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7a3629fe JC |
1 | /* |
2 | * Copyright (C) 2015 Broadcom Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | */ | |
14 | ||
15 | #include <linux/clk.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/of.h> | |
20 | #include <linux/platform_device.h> | |
21 | #include <linux/pm.h> | |
22 | #include <linux/watchdog.h> | |
23 | ||
24 | #define WDT_START_1 0xff00 | |
25 | #define WDT_START_2 0x00ff | |
26 | #define WDT_STOP_1 0xee00 | |
27 | #define WDT_STOP_2 0x00ee | |
28 | ||
29 | #define WDT_TIMEOUT_REG 0x0 | |
30 | #define WDT_CMD_REG 0x4 | |
31 | ||
32 | #define WDT_MIN_TIMEOUT 1 /* seconds */ | |
33 | #define WDT_DEFAULT_TIMEOUT 30 /* seconds */ | |
34 | #define WDT_DEFAULT_RATE 27000000 | |
35 | ||
36 | struct bcm7038_watchdog { | |
37 | void __iomem *base; | |
38 | struct watchdog_device wdd; | |
39 | u32 rate; | |
40 | struct clk *clk; | |
41 | }; | |
42 | ||
43 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
44 | ||
45 | static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog) | |
46 | { | |
47 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
48 | u32 timeout; | |
49 | ||
50 | timeout = wdt->rate * wdog->timeout; | |
51 | ||
52 | writel(timeout, wdt->base + WDT_TIMEOUT_REG); | |
53 | } | |
54 | ||
55 | static int bcm7038_wdt_ping(struct watchdog_device *wdog) | |
56 | { | |
57 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
58 | ||
59 | writel(WDT_START_1, wdt->base + WDT_CMD_REG); | |
60 | writel(WDT_START_2, wdt->base + WDT_CMD_REG); | |
61 | ||
62 | return 0; | |
63 | } | |
64 | ||
65 | static int bcm7038_wdt_start(struct watchdog_device *wdog) | |
66 | { | |
67 | bcm7038_wdt_set_timeout_reg(wdog); | |
68 | bcm7038_wdt_ping(wdog); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
73 | static int bcm7038_wdt_stop(struct watchdog_device *wdog) | |
74 | { | |
75 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
76 | ||
77 | writel(WDT_STOP_1, wdt->base + WDT_CMD_REG); | |
78 | writel(WDT_STOP_2, wdt->base + WDT_CMD_REG); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog, | |
84 | unsigned int t) | |
85 | { | |
86 | /* Can't modify timeout value if watchdog timer is running */ | |
87 | bcm7038_wdt_stop(wdog); | |
88 | wdog->timeout = t; | |
89 | bcm7038_wdt_start(wdog); | |
90 | ||
91 | return 0; | |
92 | } | |
93 | ||
94 | static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog) | |
95 | { | |
96 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
97 | u32 time_left; | |
98 | ||
99 | time_left = readl(wdt->base + WDT_CMD_REG); | |
100 | ||
101 | return time_left / wdt->rate; | |
102 | } | |
103 | ||
104 | static struct watchdog_info bcm7038_wdt_info = { | |
105 | .identity = "Broadcom BCM7038 Watchdog Timer", | |
106 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
107 | WDIOF_MAGICCLOSE | |
108 | }; | |
109 | ||
110 | static struct watchdog_ops bcm7038_wdt_ops = { | |
111 | .owner = THIS_MODULE, | |
112 | .start = bcm7038_wdt_start, | |
113 | .stop = bcm7038_wdt_stop, | |
114 | .set_timeout = bcm7038_wdt_set_timeout, | |
115 | .get_timeleft = bcm7038_wdt_get_timeleft, | |
116 | }; | |
117 | ||
118 | static int bcm7038_wdt_probe(struct platform_device *pdev) | |
119 | { | |
120 | struct device *dev = &pdev->dev; | |
121 | struct bcm7038_watchdog *wdt; | |
122 | struct resource *res; | |
123 | int err; | |
124 | ||
125 | wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); | |
126 | if (!wdt) | |
127 | return -ENOMEM; | |
128 | ||
129 | platform_set_drvdata(pdev, wdt); | |
130 | ||
