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/of_platform.h>
13 #include <linux/interrupt.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/platform_data/cros_ec_commands.h>
17 #include <linux/platform_data/cros_ec_proto.h>
18 #include <linux/suspend.h>
19 #include <asm/unaligned.h>
20 
21 #define CROS_EC_DEV_EC_INDEX 0
22 #define CROS_EC_DEV_PD_INDEX 1
23 
24 static struct cros_ec_platform ec_p = {
25 	.ec_name = CROS_EC_DEV_NAME,
26 	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
27 };
28 
29 static struct cros_ec_platform pd_p = {
30 	.ec_name = CROS_EC_DEV_PD_NAME,
31 	.cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
32 };
33 
34 static irqreturn_t ec_irq_handler(int irq, void *data)
35 {
36 	struct cros_ec_device *ec_dev = data;
37 
38 	ec_dev->last_event_time = cros_ec_get_time_ns();
39 
40 	return IRQ_WAKE_THREAD;
41 }
42 
43 /**
44  * cros_ec_handle_event() - process and forward pending events on EC
45  * @ec_dev: Device with events to process.
46  *
47  * Call this function in a loop when the kernel is notified that the EC has
48  * pending events.
49  *
50  * Return: true if more events are still pending and this function should be
51  * called again.
52  */
53 bool cros_ec_handle_event(struct cros_ec_device *ec_dev)
54 {
55 	bool wake_event;
56 	bool ec_has_more_events;
57 	int ret;
58 
59 	ret = cros_ec_get_next_event(ec_dev, &wake_event, &ec_has_more_events);
60 
61 	/*
62 	 * Signal only if wake host events or any interrupt if
63 	 * cros_ec_get_next_event() returned an error (default value for
64 	 * wake_event is true)
65 	 */
66 	if (wake_event && device_may_wakeup(ec_dev->dev))
67 		pm_wakeup_event(ec_dev->dev, 0);
68 
69 	if (ret > 0)
70 		blocking_notifier_call_chain(&ec_dev->event_notifier,
71 					     0, ec_dev);
72 
73 	return ec_has_more_events;
74 }
75 EXPORT_SYMBOL(cros_ec_handle_event);
76 
77 static irqreturn_t ec_irq_thread(int irq, void *data)
78 {
79 	struct cros_ec_device *ec_dev = data;
80 	bool ec_has_more_events;
81 
82 	do {
83 		ec_has_more_events = cros_ec_handle_event(ec_dev);
84 	} while (ec_has_more_events);
85 
86 	return IRQ_HANDLED;
87 }
88 
89 static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
90 {
91 	int ret;
92 	struct {
93 		struct cros_ec_command msg;
94 		union {
95 			struct ec_params_host_sleep_event req0;
96 			struct ec_params_host_sleep_event_v1 req1;
97 			struct ec_response_host_sleep_event_v1 resp1;
98 		} u;
99 	} __packed buf;
100 
101 	memset(&buf, 0, sizeof(buf));
102 
103 	if (ec_dev->host_sleep_v1) {
104 		buf.u.req1.sleep_event = sleep_event;
105 		buf.u.req1.suspend_params.sleep_timeout_ms =
106 				EC_HOST_SLEEP_TIMEOUT_DEFAULT;
107 
108 		buf.msg.outsize = sizeof(buf.u.req1);
109 		if ((sleep_event == HOST_SLEEP_EVENT_S3_RESUME) ||
110 		    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
111 			buf.msg.insize = sizeof(buf.u.resp1);
112 
113 		buf.msg.version = 1;
114 
115 	} else {
116 		buf.u.req0.sleep_event = sleep_event;
117 		buf.msg.outsize = sizeof(buf.u.req0);
118 	}
119 
120 	buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;
121 
122 	ret = cros_ec_cmd_xfer(ec_dev, &buf.msg);
123 
124 	/* For now, report failure to transition to S0ix with a warning. */
125 	if (ret >= 0 && ec_dev->host_sleep_v1 &&
126 	    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME)) {
127 		ec_dev->last_resume_result =
128 			buf.u.resp1.resume_response.sleep_transitions;
129 
130 		WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
131 			  EC_HOST_RESUME_SLEEP_TIMEOUT,
132 			  "EC detected sleep transition timeout. Total slp_s0 transitions: %d",
133 			  buf.u.resp1.resume_response.sleep_transitions &
134 			  EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
135 	}
136 
137 	return ret;
138 }
139 
140 /**
141  * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
142  * @ec_dev: Device to register.
