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daf42866 XH |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* | |
3 | * sunplus Watchdog Driver | |
4 | * | |
5 | * Copyright (C) 2021 Sunplus Technology Co., Ltd. | |
6 | * | |
7 | */ | |
8 | ||
9 | #include <linux/clk.h> | |
10 | #include <linux/io.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/mod_devicetable.h> | |
13 | #include <linux/platform_device.h> | |
14 | #include <linux/reset.h> | |
15 | #include <linux/watchdog.h> | |
16 | ||
17 | #define WDT_CTRL 0x00 | |
18 | #define WDT_CNT 0x04 | |
19 | ||
20 | #define WDT_STOP 0x3877 | |
21 | #define WDT_RESUME 0x4A4B | |
22 | #define WDT_CLRIRQ 0x7482 | |
23 | #define WDT_UNLOCK 0xAB00 | |
24 | #define WDT_LOCK 0xAB01 | |
25 | #define WDT_CONMAX 0xDEAF | |
26 | ||
27 | /* TIMEOUT_MAX = ffff0/90kHz =11.65, so longer than 11 seconds will time out. */ | |
28 | #define SP_WDT_MAX_TIMEOUT 11U | |
29 | #define SP_WDT_DEFAULT_TIMEOUT 10 | |
30 | ||
31 | #define STC_CLK 90000 | |
32 | ||
33 | #define DEVICE_NAME "sunplus-wdt" | |
34 | ||
35 | static unsigned int timeout; | |
36 | module_param(timeout, int, 0); | |
37 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); | |
38 | ||
39 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
40 | module_param(nowayout, bool, 0); | |
41 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
42 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
43 | ||
44 | struct sp_wdt_priv { | |
45 | struct watchdog_device wdev; | |
46 | void __iomem *base; | |
47 | struct clk *clk; | |
48 | struct reset_control *rstc; | |
49 | }; | |
50 | ||
51 | static int sp_wdt_restart(struct watchdog_device *wdev, | |
52 | unsigned long action, void *data) | |
53 | { | |
54 | struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
55 | void __iomem *base = priv->base; | |
56 | ||
57 | writel(WDT_STOP, base + WDT_CTRL); | |
58 | writel(WDT_UNLOCK, base + WDT_CTRL); | |
59 | writel(0x0001, base + WDT_CNT); | |
60 | writel(WDT_LOCK, base + WDT_CTRL); | |
61 | writel(WDT_RESUME, base + WDT_CTRL); | |
62 | ||
63 | return 0; | |
64 | } | |
65 | ||
66 | static int sp_wdt_ping(struct watchdog_device *wdev) | |
67 | { | |
68 | struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
69 | void __iomem *base = priv->base; | |
70 | u32 count; | |
71 | ||
72 | if (wdev->timeout > SP_WDT_MAX_TIMEOUT) { | |
73 | /* WDT_CONMAX sets the count to the maximum (down-counting). */ | |
74 | writel(WDT_CONMAX, base + WDT_CTRL); | |
75 | } else { | |
76 | writel(WDT_UNLOCK, base + WDT_CTRL); | |
77 | /* | |
78 | * Watchdog timer is a 20-bit down-counting based on STC_CLK. | |
79 | * This register bits[16:0] is from bit[19:4] of the watchdog | |
80 | * timer counter. | |
81 | */ | |
82 | count = (wdev->timeout * STC_CLK) >> 4; | |
83 | writel(count, base + WDT_CNT); | |
84 | writel(WDT_LOCK, base + WDT_CTRL); | |
85 | } | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | static int sp_wdt_stop(struct watchdog_device *wdev) | |
91 | { | |
92 | struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
93 | void __iomem *base = priv->base; | |
94 | ||
95 | writel(WDT_STOP, base + WDT_CTRL); | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static int sp_wdt_start(struct watchdog_device *wdev) | |
101 | { | |
102 | struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
103 | void __iomem *base = priv->base; | |
104 | ||
105 | writel(WDT_RESUME, base + WDT_CTRL); | |
106 | ||
107 | return 0; | |
108 | } | |
