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> |
16 | #include <linux/of.h> |
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(sp: to_rave_sp_wdt(wdd)->sp, |
69 | data: data, data_size, NULL, reply_data_size: 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, data: cmd, data_size: 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, data: cmd, data_size: 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, data: cmd, data_size: 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, data: cmd, data_size: 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, on: true); |
184 | if (!ret) |
185 | set_bit(WDOG_HW_RUNNING, addr: &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, on: 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, on: 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, data: cmd, data_size: 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, size: 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: 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, id: "wdt-timeout" ); |
279 | if (!IS_ERR(ptr: cell)) { |
280 | size_t len; |
281 | void *value = nvmem_cell_read(cell, len: &len); |
282 | |
283 | if (!IS_ERR(ptr: value)) { |
284 | memcpy(&timeout, value, min(len, sizeof(timeout))); |
285 | kfree(objp: value); |
286 | } |
287 | nvmem_cell_put(cell); |
288 | } |
289 | watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev); |
290 | watchdog_set_restart_priority(wdd, priority: 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) { |
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" ); |
337 | |