143  *
144  * Before calling this, allocate a pointer to a new device and then fill
145  * in all the fields up to the --private-- marker.
146  *
147  * Return: 0 on success or negative error code.
148  */
149 int cros_ec_register(struct cros_ec_device *ec_dev)
150 {
151 	struct device *dev = ec_dev->dev;
152 	int err = 0;
153 
154 	BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
155 
156 	ec_dev->max_request = sizeof(struct ec_params_hello);
157 	ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
158 	ec_dev->max_passthru = 0;
159 
160 	ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
161 	if (!ec_dev->din)
162 		return -ENOMEM;
163 
164 	ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
165 	if (!ec_dev->dout)
166 		return -ENOMEM;
167 
168 	mutex_init(&ec_dev->lock);
169 
170 	err = cros_ec_query_all(ec_dev);
171 	if (err) {
172 		dev_err(dev, "Cannot identify the EC: error %d\n", err);
173 		return err;
174 	}
175 
176 	if (ec_dev->irq > 0) {
177 		err = devm_request_threaded_irq(dev, ec_dev->irq,
178 						ec_irq_handler,
179 						ec_irq_thread,
180 						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
181 						"chromeos-ec", ec_dev);
182 		if (err) {
183 			dev_err(dev, "Failed to request IRQ %d: %d",
184 				ec_dev->irq, err);
185 			return err;
186 		}
187 	}
188 
189 	/* Register a platform device for the main EC instance */
190 	ec_dev->ec = platform_device_register_data(ec_dev->dev, "cros-ec-dev",
191 					PLATFORM_DEVID_AUTO, &ec_p,
192 					sizeof(struct cros_ec_platform));
193 	if (IS_ERR(ec_dev->ec)) {
194 		dev_err(ec_dev->dev,
195 			"Failed to create CrOS EC platform device\n");
196 		return PTR_ERR(ec_dev->ec);
197 	}
198 
199 	if (ec_dev->max_passthru) {
200 		/*
201 		 * Register a platform device for the PD behind the main EC.
202 		 * We make the following assumptions:
203 		 * - behind an EC, we have a pd
204 		 * - only one device added.
205 		 * - the EC is responsive at init time (it is not true for a
206 		 *   sensor hub).
207 		 */
208 		ec_dev->pd = platform_device_register_data(ec_dev->dev,
209 					"cros-ec-dev",
210 					PLATFORM_DEVID_AUTO, &pd_p,
211 					sizeof(struct cros_ec_platform));
212 		if (IS_ERR(ec_dev->pd)) {
213 			dev_err(ec_dev->dev,
214 				"Failed to create CrOS PD platform device\n");
215 			platform_device_unregister(ec_dev->ec);
216 			return PTR_ERR(ec_dev->pd);
217 		}
218 	}
219 
220 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
221 		err = devm_of_platform_populate(dev);
222 		if (err) {
223 			platform_device_unregister(ec_dev->pd);
224 			platform_device_unregister(ec_dev->ec);
225 			dev_err(dev, "Failed to register sub-devices\n");
226 			return err;
227 		}
228 	}
229 
230 	/*
231 	 * Clear sleep event - this will fail harmlessly on platforms that
232 	 * don't implement the sleep event host command.