109 | ||
110 | static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev) | |
111 | { | |
112 | struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev); | |
113 | void __iomem *base = priv->base; | |
114 | u32 val; | |
115 | ||
116 | val = readl(base + WDT_CNT); | |
117 | val &= 0xffff; | |
118 | val = val << 4; | |
119 | ||
120 | return val; | |
121 | } | |
122 | ||
123 | static const struct watchdog_info sp_wdt_info = { | |
124 | .identity = DEVICE_NAME, | |
125 | .options = WDIOF_SETTIMEOUT | | |
126 | WDIOF_MAGICCLOSE | | |
127 | WDIOF_KEEPALIVEPING, | |
128 | }; | |
129 | ||
130 | static const struct watchdog_ops sp_wdt_ops = { | |
131 | .owner = THIS_MODULE, | |
132 | .start = sp_wdt_start, | |
133 | .stop = sp_wdt_stop, | |
134 | .ping = sp_wdt_ping, | |
135 | .get_timeleft = sp_wdt_get_timeleft, | |
136 | .restart = sp_wdt_restart, | |
137 | }; | |
138 | ||
daf42866 XH |
139 | static void sp_reset_control_assert(void *data) |
140 | { | |
141 | reset_control_assert(data); | |
142 | } | |
143 | ||
144 | static int sp_wdt_probe(struct platform_device *pdev) | |
145 | { | |
146 | struct device *dev = &pdev->dev; | |
147 | struct sp_wdt_priv *priv; | |
148 | int ret; | |
149 | ||
150 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); | |
151 | if (!priv) | |
152 | return -ENOMEM; | |
153 | ||
bdb97018 | 154 | priv->clk = devm_clk_get_enabled(dev, NULL); |
daf42866 | 155 | if (IS_ERR(priv->clk)) |
bdb97018 | 156 | return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to enable clock\n"); |
daf42866 XH |
157 | |
158 | /* The timer and watchdog shared the STC reset */ | |
159 | priv->rstc = devm_reset_control_get_shared(dev, NULL); | |
160 | if (IS_ERR(priv->rstc)) | |
161 | return dev_err_probe(dev, PTR_ERR(priv->rstc), "Failed to get reset\n"); | |
162 | ||
163 | reset_control_deassert(priv->rstc); | |
164 | ||
165 | ret = devm_add_action_or_reset(dev, sp_reset_control_assert, priv->rstc); | |
166 | if (ret) | |
167 | return ret; | |
168 | ||
169 | priv->base = devm_platform_ioremap_resource(pdev, 0); | |
170 | if (IS_ERR(priv->base)) | |
171 | return PTR_ERR(priv->base); | |
172 | ||
173 | priv->wdev.info = &sp_wdt_info; | |
174 | priv->wdev.ops = &sp_wdt_ops; | |
175 | priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT; | |
176 | priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000; | |
177 | priv->wdev.min_timeout = 1; | |
178 | priv->wdev.parent = dev; | |
179 | ||
180 | watchdog_set_drvdata(&priv->wdev, priv); | |
181 | watchdog_init_timeout(&priv->wdev, timeout, dev); | |
182 | watchdog_set_nowayout(&priv->wdev, nowayout); | |
183 | watchdog_stop_on_reboot(&priv->wdev); | |
184 | watchdog_set_restart_priority(&priv->wdev, 128); | |
185 | ||
186 | return devm_watchdog_register_device(dev, &priv->wdev); | |
187 | } | |
188 | ||
189 | static const struct of_device_id sp_wdt_of_match[] = { | |
190 | {.compatible = "sunplus,sp7021-wdt", }, | |
191 | { /* sentinel */ } | |
192 | }; | |
193 | MODULE_DEVICE_TABLE(of, sp_wdt_of_match); | |
194 | ||
195 | static struct platform_driver sp_wdt_driver = { | |
196 | .probe = sp_wdt_probe, | |
197 | .driver = { | |
198 | .name = DEVICE_NAME, | |
199 | .of_match_table = sp_wdt_of_match, | |
200 | }, | |
201 | }; | |
202 | ||
203 | module_platform_driver(sp_wdt_driver); | |
204 | ||
205 | MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>"); | |
206 | MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver"); | |
207 | MODULE_LICENSE("GPL"); |