131 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
132 | wdt->base = devm_ioremap_resource(dev, res); | |
133 | if (IS_ERR(wdt->base)) | |
134 | return PTR_ERR(wdt->base); | |
135 | ||
136 | wdt->clk = devm_clk_get(dev, NULL); | |
137 | /* If unable to get clock, use default frequency */ | |
138 | if (!IS_ERR(wdt->clk)) { | |
139 | clk_prepare_enable(wdt->clk); | |
140 | wdt->rate = clk_get_rate(wdt->clk); | |
141 | /* Prevent divide-by-zero exception */ | |
142 | if (!wdt->rate) | |
143 | wdt->rate = WDT_DEFAULT_RATE; | |
144 | } else { | |
145 | wdt->rate = WDT_DEFAULT_RATE; | |
146 | wdt->clk = NULL; | |
147 | } | |
148 | ||
149 | wdt->wdd.info = &bcm7038_wdt_info; | |
150 | wdt->wdd.ops = &bcm7038_wdt_ops; | |
151 | wdt->wdd.min_timeout = WDT_MIN_TIMEOUT; | |
152 | wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT; | |
153 | wdt->wdd.max_timeout = 0xffffffff / wdt->rate; | |
154 | wdt->wdd.parent = dev; | |
155 | watchdog_set_drvdata(&wdt->wdd, wdt); | |
156 | ||
157 | err = watchdog_register_device(&wdt->wdd); | |
158 | if (err) { | |
159 | dev_err(dev, "Failed to register watchdog device\n"); | |
160 | clk_disable_unprepare(wdt->clk); | |
161 | return err; | |
162 | } | |
163 | ||
164 | dev_info(dev, "Registered BCM7038 Watchdog\n"); | |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
169 | static int bcm7038_wdt_remove(struct platform_device *pdev) | |
170 | { | |
171 | struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev); | |
172 | ||
173 | if (!nowayout) | |
174 | bcm7038_wdt_stop(&wdt->wdd); | |
175 | ||
176 | watchdog_unregister_device(&wdt->wdd); | |
177 | clk_disable_unprepare(wdt->clk); | |
178 | ||
179 | return 0; | |
180 | } | |
181 | ||
182 | #ifdef CONFIG_PM_SLEEP | |
183 | static int bcm7038_wdt_suspend(struct device *dev) | |
184 | { | |
185 | struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); | |
186 | ||
187 | if (watchdog_active(&wdt->wdd)) | |
188 | return bcm7038_wdt_stop(&wdt->wdd); | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
193 | static int bcm7038_wdt_resume(struct device *dev) | |
194 | { | |
195 | struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); | |
196 | ||
197 | if (watchdog_active(&wdt->wdd)) | |
198 | return bcm7038_wdt_start(&wdt->wdd); | |
199 | ||
200 | return 0; | |
201 | } | |
202 | #endif | |
203 | ||
204 | static SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, bcm7038_wdt_suspend, | |
205 | bcm7038_wdt_resume); | |
206 | ||
207 | static void bcm7038_wdt_shutdown(struct platform_device *pdev) | |
208 | { | |
209 | struct bcm7038_watchdog *wdt = platform_get_drvdata(pdev); | |
210 | ||
211 | if (watchdog_active(&wdt->wdd)) | |
212 | bcm7038_wdt_stop(&wdt->wdd); | |
213 | } | |
214 | ||
215 | static const struct of_device_id bcm7038_wdt_match[] = { | |
216 | { .compatible = "brcm,bcm7038-wdt" }, | |
217 | {}, | |
218 | }; | |
219 | ||
220 | static struct platform_driver bcm7038_wdt_driver = { | |
221 | .probe = bcm7038_wdt_probe, | |
222 | .remove = bcm7038_wdt_remove, | |
223 | .shutdown = bcm7038_wdt_shutdown, | |
224 | .driver = { | |
225 | .name = "bcm7038-wdt", | |
226 | .of_match_table = bcm7038_wdt_match, | |
227 | .pm = &bcm7038_wdt_pm_ops, | |
228 | } | |
229 | }; | |
230 | module_platform_driver(bcm7038_wdt_driver); | |
231 | ||
232 | module_param(nowayout, bool, 0); | |
233 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
234 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
235 | MODULE_LICENSE("GPL v2"); | |
236 | MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog"); | |
237 | MODULE_AUTHOR("Justin Chen"); |