1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2012-2022, Intel Corporation. All rights reserved.
4  * Intel Management Engine Interface (Intel MEI) Linux driver
5  */
6 
7 #include <linux/export.h>
8 #include <linux/sched.h>
9 #include <linux/wait.h>
10 #include <linux/delay.h>
11 
12 #include <linux/mei.h>
13 
14 #include "mei_dev.h"
15 #include "hbm.h"
16 #include "client.h"
17 
mei_dev_state_str(int state)18 const char *mei_dev_state_str(int state)
19 {
20 #define MEI_DEV_STATE(state) case MEI_DEV_##state: return #state
21 	switch (state) {
22 	MEI_DEV_STATE(INITIALIZING);
23 	MEI_DEV_STATE(INIT_CLIENTS);
24 	MEI_DEV_STATE(ENABLED);
25 	MEI_DEV_STATE(RESETTING);
26 	MEI_DEV_STATE(DISABLED);
27 	MEI_DEV_STATE(POWERING_DOWN);
28 	MEI_DEV_STATE(POWER_DOWN);
29 	MEI_DEV_STATE(POWER_UP);
30 	default:
31 		return "unknown";
32 	}
33 #undef MEI_DEV_STATE
34 }
35 
mei_pg_state_str(enum mei_pg_state state)36 const char *mei_pg_state_str(enum mei_pg_state state)
37 {
38 #define MEI_PG_STATE(state) case MEI_PG_##state: return #state
39 	switch (state) {
40 	MEI_PG_STATE(OFF);
41 	MEI_PG_STATE(ON);
42 	default:
43 		return "unknown";
44 	}
45 #undef MEI_PG_STATE
46 }
47 
48 /**
49  * mei_fw_status2str - convert fw status registers to printable string
50  *
51  * @fw_status:  firmware status
52  * @buf: string buffer at minimal size MEI_FW_STATUS_STR_SZ
53  * @len: buffer len must be >= MEI_FW_STATUS_STR_SZ
54  *
55  * Return: number of bytes written or -EINVAL if buffer is to small
56  */
mei_fw_status2str(struct mei_fw_status * fw_status,char * buf,size_t len)57 ssize_t mei_fw_status2str(struct mei_fw_status *fw_status,
58 			  char *buf, size_t len)
59 {
60 	ssize_t cnt = 0;
61 	int i;
62 
63 	buf[0] = '\0';
64 
65 	if (len < MEI_FW_STATUS_STR_SZ)
66 		return -EINVAL;
67 
68 	for (i = 0; i < fw_status->count; i++)
69 		cnt += scnprintf(buf + cnt, len - cnt, "%08X ",
70 				fw_status->status[i]);
71 
72 	/* drop last space */
73 	buf[cnt] = '\0';
74 	return cnt;
75 }
76 EXPORT_SYMBOL_GPL(mei_fw_status2str);
77 
78 /**
79  * mei_cancel_work - Cancel mei background jobs
80  *
81  * @dev: the device structure
82  */
mei_cancel_work(struct mei_device * dev)83 void mei_cancel_work(struct mei_device *dev)
84 {
85 	cancel_work_sync(&dev->reset_work);
86 	cancel_work_sync(&dev->bus_rescan_work);
87 
88 	cancel_delayed_work_sync(&dev->timer_work);
89 }
90 EXPORT_SYMBOL_GPL(mei_cancel_work);
91 
92 /**
93  * mei_reset - resets host and fw.
94  *
95  * @dev: the device structure
96  *
97  * Return: 0 on success or < 0 if the reset hasn't succeeded
98  */
mei_reset(struct mei_device * dev)99 int mei_reset(struct mei_device *dev)
100 {
101 	enum mei_dev_state state = dev->dev_state;
102 	bool interrupts_enabled;
103 	int ret;
104 
105 	if (state != MEI_DEV_INITIALIZING &&
106 	    state != MEI_DEV_DISABLED &&
107 	    state != MEI_DEV_POWER_DOWN &&
108 	    state != MEI_DEV_POWER_UP) {
109 		char fw_sts_str[MEI_FW_STATUS_STR_SZ];
110 
111 		mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
112 		dev_warn(dev->dev, "unexpected reset: dev_state = %s fw status = %s\n",
113 			 mei_dev_state_str(state), fw_sts_str);
114 	}
115 
116 	mei_clear_interrupts(dev);
117 
118 	/* we're already in reset, cancel the init timer
119 	 * if the reset was called due the hbm protocol error
120 	 * we need to call it before hw start
121 	 * so the hbm watchdog won't kick in
122 	 */
123 	mei_hbm_idle(dev);
124 
125 	/* enter reset flow */
126 	interrupts_enabled = state != MEI_DEV_POWER_DOWN;
127 	mei_set_devstate(dev, MEI_DEV_RESETTING);
128 
129 	dev->reset_count++;
130 	if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
131 		dev_err(dev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
132 		mei_set_devstate(dev, MEI_DEV_DISABLED);
133 		return -ENODEV;
134 	}
135 
136 	ret = mei_hw_reset(dev, interrupts_enabled);
137 	/* fall through and remove the sw state even if hw reset has failed */
138 
139 	/* no need to clean up software state in case of power up */
140 	if (state != MEI_DEV_INITIALIZING && state != MEI_DEV_POWER_UP)
