Merge remote-tracking branch 'stable/linux-5.15.y' into rpi-5.15.y
[platform/kernel/linux-rpi.git] / drivers / watchdog / uniphier_wdt.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Watchdog driver for the UniPhier watchdog timer
4  *
5  * (c) Copyright 2014 Panasonic Corporation
6  * (c) Copyright 2016 Socionext Inc.
7  * All rights reserved.
8  */
9
10 #include <linux/bitops.h>
11 #include <linux/mfd/syscon.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/platform_device.h>
15 #include <linux/regmap.h>
16 #include <linux/watchdog.h>
17
18 /* WDT timer setting register */
19 #define WDTTIMSET                       0x3004
20 #define   WDTTIMSET_PERIOD_MASK         (0xf << 0)
21 #define   WDTTIMSET_PERIOD_1_SEC        (0x3 << 0)
22
23 /* WDT reset selection register */
24 #define WDTRSTSEL                       0x3008
25 #define   WDTRSTSEL_RSTSEL_MASK         (0x3 << 0)
26 #define   WDTRSTSEL_RSTSEL_BOTH         (0x0 << 0)
27 #define   WDTRSTSEL_RSTSEL_IRQ_ONLY     (0x2 << 0)
28
29 /* WDT control register */
30 #define WDTCTRL                         0x300c
31 #define   WDTCTRL_STATUS                BIT(8)
32 #define   WDTCTRL_CLEAR                 BIT(1)
33 #define   WDTCTRL_ENABLE                BIT(0)
34
35 #define SEC_TO_WDTTIMSET_PRD(sec) \
36                 (ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
37
38 #define WDTST_TIMEOUT                   1000 /* usec */
39
40 #define WDT_DEFAULT_TIMEOUT             64   /* Default is 64 seconds */
41 #define WDT_PERIOD_MIN                  1
42 #define WDT_PERIOD_MAX                  128
43
44 static unsigned int timeout = 0;
45 static bool nowayout = WATCHDOG_NOWAYOUT;
46
47 struct uniphier_wdt_dev {
48         struct watchdog_device wdt_dev;
49         struct regmap   *regmap;
50 };
51
52 /*
53  * UniPhier Watchdog operations
54  */
55 static int uniphier_watchdog_ping(struct watchdog_device *w)
56 {
57         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
58         unsigned int val;
59         int ret;
60
61         /* Clear counter */
62         ret = regmap_write_bits(wdev->regmap, WDTCTRL,
63                                 WDTCTRL_CLEAR, WDTCTRL_CLEAR);
64         if (!ret)
65                 /*
66                  * As SoC specification, after clear counter,
67                  * it needs to wait until counter status is 1.
68                  */
69                 ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
70                                                (val & WDTCTRL_STATUS),
71                                                0, WDTST_TIMEOUT);
72
73         return ret;
74 }
75
76 static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
77 {
78         unsigned int val;
79         int ret;
80
81         ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
82                                        !(val & WDTCTRL_STATUS),
83                                        0, WDTST_TIMEOUT);
84         if (ret)
85                 return ret;
86
87         /* Setup period */
88         ret = regmap_write(regmap, WDTTIMSET,
89                            SEC_TO_WDTTIMSET_PRD(sec));
90         if (ret)
91                 return ret;
92
93         /* Enable and clear watchdog */
94         ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
95         if (!ret)
96                 /*
97                  * As SoC specification, after clear counter,
98                  * it needs to wait until counter status is 1.