233 	 */
234 	err = cros_ec_sleep_event(ec_dev, 0);
235 	if (err < 0)
236 		dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec",
237 			err);
238 
239 	dev_info(dev, "Chrome EC device registered\n");
240 
241 	return 0;
242 }
243 EXPORT_SYMBOL(cros_ec_register);
244 
245 /**
246  * cros_ec_unregister() - Remove a ChromeOS EC.
247  * @ec_dev: Device to unregister.
248  *
249  * Call this to deregister a ChromeOS EC, then clean up any private data.
250  *
251  * Return: 0 on success or negative error code.
252  */
253 int cros_ec_unregister(struct cros_ec_device *ec_dev)
254 {
255 	if (ec_dev->pd)
256 		platform_device_unregister(ec_dev->pd);
257 	platform_device_unregister(ec_dev->ec);
258 
259 	return 0;
260 }
261 EXPORT_SYMBOL(cros_ec_unregister);
262 
263 #ifdef CONFIG_PM_SLEEP
264 /**
265  * cros_ec_suspend() - Handle a suspend operation for the ChromeOS EC device.
266  * @ec_dev: Device to suspend.
267  *
268  * This can be called by drivers to handle a suspend event.
269  *
270  * Return: 0 on success or negative error code.
271  */
272 int cros_ec_suspend(struct cros_ec_device *ec_dev)
273 {
274 	struct device *dev = ec_dev->dev;
275 	int ret;
276 	u8 sleep_event;
277 
278 	sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
279 		      HOST_SLEEP_EVENT_S3_SUSPEND :
280 		      HOST_SLEEP_EVENT_S0IX_SUSPEND;
281 
282 	ret = cros_ec_sleep_event(ec_dev, sleep_event);
283 	if (ret < 0)
284 		dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec",
285 			ret);
286 
287 	if (device_may_wakeup(dev))
288 		ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
289 
290 	disable_irq(ec_dev->irq);
291 	ec_dev->was_wake_device = ec_dev->wake_enabled;
292 	ec_dev->suspended = true;
293 
294 	return 0;
295 }
296 EXPORT_SYMBOL(cros_ec_suspend);
297 
298 static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
299 {
300 	while (ec_dev->mkbp_event_supported &&
301 	       cros_ec_get_next_event(ec_dev, NULL, NULL) > 0)
302 		blocking_notifier_call_chain(&ec_dev->event_notifier,
303 					     1, ec_dev);
304 }
305 
306 /**
307  * cros_ec_resume() - Handle a resume operation for the ChromeOS EC device.
308  * @ec_dev: Device to resume.
309  *
310  * This can be called by drivers to handle a resume event.
311  *
312  * Return: 0 on success or negative error code.
313  */
314 int cros_ec_resume(struct cros_ec_device *ec_dev)
315 {
316 	int ret;
317 	u8 sleep_event;
318 
319 	ec_dev->suspended = false;
320 	enable_irq(ec_dev->irq);
321 
322 	sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
323 		      HOST_SLEEP_EVENT_S3_RESUME :
324 		      HOST_SLEEP_EVENT_S0IX_RESUME;
325 
326 	ret = cros_ec_sleep_event(ec_dev, sleep_event);
327 	if (ret < 0)
328 		dev_dbg(ec_dev->dev, "Error %d sending resume event to ec",
329 			ret);
330 
331 	if (ec_dev->wake_enabled) {
332 		disable_irq_wake(ec_dev->irq);
333 		ec_dev->wake_enabled = 0;
334 	}
335 	/*
336 	 * Let the mfd devices know about events that occur during
337 	 * suspend. This way the clients know what to do with them.
338 	 */
339 	cros_ec_report_events_during_suspend(ec_dev);
340 
341 
342 	return 0;
343 }
344 EXPORT_SYMBOL(cros_ec_resume);
345 
346 #endif
347 
348 MODULE_LICENSE("GPL");
349 MODULE_DESCRIPTION("ChromeOS EC core driver");
350