1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Watchdog driver for Faraday Technology FTWDT010
4 *
5 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
6 *
7 * Inspired by the out-of-tree drivers from OpenWRT:
8 * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
9 */
10
11 #include <linux/bitops.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/watchdog.h>
21
22 #define FTWDT010_WDCOUNTER 0x0
23 #define FTWDT010_WDLOAD 0x4
24 #define FTWDT010_WDRESTART 0x8
25 #define FTWDT010_WDCR 0xC
26
27 #define WDRESTART_MAGIC 0x5AB9
28
29 #define WDCR_CLOCK_5MHZ BIT(4)
30 #define WDCR_WDEXT BIT(3)
31 #define WDCR_WDINTR BIT(2)
32 #define WDCR_SYS_RST BIT(1)
33 #define WDCR_ENABLE BIT(0)
34
35 #define WDT_CLOCK 5000000 /* 5 MHz */
36
37 struct ftwdt010_wdt {
38 struct watchdog_device wdd;
39 struct device *dev;
40 void __iomem *base;
41 bool has_irq;
42 };
43
44 static inline
to_ftwdt010_wdt(struct watchdog_device * wdd)45 struct ftwdt010_wdt *to_ftwdt010_wdt(struct watchdog_device *wdd)
46 {
47 return container_of(wdd, struct ftwdt010_wdt, wdd);
48 }
49
ftwdt010_enable(struct ftwdt010_wdt * gwdt,unsigned int timeout,bool need_irq)50 static void ftwdt010_enable(struct ftwdt010_wdt *gwdt,
51 unsigned int timeout,
52 bool need_irq)
53 {
54 u32 enable;
55
56 writel(timeout * WDT_CLOCK, gwdt->base + FTWDT010_WDLOAD);
57 writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
58 /* set clock before enabling */
59 enable = WDCR_CLOCK_5MHZ | WDCR_SYS_RST;
60 writel(enable, gwdt->base + FTWDT010_WDCR);
61 if (need_irq)
62 enable |= WDCR_WDINTR;
63 enable |= WDCR_ENABLE;
64 writel(enable, gwdt->base + FTWDT010_WDCR);
65 }
66
ftwdt010_wdt_start(struct watchdog_device * wdd)67 static int ftwdt010_wdt_start(struct watchdog_device *wdd)
68 {
69 struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
70
71 ftwdt010_enable(gwdt, wdd->timeout, gwdt->has_irq);
72 return 0;
73 }
74
ftwdt010_wdt_stop(struct watchdog_device * wdd)75 static int ftwdt010_wdt_stop(struct watchdog_device *wdd)
76 {
77 struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
78
79 writel(0, gwdt->base + FTWDT010_WDCR);
80
81 return 0;
82 }
83
ftwdt010_wdt_ping(struct watchdog_device * wdd)84 static int ftwdt010_wdt_ping(struct watchdog_device *wdd)
85 {
86 struct ftwdt010_wdt *gwdt = to_ftwdt010_wdt(wdd);
87
88 writel(WDRESTART_MAGIC, gwdt->base + FTWDT010_WDRESTART);
89
90 return 0;
91 }
92
ftwdt010_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)93 static int ftwdt010_wdt_set_timeout(struct watchdog_device *wdd,
94 unsigned int timeout)
95 {
96 wdd->timeout = timeout;
97 if (watchdog_active(wdd))
98 ftwdt010_wdt_start(wdd);
99
100 return 0;
101 }
102
ftwdt010_wdt_restart(struct watchdog_device * wdd,unsigned long action,void * data)103 static int ftwdt010_wdt_restart(struct watchdog_device *wdd,
104 unsigned long action, void *data)
105 {
106 ftwdt010_enable(to_ftwdt010_wdt(wdd), 0, false);
107 return 0;
108 }
109
ftwdt010_wdt_interrupt(int irq,void * data)110 static irqreturn_t ftwdt010_wdt_interrupt(int irq, void *data)
111 {
112 struct ftwdt010_wdt *gwdt = data;
113
114 watchdog_notify_pretimeout(&gwdt->wdd);
115
116 return IRQ_HANDLED;
117 }
118
119 static const struct watchdog_ops ftwdt010_wdt_ops = {
120 .start = ftwdt010_wdt_start,
121 .stop = ftwdt010_wdt_stop,
122 .ping = ftwdt010_wdt_ping,
123 .set_timeout = ftwdt010_wdt_set_timeout,
124 .restart = ftwdt010_wdt_restart,
125 .owner = THIS_MODULE,
126 };
127
128 static const struct watchdog_info ftwdt010_wdt_info = {
129 .options = WDIOF_KEEPALIVEPING
130 | WDIOF_MAGICCLOSE
131 | WDIOF_SETTIMEOUT,
132 .identity = KBUILD_MODNAME,
133 };
134
135
ftwdt010_wdt_probe(struct platform_device * pdev)136 static int ftwdt010_wdt_probe(struct platform_device *pdev)
137 {
138 struct device *dev = &pdev->dev;
139 struct ftwdt010_wdt *gwdt;
140 unsigned int reg;
141 int irq;
142 int ret;
143
144 gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
145 if (!gwdt)
146 return -ENOMEM;
147
148 gwdt->base = devm_platform_ioremap_resource(pdev, 0);
149 if (IS_ERR(gwdt->base))
150 return PTR_ERR(gwdt->base);
151
152 gwdt->dev = dev;
153 gwdt->wdd.info = &ftwdt010_wdt_info;
154 gwdt->wdd.ops = &ftwdt010_wdt_ops;
155 gwdt->wdd.min_timeout = 1;
156 gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
157 gwdt->wdd.parent = dev;
158
159 /*
160 * If 'timeout-sec' unspecified in devicetree, assume a 13 second
161 * default.