99                  */
100                 ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
101                                                (val & WDTCTRL_STATUS),
102                                                0, WDTST_TIMEOUT);
103
104         return ret;
105 }
106
107 static int __uniphier_watchdog_stop(struct regmap *regmap)
108 {
109         /* Disable and stop watchdog */
110         return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
111 }
112
113 static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
114 {
115         int ret;
116
117         ret = __uniphier_watchdog_stop(regmap);
118         if (ret)
119                 return ret;
120
121         return __uniphier_watchdog_start(regmap, sec);
122 }
123
124 static int uniphier_watchdog_start(struct watchdog_device *w)
125 {
126         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
127         unsigned int tmp_timeout;
128
129         tmp_timeout = roundup_pow_of_two(w->timeout);
130
131         return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
132 }
133
134 static int uniphier_watchdog_stop(struct watchdog_device *w)
135 {
136         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
137
138         return __uniphier_watchdog_stop(wdev->regmap);
139 }
140
141 static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
142                                          unsigned int t)
143 {
144         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
145         unsigned int tmp_timeout;
146         int ret;
147
148         tmp_timeout = roundup_pow_of_two(t);
149         if (tmp_timeout == w->timeout)
150                 return 0;
151
152         if (watchdog_active(w)) {
153                 ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
154                 if (ret)
155                         return ret;
156         }
157
158         w->timeout = tmp_timeout;
159
160         return 0;
161 }
162
163 /*
164  * Kernel Interfaces
165  */
166 static const struct watchdog_info uniphier_wdt_info = {
167         .identity       = "uniphier-wdt",
168         .options        = WDIOF_SETTIMEOUT |
169                           WDIOF_KEEPALIVEPING |
170                           WDIOF_MAGICCLOSE |
171                           WDIOF_OVERHEAT,
172 };
173
174 static const struct watchdog_ops uniphier_wdt_ops = {
175         .owner          = THIS_MODULE,
176         .start          = uniphier_watchdog_start,
177         .stop           = uniphier_watchdog_stop,
178         .ping           = uniphier_watchdog_ping,
179         .set_timeout    = uniphier_watchdog_set_timeout,
180 };
181
182 static int uniphier_wdt_probe(struct platform_device *pdev)
183 {
184         struct device *dev = &pdev->dev;
185         struct uniphier_wdt_dev *wdev;
186         struct regmap *regmap;
187         struct device_node *parent;
188         int ret;
189
190         wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
191         if (!wdev)
192                 return -ENOMEM;
193
194         parent = of_get_parent(dev->of_node); /* parent should be syscon node */
195         regmap = syscon_node_to_regmap(parent);
196         of_node_put(parent);
197         if (IS_ERR(regmap))
198                 return PTR_ERR(regmap);
199
200         wdev->regmap = regmap;
201         wdev->wdt_dev.info = &uniphier_wdt_info;
202         wdev->wdt_dev.ops = &uniphier_wdt_ops;
203         wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
204         wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
205         wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
206         wdev->wdt_dev.parent = dev;
207
208         watchdog_init_timeout(&wdev->wdt_dev, timeout, dev);
209         watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
210         watchdog_stop_on_reboot(&wdev->wdt_dev);
211
212         watchdog_set_drvdata(&wdev->wdt_dev, wdev);
213
214         uniphier_watchdog_stop(&wdev->wdt_dev);
215         ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
216         if (ret)
217                 return ret;
218
219         ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
220         if (ret)
221                 return ret;
222
223         dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
224                  wdev->wdt_dev.timeout, nowayout);
225
226         return 0;
227 }
228
229 static const struct of_device_id uniphier_wdt_dt_ids[] = {
230         { .compatible = "socionext,uniphier-wdt" },
231         { /* sentinel */ }
232 };
233 MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
234
235 static struct platform_driver uniphier_wdt_driver = {
236         .probe          = uniphier_wdt_probe,
237         .driver         = {
238                 .name           = "uniphier-wdt",
239                 .of_match_table = uniphier_wdt_dt_ids,
240         },
241 };
242
243 module_platform_driver(uniphier_wdt_driver);
244
245 module_param(timeout, uint, 0000);
246 MODULE_PARM_DESC(timeout,
247         "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
248                                 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
249
250 module_param(nowayout, bool, 0000);
251 MODULE_PARM_DESC(nowayout,
252         "Watchdog cannot be stopped once started (default="
253                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
254
255 MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
256 MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
257 MODULE_LICENSE("GPL v2");