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 	/* clean stale FW version */
146 	dev->fw_ver_received = 0;
147 
148 	memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
149 
150 	if (ret) {
151 		dev_err(dev->dev, "hw_reset failed ret = %d\n", ret);
152 		return ret;
153 	}
154 
155 	if (state == MEI_DEV_POWER_DOWN) {
156 		dev_dbg(dev->dev, "powering down: end of reset\n");
157 		mei_set_devstate(dev, MEI_DEV_DISABLED);
158 		return 0;
159 	}
160 
161 	ret = mei_hw_start(dev);
162 	if (ret) {
163 		char fw_sts_str[MEI_FW_STATUS_STR_SZ];
164 
165 		mei_fw_status_str(dev, fw_sts_str, MEI_FW_STATUS_STR_SZ);
166 		dev_err(dev->dev, "hw_start failed ret = %d fw status = %s\n", ret, fw_sts_str);
167 		return ret;
168 	}
169 
170 	if (dev->dev_state != MEI_DEV_RESETTING) {
171 		dev_dbg(dev->dev, "wrong state = %d on link start\n", dev->dev_state);
172 		return 0;
173 	}
174 
175 	dev_dbg(dev->dev, "link is established start sending messages.\n");
176 
177 	mei_set_devstate(dev, MEI_DEV_INIT_CLIENTS);
178 	ret = mei_hbm_start_req(dev);
179 	if (ret) {
180 		dev_err(dev->dev, "hbm_start failed ret = %d\n", ret);
181 		mei_set_devstate(dev, MEI_DEV_RESETTING);
182 		return ret;
183 	}
184 
185 	return 0;
186 }
187 EXPORT_SYMBOL_GPL(mei_reset);
188 
189 /**
190  * mei_start - initializes host and fw to start work.
191  *
192  * @dev: the device structure
193  *
194  * Return: 0 on success, <0 on failure.
195  */
mei_start(struct mei_device * dev)196 int mei_start(struct mei_device *dev)
197 {
198 	int ret;
199 
200 	mutex_lock(&dev->device_lock);
201 
202 	/* acknowledge interrupt and stop interrupts */
203 	mei_clear_interrupts(dev);
204 
205 	ret = mei_hw_config(dev);
206 	if (ret)
207 		goto err;
208 
209 	dev_dbg(dev->dev, "reset in start the mei device.\n");
210 
211 	dev->reset_count = 0;
212 	do {
213 		mei_set_devstate(dev, MEI_DEV_INITIALIZING);
214 		ret = mei_reset(dev);
215 
216 		if (ret == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
217 			dev_err(dev->dev, "reset failed ret = %d", ret);
218 			goto err;
219 		}
220 	} while (ret);
221 
222 	if (mei_hbm_start_wait(dev)) {
223 		dev_err(dev->dev, "HBM haven't started");
224 		goto err;
225 	}
226 
227 	if (!mei_hbm_version_is_supported(dev)) {
228 		dev_dbg(dev->dev, "MEI start failed.\n");
229 		goto err;
230 	}
231 
232 	dev_dbg(dev->dev, "link layer has been established.\n");
233 
234 	mutex_unlock(&dev->device_lock);
235 	return 0;
236 err:
237 	dev_err(dev->dev, "link layer initialization failed.\n");
238 	mei_set_devstate(dev, MEI_DEV_DISABLED);
239 	mutex_unlock(&dev->device_lock);
240 	return -ENODEV;
241 }
242 EXPORT_SYMBOL_GPL(mei_start);
243 
244 /**
245  * mei_restart - restart device after suspend
246  *
247  * @dev: the device structure
248  *
249  * Return: 0 on success or -ENODEV if the restart hasn't succeeded
250  */
mei_restart(struct mei_device * dev)251 int mei_restart(struct mei_device *dev)
252 {
253 	int err;
254 
255 	mutex_lock(&dev->device_lock);
256 
257 	mei_set_devstate(dev, MEI_DEV_POWER_UP);
258 	dev->reset_count = 0;
259 
260 	err = mei_reset(dev);
261 
262 	mutex_unlock(&dev->device_lock);
263 
264 	if (err == -ENODEV || dev->dev_state == MEI_DEV_DISABLED) {
265 		dev_err(dev->dev, "device disabled = %d\n", err);
266 		return -ENODEV;
267 	}
268 
269 	/* try to start again */
270 	if (err)
271 		schedule_work(&dev->reset_work);
272 
273 
274 	return 0;
275 }
276 EXPORT_SYMBOL_GPL(mei_restart);
277 
mei_reset_work(struct work_struct * work)278 static void mei_reset_work(struct work_struct *work)
279 {
280 	struct mei_device *dev =
281 		container_of(work, struct mei_device,  reset_work);
282 	int ret;
283 
284 	mei_clear_interrupts(dev);
285 	mei_synchronize_irq(dev);
286 
287 	mutex_lock(&dev->device_lock);
288 
289 	ret = mei_reset(dev);
290 
291 	mutex_unlock(&dev->device_lock);
292 
293 	if (dev->dev_state == MEI_DEV_DISABLED) {
294 		dev_err(dev->dev, "device disabled = %d\n", ret);
295 		return;
296 	}
297 
298 	/* retry reset in case of failure */
299 	if (ret)
300 		schedule_work(&dev->reset_work);
301 }
302 
mei_stop(struct mei_device * dev)303 void mei_stop(struct mei_device *dev)
304 {
