get_timeleft = visconti_wdt_get_timeleft, | |
112 | .set_timeout = visconti_wdt_set_timeout, | |
113 | }; | |
114 | ||
c5b8e464 NI |
115 | static int visconti_wdt_probe(struct platform_device *pdev) |
116 | { | |
117 | struct watchdog_device *wdev; | |
118 | struct visconti_wdt_priv *priv; | |
119 | struct device *dev = &pdev->dev; | |
120 | struct clk *clk; | |
121 | int ret; | |
122 | unsigned long clk_freq; | |
123 | ||
124 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); | |
125 | if (!priv) | |
126 | return -ENOMEM; | |
127 | ||
128 | priv->base = devm_platform_ioremap_resource(pdev, 0); | |
129 | if (IS_ERR(priv->base)) | |
130 | return PTR_ERR(priv->base); | |
131 | ||
8c5210db | 132 | clk = devm_clk_get_enabled(dev, NULL); |
c5b8e464 NI |
133 | if (IS_ERR(clk)) |
134 | return dev_err_probe(dev, PTR_ERR(clk), "Could not get clock\n"); | |
135 | ||
c5b8e464 NI |
136 | clk_freq = clk_get_rate(clk); |
137 | if (!clk_freq) | |
138 | return -EINVAL; | |
139 | ||
140 | priv->div = clk_freq / VISCONTI_WDT_FREQ; | |
141 | ||
142 | /* Initialize struct watchdog_device. */ | |
143 | wdev = &priv->wdev; | |
144 | wdev->info = &visconti_wdt_info; | |
145 | wdev->ops = &visconti_wdt_ops; | |
146 | wdev->parent = dev; | |
147 | wdev->min_timeout = 1; | |
148 | wdev->max_timeout = 0xffffffff / VISCONTI_WDT_FREQ; | |
149 | wdev->timeout = min(wdev->max_timeout, WDT_DEFAULT_TIMEOUT); | |
150 | ||
151 | watchdog_set_drvdata(wdev, priv); | |
152 | watchdog_set_nowayout(wdev, nowayout); | |
153 | watchdog_stop_on_unregister(wdev); | |
154 | ||
155 | /* This overrides the default timeout only if DT configuration was found */ | |
156 | ret = watchdog_init_timeout(wdev, 0, dev); | |
157 | if (ret) | |
158 | dev_warn(dev, "Specified timeout value invalid, using default\n"); | |
159 | ||
160 | return devm_watchdog_register_device(dev, wdev); | |
161 | } | |
162 | ||
163 | static const struct of_device_id visconti_wdt_of_match[] = { | |
164 | { .compatible = "toshiba,visconti-wdt", }, | |
165 | {} | |
166 | }; | |
167 | MODULE_DEVICE_TABLE(of, visconti_wdt_of_match); | |
168 | ||
169 | static struct platform_driver visconti_wdt_driver = { | |
170 | .driver = { | |
171 | .name = "visconti_wdt", | |
172 | .of_match_table = visconti_wdt_of_match, | |
173 | }, | |
174 | .probe = visconti_wdt_probe, | |
175 | }; | |
176 | module_platform_driver(visconti_wdt_driver); | |
177 | ||
178 | MODULE_DESCRIPTION("TOSHIBA Visconti Watchdog Driver"); | |
179 | MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp"); | |
180 | MODULE_LICENSE("GPL v2"); |