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