Merge tag 'mips_5.14_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
[linux-2.6-microblaze.git] / drivers / watchdog / rti_wdt.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Watchdog driver for the K3 RTI module
4  *
5  * (c) Copyright 2019-2020 Texas Instruments Inc.
6  * All rights reserved.
7  */
8
9 #include <linux/clk.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/io.h>
13 #include <linux/kernel.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/module.h>
16 #include <linux/moduleparam.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/types.h>
20 #include <linux/watchdog.h>
21
22 #define DEFAULT_HEARTBEAT 60
23
24 /* Max heartbeat is calculated at 32kHz source clock */
25 #define MAX_HEARTBEAT   1000
26
27 /* Timer register set definition */
28 #define RTIDWDCTRL      0x90
29 #define RTIDWDPRLD      0x94
30 #define RTIWDSTATUS     0x98
31 #define RTIWDKEY        0x9c
32 #define RTIDWDCNTR      0xa0
33 #define RTIWWDRXCTRL    0xa4
34 #define RTIWWDSIZECTRL  0xa8
35
36 #define RTIWWDRX_NMI    0xa
37
38 #define RTIWWDSIZE_50P          0x50
39 #define RTIWWDSIZE_25P          0x500
40 #define RTIWWDSIZE_12P5         0x5000
41 #define RTIWWDSIZE_6P25         0x50000
42 #define RTIWWDSIZE_3P125        0x500000
43
44 #define WDENABLE_KEY    0xa98559da
45
46 #define WDKEY_SEQ0              0xe51a
47 #define WDKEY_SEQ1              0xa35c
48
49 #define WDT_PRELOAD_SHIFT       13
50
51 #define WDT_PRELOAD_MAX         0xfff
52
53 #define DWDST                   BIT(1)
54
55 static int heartbeat = DEFAULT_HEARTBEAT;
56
57 /*
58  * struct to hold data for each WDT device
59  * @base - base io address of WD device
60  * @freq - source clock frequency of WDT
61  * @wdd  - hold watchdog device as is in WDT core
62  */
63 struct rti_wdt_device {
64         void __iomem            *base;
65         unsigned long           freq;
66         struct watchdog_device  wdd;
67 };
68
69 static int rti_wdt_start(struct watchdog_device *wdd)
70 {
71         u32 timer_margin;
72         struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
73
74         /* set timeout period */
75         timer_margin = (u64)wdd->timeout * wdt->freq;
76         timer_margin >>= WDT_PRELOAD_SHIFT;
77         if (timer_margin > WDT_PRELOAD_MAX)
78                 timer_margin = WDT_PRELOAD_MAX;
79         writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
80
81         /*
82          * RTI only supports a windowed mode, where the watchdog can only
83          * be petted during the open window; not too early or not too late.
84          * The HW configuration options only allow for the open window size
85          * to be 50% or less than that; we obviouly want to configure the open
86          * window as large as possible so we select the 50% option.
87          */
88         wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
89
90         /* Generate NMI when wdt expires */
91         writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
92
93         /* Open window size 50%; this is the largest window size available */
94         writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
95
96         readl_relaxed(wdt->base + RTIWWDSIZECTRL);
97
98         /* enable watchdog */
99         writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
100         return 0;
101 }
102
103 static int rti_wdt_ping(struct watchdog_device *wdd)
104 {
105         struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
106
107         /* put watchdog in service state */
108         writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
109         /* put watchdog in active state */
110         writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
111
112         return 0;
113 }
114
115 static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
116 {
117         /*
118          * RTI only supports a windowed mode, where the watchdog can only
119          * be petted during the open window; not too early or not too late.
120          * The HW configuration options only allow for the open window size
121          * to be 50% or less than that.
122          */
123         switch (wsize) {
124         case RTIWWDSIZE_50P:
125                 /* 50% open window => 50% min heartbeat */
126                 wdd->min_hw_heartbeat_ms = 500 * heartbeat;
127                 break;
128
129         case RTIWWDSIZE_25P:
130                 /* 25% open window => 75% min heartbeat */
131                 wdd->min_hw_heartbeat_ms = 750 * heartbeat;
132                 break;
133
134         case RTIWWDSIZE_12P5:
135                 /* 12.5% open window => 87.5% min heartbeat */
136                 wdd->min_hw_heartbeat_ms = 875 * heartbeat;
137                 break;
138
139         case RTIWWDSIZE_6P25:
140                 /* 6.5% open window => 93.5% min heartbeat */
141                 wdd->min_hw_heartbeat_ms = 935 * heartbeat;
142                 break;
143
144         case RTIWWDSIZE_3P125:
145                 /* 3.125% open window => 96.9% min heartbeat */
146                 wdd->min_hw_heartbeat_ms = 969 * heartbeat;
147                 break;
148
149         default:
150                 return -EINVAL;
151         }
152
153         return 0;
154 }
155
156 static unsigned int rti_wdt_get_timeleft_ms(struct watchdog_device *wdd)
157 {
158         u64 timer_counter;
159         u32 val;
160         struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
161
162         /* if timeout has occurred then return 0 */
163         val = readl_relaxed(wdt->base + RTIWDSTATUS);
164         if (val & DWDST)
165                 return 0;
166
167         timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
168
169         timer_counter *= 1000;
170
171         do_div(timer_counter, wdt->freq);
172
173         return timer_counter;
174 }
175
176 static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
177 {
178         return rti_wdt_get_timeleft_ms(wdd) / 1000;
179 }
180
181 static const struct watchdog_info rti_wdt_info = {
182         .options = WDIOF_KEEPALIVEPING,
183         .identity = "K3 RTI Watchdog",
184 };
185
186 static const struct watchdog_ops rti_wdt_ops = {
187         .owner          = THIS_MODULE,
188         .start          = rti_wdt_start,
189         .ping           = rti_wdt_ping,
190         .get_timeleft   = rti_wdt_get_timeleft,
191 };
192
193 static int rti_wdt_probe(struct platform_device *pdev)
194 {
195         int ret = 0;
196         struct device *dev = &pdev->dev;
197         struct resource *wdt_mem;
198         struct watchdog_device *wdd;
199         struct rti_wdt_device *wdt;
200         struct clk *clk;
201         u32 last_ping = 0;
202
203         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
204         if (!wdt)
205                 return -ENOMEM;
206
207         clk = clk_get(dev, NULL);
208         if (IS_ERR(clk))
209                 return dev_err_probe(dev, PTR_ERR(clk), "failed to get clock\n");
210
211         wdt->freq = clk_get_rate(clk);
212
213         clk_put(clk);
214
215         if (!wdt->freq) {
216                 dev_err(dev, "Failed to get fck rate.\n");
217                 return -EINVAL;
218         }
219
220         /*
221          * If watchdog is running at 32k clock, it is not accurate.