162 */
163 gwdt->wdd.timeout = 13U;
164 watchdog_init_timeout(&gwdt->wdd, 0, dev);
165
166 reg = readw(gwdt->base + FTWDT010_WDCR);
167 if (reg & WDCR_ENABLE) {
168 /* Watchdog was enabled by the bootloader, disable it. */
169 reg &= ~WDCR_ENABLE;
170 writel(reg, gwdt->base + FTWDT010_WDCR);
171 }
172
173 irq = platform_get_irq(pdev, 0);
174 if (irq > 0) {
175 ret = devm_request_irq(dev, irq, ftwdt010_wdt_interrupt, 0,
176 "watchdog bark", gwdt);
177 if (ret)
178 return ret;
179 gwdt->has_irq = true;
180 }
181
182 ret = devm_watchdog_register_device(dev, &gwdt->wdd);
183 if (ret)
184 return ret;
185
186 /* Set up platform driver data */
187 platform_set_drvdata(pdev, gwdt);
188 dev_info(dev, "FTWDT010 watchdog driver enabled\n");
189
190 return 0;
191 }
192
ftwdt010_wdt_suspend(struct device * dev)193 static int __maybe_unused ftwdt010_wdt_suspend(struct device *dev)
194 {
195 struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev);
196 unsigned int reg;
197
198 reg = readw(gwdt->base + FTWDT010_WDCR);
199 reg &= ~WDCR_ENABLE;
200 writel(reg, gwdt->base + FTWDT010_WDCR);
201
202 return 0;
203 }
204
ftwdt010_wdt_resume(struct device * dev)205 static int __maybe_unused ftwdt010_wdt_resume(struct device *dev)
206 {
207 struct ftwdt010_wdt *gwdt = dev_get_drvdata(dev);
208 unsigned int reg;
209
210 if (watchdog_active(&gwdt->wdd)) {
211 reg = readw(gwdt->base + FTWDT010_WDCR);
212 reg |= WDCR_ENABLE;
213 writel(reg, gwdt->base + FTWDT010_WDCR);
214 }
215
216 return 0;
217 }
218
219 static const struct dev_pm_ops ftwdt010_wdt_dev_pm_ops = {
220 SET_SYSTEM_SLEEP_PM_OPS(ftwdt010_wdt_suspend,
221 ftwdt010_wdt_resume)
222 };
223
224 static const struct of_device_id ftwdt010_wdt_match[] = {
225 { .compatible = "faraday,ftwdt010" },
226 { .compatible = "cortina,gemini-watchdog" },
227 {},
228 };
229 MODULE_DEVICE_TABLE(of, ftwdt010_wdt_match);
230
231 static struct platform_driver ftwdt010_wdt_driver = {
232 .probe = ftwdt010_wdt_probe,
233 .driver = {
234 .name = "ftwdt010-wdt",
235 .of_match_table = ftwdt010_wdt_match,
236 .pm = &ftwdt010_wdt_dev_pm_ops,
237 },
238 };
239 module_platform_driver(ftwdt010_wdt_driver);
240 MODULE_AUTHOR("Linus Walleij");
241 MODULE_DESCRIPTION("Watchdog driver for Faraday Technology FTWDT010");
242 MODULE_LICENSE("GPL");
243