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c3bb3334 AS |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | ||
3 | /* | |
4 | * Driver for watchdog aspect of for Zodiac Inflight Innovations RAVE | |
5 | * Supervisory Processor(SP) MCU | |
6 | * | |
7 | * Copyright (C) 2017 Zodiac Inflight Innovation | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/delay.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/mfd/rave-sp.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/nvmem-consumer.h> | |
cc85f87a | 16 | #include <linux/of.h> |
c3bb3334 AS |
17 | #include <linux/platform_device.h> |
18 | #include <linux/reboot.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/watchdog.h> | |
21 | ||
22 | enum { | |
23 | RAVE_SP_RESET_BYTE = 1, | |
24 | RAVE_SP_RESET_REASON_NORMAL = 0, | |
25 | RAVE_SP_RESET_DELAY_MS = 500, | |
26 | }; | |
27 | ||
28 | /** | |
29 | * struct rave_sp_wdt_variant - RAVE SP watchdog variant | |
30 | * | |
31 | * @max_timeout: Largest possible watchdog timeout setting | |
32 | * @min_timeout: Smallest possible watchdog timeout setting | |
33 | * | |
34 | * @configure: Function to send configuration command | |
35 | * @restart: Function to send "restart" command | |
36 | */ | |
37 | struct rave_sp_wdt_variant { | |
38 | unsigned int max_timeout; | |
39 | unsigned int min_timeout; | |
40 | ||
41 | int (*configure)(struct watchdog_device *, bool); | |
42 | int (*restart)(struct watchdog_device *); | |
43 | }; | |
44 | ||
45 | /** | |
46 | * struct rave_sp_wdt - RAVE SP watchdog | |
47 | * | |
48 | * @wdd: Underlying watchdog device | |
49 | * @sp: Pointer to parent RAVE SP device | |
50 | * @variant: Device specific variant information | |
51 | * @reboot_notifier: Reboot notifier implementing machine reset | |
52 | */ | |
53 | struct rave_sp_wdt { | |
54 | struct watchdog_device wdd; | |
55 | struct rave_sp *sp; | |
56 | const struct rave_sp_wdt_variant *variant; | |
57 | struct notifier_block reboot_notifier; | |
58 | }; | |
59 | ||
60 | static struct rave_sp_wdt *to_rave_sp_wdt(struct watchdog_device *wdd) | |
61 | { | |
62 | return container_of(wdd, struct rave_sp_wdt, wdd); | |
63 | } | |
64 | ||
65 | static int rave_sp_wdt_exec(struct watchdog_device *wdd, void *data, | |
66 | size_t data_size) | |
67 | { | |
68 | return rave_sp_exec(to_rave_sp_wdt(wdd)->sp, | |
69 | data, data_size, NULL, 0); | |
70 | } | |
71 | ||
72 | static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd, bool on) | |
73 | { | |
74 | u8 cmd[] = { | |
75 | [0] = RAVE_SP_CMD_SW_WDT, | |
76 | [1] = 0, | |
77 | [2] = 0, | |
78 | [3] = on, | |
79 | [4] = on ? wdd->timeout : 0, | |
80 | }; | |
81 | ||
82 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); | |
83 | } | |
84 | ||
85 | static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd, bool on) | |
86 | { | |
87 | u8 cmd[] = { | |
88 | [0] = RAVE_SP_CMD_SW_WDT, | |
89 | [1] = 0, | |
90 | [2] = on, | |
91 | [3] = (u8)wdd->timeout, | |
92 | [4] = (u8)(wdd->timeout >> 8), | |
93 | }; | |
94 | ||
95 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); | |
96 | } | |
97 | ||
98 | /** | |
99 | * rave_sp_wdt_configure - Configure watchdog device | |
100 | * | |
101 | * @wdd: Device to configure | |
102 | * @on: Desired state of the watchdog timer (ON/OFF) | |
103 | * | |
104 | * This function configures two aspects of the watchdog timer: | |
105 | * | |
106 | * - Wheither it is ON or OFF | |
107 | * - Its timeout duration | |
108 | * | |
109 | * with first aspect specified via function argument and second via | |
110 | * the value of 'wdd->timeout'. | |
111 | */ | |
112 | static int rave_sp_wdt_configure(struct watchdog_device *wdd, bool on) | |
113 | { | |
