1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ChromeOS EC multi-function device
4  *
5  * Copyright (C) 2012 Google, Inc
6  *
7  * The ChromeOS EC multi function device is used to mux all the requests
8  * to the EC device for its multiple features: keyboard controller,
9  * battery charging and regulator control, firmware update.
10  */
11 
12 #include <linux/interrupt.h>
13 #include <linux/module.h>
14 #include <linux/of_platform.h>
15 #include <linux/platform_device.h>
16 #include <linux/platform_data/cros_ec_commands.h>
17 #include <linux/platform_data/cros_ec_proto.h>
18 #include <linux/slab.h>
19 #include <linux/suspend.h>
20 
21 #include "cros_ec.h"
22 
23 static struct cros_ec_platform ec_p = {
24 	.ec_name = CROS_EC_DEV_NAME,
25 	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
26 };
27 
28 static struct cros_ec_platform pd_p = {
29 	.ec_name = CROS_EC_DEV_PD_NAME,
30 	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
31 };
32 
33 /**
34  * cros_ec_irq_handler() - top half part of the interrupt handler
35  * @irq: IRQ id
36  * @data: (ec_dev) Device with events to process.
37  *
38  * Return: Wakeup the bottom half
39  */
40 static irqreturn_t cros_ec_irq_handler(int irq, void *data)
41 {
42 	struct cros_ec_device *ec_dev = data;
43 
44 	ec_dev->last_event_time = cros_ec_get_time_ns();
45 
46 	return IRQ_WAKE_THREAD;
47 }
48 
49 /**
50  * cros_ec_handle_event() - process and forward pending events on EC
51  * @ec_dev: Device with events to process.
52  *
53  * Call this function in a loop when the kernel is notified that the EC has
54  * pending events.
55  *
56  * Return: true if more events are still pending and this function should be
57  * called again.
58  */
59 static bool cros_ec_handle_event(struct cros_ec_device *ec_dev)
60 {
61 	bool wake_event;
62 	bool ec_has_more_events;
63 	int ret;
64 
65 	ret = cros_ec_get_next_event(ec_dev, &wake_event, &ec_has_more_events);
66 
67 	/*
68 	 * Signal only if wake host events or any interrupt if
69 	 * cros_ec_get_next_event() returned an error (default value for
70 	 * wake_event is true)
71 	 */
72 	if (wake_event && device_may_wakeup(ec_dev->dev))
73 		pm_wakeup_event(ec_dev->dev, 0);
74 
75 	if (ret > 0)
76 		blocking_notifier_call_chain(&ec_dev->event_notifier,
77 					     0, ec_dev);
78 
79 	return ec_has_more_events;
80 }
81 
82 /**
83  * cros_ec_irq_thread() - bottom half part of the interrupt handler
84  * @irq: IRQ id
85  * @data: (ec_dev) Device with events to process.
86  *
87  * Return: Interrupt handled.
88  */
89 irqreturn_t cros_ec_irq_thread(int irq, void *data)
90 {
91 	struct cros_ec_device *ec_dev = data;
92 	bool ec_has_more_events;
93 
94 	do {
95 		ec_has_more_events = cros_ec_handle_event(ec_dev);
96 	} while (ec_has_more_events);
97 
98 	return IRQ_HANDLED;
99 }
100 EXPORT_SYMBOL(cros_ec_irq_thread);
101 
102 static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
103 {
104 	int ret;
105 	struct {
106 		struct cros_ec_command msg;
107 		union {
108 			struct ec_params_host_sleep_event req0;
109 			struct ec_params_host_sleep_event_v1 req1;
110 			struct ec_response_host_sleep_event_v1 resp1;
111 		} u;
112 	} __packed buf;
113 
114 	memset(&buf, 0, sizeof(buf));
115 
116 	if (ec_dev->host_sleep_v1) {
117 		buf.u.req1.sleep_event = sleep_event;
118 		buf.u.req1.suspend_params.sleep_timeout_ms =
119 				ec_dev->suspend_timeout_ms;
120 
121 		buf.msg.outsize = sizeof(buf.u.req1);
122 		if ((sleep_event == HOST_SLEEP_EVENT_S3_RESUME) ||
123 		    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
124 			buf.msg.insize = sizeof(buf.u.resp1);
125 
126 		buf.msg.version = 1;
127 
128 	} else {
129 		buf.u.req0.sleep_event = sleep_event;
130 		buf.msg.outsize = sizeof(buf.u.req0);
131 	}
132 