222          * Adjust frequency down in this case so that we don't pet
223          * the watchdog too often.
224          */
225         if (wdt->freq < 32768)
226                 wdt->freq = wdt->freq * 9 / 10;
227
228         pm_runtime_enable(dev);
229         ret = pm_runtime_get_sync(dev);
230         if (ret) {
231                 pm_runtime_put_noidle(dev);
232                 return dev_err_probe(dev, ret, "runtime pm failed\n");
233         }
234
235         platform_set_drvdata(pdev, wdt);
236
237         wdd = &wdt->wdd;
238         wdd->info = &rti_wdt_info;
239         wdd->ops = &rti_wdt_ops;
240         wdd->min_timeout = 1;
241         wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
242                 wdt->freq * 1000;
243         wdd->parent = dev;
244
245         watchdog_set_drvdata(wdd, wdt);
246         watchdog_set_nowayout(wdd, 1);
247         watchdog_set_restart_priority(wdd, 128);
248
249         wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
250         wdt->base = devm_ioremap_resource(dev, wdt_mem);
251         if (IS_ERR(wdt->base)) {
252                 ret = PTR_ERR(wdt->base);
253                 goto err_iomap;
254         }
255
256         if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) {
257                 u32 time_left_ms;
258                 u64 heartbeat_ms;
259                 u32 wsize;
260
261                 set_bit(WDOG_HW_RUNNING, &wdd->status);
262                 time_left_ms = rti_wdt_get_timeleft_ms(wdd);
263                 heartbeat_ms = readl(wdt->base + RTIDWDPRLD);
264                 heartbeat_ms <<= WDT_PRELOAD_SHIFT;
265                 heartbeat_ms *= 1000;
266                 do_div(heartbeat_ms, wdt->freq);
267                 if (heartbeat_ms != heartbeat * 1000)
268                         dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n");
269
270                 heartbeat = heartbeat_ms;
271                 heartbeat /= 1000;
272
273                 wsize = readl(wdt->base + RTIWWDSIZECTRL);
274                 ret = rti_wdt_setup_hw_hb(wdd, wsize);
275                 if (ret) {
276                         dev_err(dev, "bad window size.\n");
277                         goto err_iomap;
278                 }
279
280                 last_ping = heartbeat_ms - time_left_ms;
281                 if (time_left_ms > heartbeat_ms) {
282                         dev_warn(dev, "time_left > heartbeat? Assuming last ping just before now.\n");
283                         last_ping = 0;
284                 }
285         }
286
287         watchdog_init_timeout(wdd, heartbeat, dev);
288
289         ret = watchdog_register_device(wdd);
290         if (ret) {
291                 dev_err(dev, "cannot register watchdog device\n");
292                 goto err_iomap;
293         }
294
295         if (last_ping)
296                 watchdog_set_last_hw_keepalive(wdd, last_ping);
297
298         return 0;
299
300 err_iomap:
301         pm_runtime_put_sync(&pdev->dev);
302         pm_runtime_disable(&pdev->dev);
303
304         return ret;
305 }
306
307 static int rti_wdt_remove(struct platform_device *pdev)
308 {
309         struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
310
311         watchdog_unregister_device(&wdt->wdd);
312         pm_runtime_put(&pdev->dev);
313         pm_runtime_disable(&pdev->dev);
314
315         return 0;
316 }
317
318 static const struct of_device_id rti_wdt_of_match[] = {
319         { .compatible = "ti,j7-rti-wdt", },
320         {},
321 };
322 MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
323
324 static struct platform_driver rti_wdt_driver = {
325         .driver = {
326                 .name = "rti-wdt",
327                 .of_match_table = rti_wdt_of_match,
328         },
329         .probe = rti_wdt_probe,
330         .remove = rti_wdt_remove,
331 };
332
333 module_platform_driver(rti_wdt_driver);
334
335 MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
336 MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
337
338 module_param(heartbeat, int, 0);
339 MODULE_PARM_DESC(heartbeat,
340                  "Watchdog heartbeat period in seconds from 1 to "
341                  __MODULE_STRING(MAX_HEARTBEAT) ", default "
342                  __MODULE_STRING(DEFAULT_HEARTBEAT));
343
344 MODULE_LICENSE("GPL");
345 MODULE_ALIAS("platform:rti-wdt");