114 | return to_rave_sp_wdt(wdd)->variant->configure(wdd, on); | |
115 | } | |
116 | ||
117 | static int rave_sp_wdt_legacy_restart(struct watchdog_device *wdd) | |
118 | { | |
119 | u8 cmd[] = { | |
120 | [0] = RAVE_SP_CMD_RESET, | |
121 | [1] = 0, | |
122 | [2] = RAVE_SP_RESET_BYTE | |
123 | }; | |
124 | ||
125 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); | |
126 | } | |
127 | ||
128 | static int rave_sp_wdt_rdu_restart(struct watchdog_device *wdd) | |
129 | { | |
130 | u8 cmd[] = { | |
131 | [0] = RAVE_SP_CMD_RESET, | |
132 | [1] = 0, | |
133 | [2] = RAVE_SP_RESET_BYTE, | |
134 | [3] = RAVE_SP_RESET_REASON_NORMAL | |
135 | }; | |
136 | ||
137 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); | |
138 | } | |
139 | ||
140 | static int rave_sp_wdt_reboot_notifier(struct notifier_block *nb, | |
141 | unsigned long action, void *data) | |
142 | { | |
143 | /* | |
144 | * Restart handler is called in atomic context which means we | |
145 | * can't communicate to SP via UART. Luckily for use SP will | |
146 | * wait 500ms before actually resetting us, so we ask it to do | |
147 | * so here and let the rest of the system go on wrapping | |
148 | * things up. | |
149 | */ | |
150 | if (action == SYS_DOWN || action == SYS_HALT) { | |
151 | struct rave_sp_wdt *sp_wd = | |
152 | container_of(nb, struct rave_sp_wdt, reboot_notifier); | |
153 | ||
154 | const int ret = sp_wd->variant->restart(&sp_wd->wdd); | |
155 | ||
156 | if (ret < 0) | |
157 | dev_err(sp_wd->wdd.parent, | |
158 | "Failed to issue restart command (%d)", ret); | |
159 | return NOTIFY_OK; | |
160 | } | |
161 | ||
162 | return NOTIFY_DONE; | |
163 | } | |
164 | ||
165 | static int rave_sp_wdt_restart(struct watchdog_device *wdd, | |
166 | unsigned long action, void *data) | |
167 | { | |
168 | /* | |
169 | * The actual work was done by reboot notifier above. SP | |
170 | * firmware waits 500 ms before issuing reset, so let's hang | |
171 | * here for twice that delay and hopefuly we'd never reach | |
172 | * the return statement. | |
173 | */ | |
174 | mdelay(2 * RAVE_SP_RESET_DELAY_MS); | |
175 | ||
176 | return -EIO; | |
177 | } | |
178 | ||
179 | static int rave_sp_wdt_start(struct watchdog_device *wdd) | |
180 | { | |
181 | int ret; | |
182 | ||
183 | ret = rave_sp_wdt_configure(wdd, true); | |
184 | if (!ret) | |
185 | set_bit(WDOG_HW_RUNNING, &wdd->status); | |
186 | ||
187 | return ret; | |
188 | } | |
189 | ||
190 | static int rave_sp_wdt_stop(struct watchdog_device *wdd) | |
191 | { | |
192 | return rave_sp_wdt_configure(wdd, false); | |
193 | } | |
194 | ||
195 | static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd, | |
196 | unsigned int timeout) | |
197 | { | |
198 | wdd->timeout = timeout; | |
199 | ||
200 | return rave_sp_wdt_configure(wdd, watchdog_active(wdd)); | |
201 | } | |
202 | ||
203 | static int rave_sp_wdt_ping(struct watchdog_device *wdd) | |
204 | { | |
205 | u8 cmd[] = { | |
206 | [0] = RAVE_SP_CMD_PET_WDT, | |
207 | [1] = 0, | |
208 | }; | |
209 | ||
210 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); | |
211 | } | |
212 | ||
213 | static const struct watchdog_info rave_sp_wdt_info = { | |
214 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
215 | .identity = "RAVE SP Watchdog", | |
216 | }; | |
217 | ||
218 | static const struct watchdog_ops rave_sp_wdt_ops = { | |
219 | .owner = THIS_MODULE, | |
220 | .start = rave_sp_wdt_start, | |
221 | .stop = rave_sp_wdt_stop, | |
222 | .ping = rave_sp_wdt_ping, | |
223 | .set_timeout = rave_sp_wdt_set_timeout, | |
224 | .restart = rave_sp_wdt_restart, | |
225 | }; | |
226 | ||
227 | static const struct rave_sp_wdt_variant rave_sp_wdt_legacy = { | |
228 | .max_timeout = 255, | |
229 | .min_timeout = 1, | |