133 	buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
134 
135 	ret = cros_ec_cmd_xfer_status(ec_dev, &buf.msg);
136 	/* Report failure to transition to system wide suspend with a warning. */
137 	if (ret >= 0 && ec_dev->host_sleep_v1 &&
138 	    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME ||
139 	     sleep_event == HOST_SLEEP_EVENT_S3_RESUME)) {
140 		ec_dev->last_resume_result =
141 			buf.u.resp1.resume_response.sleep_transitions;
142 
143 		WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
144 			  EC_HOST_RESUME_SLEEP_TIMEOUT,
145 			  "EC detected sleep transition timeout. Total sleep transitions: %d",
146 			  buf.u.resp1.resume_response.sleep_transitions &
147 			  EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
148 	}
149 
150 	return ret;
151 }
152 
153 static int cros_ec_ready_event(struct notifier_block *nb,
154 			       unsigned long queued_during_suspend,
155 			       void *_notify)
156 {
157 	struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
158 						     notifier_ready);
159 	u32 host_event = cros_ec_get_host_event(ec_dev);
160 
161 	if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
162 		mutex_lock(&ec_dev->lock);
163 		cros_ec_query_all(ec_dev);
164 		mutex_unlock(&ec_dev->lock);
165 		return NOTIFY_OK;
166 	}
167 
168 	return NOTIFY_DONE;
169 }
170 
171 /**
172  * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
173  * @ec_dev: Device to register.
174  *
175  * Before calling this, allocate a pointer to a new device and then fill
176  * in all the fields up to the --private-- marker.
177  *
178  * Return: 0 on success or negative error code.
179  */
180 int cros_ec_register(struct cros_ec_device *ec_dev)
181 {
182 	struct device *dev = ec_dev->dev;
183 	int err = 0;
184 
185 	BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
186 	BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->panic_notifier);
187 
188 	ec_dev->max_request = sizeof(struct ec_params_hello);
189 	ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
190 	ec_dev->max_passthru = 0;
191 	ec_dev->ec = NULL;
192 	ec_dev->pd = NULL;
193 	ec_dev->suspend_timeout_ms = EC_HOST_SLEEP_TIMEOUT_DEFAULT;
194 
195 	ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
196 	if (!ec_dev->din)
197 		return -ENOMEM;
198 
199 	ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
200 	if (!ec_dev->dout)
201 		return -ENOMEM;
202 
203 	lockdep_register_key(&ec_dev->lockdep_key);
204 	mutex_init(&ec_dev->lock);
205 	lockdep_set_class(&ec_dev->lock, &ec_dev->lockdep_key);
206 
207 	err = cros_ec_query_all(ec_dev);
208 	if (err) {
209 		dev_err(dev, "Cannot identify the EC: error %d\n", err);
210 		goto exit;
211 	}
212 
213 	if (ec_dev->irq > 0) {
214 		err = devm_request_threaded_irq(dev, ec_dev->irq,
215 						cros_ec_irq_handler,
216 						cros_ec_irq_thread,
217 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
218 						"chromeos-ec", ec_dev);
219 		if (err) {
220 			dev_err(dev, "Failed to request IRQ %d: %d\n",
221 				ec_dev->irq, err);
222 			goto exit;
223 		}
224 	}
225 
226 	/* Register a platform device for the main EC instance */
227 	ec_dev->ec = platform_device_register_data(ec_dev->dev, "cros-ec-dev",
228 					PLATFORM_DEVID_AUTO, &ec_p,
229 					sizeof(struct cros_ec_platform));
230 	if (IS_ERR(ec_dev->ec)) {
231 		dev_err(ec_dev->dev,
232 			"Failed to create CrOS EC platform device\n");
233 		err = PTR_ERR(ec_dev->ec);
234 		goto exit;
235 	}
236 
237 	if (ec_dev->max_passthru) {
238 		/*
239 		 * Register a platform device for the PD behind the main EC.
240 		 * We make the following assumptions:
241 		 * - behind an EC, we have a pd
242 		 * - only one device added.
243 		 * - the EC is responsive at init time (it is not true for a
244 		 *   sensor hub).
