Commit | Line | Data |
---|---|---|
336694a0 BS |
1 | /* |
2 | * Watchdog driver for Conexant Digicolor | |
3 | * | |
4 | * Copyright (C) 2015 Paradox Innovation Ltd. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License as published by the | |
8 | * Free Software Foundation; either version 2 of the License, or (at your | |
9 | * option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/clk.h> | |
17 | #include <linux/watchdog.h> | |
18 | #include <linux/reboot.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/of_address.h> | |
21 | ||
22 | #define TIMER_A_CONTROL 0 | |
23 | #define TIMER_A_COUNT 4 | |
24 | ||
25 | #define TIMER_A_ENABLE_COUNT BIT(0) | |
26 | #define TIMER_A_ENABLE_WATCHDOG BIT(1) | |
27 | ||
28 | struct dc_wdt { | |
29 | void __iomem *base; | |
30 | struct clk *clk; | |
31 | struct notifier_block restart_handler; | |
32 | spinlock_t lock; | |
33 | }; | |
34 | ||
35 | static unsigned timeout; | |
36 | module_param(timeout, uint, 0); | |
37 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); | |
38 | ||
39 | static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks) | |
40 | { | |
41 | unsigned long flags; | |
42 | ||
43 | spin_lock_irqsave(&wdt->lock, flags); | |
44 | ||
45 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
46 | writel_relaxed(ticks, wdt->base + TIMER_A_COUNT); | |
47 | writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG, | |
48 | wdt->base + TIMER_A_CONTROL); | |
49 | ||
50 | spin_unlock_irqrestore(&wdt->lock, flags); | |
51 | } | |
52 | ||
53 | static int dc_restart_handler(struct notifier_block *this, unsigned long mode, | |
54 | void *cmd) | |
55 | { | |
56 | struct dc_wdt *wdt = container_of(this, struct dc_wdt, restart_handler); | |
57 | ||
58 | dc_wdt_set(wdt, 1); | |
59 | /* wait for reset to assert... */ | |
60 | mdelay(500); | |
61 | ||
62 | return NOTIFY_DONE; | |
63 | } | |
64 | ||
65 | static int dc_wdt_start(struct watchdog_device *wdog) | |
66 | { | |
67 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
68 | ||
69 | dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk)); | |
70 | ||
71 | return 0; | |
72 | } | |
73 | ||
74 | static int dc_wdt_stop(struct watchdog_device *wdog) | |
75 | { | |
76 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
77 | ||
78 | writel_relaxed(0, wdt->base + TIMER_A_CONTROL); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) | |
84 | { | |
85 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
86 | ||
87 | dc_wdt_set(wdt, t * clk_get_rate(wdt->clk)); | |
88 | wdog->timeout = t; | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
93 | static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog) | |
94 | { | |
95 | struct dc_wdt *wdt = watchdog_get_drvdata(wdog); | |
96 | uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT); | |
97 | ||
98 | return count / clk_get_rate(wdt->clk); | |
99 | } | |
100 | ||
101 | static struct watchdog_ops dc_wdt_ops = { | |
102 | .owner = THIS_MODULE, | |
103 | .start = dc_wdt_start, | |
104 | .stop = dc_wdt_stop, | |
105 | .set_timeout = dc_wdt_set_timeout, | |
106 | .get_timeleft = dc_wdt_get_timeleft, | |
107 | }; | |
108 | ||
109 | static struct watchdog_info dc_wdt_info = { | |
110 | .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | |
111 | | WDIOF_KEEPALIVEPING, | |
112 | .identity = "Conexant Digicolor Watchdog", | |
113 | }; | |
114 | ||
115 | static struct watchdog_device dc_wdt_wdd = { | |
116 | .info = &dc_wdt_info, | |
117 | .ops = &dc_wdt_ops, | |
118 | .min_timeout = 1, | |
119 | }; | |
120 | ||
121 | static int dc_wdt_probe(struct platform_device *pdev) | |
122 | { | |
123 | struct device *dev = &pdev->dev; | |
124 | struct device_node *np = dev->of_node; | |
125 | struct dc_wdt *wdt; | |
126 | int ret; | |
127 | ||
128 | wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL); | |
129 | if (!wdt) | |
130 | return -ENOMEM; | |
131 | platform_set_drvdata(pdev, wdt); | |
132 | ||
133 | wdt->base = of_iomap(np, 0); | |
134 | if (!wdt->base) { | |
135 | dev_err(dev, "Failed to remap watchdog regs"); | |
136 | return -ENODEV; | |
137 | } | |
138 | ||
139 | wdt->clk = devm_clk_get(&pdev->dev, NULL); | |
140 | if (IS_ERR(wdt->clk)) { | |
141 | ret = PTR_ERR(wdt->clk); | |
142 | goto err_iounmap; | |
143 | } | |
144 | dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk); | |
145 | dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout; | |
146 | ||
147 | spin_lock_init(&wdt->lock); | |
148 | ||
149 | watchdog_set_drvdata(&dc_wdt_wdd, wdt); | |
150 | watchdog_init_timeout(&dc_wdt_wdd, timeout, dev); | |
151 | ret = watchdog_register_device(&dc_wdt_wdd); | |
152 | if (ret) { | |
153 | dev_err(dev, "Failed to register watchdog device"); | |
154 | goto err_iounmap; | |
155 | } | |
156 | ||
157 | wdt->restart_handler.notifier_call = dc_restart_handler; | |
158 | wdt->restart_handler.priority = 128; | |
159 | ret = register_restart_handler(&wdt->restart_handler); | |
160 | if (ret) | |
161 | dev_warn(&pdev->dev, "cannot register restart handler\n"); | |
162 | ||
163 | return 0; | |
164 | ||
165 | err_iounmap: | |
166 | iounmap(wdt->base); | |
167 | return ret; | |
168 | } | |
169 | ||
170 | static int dc_wdt_remove(struct platform_device *pdev) | |
171 | { | |
172 | struct dc_wdt *wdt = platform_get_drvdata(pdev); | |
173 | ||
174 | unregister_restart_handler(&wdt->restart_handler); | |
175 | watchdog_unregister_device(&dc_wdt_wdd); | |
176 | iounmap(wdt->base); | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
181 | static void dc_wdt_shutdown(struct platform_device *pdev) | |
182 | { | |
183 | dc_wdt_stop(&dc_wdt_wdd); | |
184 | } | |
185 | ||
186 | static const struct of_device_id dc_wdt_of_match[] = { | |
187 | { .compatible = "cnxt,cx92755-wdt", }, | |
188 | {}, | |
189 | }; | |
190 | MODULE_DEVICE_TABLE(of, dc_wdt_of_match); | |
191 | ||
192 | static struct platform_driver dc_wdt_driver = { | |
193 | .probe = dc_wdt_probe, | |
194 | .remove = dc_wdt_remove, | |
195 | .shutdown = dc_wdt_shutdown, | |
196 | .driver = { | |
197 | .name = "digicolor-wdt", | |
198 | .of_match_table = dc_wdt_of_match, | |
199 | }, | |
200 | }; | |
201 | module_platform_driver(dc_wdt_driver); | |
202 | ||
203 | MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); | |
204 | MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer"); | |
205 | MODULE_LICENSE("GPL"); |