230 | .configure = rave_sp_wdt_legacy_configure, | |
231 | .restart = rave_sp_wdt_legacy_restart, | |
232 | }; | |
233 | ||
234 | static const struct rave_sp_wdt_variant rave_sp_wdt_rdu = { | |
235 | .max_timeout = 180, | |
236 | .min_timeout = 60, | |
237 | .configure = rave_sp_wdt_rdu_configure, | |
238 | .restart = rave_sp_wdt_rdu_restart, | |
239 | }; | |
240 | ||
241 | static const struct of_device_id rave_sp_wdt_of_match[] = { | |
242 | { | |
243 | .compatible = "zii,rave-sp-watchdog-legacy", | |
244 | .data = &rave_sp_wdt_legacy, | |
245 | }, | |
246 | { | |
247 | .compatible = "zii,rave-sp-watchdog", | |
248 | .data = &rave_sp_wdt_rdu, | |
249 | }, | |
250 | { /* sentinel */ } | |
251 | }; | |
252 | ||
253 | static int rave_sp_wdt_probe(struct platform_device *pdev) | |
254 | { | |
255 | struct device *dev = &pdev->dev; | |
256 | struct watchdog_device *wdd; | |
257 | struct rave_sp_wdt *sp_wd; | |
258 | struct nvmem_cell *cell; | |
259 | __le16 timeout = 0; | |
260 | int ret; | |
261 | ||
262 | sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL); | |
263 | if (!sp_wd) | |
264 | return -ENOMEM; | |
265 | ||
266 | sp_wd->variant = of_device_get_match_data(dev); | |
267 | sp_wd->sp = dev_get_drvdata(dev->parent); | |
268 | ||
269 | wdd = &sp_wd->wdd; | |
270 | wdd->parent = dev; | |
271 | wdd->info = &rave_sp_wdt_info; | |
272 | wdd->ops = &rave_sp_wdt_ops; | |
273 | wdd->min_timeout = sp_wd->variant->min_timeout; | |
274 | wdd->max_timeout = sp_wd->variant->max_timeout; | |
275 | wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; | |
276 | wdd->timeout = 60; | |
277 | ||
278 | cell = nvmem_cell_get(dev, "wdt-timeout"); | |
279 | if (!IS_ERR(cell)) { | |
280 | size_t len; | |
281 | void *value = nvmem_cell_read(cell, &len); | |
282 | ||
283 | if (!IS_ERR(value)) { | |
284 | memcpy(&timeout, value, min(len, sizeof(timeout))); | |
285 | kfree(value); | |
286 | } | |
287 | nvmem_cell_put(cell); | |
288 | } | |
289 | watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev); | |
290 | watchdog_set_restart_priority(wdd, 255); | |
291 | watchdog_stop_on_unregister(wdd); | |
292 | ||
293 | sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier; | |
294 | ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier); | |
295 | if (ret) { | |
296 | dev_err(dev, "Failed to register reboot notifier\n"); | |
297 | return ret; | |
298 | } | |
299 | ||
300 | /* | |
301 | * We don't know if watchdog is running now. To be sure, let's | |
302 | * start it and depend on watchdog core to ping it | |
303 | */ | |
304 | wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000; | |
305 | ret = rave_sp_wdt_start(wdd); | |
306 | if (ret) { | |
307 | dev_err(dev, "Watchdog didn't start\n"); | |
308 | return ret; | |
309 | } | |
310 | ||
311 | ret = devm_watchdog_register_device(dev, wdd); | |
312 | if (ret) { | |
c3bb3334 AS |
313 | rave_sp_wdt_stop(wdd); |
314 | return ret; | |
315 | } | |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | static struct platform_driver rave_sp_wdt_driver = { | |
321 | .probe = rave_sp_wdt_probe, | |
322 | .driver = { | |
323 | .name = KBUILD_MODNAME, | |
324 | .of_match_table = rave_sp_wdt_of_match, | |
325 | }, | |
326 | }; | |
327 | ||
328 | module_platform_driver(rave_sp_wdt_driver); | |
329 | ||
330 | MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match); | |
331 | MODULE_LICENSE("GPL"); | |
332 | MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>"); | |
333 | MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>"); | |
334 | MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); | |
335 | MODULE_DESCRIPTION("RAVE SP Watchdog driver"); | |
336 | MODULE_ALIAS("platform:rave-sp-watchdog"); |