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2e62c498 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
7a3629fe JC |
2 | /* |
3 | * Copyright (C) 2015 Broadcom Corporation | |
4 | * | |
7a3629fe JC |
5 | */ |
6 | ||
7 | #include <linux/clk.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/io.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/of.h> | |
12 | #include <linux/platform_device.h> | |
d6b9c679 | 13 | #include <linux/platform_data/bcm7038_wdt.h> |
7a3629fe JC |
14 | #include <linux/pm.h> |
15 | #include <linux/watchdog.h> | |
16 | ||
17 | #define WDT_START_1 0xff00 | |
18 | #define WDT_START_2 0x00ff | |
19 | #define WDT_STOP_1 0xee00 | |
20 | #define WDT_STOP_2 0x00ee | |
21 | ||
22 | #define WDT_TIMEOUT_REG 0x0 | |
23 | #define WDT_CMD_REG 0x4 | |
24 | ||
25 | #define WDT_MIN_TIMEOUT 1 /* seconds */ | |
26 | #define WDT_DEFAULT_TIMEOUT 30 /* seconds */ | |
27 | #define WDT_DEFAULT_RATE 27000000 | |
28 | ||
29 | struct bcm7038_watchdog { | |
30 | void __iomem *base; | |
31 | struct watchdog_device wdd; | |
32 | u32 rate; | |
33 | struct clk *clk; | |
34 | }; | |
35 | ||
36 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
37 | ||
e379c219 ÁFR |
38 | static inline void bcm7038_wdt_write(u32 value, void __iomem *addr) |
39 | { | |
40 | /* MIPS chips strapped for BE will automagically configure the | |
41 | * peripheral registers for CPU-native byte order. | |
42 | */ | |
43 | if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) | |
44 | __raw_writel(value, addr); | |
45 | else | |
46 | writel_relaxed(value, addr); | |
47 | } | |
48 | ||
49 | static inline u32 bcm7038_wdt_read(void __iomem *addr) | |
50 | { | |
51 | if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) | |
52 | return __raw_readl(addr); | |
53 | else | |
54 | return readl_relaxed(addr); | |
55 | } | |
56 | ||
7a3629fe JC |
57 | static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog) |
58 | { | |
59 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
60 | u32 timeout; | |
61 | ||
62 | timeout = wdt->rate * wdog->timeout; | |
63 | ||
e379c219 | 64 | bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG); |
7a3629fe JC |
65 | } |
66 | ||
67 | static int bcm7038_wdt_ping(struct watchdog_device *wdog) | |
68 | { | |
69 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
70 | ||
e379c219 ÁFR |
71 | bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG); |
72 | bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG); | |
7a3629fe JC |
73 | |
74 | return 0; | |
75 | } | |
76 | ||
77 | static int bcm7038_wdt_start(struct watchdog_device *wdog) | |
78 | { | |
79 | bcm7038_wdt_set_timeout_reg(wdog); | |
80 | bcm7038_wdt_ping(wdog); | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
85 | static int bcm7038_wdt_stop(struct watchdog_device *wdog) | |
86 | { | |
87 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
88 | ||
e379c219 ÁFR |
89 | bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG); |
90 | bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG); | |
7a3629fe JC |
91 | |
92 | return 0; | |
93 | } | |
94 | ||
95 | static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog, | |
96 | unsigned int t) | |
97 | { | |
98 | /* Can't modify timeout value if watchdog timer is running */ | |
99 | bcm7038_wdt_stop(wdog); | |
100 | wdog->timeout = t; | |
101 | bcm7038_wdt_start(wdog); | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog) | |
107 | { | |
108 | struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog); | |
109 | u32 time_left; | |
110 | ||
e379c219 | 111 | time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG); |
7a3629fe JC |
112 | |
113 | return time_left / wdt->rate; | |
114 | } | |
115 | ||
6c368932 | 116 | static const struct watchdog_info bcm7038_wdt_info = { |
7a3629fe JC |
117 | .identity = "Broadcom BCM7038 Watchdog Timer", |
118 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
119 | WDIOF_MAGICCLOSE | |
120 | }; | |
121 | ||
85f15cfc | 122 | static const struct watchdog_ops bcm7038_wdt_ops = { |
7a3629fe JC |
123 | .owner = THIS_MODULE, |
124 | .start = bcm7038_wdt_start, | |
125 | .stop = bcm7038_wdt_stop, | |
126 | .set_timeout = bcm7038_wdt_set_timeout, | |
127 | .get_timeleft = bcm7038_wdt_get_timeleft, | |
128 | }; | |
129 | ||
69656dcd GR |
130 | static void bcm7038_clk_disable_unprepare(void *data) |