141 		mei_cl_all_disconnect(dev);
142 
143 	mei_hbm_reset(dev);
144 
145 	memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
146 
147 	if (ret) {
148 		dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
149 		return ret;
150 	}
151 
152 	if (state == MEI_DEV_POWER_DOWN) {
153 		dev_dbg(dev->dev, "powering down: end of reset\n");
154 		mei_set_devstate(dev, MEI_DEV_DISABLED);
155 		return 0;
156 	}
157 
158 	ret = mei_hw_start(dev);
159 	if (ret) {
160 		dev_err(dev->dev, "hw_start failed ret = %d\n", ret);
161 		return ret;
162 	}
163 
164 	if (dev->dev_state != MEI_DEV_RESETTING) {
165 		dev_dbg(dev->dev, "wrong state = %d on link start\n", dev->dev_state);
166 		return 0;
167 	}
168 
169 	dev_dbg(dev->dev, "link is established start sending messages.\n");
170 
171 	mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
172 	ret = mei_hbm_start_req(dev);
173 	if (ret) {
174 		dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
175 		mei_set_devstate(dev, MEI_DEV_RESETTING);
176 		return ret;
177 	}
178 
179 	return 0;
180 }
181 EXPORT_SYMBOL_GPL(mei_reset);
182 
183 /**
184  * mei_start - initializes host and fw to start work.
185  *
186  * @dev: the device structure
187  *
188  * Return: 0 on success, <0 on failure.
189  */
mei_start(struct mei_device * dev)190 int mei_start(struct mei_device *dev)
191 {
192 	int ret;
193 
194 	mutex_lock(&dev->device_lock);
195 
196 	/* acknowledge interrupt and stop interrupts */
197 	mei_clear_interrupts(dev);
198 
199 	ret = mei_hw_config(dev);
200 	if (ret)
201 		goto err;
202 
203 	dev_dbg(dev->dev, "reset in start the mei device.\n");
204 
205 	dev->reset_count = 0;
206 	do {
207 		mei_set_devstate(dev, MEI_DEV_INITIALIZING);
208 		ret = mei_reset(dev);
209 
210 		if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
211 			dev_err(dev->dev, "reset failed ret = %d", ret);
212 			goto err;
213 		}
214 	} while (ret);
215 
216 	if (mei_hbm_start_wait(dev)) {
217 		dev_err(dev->dev, "HBM haven't started");
218 		goto err;
219 	}
220 
221 	if (!mei_hbm_version_is_supported(dev)) {
222 		dev_dbg(dev->dev, "MEI start failed.\n");
223 		goto err;
224 	}
225 
226 	dev_dbg(dev->dev, "link layer has been established.\n");
227 
228 	mutex_unlock(&dev->device_lock);
229 	return 0;
230 err:
231 	dev_err(dev->dev, "link layer initialization failed.\n");
232 	mei_set_devstate(dev, MEI_DEV_DISABLED);
233 	mutex_unlock(&dev->device_lock);
234 	return -ENODEV;
235 }
236 EXPORT_SYMBOL_GPL(mei_start);
237 
238 /**
239  * mei_restart - restart device after suspend
240  *
241  * @dev: the device structure
242  *
243  * Return: 0 on success or -ENODEV if the restart hasn't succeeded
244  */
mei_restart(struct mei_device * dev)245 int mei_restart(struct mei_device *dev)
246 {
247 	int err;
248 
249 	mutex_lock(&dev->device_lock);
250 
251 	mei_set_devstate(dev, MEI_DEV_POWER_UP);
252 	dev->reset_count = 0;
253 
254 	err = mei_reset(dev);
255 
256 	mutex_unlock(&dev->device_lock);
257 
258 	if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
259 		dev_err(dev->dev, "device disabled = %d\n", err);
260 		return -ENODEV;
261 	}
262 
263 	/* try to start again */
264 	if (err)
265 		schedule_work(&dev->reset_work);
266 
267 
268 	return 0;
269 }
270 EXPORT_SYMBOL_GPL(mei_restart);
271 
mei_reset_work(struct work_struct * work)272 static void mei_reset_work(struct work_struct *work)
273 {
274 	struct mei_device *dev =
275 		container_of(work, struct mei_device,  reset_work);
276 	int ret;
277 
278 	mei_clear_interrupts(dev);
279 	mei_synchronize_irq(dev);
280 
281 	mutex_lock(&dev->device_lock);
282 
283 	ret = mei_reset(dev);
284 
285 	mutex_unlock(&dev->device_lock);
286 
287 	if (dev->dev_state == MEI_DEV_DISABLED) {
288 		dev_err(dev->dev, "device disabled = %d\n", ret);
289 		return;
290 	}
291 
292 	/* retry reset in case of failure */
293 	if (ret)
294 		schedule_work(&dev->reset_work);
295 }
296 
mei_stop(struct mei_device * dev)297 void mei_stop(struct mei_device *dev)
298 {
299 	dev_dbg(dev->dev, "stopping the device.\n");
300 
301 	mutex_lock(&dev->device_lock);
