1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
4 * JZ4740 Watchdog driver
5 */
6
7 #include <linux/mfd/ingenic-tcu.h>
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/watchdog.h>
13 #include <linux/platform_device.h>
14 #include <linux/io.h>
15 #include <linux/device.h>
16 #include <linux/clk.h>
17 #include <linux/slab.h>
18 #include <linux/err.h>
19 #include <linux/of.h>
20
21 #include <asm/mach-jz4740/timer.h>
22
23 #define JZ_WDT_CLOCK_PCLK 0x1
24 #define JZ_WDT_CLOCK_RTC 0x2
25 #define JZ_WDT_CLOCK_EXT 0x4
26
27 #define JZ_WDT_CLOCK_DIV_1 (0 << TCU_TCSR_PRESCALE_LSB)
28 #define JZ_WDT_CLOCK_DIV_4 (1 << TCU_TCSR_PRESCALE_LSB)
29 #define JZ_WDT_CLOCK_DIV_16 (2 << TCU_TCSR_PRESCALE_LSB)
30 #define JZ_WDT_CLOCK_DIV_64 (3 << TCU_TCSR_PRESCALE_LSB)
31 #define JZ_WDT_CLOCK_DIV_256 (4 << TCU_TCSR_PRESCALE_LSB)
32 #define JZ_WDT_CLOCK_DIV_1024 (5 << TCU_TCSR_PRESCALE_LSB)
33
34 #define DEFAULT_HEARTBEAT 5
35 #define MAX_HEARTBEAT 2048
36
37 static bool nowayout = WATCHDOG_NOWAYOUT;
38 module_param(nowayout, bool, 0);
39 MODULE_PARM_DESC(nowayout,
40 "Watchdog cannot be stopped once started (default="
41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42
43 static unsigned int heartbeat = DEFAULT_HEARTBEAT;
44 module_param(heartbeat, uint, 0);
45 MODULE_PARM_DESC(heartbeat,
46 "Watchdog heartbeat period in seconds from 1 to "
47 __MODULE_STRING(MAX_HEARTBEAT) ", default "
48 __MODULE_STRING(DEFAULT_HEARTBEAT));
49
50 struct jz4740_wdt_drvdata {
51 struct watchdog_device wdt;
52 void __iomem *base;
53 struct clk *rtc_clk;
54 };
55
jz4740_wdt_ping(struct watchdog_device * wdt_dev)56 static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
57 {
58 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
59
60 writew(0x0, drvdata->base + TCU_REG_WDT_TCNT);
61 return 0;
62 }
63
jz4740_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int new_timeout)64 static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
65 unsigned int new_timeout)
66 {
67 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
68 unsigned int rtc_clk_rate;
69 unsigned int timeout_value;
70 unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
71 u8 tcer;
72
73 rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
74
75 timeout_value = rtc_clk_rate * new_timeout;
76 while (timeout_value > 0xffff) {
77 if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
78 /* Requested timeout too high;
79 * use highest possible value. */
80 timeout_value = 0xffff;
81 break;
82 }
83 timeout_value >>= 2;
84 clock_div += (1 << TCU_TCSR_PRESCALE_LSB);
85 }
86
87 tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
88 writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
89 writew(clock_div, drvdata->base + TCU_REG_WDT_TCSR);
90
91 writew((u16)timeout_value, drvdata->base + TCU_REG_WDT_TDR);
92 writew(0x0, drvdata->base + TCU_REG_WDT_TCNT);
93 writew(clock_div | JZ_WDT_CLOCK_RTC, drvdata->base + TCU_REG_WDT_TCSR);
94
95 if (tcer & TCU_WDT_TCER_TCEN)
96 writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
97
98 wdt_dev->timeout = new_timeout;
99 return 0;
100 }
101
jz4740_wdt_start(struct watchdog_device * wdt_dev)102 static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
103 {
104 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
105 u8 tcer;
106
107 tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
108
109 jz4740_timer_enable_watchdog();
110 jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
111
112 /* Start watchdog if it wasn't started already */
113 if (!(tcer & TCU_WDT_TCER_TCEN))
114 writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
115
116 return 0;
117 }
118
jz4740_wdt_stop(struct watchdog_device * wdt_dev)119 static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
120 {
121 struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
122
123 writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
124 jz4740_timer_disable_watchdog();
125
126 return 0;
127 }
128
jz4740_wdt_restart(struct watchdog_device * wdt_dev,unsigned long action,void * data)129 static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,
130 unsigned long action, void *data)
131 {
132 wdt_dev->timeout = 0;
133 jz4740_wdt_start(wdt_dev);
134 return 0;
135 }
136
137 static const struct watchdog_info jz4740_wdt_info = {
138 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
139 .identity = "jz4740 Watchdog",
140 };
141
142 static const struct watchdog_ops jz4740_wdt_ops = {
143 .owner = THIS_MODULE,
144 .start = jz4740_wdt_start,
145 .stop = jz4740_wdt_stop,
146 .ping = jz4740_wdt_ping,
147 .set_timeout = jz4740_wdt_set_timeout,
148 .restart = jz4740_wdt_restart,
149 };
150
151 #ifdef CONFIG_OF
152 static const struct of_device_id jz4740_wdt_of_matches[] = {
153 { .compatible = "ingenic,jz4740-watchdog", },
154 { .compatible = "ingenic,jz4780-watchdog", },
155 { /* sentinel */ }
156 };
157 MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
158 #endif
159
jz4740_wdt_probe(struct platform_device * pdev)160 static int jz4740_wdt_probe(struct platform_device *pdev)
161 {
162 struct device *dev = &pdev->dev;
163 struct jz4740_wdt_drvdata *drvdata;
164 struct watchdog_device *jz4740_wdt;
165
166 drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),
167 GFP_KERNEL);
168 if (!drvdata)
169 return -ENOMEM;
170
171 if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
172 heartbeat = DEFAULT_HEARTBEAT;
173
174 jz4740_wdt = &drvdata->wdt;
175 jz4740_wdt->info = &jz4740_wdt_info;
176 jz4740_wdt->ops = &jz4740_wdt_ops;
177 jz4740_wdt->timeout = heartbeat;
178 jz4740_wdt->min_timeout = 1;
179 jz4740_wdt->max_timeout = MAX_HEARTBEAT;
180 jz4740_wdt->parent = dev;
181 watchdog_set_nowayout(jz4740_wdt, nowayout);
182 watchdog_set_drvdata(jz4740_wdt, drvdata);
183
184 drvdata->base = devm_platform_ioremap_resource(pdev, 0);
185 if (IS_ERR(drvdata->base))
186 return PTR_ERR(drvdata->base);
187
188 drvdata->rtc_clk = devm_clk_get(dev, "rtc");
189 if (IS_ERR(drvdata->rtc_clk)) {
190 dev_err(dev, "cannot find RTC clock\n");
191 return PTR_ERR(drvdata->rtc_clk);
192 }
193
194 return devm_watchdog_register_device(dev, &drvdata->wdt);
195 }
196
197 static struct platform_driver jz4740_wdt_driver = {
198 .probe = jz4740_wdt_probe,
199 .driver = {
200 .name = "jz4740-wdt",
201 .of_match_table = of_match_ptr(jz4740_wdt_of_matches),
202 },
203 };
204
205 module_platform_driver(jz4740_wdt_driver);
206
207 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
208 MODULE_DESCRIPTION("jz4740 Watchdog Driver");
209 MODULE_LICENSE("GPL");
210 MODULE_ALIAS("platform:jz4740-wdt");
211