245 		 */
246 		ec_dev->pd = platform_device_register_data(ec_dev->dev,
247 					"cros-ec-dev",
248 					PLATFORM_DEVID_AUTO, &pd_p,
249 					sizeof(struct cros_ec_platform));
250 		if (IS_ERR(ec_dev->pd)) {
251 			dev_err(ec_dev->dev,
252 				"Failed to create CrOS PD platform device\n");
253 			err = PTR_ERR(ec_dev->pd);
254 			goto exit;
255 		}
256 	}
257 
258 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
259 		err = devm_of_platform_populate(dev);
260 		if (err) {
261 			dev_err(dev, "Failed to register sub-devices\n");
262 			goto exit;
263 		}
264 	}
265 
266 	/*
267 	 * Clear sleep event - this will fail harmlessly on platforms that
268 	 * don't implement the sleep event host command.
269 	 */
270 	err = cros_ec_sleep_event(ec_dev, 0);
271 	if (err < 0)
272 		dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec\n",
273 			err);
274 
275 	if (ec_dev->mkbp_event_supported) {
276 		/*
277 		 * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
278 		 * event.
279 		 */
280 		ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
281 		err = blocking_notifier_chain_register(&ec_dev->event_notifier,
282 						      &ec_dev->notifier_ready);
283 		if (err)
284 			goto exit;
285 	}
286 
287 	dev_info(dev, "Chrome EC device registered\n");
288 
289 	/*
290 	 * Unlock EC that may be waiting for AP to process MKBP events.
291 	 * If the AP takes to long to answer, the EC would stop sending events.
292 	 */
293 	if (ec_dev->mkbp_event_supported)
294 		cros_ec_irq_thread(0, ec_dev);
295 
296 	return 0;
297 exit:
298 	platform_device_unregister(ec_dev->ec);
299 	platform_device_unregister(ec_dev->pd);
300 	mutex_destroy(&ec_dev->lock);
301 	lockdep_unregister_key(&ec_dev->lockdep_key);
302 	return err;
303 }
304 EXPORT_SYMBOL(cros_ec_register);
305 
306 /**
307  * cros_ec_unregister() - Remove a ChromeOS EC.
308  * @ec_dev: Device to unregister.
309  *
310  * Call this to deregister a ChromeOS EC, then clean up any private data.
311  *
312  * Return: 0 on success or negative error code.
313  */
314 void cros_ec_unregister(struct cros_ec_device *ec_dev)
315 {
316 	platform_device_unregister(ec_dev->pd);
317 	platform_device_unregister(ec_dev->ec);
318 	mutex_destroy(&ec_dev->lock);
319 	lockdep_unregister_key(&ec_dev->lockdep_key);
320 }
321 EXPORT_SYMBOL(cros_ec_unregister);
322 
323 #ifdef CONFIG_PM_SLEEP
324 static void cros_ec_send_suspend_event(struct cros_ec_device *ec_dev)
325 {
326 	int ret;
327 	u8 sleep_event;
328 
329 	sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
330 		      HOST_SLEEP_EVENT_S3_SUSPEND :
331 		      HOST_SLEEP_EVENT_S0IX_SUSPEND;
332 
333 	ret = cros_ec_sleep_event(ec_dev, sleep_event);
334 	if (ret < 0)
335 		dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec\n",
336 			ret);
337 }
338 
339 /**
340  * cros_ec_suspend_prepare() - Handle a suspend prepare operation for the ChromeOS EC device.
341  * @ec_dev: Device to suspend.
342  *
343  * This can be called by drivers to handle a suspend prepare stage of suspend.
344  *
345  * Return: 0 always.
346  */
347 int cros_ec_suspend_prepare(struct cros_ec_device *ec_dev)
348 {
349 	cros_ec_send_suspend_event(ec_dev);
350 	return 0;
351 }
352 EXPORT_SYMBOL(cros_ec_suspend_prepare);
353 
354 static void cros_ec_disable_irq(struct cros_ec_device *ec_dev)
355 {
356 	struct device *dev = ec_dev->dev;
357 	if (device_may_wakeup(dev))
358 		ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
359 	else
360 		ec_dev->wake_enabled = false;
361 
362 	disable_irq(ec_dev->irq);
363 	ec_dev->suspended = true;
364 }
365 
366 /**
367  * cros_ec_suspend_late() - Handle a suspend late operation for the ChromeOS EC device.