305 	dev_dbg(dev->dev, "stopping the device.\n");
306 
307 	mutex_lock(&dev->device_lock);
308 	mei_set_devstate(dev, MEI_DEV_POWERING_DOWN);
309 	mutex_unlock(&dev->device_lock);
310 	mei_cl_bus_remove_devices(dev);
311 	mutex_lock(&dev->device_lock);
312 	mei_set_devstate(dev, MEI_DEV_POWER_DOWN);
313 	mutex_unlock(&dev->device_lock);
314 
315 	mei_cancel_work(dev);
316 
317 	mei_clear_interrupts(dev);
318 	mei_synchronize_irq(dev);
319 	/* to catch HW-initiated reset */
320 	mei_cancel_work(dev);
321 
322 	mutex_lock(&dev->device_lock);
323 
324 	mei_reset(dev);
325 	/* move device to disabled state unconditionally */
326 	mei_set_devstate(dev, MEI_DEV_DISABLED);
327 
328 	mutex_unlock(&dev->device_lock);
329 }
330 EXPORT_SYMBOL_GPL(mei_stop);
331 
332 /**
333  * mei_write_is_idle - check if the write queues are idle
334  *
335  * @dev: the device structure
336  *
337  * Return: true of there is no pending write
338  */
mei_write_is_idle(struct mei_device * dev)339 bool mei_write_is_idle(struct mei_device *dev)
340 {
341 	bool idle = (dev->dev_state == MEI_DEV_ENABLED &&
342 		list_empty(&dev->ctrl_wr_list) &&
343 		list_empty(&dev->write_list)   &&
344 		list_empty(&dev->write_waiting_list));
345 
346 	dev_dbg(dev->dev, "write pg: is idle[%d] state=%s ctrl=%01d write=%01d wwait=%01d\n",
347 		idle,
348 		mei_dev_state_str(dev->dev_state),
349 		list_empty(&dev->ctrl_wr_list),
350 		list_empty(&dev->write_list),
351 		list_empty(&dev->write_waiting_list));
352 
353 	return idle;
354 }
355 EXPORT_SYMBOL_GPL(mei_write_is_idle);
356 
357 /**
358  * mei_device_init - initialize mei_device structure
359  *
360  * @dev: the mei device
361  * @device: the device structure
362  * @slow_fw: configure longer timeouts as FW is slow
363  * @hw_ops: hw operations
364  */
mei_device_init(struct mei_device * dev,struct device * device,bool slow_fw,const struct mei_hw_ops * hw_ops)365 void mei_device_init(struct mei_device *dev,
366 		     struct device *device,
367 		     bool slow_fw,
368 		     const struct mei_hw_ops *hw_ops)
369 {
370 	/* setup our list array */
371 	INIT_LIST_HEAD(&dev->file_list);
372 	INIT_LIST_HEAD(&dev->device_list);
373 	INIT_LIST_HEAD(&dev->me_clients);
374 	mutex_init(&dev->device_lock);
375 	init_rwsem(&dev->me_clients_rwsem);
376 	mutex_init(&dev->cl_bus_lock);
377 	init_waitqueue_head(&dev->wait_hw_ready);
378 	init_waitqueue_head(&dev->wait_pg);
379 	init_waitqueue_head(&dev->wait_hbm_start);
380 	dev->dev_state = MEI_DEV_INITIALIZING;
381 	dev->reset_count = 0;
382 
383 	INIT_LIST_HEAD(&dev->write_list);
384 	INIT_LIST_HEAD(&dev->write_waiting_list);
385 	INIT_LIST_HEAD(&dev->ctrl_wr_list);
386 	INIT_LIST_HEAD(&dev->ctrl_rd_list);
387 	dev->tx_queue_limit = MEI_TX_QUEUE_LIMIT_DEFAULT;
388 
389 	INIT_DELAYED_WORK(&dev->timer_work, mei_timer);
390 	INIT_WORK(&dev->reset_work, mei_reset_work);
391 	INIT_WORK(&dev->bus_rescan_work, mei_cl_bus_rescan_work);
392 
393 	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
394 	dev->open_handle_count = 0;
395 
396 	dev->pxp_mode = MEI_DEV_PXP_DEFAULT;
397 
398 	/*
399 	 * Reserving the first client ID
400 	 * 0: Reserved for MEI Bus Message communications
401 	 */
402 	bitmap_set(dev->host_clients_map, 0, 1);
403 
404 	dev->pg_event = MEI_PG_EVENT_IDLE;
405 	dev->ops      = hw_ops;
406 	dev->dev      = device;
407 
408 	dev->timeouts.hw_ready = mei_secs_to_jiffies(MEI_HW_READY_TIMEOUT);
409 	dev->timeouts.connect = MEI_CONNECT_TIMEOUT;
410 	dev->timeouts.client_init = MEI_CLIENTS_INIT_TIMEOUT;
411 	dev->timeouts.pgi = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
412 	dev->timeouts.d0i3 = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
413 	if (slow_fw) {
414 		dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT_SLOW);
415 		dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT_SLOW);
416 		dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT_SLOW);
417 	} else {
418 		dev->timeouts.cl_connect = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT);
419 		dev->timeouts.hbm = mei_secs_to_jiffies(MEI_HBM_TIMEOUT);
420 		dev->timeouts.mkhi_recv = msecs_to_jiffies(MKHI_RCV_TIMEOUT);
421 	}
422 }
423 EXPORT_SYMBOL_GPL(mei_device_init);
424 
425