131 | { | |
132 | clk_disable_unprepare(data); | |
133 | } | |
134 | ||
7a3629fe JC |
135 | static int bcm7038_wdt_probe(struct platform_device *pdev) |
136 | { | |
d6b9c679 | 137 | struct bcm7038_wdt_platform_data *pdata = pdev->dev.platform_data; |
7a3629fe JC |
138 | struct device *dev = &pdev->dev; |
139 | struct bcm7038_watchdog *wdt; | |
d6b9c679 | 140 | const char *clk_name = NULL; |
7a3629fe JC |
141 | int err; |
142 | ||
143 | wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); | |
144 | if (!wdt) | |
145 | return -ENOMEM; | |
146 | ||
147 | platform_set_drvdata(pdev, wdt); | |
148 | ||
0f0a6a28 | 149 | wdt->base = devm_platform_ioremap_resource(pdev, 0); |
7a3629fe JC |
150 | if (IS_ERR(wdt->base)) |
151 | return PTR_ERR(wdt->base); | |
152 | ||
d6b9c679 FF |
153 | if (pdata && pdata->clk_name) |
154 | clk_name = pdata->clk_name; | |
155 | ||
156 | wdt->clk = devm_clk_get(dev, clk_name); | |
7a3629fe JC |
157 | /* If unable to get clock, use default frequency */ |
158 | if (!IS_ERR(wdt->clk)) { | |
dd0a18ca | 159 | err = clk_prepare_enable(wdt->clk); |
69656dcd GR |
160 | if (err) |
161 | return err; | |
162 | err = devm_add_action_or_reset(dev, | |
163 | bcm7038_clk_disable_unprepare, | |
164 | wdt->clk); | |
dd0a18ca FE |
165 | if (err) |
166 | return err; | |
7a3629fe JC |
167 | wdt->rate = clk_get_rate(wdt->clk); |
168 | /* Prevent divide-by-zero exception */ | |
169 | if (!wdt->rate) | |
170 | wdt->rate = WDT_DEFAULT_RATE; | |
171 | } else { | |
172 | wdt->rate = WDT_DEFAULT_RATE; | |
173 | wdt->clk = NULL; | |
174 | } | |
175 | ||
176 | wdt->wdd.info = &bcm7038_wdt_info; | |
177 | wdt->wdd.ops = &bcm7038_wdt_ops; | |
178 | wdt->wdd.min_timeout = WDT_MIN_TIMEOUT; | |
179 | wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT; | |
180 | wdt->wdd.max_timeout = 0xffffffff / wdt->rate; | |
181 | wdt->wdd.parent = dev; | |
182 | watchdog_set_drvdata(&wdt->wdd, wdt); | |
183 | ||
69656dcd GR |
184 | watchdog_stop_on_reboot(&wdt->wdd); |
185 | watchdog_stop_on_unregister(&wdt->wdd); | |
186 | err = devm_watchdog_register_device(dev, &wdt->wdd); | |
f5429895 | 187 | if (err) |
7a3629fe | 188 | return err; |
7a3629fe JC |
189 | |
190 | dev_info(dev, "Registered BCM7038 Watchdog\n"); | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
7a3629fe JC |
195 | static int bcm7038_wdt_suspend(struct device *dev) |
196 | { | |
197 | struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); | |
198 | ||
199 | if (watchdog_active(&wdt->wdd)) | |
200 | return bcm7038_wdt_stop(&wdt->wdd); | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
205 | static int bcm7038_wdt_resume(struct device *dev) | |
206 | { | |
207 | struct bcm7038_watchdog *wdt = dev_get_drvdata(dev); | |
208 | ||
209 | if (watchdog_active(&wdt->wdd)) | |
210 | return bcm7038_wdt_start(&wdt->wdd); | |
211 | ||
212 | return 0; | |
213 | } | |
7a3629fe | 214 | |
3b956c0a PC |
215 | static DEFINE_SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops, |
216 | bcm7038_wdt_suspend, bcm7038_wdt_resume); | |
7a3629fe | 217 | |
7a3629fe | 218 | static const struct of_device_id bcm7038_wdt_match[] = { |
2dd441f1 | 219 | { .compatible = "brcm,bcm6345-wdt" }, |
7a3629fe JC |
220 | { .compatible = "brcm,bcm7038-wdt" }, |
221 | {}, | |
222 | }; | |
57d77c62 | 223 | MODULE_DEVICE_TABLE(of, bcm7038_wdt_match); |
7a3629fe | 224 | |
e764faef FF |
225 | static const struct platform_device_id bcm7038_wdt_devtype[] = { |
226 | { .name = "bcm63xx-wdt" }, | |
227 | { /* sentinel */ }, | |
228 | }; | |
229 | MODULE_DEVICE_TABLE(platform, bcm7038_wdt_devtype); | |
230 | ||
7a3629fe JC |
231 | static struct platform_driver bcm7038_wdt_driver = { |
232 | .probe = bcm7038_wdt_probe, | |
e764faef | 233 | .id_table = bcm7038_wdt_devtype, |
7a3629fe JC |
234 | .driver = { |
235 | .name = "bcm7038-wdt", | |
236 | .of_match_table = bcm7038_wdt_match, | |
3b956c0a | 237 | .pm = pm_sleep_ptr(&bcm7038_wdt_pm_ops), |
7a3629fe JC |
238 | } |
239 | }; | |
240 | module_platform_driver(bcm7038_wdt_driver); | |
241 | ||
242 | module_param(nowayout, bool, 0); | |
243 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" | |
244 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
2e62c498 | 245 | MODULE_LICENSE("GPL"); |
7a3629fe JC |
246 | MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog"); |
247 | MODULE_AUTHOR("Justin Chen"); |