368  * @ec_dev: Device to suspend.
369  *
370  * This can be called by drivers to handle a suspend late stage of suspend.
371  *
372  * Return: 0 always.
373  */
374 int cros_ec_suspend_late(struct cros_ec_device *ec_dev)
375 {
376 	cros_ec_disable_irq(ec_dev);
377 	return 0;
378 }
379 EXPORT_SYMBOL(cros_ec_suspend_late);
380 
381 /**
382  * cros_ec_suspend() - Handle a suspend operation for the ChromeOS EC device.
383  * @ec_dev: Device to suspend.
384  *
385  * This can be called by drivers to handle a suspend event.
386  *
387  * Return: 0 always.
388  */
389 int cros_ec_suspend(struct cros_ec_device *ec_dev)
390 {
391 	cros_ec_send_suspend_event(ec_dev);
392 	cros_ec_disable_irq(ec_dev);
393 	return 0;
394 }
395 EXPORT_SYMBOL(cros_ec_suspend);
396 
397 static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
398 {
399 	bool wake_event;
400 
401 	while (ec_dev->mkbp_event_supported &&
402 	       cros_ec_get_next_event(ec_dev, &wake_event, NULL) > 0) {
403 		blocking_notifier_call_chain(&ec_dev->event_notifier,
404 					     1, ec_dev);
405 
406 		if (wake_event && device_may_wakeup(ec_dev->dev))
407 			pm_wakeup_event(ec_dev->dev, 0);
408 	}
409 }
410 
411 static void cros_ec_send_resume_event(struct cros_ec_device *ec_dev)
412 {
413 	int ret;
414 	u8 sleep_event;
415 
416 	sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
417 		      HOST_SLEEP_EVENT_S3_RESUME :
418 		      HOST_SLEEP_EVENT_S0IX_RESUME;
419 
420 	ret = cros_ec_sleep_event(ec_dev, sleep_event);
421 	if (ret < 0)
422 		dev_dbg(ec_dev->dev, "Error %d sending resume event to ec\n",
423 			ret);
424 }
425 
426 /**
427  * cros_ec_resume_complete() - Handle a resume complete operation for the ChromeOS EC device.
428  * @ec_dev: Device to resume.
429  *
430  * This can be called by drivers to handle a resume complete stage of resume.
431  */
432 void cros_ec_resume_complete(struct cros_ec_device *ec_dev)
433 {
434 	cros_ec_send_resume_event(ec_dev);
435 
436 	/*
437 	 * Let the mfd devices know about events that occur during
438 	 * suspend. This way the clients know what to do with them.
439 	 */
440 	cros_ec_report_events_during_suspend(ec_dev);
441 }
442 EXPORT_SYMBOL(cros_ec_resume_complete);
443 
444 static void cros_ec_enable_irq(struct cros_ec_device *ec_dev)
445 {
446 	ec_dev->suspended = false;
447 	enable_irq(ec_dev->irq);
448 
449 	if (ec_dev->wake_enabled)
450 		disable_irq_wake(ec_dev->irq);
451 }
452 
453 /**
454  * cros_ec_resume_early() - Handle a resume early operation for the ChromeOS EC device.
455  * @ec_dev: Device to resume.
456  *
457  * This can be called by drivers to handle a resume early stage of resume.
458  *
459  * Return: 0 always.
460  */
461 int cros_ec_resume_early(struct cros_ec_device *ec_dev)
462 {
463 	cros_ec_enable_irq(ec_dev);
464 	return 0;
465 }
466 EXPORT_SYMBOL(cros_ec_resume_early);
467 
468 /**
469  * cros_ec_resume() - Handle a resume operation for the ChromeOS EC device.
470  * @ec_dev: Device to resume.
471  *
472  * This can be called by drivers to handle a resume event.
473  *
474  * Return: 0 always.
475  */
476 int cros_ec_resume(struct cros_ec_device *ec_dev)
477 {
478 	cros_ec_resume_early(ec_dev);
479 	cros_ec_resume_complete(ec_dev);
480 	return 0;
481 }
482 EXPORT_SYMBOL(cros_ec_resume);
483 
484 #endif
485 
486 MODULE_LICENSE("GPL");
487 MODULE_DESCRIPTION("ChromeOS EC core driver");
488