302 	mei_set_devstate(dev, MEI_DEV_POWERING_DOWN);
303 	mutex_unlock(&dev->device_lock);
304 	mei_cl_bus_remove_devices(dev);
305 	mutex_lock(&dev->device_lock);
306 	mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
307 	mutex_unlock(&dev->device_lock);
308 
309 	mei_cancel_work(dev);
310 
311 	mei_clear_interrupts(dev);
312 	mei_synchronize_irq(dev);
313 	/* to catch HW-initiated reset */
314 	mei_cancel_work(dev);
315 
316 	mutex_lock(&dev->device_lock);
317 
318 	mei_reset(dev);
319 	/* move device to disabled state unconditionally */
320 	mei_set_devstate(dev, MEI_DEV_DISABLED);
321 
322 	mutex_unlock(&dev->device_lock);
323 }
324 EXPORT_SYMBOL_GPL(mei_stop);
325 
326 /**
327  * mei_write_is_idle - check if the write queues are idle
328  *
329  * @dev: the device structure
330  *
331  * Return: true of there is no pending write
332  */
mei_write_is_idle(struct mei_device * dev)333 bool mei_write_is_idle(struct mei_device *dev)
334 {
335 	bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
336 		list_empty(&dev->ctrl_wr_list) &&
337 		list_empty(&dev->write_list)   &&
338 		list_empty(&dev->write_waiting_list));
339 
340 	dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
341 		idle,
342 		mei_dev_state_str(dev->dev_state),
343 		list_empty(&dev->ctrl_wr_list),
344 		list_empty(&dev->write_list),
345 		list_empty(&dev->write_waiting_list));
346 
347 	return idle;
348 }
349 EXPORT_SYMBOL_GPL(mei_write_is_idle);
350 
351 /**
352  * mei_device_init - initialize mei_device structure
353  *
354  * @dev: the mei device
355  * @device: the device structure
356  * @slow_fw: configure longer timeouts as FW is slow
357  * @hw_ops: hw operations
358  */
mei_device_init(struct mei_device * dev,struct device * device,bool slow_fw,const struct mei_hw_ops * hw_ops)359 void mei_device_init(struct mei_device *dev,
360 		     struct device *device,
361 		     bool slow_fw,
362 		     const struct mei_hw_ops *hw_ops)
363 {
364 	/* setup our list array */
365 	INIT_LIST_HEAD(&dev->file_list);
366 	INIT_LIST_HEAD(&dev->device_list);
367 	INIT_LIST_HEAD(&dev->me_clients);
368 	mutex_init(&dev->device_lock);
369 	init_rwsem(&dev->me_clients_rwsem);
370 	mutex_init(&dev->cl_bus_lock);
371 	init_waitqueue_head(&dev->wait_hw_ready);
372 	init_waitqueue_head(&dev->wait_pg);
373 	init_waitqueue_head(&dev->wait_hbm_start);
374 	dev->dev_state = MEI_DEV_INITIALIZING;
375 	dev->reset_count = 0;
376 
377 	INIT_LIST_HEAD(&dev->write_list);
378 	INIT_LIST_HEAD(&dev->write_waiting_list);
379 	INIT_LIST_HEAD(&dev->ctrl_wr_list);
380 	INIT_LIST_HEAD(&dev->ctrl_rd_list);
381 	dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;
382 
383 	INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
384 	INIT_WORK(&dev->reset_work, mei_reset_work);
385 	INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
386 
387 	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
388 	dev->open_handle_count = 0;
389 
390 	dev->pxp_mode = MEI_DEV_PXP_DEFAULT;
391 
392 	/*
393 	 * Reserving the first client ID
394 	 * 0: Reserved for MEI Bus Message communications
395 	 */
396 	bitmap_set(dev->host_clients_map, 0, 1);
397 
398 	dev->pg_event = MEI_PG_EVENT_IDLE;
399 	dev->ops      = hw_ops;
400 	dev->dev      = device;
401 
402 	dev->timeouts.hw_ready = mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT);
403 	dev->timeouts.connect = MEI_CONNECT_TIMEOUT;
404 	dev->timeouts.client_init = MEI_CLIENTS_INIT_TIMEOUT;
405 	dev->timeouts.pgi = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
406 	dev->timeouts.d0i3 = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
407 	if (slow_fw) {
408 		dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT_SLOW);
409 		dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT_SLOW);
410 		dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT_SLOW);
411 	} else {
412 		dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT);
413 		dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT);
414 		dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT);
415 	}
416 }
417 EXPORT_SYMBOL_GPL(mei_device_init);
418 
419